Repo created

terminal-emulator/build.gradle

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+apply plugin: 'com.android.library'
+apply plugin: 'maven-publish'
+
+android {
+    compileSdkVersion project.properties.compileSdkVersion.toInteger()
+    ndkVersion = System.getenv("JITPACK_NDK_VERSION") ?: project.properties.ndkVersion
+
+    defaultConfig {
+        minSdkVersion project.properties.minSdkVersion.toInteger()
+        targetSdkVersion project.properties.targetSdkVersion.toInteger()
+
+        externalNativeBuild {
+            ndkBuild {
+                cFlags "-std=c11", "-Wall", "-Wextra", "-Werror", "-Os", "-fno-stack-protector", "-Wl,--gc-sections"
+            }
+        }
+
+        ndk {
+            abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'
+        }
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+
+    externalNativeBuild {
+        ndkBuild {
+            path "src/main/jni/Android.mk"
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    testOptions {
+        unitTests.returnDefaultValues = true
+    }
+}
+
+tasks.withType(Test) {
+    testLogging {
+        events "started", "passed", "skipped", "failed"
+    }
+}
+
+dependencies {
+    testImplementation 'junit:junit:4.13.2'
+}
+
+task sourceJar(type: Jar) {
+    from android.sourceSets.main.java.srcDirs
+    classifier "sources"
+}
+
+afterEvaluate {
+    publishing {
+        publications {
+            // Creates a Maven publication called "release".
+            release(MavenPublication) {
+                from components.release
+                groupId = 'com.termux'
+                artifactId = 'terminal-emulator'
+                version = '0.118.0'
+                artifact(sourceJar)
+            }
+        }
+    }
+}

terminal-emulator/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# By default, the flags in this file are appended to flags specified
+# in /Users/fornwall/lib/android-sdk/tools/proguard/proguard-android.txt
+# You can edit the include path and order by changing the proguardFiles
+# directive in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# Add any project specific keep options here:
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

terminal-emulator/src/main/AndroidManifest.xml

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+<manifest package="com.termux.terminal">
+</manifest>

terminal-emulator/src/main/java/com/termux/terminal/ByteQueue.java

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+package com.termux.terminal;
+
+/** A circular byte buffer allowing one producer and one consumer thread. */
+final class ByteQueue {
+
+    private final byte[] mBuffer;
+    private int mHead;
+    private int mStoredBytes;
+    private boolean mOpen = true;
+
+    public ByteQueue(int size) {
+        mBuffer = new byte[size];
+    }
+
+    public synchronized void close() {
+        mOpen = false;
+        notify();
+    }
+
+    public synchronized int read(byte[] buffer, boolean block) {
+        while (mStoredBytes == 0 && mOpen) {
+            if (block) {
+                try {
+                    wait();
+                } catch (InterruptedException e) {
+                    // Ignore.
+                }
+            } else {
+                return 0;
+            }
+        }
+        if (!mOpen) return -1;
+
+        int totalRead = 0;
+        int bufferLength = mBuffer.length;
+        boolean wasFull = bufferLength == mStoredBytes;
+        int length = buffer.length;
+        int offset = 0;
+        while (length > 0 && mStoredBytes > 0) {
+            int oneRun = Math.min(bufferLength - mHead, mStoredBytes);
+            int bytesToCopy = Math.min(length, oneRun);
+            System.arraycopy(mBuffer, mHead, buffer, offset, bytesToCopy);
+            mHead += bytesToCopy;
+            if (mHead >= bufferLength) mHead = 0;
+            mStoredBytes -= bytesToCopy;
+            length -= bytesToCopy;
+            offset += bytesToCopy;
+            totalRead += bytesToCopy;
+        }
+        if (wasFull) notify();
+        return totalRead;
+    }
+
+    /**
+     * Attempt to write the specified portion of the provided buffer to the queue.
+     * <p/>
+     * Returns whether the output was totally written, false if it was closed before.
+     */
+    public boolean write(byte[] buffer, int offset, int lengthToWrite) {
+        if (lengthToWrite + offset > buffer.length) {
+            throw new IllegalArgumentException("length + offset > buffer.length");
+        } else if (lengthToWrite <= 0) {
+            throw new IllegalArgumentException("length <= 0");
+        }
+
+        final int bufferLength = mBuffer.length;
+
+        synchronized (this) {
+            while (lengthToWrite > 0) {
+                while (bufferLength == mStoredBytes && mOpen) {
+                    try {
+                        wait();
+                    } catch (InterruptedException e) {
+                        // Ignore.
+                    }
+                }
+                if (!mOpen) return false;
+                final boolean wasEmpty = mStoredBytes == 0;
+                int bytesToWriteBeforeWaiting = Math.min(lengthToWrite, bufferLength - mStoredBytes);
+                lengthToWrite -= bytesToWriteBeforeWaiting;
+
+                while (bytesToWriteBeforeWaiting > 0) {
+                    int tail = mHead + mStoredBytes;
+                    int oneRun;
+                    if (tail >= bufferLength) {
+                        // Buffer: [.............]
+                        // ________________H_______T
+                        // =>
+                        // Buffer: [.............]
+                        // ___________T____H
+                        // onRun= _____----_
+                        tail = tail - bufferLength;
+                        oneRun = mHead - tail;
+                    } else {
+                        oneRun = bufferLength - tail;
+                    }
+                    int bytesToCopy = Math.min(oneRun, bytesToWriteBeforeWaiting);
+                    System.arraycopy(buffer, offset, mBuffer, tail, bytesToCopy);
+                    offset += bytesToCopy;
+                    bytesToWriteBeforeWaiting -= bytesToCopy;
+                    mStoredBytes += bytesToCopy;
+                }
+                if (wasEmpty) notify();
+            }
+        }
+        return true;
+    }
+}

terminal-emulator/src/main/java/com/termux/terminal/JNI.java

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+package com.termux.terminal;
+
+/**
+ * Native methods for creating and managing pseudoterminal subprocesses. C code is in jni/termux.c.
+ */
+final class JNI {
+
+    static {
+        System.loadLibrary("termux");
+    }
+
+    /**
+     * Create a subprocess. Differs from {@link ProcessBuilder} in that a pseudoterminal is used to communicate with the
+     * subprocess.
+     * <p/>
+     * Callers are responsible for calling {@link #close(int)} on the returned file descriptor.
+     *
+     * @param cmd       The command to execute
+     * @param cwd       The current working directory for the executed command
+     * @param args      An array of arguments to the command
+     * @param envVars   An array of strings of the form "VAR=value" to be added to the environment of the process
+     * @param processId A one-element array to which the process ID of the started process will be written.
+     * @return the file descriptor resulting from opening /dev/ptmx master device. The sub process will have opened the
+     * slave device counterpart (/dev/pts/$N) and have it as stdint, stdout and stderr.
+     */
+    public static native int createSubprocess(String cmd, String cwd, String[] args, String[] envVars, int[] processId, int rows, int columns, int cellWidth, int cellHeight);
+
+    /** Set the window size for a given pty, which allows connected programs to learn how large their screen is. */
+    public static native void setPtyWindowSize(int fd, int rows, int cols, int cellWidth, int cellHeight);
+
+    /**
+     * Causes the calling thread to wait for the process associated with the receiver to finish executing.
+     *
+     * @return if >= 0, the exit status of the process. If < 0, the signal causing the process to stop negated.
+     */
+    public static native int waitFor(int processId);
+
+    /** Close a file descriptor through the close(2) system call. */
+    public static native void close(int fileDescriptor);
+
+}

terminal-emulator/src/main/java/com/termux/terminal/KeyHandler.java

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+package com.termux.terminal;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static android.view.KeyEvent.KEYCODE_BACK;
+import static android.view.KeyEvent.KEYCODE_BREAK;
+import static android.view.KeyEvent.KEYCODE_DEL;
+import static android.view.KeyEvent.KEYCODE_DPAD_CENTER;
+import static android.view.KeyEvent.KEYCODE_DPAD_DOWN;
+import static android.view.KeyEvent.KEYCODE_DPAD_LEFT;
+import static android.view.KeyEvent.KEYCODE_DPAD_RIGHT;
+import static android.view.KeyEvent.KEYCODE_DPAD_UP;
+import static android.view.KeyEvent.KEYCODE_ENTER;
+import static android.view.KeyEvent.KEYCODE_ESCAPE;
+import static android.view.KeyEvent.KEYCODE_F1;
+import static android.view.KeyEvent.KEYCODE_F10;
+import static android.view.KeyEvent.KEYCODE_F11;
+import static android.view.KeyEvent.KEYCODE_F12;
+import static android.view.KeyEvent.KEYCODE_F2;
+import static android.view.KeyEvent.KEYCODE_F3;
+import static android.view.KeyEvent.KEYCODE_F4;
+import static android.view.KeyEvent.KEYCODE_F5;
+import static android.view.KeyEvent.KEYCODE_F6;
+import static android.view.KeyEvent.KEYCODE_F7;
+import static android.view.KeyEvent.KEYCODE_F8;
+import static android.view.KeyEvent.KEYCODE_F9;
+import static android.view.KeyEvent.KEYCODE_FORWARD_DEL;
+import static android.view.KeyEvent.KEYCODE_INSERT;
+import static android.view.KeyEvent.KEYCODE_MOVE_END;
+import static android.view.KeyEvent.KEYCODE_MOVE_HOME;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_0;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_1;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_2;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_3;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_4;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_5;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_6;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_7;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_8;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_9;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_ADD;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_COMMA;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_DIVIDE;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_DOT;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_ENTER;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_EQUALS;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_MULTIPLY;
+import static android.view.KeyEvent.KEYCODE_NUMPAD_SUBTRACT;
+import static android.view.KeyEvent.KEYCODE_NUM_LOCK;
+import static android.view.KeyEvent.KEYCODE_PAGE_DOWN;
+import static android.view.KeyEvent.KEYCODE_PAGE_UP;
+import static android.view.KeyEvent.KEYCODE_SPACE;
+import static android.view.KeyEvent.KEYCODE_SYSRQ;
+import static android.view.KeyEvent.KEYCODE_TAB;
+
+public final class KeyHandler {
+
+    public static final int KEYMOD_ALT = 0x80000000;
+    public static final int KEYMOD_CTRL = 0x40000000;
+    public static final int KEYMOD_SHIFT = 0x20000000;
+    public static final int KEYMOD_NUM_LOCK = 0x10000000;
+
+    private static final Map<String, Integer> TERMCAP_TO_KEYCODE = new HashMap<>();
+
+    static {
+        // terminfo: http://pubs.opengroup.org/onlinepubs/7990989799/xcurses/terminfo.html
+        // termcap: http://man7.org/linux/man-pages/man5/termcap.5.html
+        TERMCAP_TO_KEYCODE.put("%i", KEYMOD_SHIFT | KEYCODE_DPAD_RIGHT);
+        TERMCAP_TO_KEYCODE.put("#2", KEYMOD_SHIFT | KEYCODE_MOVE_HOME); // Shifted home
+        TERMCAP_TO_KEYCODE.put("#4", KEYMOD_SHIFT | KEYCODE_DPAD_LEFT);
+        TERMCAP_TO_KEYCODE.put("*7", KEYMOD_SHIFT | KEYCODE_MOVE_END); // Shifted end key
+
+        TERMCAP_TO_KEYCODE.put("k1", KEYCODE_F1);
+        TERMCAP_TO_KEYCODE.put("k2", KEYCODE_F2);
+        TERMCAP_TO_KEYCODE.put("k3", KEYCODE_F3);
+        TERMCAP_TO_KEYCODE.put("k4", KEYCODE_F4);
+        TERMCAP_TO_KEYCODE.put("k5", KEYCODE_F5);
+        TERMCAP_TO_KEYCODE.put("k6", KEYCODE_F6);
+        TERMCAP_TO_KEYCODE.put("k7", KEYCODE_F7);
+        TERMCAP_TO_KEYCODE.put("k8", KEYCODE_F8);
+        TERMCAP_TO_KEYCODE.put("k9", KEYCODE_F9);
+        TERMCAP_TO_KEYCODE.put("k;", KEYCODE_F10);
+        TERMCAP_TO_KEYCODE.put("F1", KEYCODE_F11);
+        TERMCAP_TO_KEYCODE.put("F2", KEYCODE_F12);
+        TERMCAP_TO_KEYCODE.put("F3", KEYMOD_SHIFT | KEYCODE_F1);
+        TERMCAP_TO_KEYCODE.put("F4", KEYMOD_SHIFT | KEYCODE_F2);
+        TERMCAP_TO_KEYCODE.put("F5", KEYMOD_SHIFT | KEYCODE_F3);
+        TERMCAP_TO_KEYCODE.put("F6", KEYMOD_SHIFT | KEYCODE_F4);
+        TERMCAP_TO_KEYCODE.put("F7", KEYMOD_SHIFT | KEYCODE_F5);
+        TERMCAP_TO_KEYCODE.put("F8", KEYMOD_SHIFT | KEYCODE_F6);
+        TERMCAP_TO_KEYCODE.put("F9", KEYMOD_SHIFT | KEYCODE_F7);
+        TERMCAP_TO_KEYCODE.put("FA", KEYMOD_SHIFT | KEYCODE_F8);
+        TERMCAP_TO_KEYCODE.put("FB", KEYMOD_SHIFT | KEYCODE_F9);
+        TERMCAP_TO_KEYCODE.put("FC", KEYMOD_SHIFT | KEYCODE_F10);
+        TERMCAP_TO_KEYCODE.put("FD", KEYMOD_SHIFT | KEYCODE_F11);
+        TERMCAP_TO_KEYCODE.put("FE", KEYMOD_SHIFT | KEYCODE_F12);
+
+        TERMCAP_TO_KEYCODE.put("kb", KEYCODE_DEL); // backspace key
+
+        TERMCAP_TO_KEYCODE.put("kd", KEYCODE_DPAD_DOWN); // terminfo=kcud1, down-arrow key
+        TERMCAP_TO_KEYCODE.put("kh", KEYCODE_MOVE_HOME);
+        TERMCAP_TO_KEYCODE.put("kl", KEYCODE_DPAD_LEFT);
+        TERMCAP_TO_KEYCODE.put("kr", KEYCODE_DPAD_RIGHT);
+
+        // K1=Upper left of keypad:
+        // t_K1 <kHome> keypad home key
+        // t_K3 <kPageUp> keypad page-up key
+        // t_K4 <kEnd> keypad end key
+        // t_K5 <kPageDown> keypad page-down key
+        TERMCAP_TO_KEYCODE.put("K1", KEYCODE_MOVE_HOME);
+        TERMCAP_TO_KEYCODE.put("K3", KEYCODE_PAGE_UP);
+        TERMCAP_TO_KEYCODE.put("K4", KEYCODE_MOVE_END);
+        TERMCAP_TO_KEYCODE.put("K5", KEYCODE_PAGE_DOWN);
+
+        TERMCAP_TO_KEYCODE.put("ku", KEYCODE_DPAD_UP);
+
+        TERMCAP_TO_KEYCODE.put("kB", KEYMOD_SHIFT | KEYCODE_TAB); // termcap=kB, terminfo=kcbt: Back-tab
+        TERMCAP_TO_KEYCODE.put("kD", KEYCODE_FORWARD_DEL); // terminfo=kdch1, delete-character key
+        TERMCAP_TO_KEYCODE.put("kDN", KEYMOD_SHIFT | KEYCODE_DPAD_DOWN); // non-standard shifted arrow down
+        TERMCAP_TO_KEYCODE.put("kF", KEYMOD_SHIFT | KEYCODE_DPAD_DOWN); // terminfo=kind, scroll-forward key
+        TERMCAP_TO_KEYCODE.put("kI", KEYCODE_INSERT);
+        TERMCAP_TO_KEYCODE.put("kN", KEYCODE_PAGE_UP);
+        TERMCAP_TO_KEYCODE.put("kP", KEYCODE_PAGE_DOWN);
+        TERMCAP_TO_KEYCODE.put("kR", KEYMOD_SHIFT | KEYCODE_DPAD_UP); // terminfo=kri, scroll-backward key
+        TERMCAP_TO_KEYCODE.put("kUP", KEYMOD_SHIFT | KEYCODE_DPAD_UP); // non-standard shifted up
+
+        TERMCAP_TO_KEYCODE.put("@7", KEYCODE_MOVE_END);
+        TERMCAP_TO_KEYCODE.put("@8", KEYCODE_NUMPAD_ENTER);
+    }
+
+    static String getCodeFromTermcap(String termcap, boolean cursorKeysApplication, boolean keypadApplication) {
+        Integer keyCodeAndMod = TERMCAP_TO_KEYCODE.get(termcap);
+        if (keyCodeAndMod == null) return null;
+        int keyCode = keyCodeAndMod;
+        int keyMod = 0;
+        if ((keyCode & KEYMOD_SHIFT) != 0) {
+            keyMod |= KEYMOD_SHIFT;
+            keyCode &= ~KEYMOD_SHIFT;
+        }
+        if ((keyCode & KEYMOD_CTRL) != 0) {
+            keyMod |= KEYMOD_CTRL;
+            keyCode &= ~KEYMOD_CTRL;
+        }
+        if ((keyCode & KEYMOD_ALT) != 0) {
+            keyMod |= KEYMOD_ALT;
+            keyCode &= ~KEYMOD_ALT;
+        }
+        if ((keyCode & KEYMOD_NUM_LOCK) != 0) {
+            keyMod |= KEYMOD_NUM_LOCK;
+            keyCode &= ~KEYMOD_NUM_LOCK;
+        }
+        return getCode(keyCode, keyMod, cursorKeysApplication, keypadApplication);
+    }
+
+    public static String getCode(int keyCode, int keyMode, boolean cursorApp, boolean keypadApplication) {
+        boolean numLockOn = (keyMode & KEYMOD_NUM_LOCK) != 0;
+        keyMode &= ~KEYMOD_NUM_LOCK;
+        switch (keyCode) {
+            case KEYCODE_DPAD_CENTER:
+                return "\015";
+
+            case KEYCODE_DPAD_UP:
+                return (keyMode == 0) ? (cursorApp ? "\033OA" : "\033[A") : transformForModifiers("\033[1", keyMode, 'A');
+            case KEYCODE_DPAD_DOWN:
+                return (keyMode == 0) ? (cursorApp ? "\033OB" : "\033[B") : transformForModifiers("\033[1", keyMode, 'B');
+            case KEYCODE_DPAD_RIGHT:
+                return (keyMode == 0) ? (cursorApp ? "\033OC" : "\033[C") : transformForModifiers("\033[1", keyMode, 'C');
+            case KEYCODE_DPAD_LEFT:
+                return (keyMode == 0) ? (cursorApp ? "\033OD" : "\033[D") : transformForModifiers("\033[1", keyMode, 'D');
+
+            case KEYCODE_MOVE_HOME:
+                // Note that KEYCODE_HOME is handled by the system and never delivered to applications.
+                // On a Logitech k810 keyboard KEYCODE_MOVE_HOME is sent by FN+LeftArrow.
+                return (keyMode == 0) ? (cursorApp ? "\033OH" : "\033[H") : transformForModifiers("\033[1", keyMode, 'H');
+            case KEYCODE_MOVE_END:
+                return (keyMode == 0) ? (cursorApp ? "\033OF" : "\033[F") : transformForModifiers("\033[1", keyMode, 'F');
+
+            // An xterm can send function keys F1 to F4 in two modes: vt100 compatible or
+            // not. Because Vim may not know what the xterm is sending, both types of keys
+            // are recognized. The same happens for the <Home> and <End> keys.
+            // normal vt100 ~
+            // <F1> t_k1 <Esc>[11~ <xF1> <Esc>OP *<xF1>-xterm*
+            // <F2> t_k2 <Esc>[12~ <xF2> <Esc>OQ *<xF2>-xterm*
+            // <F3> t_k3 <Esc>[13~ <xF3> <Esc>OR *<xF3>-xterm*
+            // <F4> t_k4 <Esc>[14~ <xF4> <Esc>OS *<xF4>-xterm*
+            // <Home> t_kh <Esc>[7~ <xHome> <Esc>OH *<xHome>-xterm*
+            // <End> t_@7 <Esc>[4~ <xEnd> <Esc>OF *<xEnd>-xterm*
+            case KEYCODE_F1:
+                return (keyMode == 0) ? "\033OP" : transformForModifiers("\033[1", keyMode, 'P');
+            case KEYCODE_F2:
+                return (keyMode == 0) ? "\033OQ" : transformForModifiers("\033[1", keyMode, 'Q');
+            case KEYCODE_F3:
+                return (keyMode == 0) ? "\033OR" : transformForModifiers("\033[1", keyMode, 'R');
+            case KEYCODE_F4:
+                return (keyMode == 0) ? "\033OS" : transformForModifiers("\033[1", keyMode, 'S');
+            case KEYCODE_F5:
+                return transformForModifiers("\033[15", keyMode, '~');
+            case KEYCODE_F6:
+                return transformForModifiers("\033[17", keyMode, '~');
+            case KEYCODE_F7:
+                return transformForModifiers("\033[18", keyMode, '~');
+            case KEYCODE_F8:
+                return transformForModifiers("\033[19", keyMode, '~');
+            case KEYCODE_F9:
+                return transformForModifiers("\033[20", keyMode, '~');
+            case KEYCODE_F10:
+                return transformForModifiers("\033[21", keyMode, '~');
+            case KEYCODE_F11:
+                return transformForModifiers("\033[23", keyMode, '~');
+            case KEYCODE_F12:
+                return transformForModifiers("\033[24", keyMode, '~');
+
+            case KEYCODE_SYSRQ:
+                return "\033[32~"; // Sys Request / Print
+            // Is this Scroll lock? case Cancel: return "\033[33~";
+            case KEYCODE_BREAK:
+                return "\033[34~"; // Pause/Break
+
+            case KEYCODE_ESCAPE:
+            case KEYCODE_BACK:
+                return "\033";
+
+            case KEYCODE_INSERT:
+                return transformForModifiers("\033[2", keyMode, '~');
+            case KEYCODE_FORWARD_DEL:
+                return transformForModifiers("\033[3", keyMode, '~');
+
+            case KEYCODE_PAGE_UP:
+                return "\033[5~";
+            case KEYCODE_PAGE_DOWN:
+                return "\033[6~";
+            case KEYCODE_DEL:
+                String prefix = ((keyMode & KEYMOD_ALT) == 0) ? "" : "\033";
+                // Just do what xterm and gnome-terminal does:
+                return prefix + (((keyMode & KEYMOD_CTRL) == 0) ? "\u007F" : "\u0008");
+            case KEYCODE_NUM_LOCK:
+                if (keypadApplication) {
+                    return "\033OP";
+                } else {
+                    return null;
+                }
+            case KEYCODE_SPACE:
+                // If ctrl is not down, return null so that it goes through normal input processing (which may e.g. cause a
+                // combining accent to be written):
+                return ((keyMode & KEYMOD_CTRL) == 0) ? null : "\0";
+            case KEYCODE_TAB:
+                // This is back-tab when shifted:
+                return (keyMode & KEYMOD_SHIFT) == 0 ? "\011" : "\033[Z";
+            case KEYCODE_ENTER:
+                return ((keyMode & KEYMOD_ALT) == 0) ? "\r" : "\033\r";
+
+            case KEYCODE_NUMPAD_ENTER:
+                return keypadApplication ? transformForModifiers("\033O", keyMode, 'M') : "\n";
+            case KEYCODE_NUMPAD_MULTIPLY:
+                return keypadApplication ? transformForModifiers("\033O", keyMode, 'j') : "*";
+            case KEYCODE_NUMPAD_ADD:
+                return keypadApplication ? transformForModifiers("\033O", keyMode, 'k') : "+";
+            case KEYCODE_NUMPAD_COMMA:
+                return ",";
+            case KEYCODE_NUMPAD_DOT:
+                if (numLockOn) {
+                    return keypadApplication ? "\033On" : ".";
+                } else {
+                    // DELETE
+                    return transformForModifiers("\033[3", keyMode, '~');
+                }
+            case KEYCODE_NUMPAD_SUBTRACT:
+                return keypadApplication ? transformForModifiers("\033O", keyMode, 'm') : "-";
+            case KEYCODE_NUMPAD_DIVIDE:
+                return keypadApplication ? transformForModifiers("\033O", keyMode, 'o') : "/";
+            case KEYCODE_NUMPAD_0:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 'p') : "0";
+                } else {
+                    // INSERT
+                    return transformForModifiers("\033[2", keyMode, '~');
+                }
+            case KEYCODE_NUMPAD_1:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 'q') : "1";
+                } else {
+                    // END
+                    return (keyMode == 0) ? (cursorApp ? "\033OF" : "\033[F") : transformForModifiers("\033[1", keyMode, 'F');
+                }
+            case KEYCODE_NUMPAD_2:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 'r') : "2";
+                } else {
+                    // DOWN
+                    return (keyMode == 0) ? (cursorApp ? "\033OB" : "\033[B") : transformForModifiers("\033[1", keyMode, 'B');
+                }
+            case KEYCODE_NUMPAD_3:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 's') : "3";
+                } else {
+                    // PGDN
+                    return "\033[6~";
+                }
+            case KEYCODE_NUMPAD_4:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 't') : "4";
+                } else {
+                    // LEFT
+                    return (keyMode == 0) ? (cursorApp ? "\033OD" : "\033[D") : transformForModifiers("\033[1", keyMode, 'D');
+                }
+            case KEYCODE_NUMPAD_5:
+                return keypadApplication ? transformForModifiers("\033O", keyMode, 'u') : "5";
+            case KEYCODE_NUMPAD_6:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 'v') : "6";
+                } else {
+                    // RIGHT
+                    return (keyMode == 0) ? (cursorApp ? "\033OC" : "\033[C") : transformForModifiers("\033[1", keyMode, 'C');
+                }
+            case KEYCODE_NUMPAD_7:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 'w') : "7";
+                } else {
+                    // HOME
+                    return (keyMode == 0) ? (cursorApp ? "\033OH" : "\033[H") : transformForModifiers("\033[1", keyMode, 'H');
+                }
+            case KEYCODE_NUMPAD_8:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 'x') : "8";
+                } else {
+                    // UP
+                    return (keyMode == 0) ? (cursorApp ? "\033OA" : "\033[A") : transformForModifiers("\033[1", keyMode, 'A');
+                }
+            case KEYCODE_NUMPAD_9:
+                if (numLockOn) {
+                    return keypadApplication ? transformForModifiers("\033O", keyMode, 'y') : "9";
+                } else {
+                    // PGUP
+                    return "\033[5~";
+                }
+            case KEYCODE_NUMPAD_EQUALS:
+                return keypadApplication ? transformForModifiers("\033O", keyMode, 'X') : "=";
+        }
+
+        return null;
+    }
+
+    private static String transformForModifiers(String start, int keymod, char lastChar) {
+        int modifier;
+        switch (keymod) {
+            case KEYMOD_SHIFT:
+                modifier = 2;
+                break;
+            case KEYMOD_ALT:
+                modifier = 3;
+                break;
+            case (KEYMOD_SHIFT | KEYMOD_ALT):
+                modifier = 4;
+                break;
+            case KEYMOD_CTRL:
+                modifier = 5;
+                break;
+            case KEYMOD_SHIFT | KEYMOD_CTRL:
+                modifier = 6;
+                break;
+            case KEYMOD_ALT | KEYMOD_CTRL:
+                modifier = 7;
+                break;
+            case KEYMOD_SHIFT | KEYMOD_ALT | KEYMOD_CTRL:
+                modifier = 8;
+                break;
+            default:
+                return start + lastChar;
+        }
+        return start + (";" + modifier) + lastChar;
+    }
+}

terminal-emulator/src/main/java/com/termux/terminal/Logger.java

@@ -0,0 +1,80 @@
+package com.termux.terminal;
+
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+public class Logger {
+
+    public static void logError(TerminalSessionClient client, String logTag, String message) {
+        if (client != null)
+            client.logError(logTag, message);
+        else
+            Log.e(logTag, message);
+    }
+
+    public static void logWarn(TerminalSessionClient client, String logTag, String message) {
+        if (client != null)
+            client.logWarn(logTag, message);
+        else
+            Log.w(logTag, message);
+    }
+
+    public static void logInfo(TerminalSessionClient client, String logTag, String message) {
+        if (client != null)
+            client.logInfo(logTag, message);
+        else
+            Log.i(logTag, message);
+    }
+
+    public static void logDebug(TerminalSessionClient client, String logTag, String message) {
+        if (client != null)
+            client.logDebug(logTag, message);
+        else
+            Log.d(logTag, message);
+    }
+
+    public static void logVerbose(TerminalSessionClient client, String logTag, String message) {
+        if (client != null)
+            client.logVerbose(logTag, message);
+        else
+            Log.v(logTag, message);
+    }
+
+    public static void logStackTraceWithMessage(TerminalSessionClient client, String tag, String message, Throwable throwable) {
+        logError(client, tag, getMessageAndStackTraceString(message, throwable));
+    }
+
+    public static String getMessageAndStackTraceString(String message, Throwable throwable) {
+        if (message == null && throwable == null)
+            return null;
+        else if (message != null && throwable != null)
+            return message + ":\n" + getStackTraceString(throwable);
+        else if (throwable == null)
+            return message;
+        else
+            return getStackTraceString(throwable);
+    }
+
+    public static String getStackTraceString(Throwable throwable) {
+        if (throwable == null) return null;
+
+        String stackTraceString = null;
+
+        try {
+            StringWriter errors = new StringWriter();
+            PrintWriter pw = new PrintWriter(errors);
+            throwable.printStackTrace(pw);
+            pw.close();
+            stackTraceString = errors.toString();
+            errors.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        return stackTraceString;
+    }
+
+}

terminal-emulator/src/main/java/com/termux/terminal/TerminalBuffer.java

@@ -0,0 +1,497 @@
+package com.termux.terminal;
+
+import java.util.Arrays;
+
+/**
+ * A circular buffer of {@link TerminalRow}:s which keeps notes about what is visible on a logical screen and the scroll
+ * history.
+ * <p>
+ * See {@link #externalToInternalRow(int)} for how to map from logical screen rows to array indices.
+ */
+public final class TerminalBuffer {
+
+    TerminalRow[] mLines;
+    /** The length of {@link #mLines}. */
+    int mTotalRows;
+    /** The number of rows and columns visible on the screen. */
+    int mScreenRows, mColumns;
+    /** The number of rows kept in history. */
+    private int mActiveTranscriptRows = 0;
+    /** The index in the circular buffer where the visible screen starts. */
+    private int mScreenFirstRow = 0;
+
+    /**
+     * Create a transcript screen.
+     *
+     * @param columns    the width of the screen in characters.
+     * @param totalRows  the height of the entire text area, in rows of text.
+     * @param screenRows the height of just the screen, not including the transcript that holds lines that have scrolled off
+     *                   the top of the screen.
+     */
+    public TerminalBuffer(int columns, int totalRows, int screenRows) {
+        mColumns = columns;
+        mTotalRows = totalRows;
+        mScreenRows = screenRows;
+        mLines = new TerminalRow[totalRows];
+
+        blockSet(0, 0, columns, screenRows, ' ', TextStyle.NORMAL);
+    }
+
+    public String getTranscriptText() {
+        return getSelectedText(0, -getActiveTranscriptRows(), mColumns, mScreenRows).trim();
+    }
+
+    public String getTranscriptTextWithoutJoinedLines() {
+        return getSelectedText(0, -getActiveTranscriptRows(), mColumns, mScreenRows, false).trim();
+    }
+
+    public String getTranscriptTextWithFullLinesJoined() {
+        return getSelectedText(0, -getActiveTranscriptRows(), mColumns, mScreenRows, true, true).trim();
+    }
+
+    public String getSelectedText(int selX1, int selY1, int selX2, int selY2) {
+        return getSelectedText(selX1, selY1, selX2, selY2, true);
+    }
+
+    public String getSelectedText(int selX1, int selY1, int selX2, int selY2, boolean joinBackLines) {
+        return getSelectedText(selX1, selY1, selX2, selY2, joinBackLines, false);
+    }
+
+    public String getSelectedText(int selX1, int selY1, int selX2, int selY2, boolean joinBackLines, boolean joinFullLines) {
+        final StringBuilder builder = new StringBuilder();
+        final int columns = mColumns;
+
+        if (selY1 < -getActiveTranscriptRows()) selY1 = -getActiveTranscriptRows();
+        if (selY2 >= mScreenRows) selY2 = mScreenRows - 1;
+
+        for (int row = selY1; row <= selY2; row++) {
+            int x1 = (row == selY1) ? selX1 : 0;
+            int x2;
+            if (row == selY2) {
+                x2 = selX2 + 1;
+                if (x2 > columns) x2 = columns;
+            } else {
+                x2 = columns;
+            }
+            TerminalRow lineObject = mLines[externalToInternalRow(row)];
+            int x1Index = lineObject.findStartOfColumn(x1);
+            int x2Index = (x2 < mColumns) ? lineObject.findStartOfColumn(x2) : lineObject.getSpaceUsed();
+            if (x2Index == x1Index) {
+                // Selected the start of a wide character.
+                x2Index = lineObject.findStartOfColumn(x2 + 1);
+            }
+            char[] line = lineObject.mText;
+            int lastPrintingCharIndex = -1;
+            int i;
+            boolean rowLineWrap = getLineWrap(row);
+            if (rowLineWrap && x2 == columns) {
+                // If the line was wrapped, we shouldn't lose trailing space:
+                lastPrintingCharIndex = x2Index - 1;
+            } else {
+                for (i = x1Index; i < x2Index; ++i) {
+                    char c = line[i];
+                    if (c != ' ') lastPrintingCharIndex = i;
+                }
+            }
+
+            int len = lastPrintingCharIndex - x1Index + 1;
+            if (lastPrintingCharIndex != -1 && len > 0)
+                builder.append(line, x1Index, len);
+
+            boolean lineFillsWidth = lastPrintingCharIndex == x2Index - 1;
+            if ((!joinBackLines || !rowLineWrap) && (!joinFullLines || !lineFillsWidth)
+                && row < selY2 && row < mScreenRows - 1) builder.append('\n');
+        }
+        return builder.toString();
+    }
+
+    public String getWordAtLocation(int x, int y) {
+        // Set y1 and y2 to the lines where the wrapped line starts and ends.
+        // I.e. if a line that is wrapped to 3 lines starts at line 4, and this
+        // is called with y=5, then y1 would be set to 4 and y2 would be set to 6.
+        int y1 = y;
+        int y2 = y;
+        while (y1 > 0 && !getSelectedText(0, y1 - 1, mColumns, y, true, true).contains("\n")) {
+            y1--;
+        }
+        while (y2 < mScreenRows && !getSelectedText(0, y, mColumns, y2 + 1, true, true).contains("\n")) {
+            y2++;
+        }
+
+        // Get the text for the whole wrapped line
+        String text = getSelectedText(0, y1, mColumns, y2, true, true);
+        // The index of x in text
+        int textOffset = (y - y1) * mColumns + x;
+
+        if (textOffset >= text.length()) {
+          // The click was to the right of the last word on the line, so
+          // there's no word to return
+          return "";
+        }
+
+        // Set x1 and x2 to the indices of the last space before x and the
+        // first space after x in text respectively
+        int x1 = text.lastIndexOf(' ', textOffset);
+        int x2 = text.indexOf(' ', textOffset);
+        if (x2 == -1) {
+            x2 = text.length();
+        }
+
+        if (x1 == x2) {
+          // The click was on a space, so there's no word to return
+          return "";
+        }
+        return text.substring(x1 + 1, x2);
+    }
+
+    public int getActiveTranscriptRows() {
+        return mActiveTranscriptRows;
+    }
+
+    public int getActiveRows() {
+        return mActiveTranscriptRows + mScreenRows;
+    }
+
+    /**
+     * Convert a row value from the public external coordinate system to our internal private coordinate system.
+     *
+     * <pre>
+     * - External coordinate system: -mActiveTranscriptRows to mScreenRows-1, with the screen being 0..mScreenRows-1.
+     * - Internal coordinate system: the mScreenRows lines starting at mScreenFirstRow comprise the screen, while the
+     *   mActiveTranscriptRows lines ending at mScreenFirstRow-1 form the transcript (as a circular buffer).
+     *
+     * External ↔ Internal:
+     *
+     * [ ...                            ]     [ ...                                     ]
+     * [ -mActiveTranscriptRows         ]     [ mScreenFirstRow - mActiveTranscriptRows ]
+     * [ ...                            ]     [ ...                                     ]
+     * [ 0 (visible screen starts here) ]  ↔  [ mScreenFirstRow                         ]
+     * [ ...                            ]     [ ...                                     ]
+     * [ mScreenRows-1                  ]     [ mScreenFirstRow + mScreenRows-1         ]
+     * </pre>
+     *
+     * @param externalRow a row in the external coordinate system.
+     * @return The row corresponding to the input argument in the private coordinate system.
+     */
+    public int externalToInternalRow(int externalRow) {
+        if (externalRow < -mActiveTranscriptRows || externalRow > mScreenRows)
+            throw new IllegalArgumentException("extRow=" + externalRow + ", mScreenRows=" + mScreenRows + ", mActiveTranscriptRows=" + mActiveTranscriptRows);
+        final int internalRow = mScreenFirstRow + externalRow;
+        return (internalRow < 0) ? (mTotalRows + internalRow) : (internalRow % mTotalRows);
+    }
+
+    public void setLineWrap(int row) {
+        mLines[externalToInternalRow(row)].mLineWrap = true;
+    }
+
+    public boolean getLineWrap(int row) {
+        return mLines[externalToInternalRow(row)].mLineWrap;
+    }
+
+    public void clearLineWrap(int row) {
+        mLines[externalToInternalRow(row)].mLineWrap = false;
+    }
+
+    /**
+     * Resize the screen which this transcript backs. Currently, this only works if the number of columns does not
+     * change or the rows expand (that is, it only works when shrinking the number of rows).
+     *
+     * @param newColumns The number of columns the screen should have.
+     * @param newRows    The number of rows the screen should have.
+     * @param cursor     An int[2] containing the (column, row) cursor location.
+     */
+    public void resize(int newColumns, int newRows, int newTotalRows, int[] cursor, long currentStyle, boolean altScreen) {
+        // newRows > mTotalRows should not normally happen since mTotalRows is TRANSCRIPT_ROWS (10000):
+        if (newColumns == mColumns && newRows <= mTotalRows) {
+            // Fast resize where just the rows changed.
+            int shiftDownOfTopRow = mScreenRows - newRows;
+            if (shiftDownOfTopRow > 0 && shiftDownOfTopRow < mScreenRows) {
+                // Shrinking. Check if we can skip blank rows at bottom below cursor.
+                for (int i = mScreenRows - 1; i > 0; i--) {
+                    if (cursor[1] >= i) break;
+                    int r = externalToInternalRow(i);
+                    if (mLines[r] == null || mLines[r].isBlank()) {
+                        if (--shiftDownOfTopRow == 0) break;
+                    }
+                }
+            } else if (shiftDownOfTopRow < 0) {
+                // Negative shift down = expanding. Only move screen up if there is transcript to show:
+                int actualShift = Math.max(shiftDownOfTopRow, -mActiveTranscriptRows);
+                if (shiftDownOfTopRow != actualShift) {
+                    // The new lines revealed by the resizing are not all from the transcript. Blank the below ones.
+                    for (int i = 0; i < actualShift - shiftDownOfTopRow; i++)
+                        allocateFullLineIfNecessary((mScreenFirstRow + mScreenRows + i) % mTotalRows).clear(currentStyle);
+                    shiftDownOfTopRow = actualShift;
+                }
+            }
+            mScreenFirstRow += shiftDownOfTopRow;
+            mScreenFirstRow = (mScreenFirstRow < 0) ? (mScreenFirstRow + mTotalRows) : (mScreenFirstRow % mTotalRows);
+            mTotalRows = newTotalRows;
+            mActiveTranscriptRows = altScreen ? 0 : Math.max(0, mActiveTranscriptRows + shiftDownOfTopRow);
+            cursor[1] -= shiftDownOfTopRow;
+            mScreenRows = newRows;
+        } else {
+            // Copy away old state and update new:
+            TerminalRow[] oldLines = mLines;
+            mLines = new TerminalRow[newTotalRows];
+            for (int i = 0; i < newTotalRows; i++)
+                mLines[i] = new TerminalRow(newColumns, currentStyle);
+
+            final int oldActiveTranscriptRows = mActiveTranscriptRows;
+            final int oldScreenFirstRow = mScreenFirstRow;
+            final int oldScreenRows = mScreenRows;
+            final int oldTotalRows = mTotalRows;
+            mTotalRows = newTotalRows;
+            mScreenRows = newRows;
+            mActiveTranscriptRows = mScreenFirstRow = 0;
+            mColumns = newColumns;
+
+            int newCursorRow = -1;
+            int newCursorColumn = -1;
+            int oldCursorRow = cursor[1];
+            int oldCursorColumn = cursor[0];
+            boolean newCursorPlaced = false;
+
+            int currentOutputExternalRow = 0;
+            int currentOutputExternalColumn = 0;
+
+            // Loop over every character in the initial state.
+            // Blank lines should be skipped only if at end of transcript (just as is done in the "fast" resize), so we
+            // keep track how many blank lines we have skipped if we later on find a non-blank line.
+            int skippedBlankLines = 0;
+            for (int externalOldRow = -oldActiveTranscriptRows; externalOldRow < oldScreenRows; externalOldRow++) {
+                // Do what externalToInternalRow() does but for the old state:
+                int internalOldRow = oldScreenFirstRow + externalOldRow;
+                internalOldRow = (internalOldRow < 0) ? (oldTotalRows + internalOldRow) : (internalOldRow % oldTotalRows);
+
+                TerminalRow oldLine = oldLines[internalOldRow];
+                boolean cursorAtThisRow = externalOldRow == oldCursorRow;
+                // The cursor may only be on a non-null line, which we should not skip:
+                if (oldLine == null || (!(!newCursorPlaced && cursorAtThisRow)) && oldLine.isBlank()) {
+                    skippedBlankLines++;
+                    continue;
+                } else if (skippedBlankLines > 0) {
+                    // After skipping some blank lines we encounter a non-blank line. Insert the skipped blank lines.
+                    for (int i = 0; i < skippedBlankLines; i++) {
+                        if (currentOutputExternalRow == mScreenRows - 1) {
+                            scrollDownOneLine(0, mScreenRows, currentStyle);
+                        } else {
+                            currentOutputExternalRow++;
+                        }
+                        currentOutputExternalColumn = 0;
+                    }
+                    skippedBlankLines = 0;
+                }
+
+                int lastNonSpaceIndex = 0;
+                boolean justToCursor = false;
+                if (cursorAtThisRow || oldLine.mLineWrap) {
+                    // Take the whole line, either because of cursor on it, or if line wrapping.
+                    lastNonSpaceIndex = oldLine.getSpaceUsed();
+                    if (cursorAtThisRow) justToCursor = true;
+                } else {
+                    for (int i = 0; i < oldLine.getSpaceUsed(); i++)
+                        // NEWLY INTRODUCED BUG! Should not index oldLine.mStyle with char indices
+                        if (oldLine.mText[i] != ' '/* || oldLine.mStyle[i] != currentStyle */)
+                            lastNonSpaceIndex = i + 1;
+                }
+
+                int currentOldCol = 0;
+                long styleAtCol = 0;
+                for (int i = 0; i < lastNonSpaceIndex; i++) {
+                    // Note that looping over java character, not cells.
+                    char c = oldLine.mText[i];
+                    int codePoint = (Character.isHighSurrogate(c)) ? Character.toCodePoint(c, oldLine.mText[++i]) : c;
+                    int displayWidth = WcWidth.width(codePoint);
+                    // Use the last style if this is a zero-width character:
+                    if (displayWidth > 0) styleAtCol = oldLine.getStyle(currentOldCol);
+
+                    // Line wrap as necessary:
+                    if (currentOutputExternalColumn + displayWidth > mColumns) {
+                        setLineWrap(currentOutputExternalRow);
+                        if (currentOutputExternalRow == mScreenRows - 1) {
+                            if (newCursorPlaced) newCursorRow--;
+                            scrollDownOneLine(0, mScreenRows, currentStyle);
+                        } else {
+                            currentOutputExternalRow++;
+                        }
+                        currentOutputExternalColumn = 0;
+                    }
+
+                    int offsetDueToCombiningChar = ((displayWidth <= 0 && currentOutputExternalColumn > 0) ? 1 : 0);
+                    int outputColumn = currentOutputExternalColumn - offsetDueToCombiningChar;
+                    setChar(outputColumn, currentOutputExternalRow, codePoint, styleAtCol);
+
+                    if (displayWidth > 0) {
+                        if (oldCursorRow == externalOldRow && oldCursorColumn == currentOldCol) {
+                            newCursorColumn = currentOutputExternalColumn;
+                            newCursorRow = currentOutputExternalRow;
+                            newCursorPlaced = true;
+                        }
+                        currentOldCol += displayWidth;
+                        currentOutputExternalColumn += displayWidth;
+                        if (justToCursor && newCursorPlaced) break;
+                    }
+                }
+                // Old row has been copied. Check if we need to insert newline if old line was not wrapping:
+                if (externalOldRow != (oldScreenRows - 1) && !oldLine.mLineWrap) {
+                    if (currentOutputExternalRow == mScreenRows - 1) {
+                        if (newCursorPlaced) newCursorRow--;
+                        scrollDownOneLine(0, mScreenRows, currentStyle);
+                    } else {
+                        currentOutputExternalRow++;
+                    }
+                    currentOutputExternalColumn = 0;
+                }
+            }
+
+            cursor[0] = newCursorColumn;
+            cursor[1] = newCursorRow;
+        }
+
+        // Handle cursor scrolling off screen:
+        if (cursor[0] < 0 || cursor[1] < 0) cursor[0] = cursor[1] = 0;
+    }
+
+    /**
+     * Block copy lines and associated metadata from one location to another in the circular buffer, taking wraparound
+     * into account.
+     *
+     * @param srcInternal The first line to be copied.
+     * @param len         The number of lines to be copied.
+     */
+    private void blockCopyLinesDown(int srcInternal, int len) {
+        if (len == 0) return;
+        int totalRows = mTotalRows;
+
+        int start = len - 1;
+        // Save away line to be overwritten:
+        TerminalRow lineToBeOverWritten = mLines[(srcInternal + start + 1) % totalRows];
+        // Do the copy from bottom to top.
+        for (int i = start; i >= 0; --i)
+            mLines[(srcInternal + i + 1) % totalRows] = mLines[(srcInternal + i) % totalRows];
+        // Put back overwritten line, now above the block:
+        mLines[(srcInternal) % totalRows] = lineToBeOverWritten;
+    }
+
+    /**
+     * Scroll the screen down one line. To scroll the whole screen of a 24 line screen, the arguments would be (0, 24).
+     *
+     * @param topMargin    First line that is scrolled.
+     * @param bottomMargin One line after the last line that is scrolled.
+     * @param style        the style for the newly exposed line.
+     */
+    public void scrollDownOneLine(int topMargin, int bottomMargin, long style) {
+        if (topMargin > bottomMargin - 1 || topMargin < 0 || bottomMargin > mScreenRows)
+            throw new IllegalArgumentException("topMargin=" + topMargin + ", bottomMargin=" + bottomMargin + ", mScreenRows=" + mScreenRows);
+
+        // Copy the fixed topMargin lines one line down so that they remain on screen in same position:
+        blockCopyLinesDown(mScreenFirstRow, topMargin);
+        // Copy the fixed mScreenRows-bottomMargin lines one line down so that they remain on screen in same
+        // position:
+        blockCopyLinesDown(externalToInternalRow(bottomMargin), mScreenRows - bottomMargin);
+
+        // Update the screen location in the ring buffer:
+        mScreenFirstRow = (mScreenFirstRow + 1) % mTotalRows;
+        // Note that the history has grown if not already full:
+        if (mActiveTranscriptRows < mTotalRows - mScreenRows) mActiveTranscriptRows++;
+
+        // Blank the newly revealed line above the bottom margin:
+        int blankRow = externalToInternalRow(bottomMargin - 1);
+        if (mLines[blankRow] == null) {
+            mLines[blankRow] = new TerminalRow(mColumns, style);
+        } else {
+            mLines[blankRow].clear(style);
+        }
+    }
+
+    /**
+     * Block copy characters from one position in the screen to another. The two positions can overlap. All characters
+     * of the source and destination must be within the bounds of the screen, or else an InvalidParameterException will
+     * be thrown.
+     *
+     * @param sx source X coordinate
+     * @param sy source Y coordinate
+     * @param w  width
+     * @param h  height
+     * @param dx destination X coordinate
+     * @param dy destination Y coordinate
+     */
+    public void blockCopy(int sx, int sy, int w, int h, int dx, int dy) {
+        if (w == 0) return;
+        if (sx < 0 || sx + w > mColumns || sy < 0 || sy + h > mScreenRows || dx < 0 || dx + w > mColumns || dy < 0 || dy + h > mScreenRows)
+            throw new IllegalArgumentException();
+        boolean copyingUp = sy > dy;
+        for (int y = 0; y < h; y++) {
+            int y2 = copyingUp ? y : (h - (y + 1));
+            TerminalRow sourceRow = allocateFullLineIfNecessary(externalToInternalRow(sy + y2));
+            allocateFullLineIfNecessary(externalToInternalRow(dy + y2)).copyInterval(sourceRow, sx, sx + w, dx);
+        }
+    }
+
+    /**
+     * Block set characters. All characters must be within the bounds of the screen, or else and
+     * InvalidParemeterException will be thrown. Typically this is called with a "val" argument of 32 to clear a block
+     * of characters.
+     */
+    public void blockSet(int sx, int sy, int w, int h, int val, long style) {
+        if (sx < 0 || sx + w > mColumns || sy < 0 || sy + h > mScreenRows) {
+            throw new IllegalArgumentException(
+                "Illegal arguments! blockSet(" + sx + ", " + sy + ", " + w + ", " + h + ", " + val + ", " + mColumns + ", " + mScreenRows + ")");
+        }
+        for (int y = 0; y < h; y++)
+            for (int x = 0; x < w; x++)
+                setChar(sx + x, sy + y, val, style);
+    }
+
+    public TerminalRow allocateFullLineIfNecessary(int row) {
+        return (mLines[row] == null) ? (mLines[row] = new TerminalRow(mColumns, 0)) : mLines[row];
+    }
+
+    public void setChar(int column, int row, int codePoint, long style) {
+        if (row  < 0 || row >= mScreenRows || column < 0 || column >= mColumns)
+            throw new IllegalArgumentException("TerminalBuffer.setChar(): row=" + row + ", column=" + column + ", mScreenRows=" + mScreenRows + ", mColumns=" + mColumns);
+        row = externalToInternalRow(row);
+        allocateFullLineIfNecessary(row).setChar(column, codePoint, style);
+    }
+
+    public long getStyleAt(int externalRow, int column) {
+        return allocateFullLineIfNecessary(externalToInternalRow(externalRow)).getStyle(column);
+    }
+
+    /** Support for http://vt100.net/docs/vt510-rm/DECCARA and http://vt100.net/docs/vt510-rm/DECCARA */
+    public void setOrClearEffect(int bits, boolean setOrClear, boolean reverse, boolean rectangular, int leftMargin, int rightMargin, int top, int left,
+                                 int bottom, int right) {
+        for (int y = top; y < bottom; y++) {
+            TerminalRow line = mLines[externalToInternalRow(y)];
+            int startOfLine = (rectangular || y == top) ? left : leftMargin;
+            int endOfLine = (rectangular || y + 1 == bottom) ? right : rightMargin;
+            for (int x = startOfLine; x < endOfLine; x++) {
+                long currentStyle = line.getStyle(x);
+                int foreColor = TextStyle.decodeForeColor(currentStyle);
+                int backColor = TextStyle.decodeBackColor(currentStyle);
+                int effect = TextStyle.decodeEffect(currentStyle);
+                if (reverse) {
+                    // Clear out the bits to reverse and add them back in reversed:
+                    effect = (effect & ~bits) | (bits & ~effect);
+                } else if (setOrClear) {
+                    effect |= bits;
+                } else {
+                    effect &= ~bits;
+                }
+                line.mStyle[x] = TextStyle.encode(foreColor, backColor, effect);
+            }
+        }
+    }
+
+    public void clearTranscript() {
+        if (mScreenFirstRow < mActiveTranscriptRows) {
+            Arrays.fill(mLines, mTotalRows + mScreenFirstRow - mActiveTranscriptRows, mTotalRows, null);
+            Arrays.fill(mLines, 0, mScreenFirstRow, null);
+        } else {
+            Arrays.fill(mLines, mScreenFirstRow - mActiveTranscriptRows, mScreenFirstRow, null);
+        }
+        mActiveTranscriptRows = 0;
+    }
+
+}

terminal-emulator/src/main/java/com/termux/terminal/TerminalColorScheme.java

@@ -0,0 +1,126 @@
+package com.termux.terminal;
+
+import java.util.Map;
+import java.util.Properties;
+
+/**
+ * Color scheme for a terminal with default colors, which may be overridden (and then reset) from the shell using
+ * Operating System Control (OSC) sequences.
+ *
+ * @see TerminalColors
+ */
+public final class TerminalColorScheme {
+
+    /** http://upload.wikimedia.org/wikipedia/en/1/15/Xterm_256color_chart.svg, but with blue color brighter. */
+    private static final int[] DEFAULT_COLORSCHEME = {
+        // 16 original colors. First 8 are dim.
+        0xff000000, // black
+        0xffcd0000, // dim red
+        0xff00cd00, // dim green
+        0xffcdcd00, // dim yellow
+        0xff6495ed, // dim blue
+        0xffcd00cd, // dim magenta
+        0xff00cdcd, // dim cyan
+        0xffe5e5e5, // dim white
+        // Second 8 are bright:
+        0xff7f7f7f, // medium grey
+        0xffff0000, // bright red
+        0xff00ff00, // bright green
+        0xffffff00, // bright yellow
+        0xff5c5cff, // light blue
+        0xffff00ff, // bright magenta
+        0xff00ffff, // bright cyan
+        0xffffffff, // bright white
+
+        // 216 color cube, six shades of each color:
+        0xff000000, 0xff00005f, 0xff000087, 0xff0000af, 0xff0000d7, 0xff0000ff, 0xff005f00, 0xff005f5f, 0xff005f87, 0xff005faf, 0xff005fd7, 0xff005fff,
+        0xff008700, 0xff00875f, 0xff008787, 0xff0087af, 0xff0087d7, 0xff0087ff, 0xff00af00, 0xff00af5f, 0xff00af87, 0xff00afaf, 0xff00afd7, 0xff00afff,
+        0xff00d700, 0xff00d75f, 0xff00d787, 0xff00d7af, 0xff00d7d7, 0xff00d7ff, 0xff00ff00, 0xff00ff5f, 0xff00ff87, 0xff00ffaf, 0xff00ffd7, 0xff00ffff,
+        0xff5f0000, 0xff5f005f, 0xff5f0087, 0xff5f00af, 0xff5f00d7, 0xff5f00ff, 0xff5f5f00, 0xff5f5f5f, 0xff5f5f87, 0xff5f5faf, 0xff5f5fd7, 0xff5f5fff,
+        0xff5f8700, 0xff5f875f, 0xff5f8787, 0xff5f87af, 0xff5f87d7, 0xff5f87ff, 0xff5faf00, 0xff5faf5f, 0xff5faf87, 0xff5fafaf, 0xff5fafd7, 0xff5fafff,
+        0xff5fd700, 0xff5fd75f, 0xff5fd787, 0xff5fd7af, 0xff5fd7d7, 0xff5fd7ff, 0xff5fff00, 0xff5fff5f, 0xff5fff87, 0xff5fffaf, 0xff5fffd7, 0xff5fffff,
+        0xff870000, 0xff87005f, 0xff870087, 0xff8700af, 0xff8700d7, 0xff8700ff, 0xff875f00, 0xff875f5f, 0xff875f87, 0xff875faf, 0xff875fd7, 0xff875fff,
+        0xff878700, 0xff87875f, 0xff878787, 0xff8787af, 0xff8787d7, 0xff8787ff, 0xff87af00, 0xff87af5f, 0xff87af87, 0xff87afaf, 0xff87afd7, 0xff87afff,
+        0xff87d700, 0xff87d75f, 0xff87d787, 0xff87d7af, 0xff87d7d7, 0xff87d7ff, 0xff87ff00, 0xff87ff5f, 0xff87ff87, 0xff87ffaf, 0xff87ffd7, 0xff87ffff,
+        0xffaf0000, 0xffaf005f, 0xffaf0087, 0xffaf00af, 0xffaf00d7, 0xffaf00ff, 0xffaf5f00, 0xffaf5f5f, 0xffaf5f87, 0xffaf5faf, 0xffaf5fd7, 0xffaf5fff,
+        0xffaf8700, 0xffaf875f, 0xffaf8787, 0xffaf87af, 0xffaf87d7, 0xffaf87ff, 0xffafaf00, 0xffafaf5f, 0xffafaf87, 0xffafafaf, 0xffafafd7, 0xffafafff,
+        0xffafd700, 0xffafd75f, 0xffafd787, 0xffafd7af, 0xffafd7d7, 0xffafd7ff, 0xffafff00, 0xffafff5f, 0xffafff87, 0xffafffaf, 0xffafffd7, 0xffafffff,
+        0xffd70000, 0xffd7005f, 0xffd70087, 0xffd700af, 0xffd700d7, 0xffd700ff, 0xffd75f00, 0xffd75f5f, 0xffd75f87, 0xffd75faf, 0xffd75fd7, 0xffd75fff,
+        0xffd78700, 0xffd7875f, 0xffd78787, 0xffd787af, 0xffd787d7, 0xffd787ff, 0xffd7af00, 0xffd7af5f, 0xffd7af87, 0xffd7afaf, 0xffd7afd7, 0xffd7afff,
+        0xffd7d700, 0xffd7d75f, 0xffd7d787, 0xffd7d7af, 0xffd7d7d7, 0xffd7d7ff, 0xffd7ff00, 0xffd7ff5f, 0xffd7ff87, 0xffd7ffaf, 0xffd7ffd7, 0xffd7ffff,
+        0xffff0000, 0xffff005f, 0xffff0087, 0xffff00af, 0xffff00d7, 0xffff00ff, 0xffff5f00, 0xffff5f5f, 0xffff5f87, 0xffff5faf, 0xffff5fd7, 0xffff5fff,
+        0xffff8700, 0xffff875f, 0xffff8787, 0xffff87af, 0xffff87d7, 0xffff87ff, 0xffffaf00, 0xffffaf5f, 0xffffaf87, 0xffffafaf, 0xffffafd7, 0xffffafff,
+        0xffffd700, 0xffffd75f, 0xffffd787, 0xffffd7af, 0xffffd7d7, 0xffffd7ff, 0xffffff00, 0xffffff5f, 0xffffff87, 0xffffffaf, 0xffffffd7, 0xffffffff,
+
+        // 24 grey scale ramp:
+        0xff080808, 0xff121212, 0xff1c1c1c, 0xff262626, 0xff303030, 0xff3a3a3a, 0xff444444, 0xff4e4e4e, 0xff585858, 0xff626262, 0xff6c6c6c, 0xff767676,
+        0xff808080, 0xff8a8a8a, 0xff949494, 0xff9e9e9e, 0xffa8a8a8, 0xffb2b2b2, 0xffbcbcbc, 0xffc6c6c6, 0xffd0d0d0, 0xffdadada, 0xffe4e4e4, 0xffeeeeee,
+
+        // COLOR_INDEX_DEFAULT_FOREGROUND, COLOR_INDEX_DEFAULT_BACKGROUND and COLOR_INDEX_DEFAULT_CURSOR:
+        0xffffffff, 0xff000000, 0xffffffff};
+
+    public final int[] mDefaultColors = new int[TextStyle.NUM_INDEXED_COLORS];
+
+    public TerminalColorScheme() {
+        reset();
+    }
+
+    private void reset() {
+        System.arraycopy(DEFAULT_COLORSCHEME, 0, mDefaultColors, 0, TextStyle.NUM_INDEXED_COLORS);
+    }
+
+    public void updateWith(Properties props) {
+        reset();
+        boolean cursorPropExists = false;
+        for (Map.Entry<Object, Object> entries : props.entrySet()) {
+            String key = (String) entries.getKey();
+            String value = (String) entries.getValue();
+            int colorIndex;
+
+            if (key.equals("foreground")) {
+                colorIndex = TextStyle.COLOR_INDEX_FOREGROUND;
+            } else if (key.equals("background")) {
+                colorIndex = TextStyle.COLOR_INDEX_BACKGROUND;
+            } else if (key.equals("cursor")) {
+                colorIndex = TextStyle.COLOR_INDEX_CURSOR;
+                cursorPropExists = true;
+            } else if (key.startsWith("color")) {
+                try {
+                    colorIndex = Integer.parseInt(key.substring(5));
+                } catch (NumberFormatException e) {
+                    throw new IllegalArgumentException("Invalid property: '" + key + "'");
+                }
+            } else {
+                throw new IllegalArgumentException("Invalid property: '" + key + "'");
+            }
+
+            int colorValue = TerminalColors.parse(value);
+            if (colorValue == 0)
+                throw new IllegalArgumentException("Property '" + key + "' has invalid color: '" + value + "'");
+
+            mDefaultColors[colorIndex] = colorValue;
+        }
+
+        if (!cursorPropExists)
+            setCursorColorForBackground();
+    }
+
+    /**
+     * If the "cursor" color is not set by user, we need to decide on the appropriate color that will
+     * be visible on the current terminal background. White will not be visible on light backgrounds
+     * and black won't be visible on dark backgrounds. So we find the perceived brightness of the
+     * background color and if its below the threshold (too dark), we use white cursor and if its
+     * above (too bright), we use black cursor.
+     */
+    public void setCursorColorForBackground() {
+        int backgroundColor = mDefaultColors[TextStyle.COLOR_INDEX_BACKGROUND];
+        int brightness = TerminalColors.getPerceivedBrightnessOfColor(backgroundColor);
+        if (brightness > 0) {
+            if (brightness < 130)
+                mDefaultColors[TextStyle.COLOR_INDEX_CURSOR] = 0xffffffff;
+            else
+                mDefaultColors[TextStyle.COLOR_INDEX_CURSOR] = 0xff000000;
+        }
+    }
+
+}

terminal-emulator/src/main/java/com/termux/terminal/TerminalColors.java

@@ -0,0 +1,96 @@
+package com.termux.terminal;
+
+import android.graphics.Color;
+
+/** Current terminal colors (if different from default). */
+public final class TerminalColors {
+
+    /** Static data - a bit ugly but ok for now. */
+    public static final TerminalColorScheme COLOR_SCHEME = new TerminalColorScheme();
+
+    /**
+     * The current terminal colors, which are normally set from the color theme, but may be set dynamically with the OSC
+     * 4 control sequence.
+     */
+    public final int[] mCurrentColors = new int[TextStyle.NUM_INDEXED_COLORS];
+
+    /** Create a new instance with default colors from the theme. */
+    public TerminalColors() {
+        reset();
+    }
+
+    /** Reset a particular indexed color with the default color from the color theme. */
+    public void reset(int index) {
+        mCurrentColors[index] = COLOR_SCHEME.mDefaultColors[index];
+    }
+
+    /** Reset all indexed colors with the default color from the color theme. */
+    public void reset() {
+        System.arraycopy(COLOR_SCHEME.mDefaultColors, 0, mCurrentColors, 0, TextStyle.NUM_INDEXED_COLORS);
+    }
+
+    /**
+     * Parse color according to http://manpages.ubuntu.com/manpages/intrepid/man3/XQueryColor.3.html
+     * <p/>
+     * Highest bit is set if successful, so return value is 0xFF${R}${G}${B}. Return 0 if failed.
+     */
+    static int parse(String c) {
+        try {
+            int skipInitial, skipBetween;
+            if (c.charAt(0) == '#') {
+                // #RGB, #RRGGBB, #RRRGGGBBB or #RRRRGGGGBBBB. Most significant bits.
+                skipInitial = 1;
+                skipBetween = 0;
+            } else if (c.startsWith("rgb:")) {
+                // rgb:<red>/<green>/<blue> where <red>, <green>, <blue> := h | hh | hhh | hhhh. Scaled.
+                skipInitial = 4;
+                skipBetween = 1;
+            } else {
+                return 0;
+            }
+            int charsForColors = c.length() - skipInitial - 2 * skipBetween;
+            if (charsForColors % 3 != 0) return 0; // Unequal lengths.
+            int componentLength = charsForColors / 3;
+            double mult = 255 / (Math.pow(2, componentLength * 4) - 1);
+
+            int currentPosition = skipInitial;
+            String rString = c.substring(currentPosition, currentPosition + componentLength);
+            currentPosition += componentLength + skipBetween;
+            String gString = c.substring(currentPosition, currentPosition + componentLength);
+            currentPosition += componentLength + skipBetween;
+            String bString = c.substring(currentPosition, currentPosition + componentLength);
+
+            int r = (int) (Integer.parseInt(rString, 16) * mult);
+            int g = (int) (Integer.parseInt(gString, 16) * mult);
+            int b = (int) (Integer.parseInt(bString, 16) * mult);
+            return 0xFF << 24 | r << 16 | g << 8 | b;
+        } catch (NumberFormatException | IndexOutOfBoundsException e) {
+            return 0;
+        }
+    }
+
+    /** Try parse a color from a text parameter and into a specified index. */
+    public void tryParseColor(int intoIndex, String textParameter) {
+        int c = parse(textParameter);
+        if (c != 0) mCurrentColors[intoIndex] = c;
+    }
+
+    /**
+     * Get the perceived brightness of the color based on its RGB components.
+     *
+     * https://www.nbdtech.com/Blog/archive/2008/04/27/Calculating-the-Perceived-Brightness-of-a-Color.aspx
+     * http://alienryderflex.com/hsp.html
+     *
+     * @param color The color code int.
+     * @return Returns value between 0-255.
+     */
+    public static int getPerceivedBrightnessOfColor(int color) {
+        return (int)
+            Math.floor(Math.sqrt(
+                Math.pow(Color.red(color), 2) * 0.241 +
+                    Math.pow(Color.green(color), 2) * 0.691 +
+                    Math.pow(Color.blue(color), 2) * 0.068
+            ));
+    }
+
+}

terminal-emulator/src/main/java/com/termux/terminal/TerminalOutput.java

@@ -0,0 +1,32 @@
+package com.termux.terminal;
+
+import java.nio.charset.StandardCharsets;
+
+/** A client which receives callbacks from events triggered by feeding input to a {@link TerminalEmulator}. */
+public abstract class TerminalOutput {
+
+    /** Write a string using the UTF-8 encoding to the terminal client. */
+    public final void write(String data) {
+        if (data == null) return;
+        byte[] bytes = data.getBytes(StandardCharsets.UTF_8);
+        write(bytes, 0, bytes.length);
+    }
+
+    /** Write bytes to the terminal client. */
+    public abstract void write(byte[] data, int offset, int count);
+
+    /** Notify the terminal client that the terminal title has changed. */
+    public abstract void titleChanged(String oldTitle, String newTitle);
+
+    /** Notify the terminal client that text should be copied to clipboard. */
+    public abstract void onCopyTextToClipboard(String text);
+
+    /** Notify the terminal client that text should be pasted from clipboard. */
+    public abstract void onPasteTextFromClipboard();
+
+    /** Notify the terminal client that a bell character (ASCII 7, bell, BEL, \a, ^G)) has been received. */
+    public abstract void onBell();
+
+    public abstract void onColorsChanged();
+
+}

terminal-emulator/src/main/java/com/termux/terminal/TerminalRow.java

@@ -0,0 +1,283 @@
+package com.termux.terminal;
+
+import java.util.Arrays;
+
+/**
+ * A row in a terminal, composed of a fixed number of cells.
+ * <p>
+ * The text in the row is stored in a char[] array, {@link #mText}, for quick access during rendering.
+ */
+public final class TerminalRow {
+
+    private static final float SPARE_CAPACITY_FACTOR = 1.5f;
+
+    /**
+     * Max combining characters that can exist in a column, that are separate from the base character
+     * itself. Any additional combining characters will be ignored and not added to the column.
+     *
+     * There does not seem to be limit in unicode standard for max number of combination characters
+     * that can be combined but such characters are primarily under 10.
+     *
+     * "Section 3.6 Combination" of unicode standard contains combining characters info.
+     * - https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf
+     * - https://en.wikipedia.org/wiki/Combining_character#Unicode_ranges
+     * - https://stackoverflow.com/questions/71237212/what-is-the-maximum-number-of-unicode-combined-characters-that-may-be-needed-to
+     *
+     * UAX15-D3 Stream-Safe Text Format limits to max 30 combining characters.
+     * > The value of 30 is chosen to be significantly beyond what is required for any linguistic or technical usage.
+     * > While it would have been feasible to chose a smaller number, this value provides a very wide margin,
+     * > yet is well within the buffer size limits of practical implementations.
+     * - https://unicode.org/reports/tr15/#Stream_Safe_Text_Format
+     * - https://stackoverflow.com/a/11983435/14686958
+     *
+     * We choose the value 15 because it should be enough for terminal based applications and keep
+     * the memory usage low for a terminal row, won't affect performance or cause terminal to
+     * lag or hang, and will keep malicious applications from causing harm. The value can be
+     * increased if ever needed for legitimate applications.
+     */
+    private static final int MAX_COMBINING_CHARACTERS_PER_COLUMN = 15;
+
+    /** The number of columns in this terminal row. */
+    private final int mColumns;
+    /** The text filling this terminal row. */
+    public char[] mText;
+    /** The number of java chars used in {@link #mText}. */
+    private short mSpaceUsed;
+    /** If this row has been line wrapped due to text output at the end of line. */
+    boolean mLineWrap;
+    /** The style bits of each cell in the row. See {@link TextStyle}. */
+    final long[] mStyle;
+    /** If this row might contain chars with width != 1, used for deactivating fast path */
+    boolean mHasNonOneWidthOrSurrogateChars;
+
+    /** Construct a blank row (containing only whitespace, ' ') with a specified style. */
+    public TerminalRow(int columns, long style) {
+        mColumns = columns;
+        mText = new char[(int) (SPARE_CAPACITY_FACTOR * columns)];
+        mStyle = new long[columns];
+        clear(style);
+    }
+
+    /** NOTE: The sourceX2 is exclusive. */
+    public void copyInterval(TerminalRow line, int sourceX1, int sourceX2, int destinationX) {
+        mHasNonOneWidthOrSurrogateChars |= line.mHasNonOneWidthOrSurrogateChars;
+        final int x1 = line.findStartOfColumn(sourceX1);
+        final int x2 = line.findStartOfColumn(sourceX2);
+        boolean startingFromSecondHalfOfWideChar = (sourceX1 > 0 && line.wideDisplayCharacterStartingAt(sourceX1 - 1));
+        final char[] sourceChars = (this == line) ? Arrays.copyOf(line.mText, line.mText.length) : line.mText;
+        int latestNonCombiningWidth = 0;
+        for (int i = x1; i < x2; i++) {
+            char sourceChar = sourceChars[i];
+            int codePoint = Character.isHighSurrogate(sourceChar) ? Character.toCodePoint(sourceChar, sourceChars[++i]) : sourceChar;
+            if (startingFromSecondHalfOfWideChar) {
+                // Just treat copying second half of wide char as copying whitespace.
+                codePoint = ' ';
+                startingFromSecondHalfOfWideChar = false;
+            }
+            int w = WcWidth.width(codePoint);
+            if (w > 0) {
+                destinationX += latestNonCombiningWidth;
+                sourceX1 += latestNonCombiningWidth;
+                latestNonCombiningWidth = w;
+            }
+            setChar(destinationX, codePoint, line.getStyle(sourceX1));
+        }
+    }
+
+    public int getSpaceUsed() {
+        return mSpaceUsed;
+    }
+
+    /** Note that the column may end of second half of wide character. */
+    public int findStartOfColumn(int column) {
+        if (column == mColumns) return getSpaceUsed();
+
+        int currentColumn = 0;
+        int currentCharIndex = 0;
+        while (true) { // 0<2 1 < 2
+            int newCharIndex = currentCharIndex;
+            char c = mText[newCharIndex++]; // cci=1, cci=2
+            boolean isHigh = Character.isHighSurrogate(c);
+            int codePoint = isHigh ? Character.toCodePoint(c, mText[newCharIndex++]) : c;
+            int wcwidth = WcWidth.width(codePoint); // 1, 2
+            if (wcwidth > 0) {
+                currentColumn += wcwidth;
+                if (currentColumn == column) {
+                    while (newCharIndex < mSpaceUsed) {
+                        // Skip combining chars.
+                        if (Character.isHighSurrogate(mText[newCharIndex])) {
+                            if (WcWidth.width(Character.toCodePoint(mText[newCharIndex], mText[newCharIndex + 1])) <= 0) {
+                                newCharIndex += 2;
+                            } else {
+                                break;
+                            }
+                        } else if (WcWidth.width(mText[newCharIndex]) <= 0) {
+                            newCharIndex++;
+                        } else {
+                            break;
+                        }
+                    }
+                    return newCharIndex;
+                } else if (currentColumn > column) {
+                    // Wide column going past end.
+                    return currentCharIndex;
+                }
+            }
+            currentCharIndex = newCharIndex;
+        }
+    }
+
+    private boolean wideDisplayCharacterStartingAt(int column) {
+        for (int currentCharIndex = 0, currentColumn = 0; currentCharIndex < mSpaceUsed; ) {
+            char c = mText[currentCharIndex++];
+            int codePoint = Character.isHighSurrogate(c) ? Character.toCodePoint(c, mText[currentCharIndex++]) : c;
+            int wcwidth = WcWidth.width(codePoint);
+            if (wcwidth > 0) {
+                if (currentColumn == column && wcwidth == 2) return true;
+                currentColumn += wcwidth;
+                if (currentColumn > column) return false;
+            }
+        }
+        return false;
+    }
+
+    public void clear(long style) {
+        Arrays.fill(mText, ' ');
+        Arrays.fill(mStyle, style);
+        mSpaceUsed = (short) mColumns;
+        mHasNonOneWidthOrSurrogateChars = false;
+    }
+
+    // https://github.com/steven676/Android-Terminal-Emulator/commit/9a47042620bec87617f0b4f5d50568535668fe26
+    public void setChar(int columnToSet, int codePoint, long style) {
+        if (columnToSet  < 0 || columnToSet >= mStyle.length)
+            throw new IllegalArgumentException("TerminalRow.setChar(): columnToSet=" + columnToSet + ", codePoint=" + codePoint + ", style=" + style);
+
+        mStyle[columnToSet] = style;
+
+        final int newCodePointDisplayWidth = WcWidth.width(codePoint);
+
+        // Fast path when we don't have any chars with width != 1
+        if (!mHasNonOneWidthOrSurrogateChars) {
+            if (codePoint >= Character.MIN_SUPPLEMENTARY_CODE_POINT || newCodePointDisplayWidth != 1) {
+                mHasNonOneWidthOrSurrogateChars = true;
+            } else {
+                mText[columnToSet] = (char) codePoint;
+                return;
+            }
+        }
+
+        final boolean newIsCombining = newCodePointDisplayWidth <= 0;
+
+        boolean wasExtraColForWideChar = (columnToSet > 0) && wideDisplayCharacterStartingAt(columnToSet - 1);
+
+        if (newIsCombining) {
+            // When standing at second half of wide character and inserting combining:
+            if (wasExtraColForWideChar) columnToSet--;
+        } else {
+            // Check if we are overwriting the second half of a wide character starting at the previous column:
+            if (wasExtraColForWideChar) setChar(columnToSet - 1, ' ', style);
+            // Check if we are overwriting the first half of a wide character starting at the next column:
+            boolean overwritingWideCharInNextColumn = newCodePointDisplayWidth == 2 && wideDisplayCharacterStartingAt(columnToSet + 1);
+            if (overwritingWideCharInNextColumn) setChar(columnToSet + 1, ' ', style);
+        }
+
+        char[] text = mText;
+        final int oldStartOfColumnIndex = findStartOfColumn(columnToSet);
+        final int oldCodePointDisplayWidth = WcWidth.width(text, oldStartOfColumnIndex);
+
+        // Get the number of elements in the mText array this column uses now
+        int oldCharactersUsedForColumn;
+        if (columnToSet + oldCodePointDisplayWidth < mColumns) {
+            int oldEndOfColumnIndex = findStartOfColumn(columnToSet + oldCodePointDisplayWidth);
+            oldCharactersUsedForColumn = oldEndOfColumnIndex - oldStartOfColumnIndex;
+        } else {
+            // Last character.
+            oldCharactersUsedForColumn = mSpaceUsed - oldStartOfColumnIndex;
+        }
+
+        // If MAX_COMBINING_CHARACTERS_PER_COLUMN already exist in column, then ignore adding additional combining characters.
+        if (newIsCombining) {
+            int combiningCharsCount = WcWidth.zeroWidthCharsCount(mText, oldStartOfColumnIndex, oldStartOfColumnIndex + oldCharactersUsedForColumn);
+            if (combiningCharsCount >= MAX_COMBINING_CHARACTERS_PER_COLUMN)
+                return;
+        }
+
+        // Find how many chars this column will need
+        int newCharactersUsedForColumn = Character.charCount(codePoint);
+        if (newIsCombining) {
+            // Combining characters are added to the contents of the column instead of overwriting them, so that they
+            // modify the existing contents.
+            // FIXME: Unassigned characters also get width=0.
+            newCharactersUsedForColumn += oldCharactersUsedForColumn;
+        }
+
+        int oldNextColumnIndex = oldStartOfColumnIndex + oldCharactersUsedForColumn;
+        int newNextColumnIndex = oldStartOfColumnIndex + newCharactersUsedForColumn;
+
+        final int javaCharDifference = newCharactersUsedForColumn - oldCharactersUsedForColumn;
+        if (javaCharDifference > 0) {
+            // Shift the rest of the line right.
+            int oldCharactersAfterColumn = mSpaceUsed - oldNextColumnIndex;
+            if (mSpaceUsed + javaCharDifference > text.length) {
+                // We need to grow the array
+                char[] newText = new char[text.length + mColumns];
+                System.arraycopy(text, 0, newText, 0, oldNextColumnIndex);
+                System.arraycopy(text, oldNextColumnIndex, newText, newNextColumnIndex, oldCharactersAfterColumn);
+                mText = text = newText;
+            } else {
+                System.arraycopy(text, oldNextColumnIndex, text, newNextColumnIndex, oldCharactersAfterColumn);
+            }
+        } else if (javaCharDifference < 0) {
+            // Shift the rest of the line left.
+            System.arraycopy(text, oldNextColumnIndex, text, newNextColumnIndex, mSpaceUsed - oldNextColumnIndex);
+        }
+        mSpaceUsed += javaCharDifference;
+
+        // Store char. A combining character is stored at the end of the existing contents so that it modifies them:
+        //noinspection ResultOfMethodCallIgnored - since we already now how many java chars is used.
+        Character.toChars(codePoint, text, oldStartOfColumnIndex + (newIsCombining ? oldCharactersUsedForColumn : 0));
+
+        if (oldCodePointDisplayWidth == 2 && newCodePointDisplayWidth == 1) {
+            // Replace second half of wide char with a space. Which mean that we actually add a ' ' java character.
+            if (mSpaceUsed + 1 > text.length) {
+                char[] newText = new char[text.length + mColumns];
+                System.arraycopy(text, 0, newText, 0, newNextColumnIndex);
+                System.arraycopy(text, newNextColumnIndex, newText, newNextColumnIndex + 1, mSpaceUsed - newNextColumnIndex);
+                mText = text = newText;
+            } else {
+                System.arraycopy(text, newNextColumnIndex, text, newNextColumnIndex + 1, mSpaceUsed - newNextColumnIndex);
+            }
+            text[newNextColumnIndex] = ' ';
+
+            ++mSpaceUsed;
+        } else if (oldCodePointDisplayWidth == 1 && newCodePointDisplayWidth == 2) {
+            if (columnToSet == mColumns - 1) {
+                throw new IllegalArgumentException("Cannot put wide character in last column");
+            } else if (columnToSet == mColumns - 2) {
+                // Truncate the line to the second part of this wide char:
+                mSpaceUsed = (short) newNextColumnIndex;
+            } else {
+                // Overwrite the contents of the next column, which mean we actually remove java characters. Due to the
+                // check at the beginning of this method we know that we are not overwriting a wide char.
+                int newNextNextColumnIndex = newNextColumnIndex + (Character.isHighSurrogate(mText[newNextColumnIndex]) ? 2 : 1);
+                int nextLen = newNextNextColumnIndex - newNextColumnIndex;
+
+                // Shift the array leftwards.
+                System.arraycopy(text, newNextNextColumnIndex, text, newNextColumnIndex, mSpaceUsed - newNextNextColumnIndex);
+                mSpaceUsed -= nextLen;
+            }
+        }
+    }
+
+    boolean isBlank() {
+        for (int charIndex = 0, charLen = getSpaceUsed(); charIndex < charLen; charIndex++)
+            if (mText[charIndex] != ' ') return false;
+        return true;
+    }
+
+    public final long getStyle(int column) {
+        return mStyle[column];
+    }
+
+}

terminal-emulator/src/main/java/com/termux/terminal/TerminalSession.java

@@ -0,0 +1,372 @@
+package com.termux.terminal;
+
+import android.annotation.SuppressLint;
+import android.os.Handler;
+import android.os.Message;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.OsConstants;
+
+import java.io.File;
+import java.io.FileDescriptor;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.lang.reflect.Field;
+import java.nio.charset.StandardCharsets;
+import java.util.UUID;
+
+/**
+ * A terminal session, consisting of a process coupled to a terminal interface.
+ * <p>
+ * The subprocess will be executed by the constructor, and when the size is made known by a call to
+ * {@link #updateSize(int, int, int, int)} terminal emulation will begin and threads will be spawned to handle the subprocess I/O.
+ * All terminal emulation and callback methods will be performed on the main thread.
+ * <p>
+ * The child process may be exited forcefully by using the {@link #finishIfRunning()} method.
+ * <p>
+ * NOTE: The terminal session may outlive the EmulatorView, so be careful with callbacks!
+ */
+public final class TerminalSession extends TerminalOutput {
+
+    private static final int MSG_NEW_INPUT = 1;
+    private static final int MSG_PROCESS_EXITED = 4;
+
+    public final String mHandle = UUID.randomUUID().toString();
+
+    TerminalEmulator mEmulator;
+
+    /**
+     * A queue written to from a separate thread when the process outputs, and read by main thread to process by
+     * terminal emulator.
+     */
+    final ByteQueue mProcessToTerminalIOQueue = new ByteQueue(4096);
+    /**
+     * A queue written to from the main thread due to user interaction, and read by another thread which forwards by
+     * writing to the {@link #mTerminalFileDescriptor}.
+     */
+    final ByteQueue mTerminalToProcessIOQueue = new ByteQueue(4096);
+    /** Buffer to write translate code points into utf8 before writing to mTerminalToProcessIOQueue */
+    private final byte[] mUtf8InputBuffer = new byte[5];
+
+    /** Callback which gets notified when a session finishes or changes title. */
+    TerminalSessionClient mClient;
+
+    /** The pid of the shell process. 0 if not started and -1 if finished running. */
+    int mShellPid;
+
+    /** The exit status of the shell process. Only valid if ${@link #mShellPid} is -1. */
+    int mShellExitStatus;
+
+    /**
+     * The file descriptor referencing the master half of a pseudo-terminal pair, resulting from calling
+     * {@link JNI#createSubprocess(String, String, String[], String[], int[], int, int, int, int)}.
+     */
+    private int mTerminalFileDescriptor;
+
+    /** Set by the application for user identification of session, not by terminal. */
+    public String mSessionName;
+
+    final Handler mMainThreadHandler = new MainThreadHandler();
+
+    private final String mShellPath;
+    private final String mCwd;
+    private final String[] mArgs;
+    private final String[] mEnv;
+    private final Integer mTranscriptRows;
+
+
+    private static final String LOG_TAG = "TerminalSession";
+
+    public TerminalSession(String shellPath, String cwd, String[] args, String[] env, Integer transcriptRows, TerminalSessionClient client) {
+        this.mShellPath = shellPath;
+        this.mCwd = cwd;
+        this.mArgs = args;
+        this.mEnv = env;
+        this.mTranscriptRows = transcriptRows;
+        this.mClient = client;
+    }
+
+    /**
+     * @param client The {@link TerminalSessionClient} interface implementation to allow
+     *               for communication between {@link TerminalSession} and its client.
+     */
+    public void updateTerminalSessionClient(TerminalSessionClient client) {
+        mClient = client;
+
+        if (mEmulator != null)
+            mEmulator.updateTerminalSessionClient(client);
+    }
+
+    /** Inform the attached pty of the new size and reflow or initialize the emulator. */
+    public void updateSize(int columns, int rows, int cellWidthPixels, int cellHeightPixels) {
+        if (mEmulator == null) {
+            initializeEmulator(columns, rows, cellWidthPixels, cellHeightPixels);
+        } else {
+            JNI.setPtyWindowSize(mTerminalFileDescriptor, rows, columns, cellWidthPixels, cellHeightPixels);
+            mEmulator.resize(columns, rows, cellWidthPixels, cellHeightPixels);
+        }
+    }
+
+    /** The terminal title as set through escape sequences or null if none set. */
+    public String getTitle() {
+        return (mEmulator == null) ? null : mEmulator.getTitle();
+    }
+
+    /**
+     * Set the terminal emulator's window size and start terminal emulation.
+     *
+     * @param columns The number of columns in the terminal window.
+     * @param rows    The number of rows in the terminal window.
+     */
+    public void initializeEmulator(int columns, int rows, int cellWidthPixels, int cellHeightPixels) {
+        mEmulator = new TerminalEmulator(this, columns, rows, cellWidthPixels, cellHeightPixels, mTranscriptRows, mClient);
+
+        int[] processId = new int[1];
+        mTerminalFileDescriptor = JNI.createSubprocess(mShellPath, mCwd, mArgs, mEnv, processId, rows, columns, cellWidthPixels, cellHeightPixels);
+        mShellPid = processId[0];
+
+        final FileDescriptor terminalFileDescriptorWrapped = wrapFileDescriptor(mTerminalFileDescriptor, mClient);
+
+        new Thread("TermSessionInputReader[pid=" + mShellPid + "]") {
+            @Override
+            public void run() {
+                try (InputStream termIn = new FileInputStream(terminalFileDescriptorWrapped)) {
+                    final byte[] buffer = new byte[4096];
+                    while (true) {
+                        int read = termIn.read(buffer);
+                        if (read == -1) return;
+                        if (!mProcessToTerminalIOQueue.write(buffer, 0, read)) return;
+                        mMainThreadHandler.sendEmptyMessage(MSG_NEW_INPUT);
+                    }
+                } catch (Exception e) {
+                    // Ignore, just shutting down.
+                }
+            }
+        }.start();
+
+        new Thread("TermSessionOutputWriter[pid=" + mShellPid + "]") {
+            @Override
+            public void run() {
+                final byte[] buffer = new byte[4096];
+                try (FileOutputStream termOut = new FileOutputStream(terminalFileDescriptorWrapped)) {
+                    while (true) {
+                        int bytesToWrite = mTerminalToProcessIOQueue.read(buffer, true);
+                        if (bytesToWrite == -1) return;
+                        termOut.write(buffer, 0, bytesToWrite);
+                    }
+                } catch (IOException e) {
+                    // Ignore.
+                }
+            }
+        }.start();
+
+        new Thread("TermSessionWaiter[pid=" + mShellPid + "]") {
+            @Override
+            public void run() {
+                int processExitCode = JNI.waitFor(mShellPid);
+                mMainThreadHandler.sendMessage(mMainThreadHandler.obtainMessage(MSG_PROCESS_EXITED, processExitCode));
+            }
+        }.start();
+
+    }
+
+    /** Write data to the shell process. */
+    @Override
+    public void write(byte[] data, int offset, int count) {
+        if (mShellPid > 0) mTerminalToProcessIOQueue.write(data, offset, count);
+    }
+
+    /** Write the Unicode code point to the terminal encoded in UTF-8. */
+    public void writeCodePoint(boolean prependEscape, int codePoint) {
+        if (codePoint > 1114111 || (codePoint >= 0xD800 && codePoint <= 0xDFFF)) {
+            // 1114111 (= 2**16 + 1024**2 - 1) is the highest code point, [0xD800,0xDFFF] is the surrogate range.
+            throw new IllegalArgumentException("Invalid code point: " + codePoint);
+        }
+
+        int bufferPosition = 0;
+        if (prependEscape) mUtf8InputBuffer[bufferPosition++] = 27;
+
+        if (codePoint <= /* 7 bits */0b1111111) {
+            mUtf8InputBuffer[bufferPosition++] = (byte) codePoint;
+        } else if (codePoint <= /* 11 bits */0b11111111111) {
+            /* 110xxxxx leading byte with leading 5 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b11000000 | (codePoint >> 6));
+            /* 10xxxxxx continuation byte with following 6 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b10000000 | (codePoint & 0b111111));
+        } else if (codePoint <= /* 16 bits */0b1111111111111111) {
+            /* 1110xxxx leading byte with leading 4 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b11100000 | (codePoint >> 12));
+            /* 10xxxxxx continuation byte with following 6 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b10000000 | ((codePoint >> 6) & 0b111111));
+            /* 10xxxxxx continuation byte with following 6 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b10000000 | (codePoint & 0b111111));
+        } else { /* We have checked codePoint <= 1114111 above, so we have max 21 bits = 0b111111111111111111111 */
+            /* 11110xxx leading byte with leading 3 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b11110000 | (codePoint >> 18));
+            /* 10xxxxxx continuation byte with following 6 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b10000000 | ((codePoint >> 12) & 0b111111));
+            /* 10xxxxxx continuation byte with following 6 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b10000000 | ((codePoint >> 6) & 0b111111));
+            /* 10xxxxxx continuation byte with following 6 bits */
+            mUtf8InputBuffer[bufferPosition++] = (byte) (0b10000000 | (codePoint & 0b111111));
+        }
+        write(mUtf8InputBuffer, 0, bufferPosition);
+    }
+
+    public TerminalEmulator getEmulator() {
+        return mEmulator;
+    }
+
+    /** Notify the {@link #mClient} that the screen has changed. */
+    protected void notifyScreenUpdate() {
+        mClient.onTextChanged(this);
+    }
+
+    /** Reset state for terminal emulator state. */
+    public void reset() {
+        mEmulator.reset();
+        notifyScreenUpdate();
+    }
+
+    /** Finish this terminal session by sending SIGKILL to the shell. */
+    public void finishIfRunning() {
+        if (isRunning()) {
+            try {
+                Os.kill(mShellPid, OsConstants.SIGKILL);
+            } catch (ErrnoException e) {
+                Logger.logWarn(mClient, LOG_TAG, "Failed sending SIGKILL: " + e.getMessage());
+            }
+        }
+    }
+
+    /** Cleanup resources when the process exits. */
+    void cleanupResources(int exitStatus) {
+        synchronized (this) {
+            mShellPid = -1;
+            mShellExitStatus = exitStatus;
+        }
+
+        // Stop the reader and writer threads, and close the I/O streams
+        mTerminalToProcessIOQueue.close();
+        mProcessToTerminalIOQueue.close();
+        JNI.close(mTerminalFileDescriptor);
+    }
+
+    @Override
+    public void titleChanged(String oldTitle, String newTitle) {
+        mClient.onTitleChanged(this);
+    }
+
+    public synchronized boolean isRunning() {
+        return mShellPid != -1;
+    }
+
+    /** Only valid if not {@link #isRunning()}. */
+    public synchronized int getExitStatus() {
+        return mShellExitStatus;
+    }
+
+    @Override
+    public void onCopyTextToClipboard(String text) {
+        mClient.onCopyTextToClipboard(this, text);
+    }
+
+    @Override
+    public void onPasteTextFromClipboard() {
+        mClient.onPasteTextFromClipboard(this);
+    }
+
+    @Override
+    public void onBell() {
+        mClient.onBell(this);
+    }
+
+    @Override
+    public void onColorsChanged() {
+        mClient.onColorsChanged(this);
+    }
+
+    public int getPid() {
+        return mShellPid;
+    }
+
+    /** Returns the shell's working directory or null if it was unavailable. */
+    public String getCwd() {
+        if (mShellPid < 1) {
+            return null;
+        }
+        try {
+            final String cwdSymlink = String.format("/proc/%s/cwd/", mShellPid);
+            String outputPath = new File(cwdSymlink).getCanonicalPath();
+            String outputPathWithTrailingSlash = outputPath;
+            if (!outputPath.endsWith("/")) {
+                outputPathWithTrailingSlash += '/';
+            }
+            if (!cwdSymlink.equals(outputPathWithTrailingSlash)) {
+                return outputPath;
+            }
+        } catch (IOException | SecurityException e) {
+            Logger.logStackTraceWithMessage(mClient, LOG_TAG, "Error getting current directory", e);
+        }
+        return null;
+    }
+
+    private static FileDescriptor wrapFileDescriptor(int fileDescriptor, TerminalSessionClient client) {
+        FileDescriptor result = new FileDescriptor();
+        try {
+            Field descriptorField;
+            try {
+                descriptorField = FileDescriptor.class.getDeclaredField("descriptor");
+            } catch (NoSuchFieldException e) {
+                // For desktop java:
+                descriptorField = FileDescriptor.class.getDeclaredField("fd");
+            }
+            descriptorField.setAccessible(true);
+            descriptorField.set(result, fileDescriptor);
+        } catch (NoSuchFieldException | IllegalAccessException | IllegalArgumentException e) {
+            Logger.logStackTraceWithMessage(client, LOG_TAG, "Error accessing FileDescriptor#descriptor private field", e);
+            System.exit(1);
+        }
+        return result;
+    }
+
+    @SuppressLint("HandlerLeak")
+    class MainThreadHandler extends Handler {
+
+        final byte[] mReceiveBuffer = new byte[4 * 1024];
+
+        @Override
+        public void handleMessage(Message msg) {
+            int bytesRead = mProcessToTerminalIOQueue.read(mReceiveBuffer, false);
+            if (bytesRead > 0) {
+                mEmulator.append(mReceiveBuffer, bytesRead);
+                notifyScreenUpdate();
+            }
+
+            if (msg.what == MSG_PROCESS_EXITED) {
+                int exitCode = (Integer) msg.obj;
+                cleanupResources(exitCode);
+
+                String exitDescription = "\r\n[Process completed";
+                if (exitCode > 0) {
+                    // Non-zero process exit.
+                    exitDescription += " (code " + exitCode + ")";
+                } else if (exitCode < 0) {
+                    // Negated signal.
+                    exitDescription += " (signal " + (-exitCode) + ")";
+                }
+                exitDescription += " - press Enter]";
+
+                byte[] bytesToWrite = exitDescription.getBytes(StandardCharsets.UTF_8);
+                mEmulator.append(bytesToWrite, bytesToWrite.length);
+                notifyScreenUpdate();
+
+                mClient.onSessionFinished(TerminalSession.this);
+            }
+        }
+
+    }
+
+}

terminal-emulator/src/main/java/com/termux/terminal/TerminalSessionClient.java

@@ -0,0 +1,46 @@
+package com.termux.terminal;
+
+/**
+ * The interface for communication between {@link TerminalSession} and its client. It is used to
+ * send callbacks to the client when {@link TerminalSession} changes or for sending other
+ * back data to the client like logs.
+ */
+public interface TerminalSessionClient {
+
+    void onTextChanged(TerminalSession changedSession);
+
+    void onTitleChanged(TerminalSession changedSession);
+
+    void onSessionFinished(TerminalSession finishedSession);
+
+    void onCopyTextToClipboard(TerminalSession session, String text);
+
+    void onPasteTextFromClipboard(TerminalSession session);
+
+    void onBell(TerminalSession session);
+
+    void onColorsChanged(TerminalSession session);
+
+    void onTerminalCursorStateChange(boolean state);
+
+
+
+    Integer getTerminalCursorStyle();
+
+
+
+    void logError(String tag, String message);
+
+    void logWarn(String tag, String message);
+
+    void logInfo(String tag, String message);
+
+    void logDebug(String tag, String message);
+
+    void logVerbose(String tag, String message);
+
+    void logStackTraceWithMessage(String tag, String message, Exception e);
+
+    void logStackTrace(String tag, Exception e);
+
+}

terminal-emulator/src/main/java/com/termux/terminal/TextStyle.java

@@ -0,0 +1,90 @@
+package com.termux.terminal;
+
+/**
+ * <p>
+ * Encodes effects, foreground and background colors into a 64 bit long, which are stored for each cell in a terminal
+ * row in {@link TerminalRow#mStyle}.
+ * </p>
+ * <p>
+ * The bit layout is:
+ * </p>
+ * - 16 flags (11 currently used).
+ * - 24 for foreground color (only 9 first bits if a color index).
+ * - 24 for background color (only 9 first bits if a color index).
+ */
+public final class TextStyle {
+
+    public final static int CHARACTER_ATTRIBUTE_BOLD = 1;
+    public final static int CHARACTER_ATTRIBUTE_ITALIC = 1 << 1;
+    public final static int CHARACTER_ATTRIBUTE_UNDERLINE = 1 << 2;
+    public final static int CHARACTER_ATTRIBUTE_BLINK = 1 << 3;
+    public final static int CHARACTER_ATTRIBUTE_INVERSE = 1 << 4;
+    public final static int CHARACTER_ATTRIBUTE_INVISIBLE = 1 << 5;
+    public final static int CHARACTER_ATTRIBUTE_STRIKETHROUGH = 1 << 6;
+    /**
+     * The selective erase control functions (DECSED and DECSEL) can only erase characters defined as erasable.
+     * <p>
+     * This bit is set if DECSCA (Select Character Protection Attribute) has been used to define the characters that
+     * come after it as erasable from the screen.
+     * </p>
+     */
+    public final static int CHARACTER_ATTRIBUTE_PROTECTED = 1 << 7;
+    /** Dim colors. Also known as faint or half intensity. */
+    public final static int CHARACTER_ATTRIBUTE_DIM = 1 << 8;
+    /** If true (24-bit) color is used for the cell for foreground. */
+    private final static int CHARACTER_ATTRIBUTE_TRUECOLOR_FOREGROUND = 1 << 9;
+    /** If true (24-bit) color is used for the cell for foreground. */
+    private final static int CHARACTER_ATTRIBUTE_TRUECOLOR_BACKGROUND= 1 << 10;
+
+    public final static int COLOR_INDEX_FOREGROUND = 256;
+    public final static int COLOR_INDEX_BACKGROUND = 257;
+    public final static int COLOR_INDEX_CURSOR = 258;
+
+    /** The 256 standard color entries and the three special (foreground, background and cursor) ones. */
+    public final static int NUM_INDEXED_COLORS = 259;
+
+    /** Normal foreground and background colors and no effects. */
+    final static long NORMAL = encode(COLOR_INDEX_FOREGROUND, COLOR_INDEX_BACKGROUND, 0);
+
+    static long encode(int foreColor, int backColor, int effect) {
+        long result = effect & 0b111111111;
+        if ((0xff000000 & foreColor) == 0xff000000) {
+            // 24-bit color.
+            result |= CHARACTER_ATTRIBUTE_TRUECOLOR_FOREGROUND | ((foreColor & 0x00ffffffL) << 40L);
+        } else {
+            // Indexed color.
+            result |= (foreColor & 0b111111111L) << 40;
+        }
+        if ((0xff000000 & backColor) == 0xff000000) {
+            // 24-bit color.
+            result |= CHARACTER_ATTRIBUTE_TRUECOLOR_BACKGROUND | ((backColor & 0x00ffffffL) << 16L);
+        } else {
+            // Indexed color.
+            result |= (backColor & 0b111111111L) << 16L;
+        }
+
+        return result;
+    }
+
+    public static int decodeForeColor(long style) {
+        if ((style & CHARACTER_ATTRIBUTE_TRUECOLOR_FOREGROUND) == 0) {
+            return (int) ((style >>> 40) & 0b111111111L);
+        } else {
+            return 0xff000000 | (int) ((style >>> 40) & 0x00ffffffL);
+        }
+
+    }
+
+    public static int decodeBackColor(long style) {
+        if ((style & CHARACTER_ATTRIBUTE_TRUECOLOR_BACKGROUND) == 0) {
+            return (int) ((style >>> 16) & 0b111111111L);
+        } else {
+            return 0xff000000 | (int) ((style >>> 16) & 0x00ffffffL);
+        }
+    }
+
+    public static int decodeEffect(long style) {
+        return (int) (style & 0b11111111111);
+    }
+
+}

terminal-emulator/src/main/java/com/termux/terminal/WcWidth.java

@@ -0,0 +1,566 @@
+package com.termux.terminal;
+
+/**
+ * Implementation of wcwidth(3) for Unicode 15.
+ *
+ * Implementation from https://github.com/jquast/wcwidth but we return 0 for unprintable characters.
+ *
+ * IMPORTANT:
+ * Must be kept in sync with the following:
+ * https://github.com/termux/wcwidth
+ * https://github.com/termux/libandroid-support
+ * https://github.com/termux/termux-packages/tree/master/packages/libandroid-support
+ */
+public final class WcWidth {
+
+    // From https://github.com/jquast/wcwidth/blob/master/wcwidth/table_zero.py
+    // from https://github.com/jquast/wcwidth/pull/64
+    // at commit 1b9b6585b0080ea5cb88dc9815796505724793fe (2022-12-16):
+    private static final int[][] ZERO_WIDTH = {
+        {0x00300, 0x0036f},  // Combining Grave Accent  ..Combining Latin Small Le
+        {0x00483, 0x00489},  // Combining Cyrillic Titlo..Combining Cyrillic Milli
+        {0x00591, 0x005bd},  // Hebrew Accent Etnahta   ..Hebrew Point Meteg
+        {0x005bf, 0x005bf},  // Hebrew Point Rafe       ..Hebrew Point Rafe
+        {0x005c1, 0x005c2},  // Hebrew Point Shin Dot   ..Hebrew Point Sin Dot
+        {0x005c4, 0x005c5},  // Hebrew Mark Upper Dot   ..Hebrew Mark Lower Dot
+        {0x005c7, 0x005c7},  // Hebrew Point Qamats Qata..Hebrew Point Qamats Qata
+        {0x00610, 0x0061a},  // Arabic Sign Sallallahou ..Arabic Small Kasra
+        {0x0064b, 0x0065f},  // Arabic Fathatan         ..Arabic Wavy Hamza Below
+        {0x00670, 0x00670},  // Arabic Letter Superscrip..Arabic Letter Superscrip
+        {0x006d6, 0x006dc},  // Arabic Small High Ligatu..Arabic Small High Seen
+        {0x006df, 0x006e4},  // Arabic Small High Rounde..Arabic Small High Madda
+        {0x006e7, 0x006e8},  // Arabic Small High Yeh   ..Arabic Small High Noon
+        {0x006ea, 0x006ed},  // Arabic Empty Centre Low ..Arabic Small Low Meem
+        {0x00711, 0x00711},  // Syriac Letter Superscrip..Syriac Letter Superscrip
+        {0x00730, 0x0074a},  // Syriac Pthaha Above     ..Syriac Barrekh
+        {0x007a6, 0x007b0},  // Thaana Abafili          ..Thaana Sukun
+        {0x007eb, 0x007f3},  // Nko Combining Short High..Nko Combining Double Dot
+        {0x007fd, 0x007fd},  // Nko Dantayalan          ..Nko Dantayalan
+        {0x00816, 0x00819},  // Samaritan Mark In       ..Samaritan Mark Dagesh
+        {0x0081b, 0x00823},  // Samaritan Mark Epentheti..Samaritan Vowel Sign A
+        {0x00825, 0x00827},  // Samaritan Vowel Sign Sho..Samaritan Vowel Sign U
+        {0x00829, 0x0082d},  // Samaritan Vowel Sign Lon..Samaritan Mark Nequdaa
+        {0x00859, 0x0085b},  // Mandaic Affrication Mark..Mandaic Gemination Mark
+        {0x00898, 0x0089f},  // Arabic Small High Word A..Arabic Half Madda Over M
+        {0x008ca, 0x008e1},  // Arabic Small High Farsi ..Arabic Small High Sign S
+        {0x008e3, 0x00902},  // Arabic Turned Damma Belo..Devanagari Sign Anusvara
+        {0x0093a, 0x0093a},  // Devanagari Vowel Sign Oe..Devanagari Vowel Sign Oe
+        {0x0093c, 0x0093c},  // Devanagari Sign Nukta   ..Devanagari Sign Nukta
+        {0x00941, 0x00948},  // Devanagari Vowel Sign U ..Devanagari Vowel Sign Ai
+        {0x0094d, 0x0094d},  // Devanagari Sign Virama  ..Devanagari Sign Virama
+        {0x00951, 0x00957},  // Devanagari Stress Sign U..Devanagari Vowel Sign Uu
+        {0x00962, 0x00963},  // Devanagari Vowel Sign Vo..Devanagari Vowel Sign Vo
+        {0x00981, 0x00981},  // Bengali Sign Candrabindu..Bengali Sign Candrabindu
+        {0x009bc, 0x009bc},  // Bengali Sign Nukta      ..Bengali Sign Nukta
+        {0x009c1, 0x009c4},  // Bengali Vowel Sign U    ..Bengali Vowel Sign Vocal
+        {0x009cd, 0x009cd},  // Bengali Sign Virama     ..Bengali Sign Virama
+        {0x009e2, 0x009e3},  // Bengali Vowel Sign Vocal..Bengali Vowel Sign Vocal
+        {0x009fe, 0x009fe},  // Bengali Sandhi Mark     ..Bengali Sandhi Mark
+        {0x00a01, 0x00a02},  // Gurmukhi Sign Adak Bindi..Gurmukhi Sign Bindi
+        {0x00a3c, 0x00a3c},  // Gurmukhi Sign Nukta     ..Gurmukhi Sign Nukta
+        {0x00a41, 0x00a42},  // Gurmukhi Vowel Sign U   ..Gurmukhi Vowel Sign Uu
+        {0x00a47, 0x00a48},  // Gurmukhi Vowel Sign Ee  ..Gurmukhi Vowel Sign Ai
+        {0x00a4b, 0x00a4d},  // Gurmukhi Vowel Sign Oo  ..Gurmukhi Sign Virama
+        {0x00a51, 0x00a51},  // Gurmukhi Sign Udaat     ..Gurmukhi Sign Udaat
+        {0x00a70, 0x00a71},  // Gurmukhi Tippi          ..Gurmukhi Addak
+        {0x00a75, 0x00a75},  // Gurmukhi Sign Yakash    ..Gurmukhi Sign Yakash
+        {0x00a81, 0x00a82},  // Gujarati Sign Candrabind..Gujarati Sign Anusvara
+        {0x00abc, 0x00abc},  // Gujarati Sign Nukta     ..Gujarati Sign Nukta
+        {0x00ac1, 0x00ac5},  // Gujarati Vowel Sign U   ..Gujarati Vowel Sign Cand
+        {0x00ac7, 0x00ac8},  // Gujarati Vowel Sign E   ..Gujarati Vowel Sign Ai
+        {0x00acd, 0x00acd},  // Gujarati Sign Virama    ..Gujarati Sign Virama
+        {0x00ae2, 0x00ae3},  // Gujarati Vowel Sign Voca..Gujarati Vowel Sign Voca
+        {0x00afa, 0x00aff},  // Gujarati Sign Sukun     ..Gujarati Sign Two-circle
+        {0x00b01, 0x00b01},  // Oriya Sign Candrabindu  ..Oriya Sign Candrabindu
+        {0x00b3c, 0x00b3c},  // Oriya Sign Nukta        ..Oriya Sign Nukta
+        {0x00b3f, 0x00b3f},  // Oriya Vowel Sign I      ..Oriya Vowel Sign I
+        {0x00b41, 0x00b44},  // Oriya Vowel Sign U      ..Oriya Vowel Sign Vocalic
+        {0x00b4d, 0x00b4d},  // Oriya Sign Virama       ..Oriya Sign Virama
+        {0x00b55, 0x00b56},  // Oriya Sign Overline     ..Oriya Ai Length Mark
+        {0x00b62, 0x00b63},  // Oriya Vowel Sign Vocalic..Oriya Vowel Sign Vocalic
+        {0x00b82, 0x00b82},  // Tamil Sign Anusvara     ..Tamil Sign Anusvara
+        {0x00bc0, 0x00bc0},  // Tamil Vowel Sign Ii     ..Tamil Vowel Sign Ii
+        {0x00bcd, 0x00bcd},  // Tamil Sign Virama       ..Tamil Sign Virama
+        {0x00c00, 0x00c00},  // Telugu Sign Combining Ca..Telugu Sign Combining Ca
+        {0x00c04, 0x00c04},  // Telugu Sign Combining An..Telugu Sign Combining An
+        {0x00c3c, 0x00c3c},  // Telugu Sign Nukta       ..Telugu Sign Nukta
+        {0x00c3e, 0x00c40},  // Telugu Vowel Sign Aa    ..Telugu Vowel Sign Ii
+        {0x00c46, 0x00c48},  // Telugu Vowel Sign E     ..Telugu Vowel Sign Ai
+        {0x00c4a, 0x00c4d},  // Telugu Vowel Sign O     ..Telugu Sign Virama
+        {0x00c55, 0x00c56},  // Telugu Length Mark      ..Telugu Ai Length Mark
+        {0x00c62, 0x00c63},  // Telugu Vowel Sign Vocali..Telugu Vowel Sign Vocali
+        {0x00c81, 0x00c81},  // Kannada Sign Candrabindu..Kannada Sign Candrabindu
+        {0x00cbc, 0x00cbc},  // Kannada Sign Nukta      ..Kannada Sign Nukta
+        {0x00cbf, 0x00cbf},  // Kannada Vowel Sign I    ..Kannada Vowel Sign I
+        {0x00cc6, 0x00cc6},  // Kannada Vowel Sign E    ..Kannada Vowel Sign E
+        {0x00ccc, 0x00ccd},  // Kannada Vowel Sign Au   ..Kannada Sign Virama
+        {0x00ce2, 0x00ce3},  // Kannada Vowel Sign Vocal..Kannada Vowel Sign Vocal
+        {0x00d00, 0x00d01},  // Malayalam Sign Combining..Malayalam Sign Candrabin
+        {0x00d3b, 0x00d3c},  // Malayalam Sign Vertical ..Malayalam Sign Circular
+        {0x00d41, 0x00d44},  // Malayalam Vowel Sign U  ..Malayalam Vowel Sign Voc
+        {0x00d4d, 0x00d4d},  // Malayalam Sign Virama   ..Malayalam Sign Virama
+        {0x00d62, 0x00d63},  // Malayalam Vowel Sign Voc..Malayalam Vowel Sign Voc
+        {0x00d81, 0x00d81},  // Sinhala Sign Candrabindu..Sinhala Sign Candrabindu
+        {0x00dca, 0x00dca},  // Sinhala Sign Al-lakuna  ..Sinhala Sign Al-lakuna
+        {0x00dd2, 0x00dd4},  // Sinhala Vowel Sign Ketti..Sinhala Vowel Sign Ketti
+        {0x00dd6, 0x00dd6},  // Sinhala Vowel Sign Diga ..Sinhala Vowel Sign Diga
+        {0x00e31, 0x00e31},  // Thai Character Mai Han-a..Thai Character Mai Han-a
+        {0x00e34, 0x00e3a},  // Thai Character Sara I   ..Thai Character Phinthu
+        {0x00e47, 0x00e4e},  // Thai Character Maitaikhu..Thai Character Yamakkan
+        {0x00eb1, 0x00eb1},  // Lao Vowel Sign Mai Kan  ..Lao Vowel Sign Mai Kan
+        {0x00eb4, 0x00ebc},  // Lao Vowel Sign I        ..Lao Semivowel Sign Lo
+        {0x00ec8, 0x00ece},  // Lao Tone Mai Ek         ..(nil)
+        {0x00f18, 0x00f19},  // Tibetan Astrological Sig..Tibetan Astrological Sig
+        {0x00f35, 0x00f35},  // Tibetan Mark Ngas Bzung ..Tibetan Mark Ngas Bzung
+        {0x00f37, 0x00f37},  // Tibetan Mark Ngas Bzung ..Tibetan Mark Ngas Bzung
+        {0x00f39, 0x00f39},  // Tibetan Mark Tsa -phru  ..Tibetan Mark Tsa -phru
+        {0x00f71, 0x00f7e},  // Tibetan Vowel Sign Aa   ..Tibetan Sign Rjes Su Nga
+        {0x00f80, 0x00f84},  // Tibetan Vowel Sign Rever..Tibetan Mark Halanta
+        {0x00f86, 0x00f87},  // Tibetan Sign Lci Rtags  ..Tibetan Sign Yang Rtags
+        {0x00f8d, 0x00f97},  // Tibetan Subjoined Sign L..Tibetan Subjoined Letter
+        {0x00f99, 0x00fbc},  // Tibetan Subjoined Letter..Tibetan Subjoined Letter
+        {0x00fc6, 0x00fc6},  // Tibetan Symbol Padma Gda..Tibetan Symbol Padma Gda
+        {0x0102d, 0x01030},  // Myanmar Vowel Sign I    ..Myanmar Vowel Sign Uu
+        {0x01032, 0x01037},  // Myanmar Vowel Sign Ai   ..Myanmar Sign Dot Below
+        {0x01039, 0x0103a},  // Myanmar Sign Virama     ..Myanmar Sign Asat
+        {0x0103d, 0x0103e},  // Myanmar Consonant Sign M..Myanmar Consonant Sign M
+        {0x01058, 0x01059},  // Myanmar Vowel Sign Vocal..Myanmar Vowel Sign Vocal
+        {0x0105e, 0x01060},  // Myanmar Consonant Sign M..Myanmar Consonant Sign M
+        {0x01071, 0x01074},  // Myanmar Vowel Sign Geba ..Myanmar Vowel Sign Kayah
+        {0x01082, 0x01082},  // Myanmar Consonant Sign S..Myanmar Consonant Sign S
+        {0x01085, 0x01086},  // Myanmar Vowel Sign Shan ..Myanmar Vowel Sign Shan
+        {0x0108d, 0x0108d},  // Myanmar Sign Shan Counci..Myanmar Sign Shan Counci
+        {0x0109d, 0x0109d},  // Myanmar Vowel Sign Aiton..Myanmar Vowel Sign Aiton
+        {0x0135d, 0x0135f},  // Ethiopic Combining Gemin..Ethiopic Combining Gemin
+        {0x01712, 0x01714},  // Tagalog Vowel Sign I    ..Tagalog Sign Virama
+        {0x01732, 0x01733},  // Hanunoo Vowel Sign I    ..Hanunoo Vowel Sign U
+        {0x01752, 0x01753},  // Buhid Vowel Sign I      ..Buhid Vowel Sign U
+        {0x01772, 0x01773},  // Tagbanwa Vowel Sign I   ..Tagbanwa Vowel Sign U
+        {0x017b4, 0x017b5},  // Khmer Vowel Inherent Aq ..Khmer Vowel Inherent Aa
+        {0x017b7, 0x017bd},  // Khmer Vowel Sign I      ..Khmer Vowel Sign Ua
+        {0x017c6, 0x017c6},  // Khmer Sign Nikahit      ..Khmer Sign Nikahit
+        {0x017c9, 0x017d3},  // Khmer Sign Muusikatoan  ..Khmer Sign Bathamasat
+        {0x017dd, 0x017dd},  // Khmer Sign Atthacan     ..Khmer Sign Atthacan
+        {0x0180b, 0x0180d},  // Mongolian Free Variation..Mongolian Free Variation
+        {0x0180f, 0x0180f},  // Mongolian Free Variation..Mongolian Free Variation
+        {0x01885, 0x01886},  // Mongolian Letter Ali Gal..Mongolian Letter Ali Gal
+        {0x018a9, 0x018a9},  // Mongolian Letter Ali Gal..Mongolian Letter Ali Gal
+        {0x01920, 0x01922},  // Limbu Vowel Sign A      ..Limbu Vowel Sign U
+        {0x01927, 0x01928},  // Limbu Vowel Sign E      ..Limbu Vowel Sign O
+        {0x01932, 0x01932},  // Limbu Small Letter Anusv..Limbu Small Letter Anusv
+        {0x01939, 0x0193b},  // Limbu Sign Mukphreng    ..Limbu Sign Sa-i
+        {0x01a17, 0x01a18},  // Buginese Vowel Sign I   ..Buginese Vowel Sign U
+        {0x01a1b, 0x01a1b},  // Buginese Vowel Sign Ae  ..Buginese Vowel Sign Ae
+        {0x01a56, 0x01a56},  // Tai Tham Consonant Sign ..Tai Tham Consonant Sign
+        {0x01a58, 0x01a5e},  // Tai Tham Sign Mai Kang L..Tai Tham Consonant Sign
+        {0x01a60, 0x01a60},  // Tai Tham Sign Sakot     ..Tai Tham Sign Sakot
+        {0x01a62, 0x01a62},  // Tai Tham Vowel Sign Mai ..Tai Tham Vowel Sign Mai
+        {0x01a65, 0x01a6c},  // Tai Tham Vowel Sign I   ..Tai Tham Vowel Sign Oa B
+        {0x01a73, 0x01a7c},  // Tai Tham Vowel Sign Oa A..Tai Tham Sign Khuen-lue
+        {0x01a7f, 0x01a7f},  // Tai Tham Combining Crypt..Tai Tham Combining Crypt
+        {0x01ab0, 0x01ace},  // Combining Doubled Circum..Combining Latin Small Le
+        {0x01b00, 0x01b03},  // Balinese Sign Ulu Ricem ..Balinese Sign Surang
+        {0x01b34, 0x01b34},  // Balinese Sign Rerekan   ..Balinese Sign Rerekan
+        {0x01b36, 0x01b3a},  // Balinese Vowel Sign Ulu ..Balinese Vowel Sign Ra R
+        {0x01b3c, 0x01b3c},  // Balinese Vowel Sign La L..Balinese Vowel Sign La L
+        {0x01b42, 0x01b42},  // Balinese Vowel Sign Pepe..Balinese Vowel Sign Pepe
+        {0x01b6b, 0x01b73},  // Balinese Musical Symbol ..Balinese Musical Symbol
+        {0x01b80, 0x01b81},  // Sundanese Sign Panyecek ..Sundanese Sign Panglayar
+        {0x01ba2, 0x01ba5},  // Sundanese Consonant Sign..Sundanese Vowel Sign Pan
+        {0x01ba8, 0x01ba9},  // Sundanese Vowel Sign Pam..Sundanese Vowel Sign Pan
+        {0x01bab, 0x01bad},  // Sundanese Sign Virama   ..Sundanese Consonant Sign
+        {0x01be6, 0x01be6},  // Batak Sign Tompi        ..Batak Sign Tompi
+        {0x01be8, 0x01be9},  // Batak Vowel Sign Pakpak ..Batak Vowel Sign Ee
+        {0x01bed, 0x01bed},  // Batak Vowel Sign Karo O ..Batak Vowel Sign Karo O
+        {0x01bef, 0x01bf1},  // Batak Vowel Sign U For S..Batak Consonant Sign H
+        {0x01c2c, 0x01c33},  // Lepcha Vowel Sign E     ..Lepcha Consonant Sign T
+        {0x01c36, 0x01c37},  // Lepcha Sign Ran         ..Lepcha Sign Nukta
+        {0x01cd0, 0x01cd2},  // Vedic Tone Karshana     ..Vedic Tone Prenkha
+        {0x01cd4, 0x01ce0},  // Vedic Sign Yajurvedic Mi..Vedic Tone Rigvedic Kash
+        {0x01ce2, 0x01ce8},  // Vedic Sign Visarga Svari..Vedic Sign Visarga Anuda
+        {0x01ced, 0x01ced},  // Vedic Sign Tiryak       ..Vedic Sign Tiryak
+        {0x01cf4, 0x01cf4},  // Vedic Tone Candra Above ..Vedic Tone Candra Above
+        {0x01cf8, 0x01cf9},  // Vedic Tone Ring Above   ..Vedic Tone Double Ring A
+        {0x01dc0, 0x01dff},  // Combining Dotted Grave A..Combining Right Arrowhea
+        {0x020d0, 0x020f0},  // Combining Left Harpoon A..Combining Asterisk Above
+        {0x02cef, 0x02cf1},  // Coptic Combining Ni Abov..Coptic Combining Spiritu
+        {0x02d7f, 0x02d7f},  // Tifinagh Consonant Joine..Tifinagh Consonant Joine
+        {0x02de0, 0x02dff},  // Combining Cyrillic Lette..Combining Cyrillic Lette
+        {0x0302a, 0x0302d},  // Ideographic Level Tone M..Ideographic Entering Ton
+        {0x03099, 0x0309a},  // Combining Katakana-hirag..Combining Katakana-hirag
+        {0x0a66f, 0x0a672},  // Combining Cyrillic Vzmet..Combining Cyrillic Thous
+        {0x0a674, 0x0a67d},  // Combining Cyrillic Lette..Combining Cyrillic Payer
+        {0x0a69e, 0x0a69f},  // Combining Cyrillic Lette..Combining Cyrillic Lette
+        {0x0a6f0, 0x0a6f1},  // Bamum Combining Mark Koq..Bamum Combining Mark Tuk
+        {0x0a802, 0x0a802},  // Syloti Nagri Sign Dvisva..Syloti Nagri Sign Dvisva
+        {0x0a806, 0x0a806},  // Syloti Nagri Sign Hasant..Syloti Nagri Sign Hasant
+        {0x0a80b, 0x0a80b},  // Syloti Nagri Sign Anusva..Syloti Nagri Sign Anusva
+        {0x0a825, 0x0a826},  // Syloti Nagri Vowel Sign ..Syloti Nagri Vowel Sign
+        {0x0a82c, 0x0a82c},  // Syloti Nagri Sign Altern..Syloti Nagri Sign Altern
+        {0x0a8c4, 0x0a8c5},  // Saurashtra Sign Virama  ..Saurashtra Sign Candrabi
+        {0x0a8e0, 0x0a8f1},  // Combining Devanagari Dig..Combining Devanagari Sig
+        {0x0a8ff, 0x0a8ff},  // Devanagari Vowel Sign Ay..Devanagari Vowel Sign Ay
+        {0x0a926, 0x0a92d},  // Kayah Li Vowel Ue       ..Kayah Li Tone Calya Plop
+        {0x0a947, 0x0a951},  // Rejang Vowel Sign I     ..Rejang Consonant Sign R
+        {0x0a980, 0x0a982},  // Javanese Sign Panyangga ..Javanese Sign Layar
+        {0x0a9b3, 0x0a9b3},  // Javanese Sign Cecak Telu..Javanese Sign Cecak Telu
+        {0x0a9b6, 0x0a9b9},  // Javanese Vowel Sign Wulu..Javanese Vowel Sign Suku
+        {0x0a9bc, 0x0a9bd},  // Javanese Vowel Sign Pepe..Javanese Consonant Sign
+        {0x0a9e5, 0x0a9e5},  // Myanmar Sign Shan Saw   ..Myanmar Sign Shan Saw
+        {0x0aa29, 0x0aa2e},  // Cham Vowel Sign Aa      ..Cham Vowel Sign Oe
+        {0x0aa31, 0x0aa32},  // Cham Vowel Sign Au      ..Cham Vowel Sign Ue
+        {0x0aa35, 0x0aa36},  // Cham Consonant Sign La  ..Cham Consonant Sign Wa
+        {0x0aa43, 0x0aa43},  // Cham Consonant Sign Fina..Cham Consonant Sign Fina
+        {0x0aa4c, 0x0aa4c},  // Cham Consonant Sign Fina..Cham Consonant Sign Fina
+        {0x0aa7c, 0x0aa7c},  // Myanmar Sign Tai Laing T..Myanmar Sign Tai Laing T
+        {0x0aab0, 0x0aab0},  // Tai Viet Mai Kang       ..Tai Viet Mai Kang
+        {0x0aab2, 0x0aab4},  // Tai Viet Vowel I        ..Tai Viet Vowel U
+        {0x0aab7, 0x0aab8},  // Tai Viet Mai Khit       ..Tai Viet Vowel Ia
+        {0x0aabe, 0x0aabf},  // Tai Viet Vowel Am       ..Tai Viet Tone Mai Ek
+        {0x0aac1, 0x0aac1},  // Tai Viet Tone Mai Tho   ..Tai Viet Tone Mai Tho
+        {0x0aaec, 0x0aaed},  // Meetei Mayek Vowel Sign ..Meetei Mayek Vowel Sign
+        {0x0aaf6, 0x0aaf6},  // Meetei Mayek Virama     ..Meetei Mayek Virama
+        {0x0abe5, 0x0abe5},  // Meetei Mayek Vowel Sign ..Meetei Mayek Vowel Sign
+        {0x0abe8, 0x0abe8},  // Meetei Mayek Vowel Sign ..Meetei Mayek Vowel Sign
+        {0x0abed, 0x0abed},  // Meetei Mayek Apun Iyek  ..Meetei Mayek Apun Iyek
+        {0x0fb1e, 0x0fb1e},  // Hebrew Point Judeo-spani..Hebrew Point Judeo-spani
+        {0x0fe00, 0x0fe0f},  // Variation Selector-1    ..Variation Selector-16
+        {0x0fe20, 0x0fe2f},  // Combining Ligature Left ..Combining Cyrillic Titlo
+        {0x101fd, 0x101fd},  // Phaistos Disc Sign Combi..Phaistos Disc Sign Combi
+        {0x102e0, 0x102e0},  // Coptic Epact Thousands M..Coptic Epact Thousands M
+        {0x10376, 0x1037a},  // Combining Old Permic Let..Combining Old Permic Let
+        {0x10a01, 0x10a03},  // Kharoshthi Vowel Sign I ..Kharoshthi Vowel Sign Vo
+        {0x10a05, 0x10a06},  // Kharoshthi Vowel Sign E ..Kharoshthi Vowel Sign O
+        {0x10a0c, 0x10a0f},  // Kharoshthi Vowel Length ..Kharoshthi Sign Visarga
+        {0x10a38, 0x10a3a},  // Kharoshthi Sign Bar Abov..Kharoshthi Sign Dot Belo
+        {0x10a3f, 0x10a3f},  // Kharoshthi Virama       ..Kharoshthi Virama
+        {0x10ae5, 0x10ae6},  // Manichaean Abbreviation ..Manichaean Abbreviation
+        {0x10d24, 0x10d27},  // Hanifi Rohingya Sign Har..Hanifi Rohingya Sign Tas
+        {0x10eab, 0x10eac},  // Yezidi Combining Hamza M..Yezidi Combining Madda M
+        {0x10efd, 0x10eff},  // (nil)                   ..(nil)
+        {0x10f46, 0x10f50},  // Sogdian Combining Dot Be..Sogdian Combining Stroke
+        {0x10f82, 0x10f85},  // Old Uyghur Combining Dot..Old Uyghur Combining Two
+        {0x11001, 0x11001},  // Brahmi Sign Anusvara    ..Brahmi Sign Anusvara
+        {0x11038, 0x11046},  // Brahmi Vowel Sign Aa    ..Brahmi Virama
+        {0x11070, 0x11070},  // Brahmi Sign Old Tamil Vi..Brahmi Sign Old Tamil Vi
+        {0x11073, 0x11074},  // Brahmi Vowel Sign Old Ta..Brahmi Vowel Sign Old Ta
+        {0x1107f, 0x11081},  // Brahmi Number Joiner    ..Kaithi Sign Anusvara
+        {0x110b3, 0x110b6},  // Kaithi Vowel Sign U     ..Kaithi Vowel Sign Ai
+        {0x110b9, 0x110ba},  // Kaithi Sign Virama      ..Kaithi Sign Nukta
+        {0x110c2, 0x110c2},  // Kaithi Vowel Sign Vocali..Kaithi Vowel Sign Vocali
+        {0x11100, 0x11102},  // Chakma Sign Candrabindu ..Chakma Sign Visarga
+        {0x11127, 0x1112b},  // Chakma Vowel Sign A     ..Chakma Vowel Sign Uu
+        {0x1112d, 0x11134},  // Chakma Vowel Sign Ai    ..Chakma Maayyaa
+        {0x11173, 0x11173},  // Mahajani Sign Nukta     ..Mahajani Sign Nukta
+        {0x11180, 0x11181},  // Sharada Sign Candrabindu..Sharada Sign Anusvara
+        {0x111b6, 0x111be},  // Sharada Vowel Sign U    ..Sharada Vowel Sign O
+        {0x111c9, 0x111cc},  // Sharada Sandhi Mark     ..Sharada Extra Short Vowe
+        {0x111cf, 0x111cf},  // Sharada Sign Inverted Ca..Sharada Sign Inverted Ca
+        {0x1122f, 0x11231},  // Khojki Vowel Sign U     ..Khojki Vowel Sign Ai
+        {0x11234, 0x11234},  // Khojki Sign Anusvara    ..Khojki Sign Anusvara
+        {0x11236, 0x11237},  // Khojki Sign Nukta       ..Khojki Sign Shadda
+        {0x1123e, 0x1123e},  // Khojki Sign Sukun       ..Khojki Sign Sukun
+        {0x11241, 0x11241},  // (nil)                   ..(nil)
+        {0x112df, 0x112df},  // Khudawadi Sign Anusvara ..Khudawadi Sign Anusvara
+        {0x112e3, 0x112ea},  // Khudawadi Vowel Sign U  ..Khudawadi Sign Virama
+        {0x11300, 0x11301},  // Grantha Sign Combining A..Grantha Sign Candrabindu
+        {0x1133b, 0x1133c},  // Combining Bindu Below   ..Grantha Sign Nukta
+        {0x11340, 0x11340},  // Grantha Vowel Sign Ii   ..Grantha Vowel Sign Ii
+        {0x11366, 0x1136c},  // Combining Grantha Digit ..Combining Grantha Digit
+        {0x11370, 0x11374},  // Combining Grantha Letter..Combining Grantha Letter
+        {0x11438, 0x1143f},  // Newa Vowel Sign U       ..Newa Vowel Sign Ai
+        {0x11442, 0x11444},  // Newa Sign Virama        ..Newa Sign Anusvara
+        {0x11446, 0x11446},  // Newa Sign Nukta         ..Newa Sign Nukta
+        {0x1145e, 0x1145e},  // Newa Sandhi Mark        ..Newa Sandhi Mark
+        {0x114b3, 0x114b8},  // Tirhuta Vowel Sign U    ..Tirhuta Vowel Sign Vocal
+        {0x114ba, 0x114ba},  // Tirhuta Vowel Sign Short..Tirhuta Vowel Sign Short
+        {0x114bf, 0x114c0},  // Tirhuta Sign Candrabindu..Tirhuta Sign Anusvara
+        {0x114c2, 0x114c3},  // Tirhuta Sign Virama     ..Tirhuta Sign Nukta
+        {0x115b2, 0x115b5},  // Siddham Vowel Sign U    ..Siddham Vowel Sign Vocal
+        {0x115bc, 0x115bd},  // Siddham Sign Candrabindu..Siddham Sign Anusvara
+        {0x115bf, 0x115c0},  // Siddham Sign Virama     ..Siddham Sign Nukta
+        {0x115dc, 0x115dd},  // Siddham Vowel Sign Alter..Siddham Vowel Sign Alter
+        {0x11633, 0x1163a},  // Modi Vowel Sign U       ..Modi Vowel Sign Ai
+        {0x1163d, 0x1163d},  // Modi Sign Anusvara      ..Modi Sign Anusvara
+        {0x1163f, 0x11640},  // Modi Sign Virama        ..Modi Sign Ardhacandra
+        {0x116ab, 0x116ab},  // Takri Sign Anusvara     ..Takri Sign Anusvara
+        {0x116ad, 0x116ad},  // Takri Vowel Sign Aa     ..Takri Vowel Sign Aa
+        {0x116b0, 0x116b5},  // Takri Vowel Sign U      ..Takri Vowel Sign Au
+        {0x116b7, 0x116b7},  // Takri Sign Nukta        ..Takri Sign Nukta
+        {0x1171d, 0x1171f},  // Ahom Consonant Sign Medi..Ahom Consonant Sign Medi
+        {0x11722, 0x11725},  // Ahom Vowel Sign I       ..Ahom Vowel Sign Uu
+        {0x11727, 0x1172b},  // Ahom Vowel Sign Aw      ..Ahom Sign Killer
+        {0x1182f, 0x11837},  // Dogra Vowel Sign U      ..Dogra Sign Anusvara
+        {0x11839, 0x1183a},  // Dogra Sign Virama       ..Dogra Sign Nukta
+        {0x1193b, 0x1193c},  // Dives Akuru Sign Anusvar..Dives Akuru Sign Candrab
+        {0x1193e, 0x1193e},  // Dives Akuru Virama      ..Dives Akuru Virama
+        {0x11943, 0x11943},  // Dives Akuru Sign Nukta  ..Dives Akuru Sign Nukta
+        {0x119d4, 0x119d7},  // Nandinagari Vowel Sign U..Nandinagari Vowel Sign V
+        {0x119da, 0x119db},  // Nandinagari Vowel Sign E..Nandinagari Vowel Sign A
+        {0x119e0, 0x119e0},  // Nandinagari Sign Virama ..Nandinagari Sign Virama
+        {0x11a01, 0x11a0a},  // Zanabazar Square Vowel S..Zanabazar Square Vowel L
+        {0x11a33, 0x11a38},  // Zanabazar Square Final C..Zanabazar Square Sign An
+        {0x11a3b, 0x11a3e},  // Zanabazar Square Cluster..Zanabazar Square Cluster
+        {0x11a47, 0x11a47},  // Zanabazar Square Subjoin..Zanabazar Square Subjoin
+        {0x11a51, 0x11a56},  // Soyombo Vowel Sign I    ..Soyombo Vowel Sign Oe
+        {0x11a59, 0x11a5b},  // Soyombo Vowel Sign Vocal..Soyombo Vowel Length Mar
+        {0x11a8a, 0x11a96},  // Soyombo Final Consonant ..Soyombo Sign Anusvara
+        {0x11a98, 0x11a99},  // Soyombo Gemination Mark ..Soyombo Subjoiner
+        {0x11c30, 0x11c36},  // Bhaiksuki Vowel Sign I  ..Bhaiksuki Vowel Sign Voc
+        {0x11c38, 0x11c3d},  // Bhaiksuki Vowel Sign E  ..Bhaiksuki Sign Anusvara
+        {0x11c3f, 0x11c3f},  // Bhaiksuki Sign Virama   ..Bhaiksuki Sign Virama
+        {0x11c92, 0x11ca7},  // Marchen Subjoined Letter..Marchen Subjoined Letter
+        {0x11caa, 0x11cb0},  // Marchen Subjoined Letter..Marchen Vowel Sign Aa
+        {0x11cb2, 0x11cb3},  // Marchen Vowel Sign U    ..Marchen Vowel Sign E
+        {0x11cb5, 0x11cb6},  // Marchen Sign Anusvara   ..Marchen Sign Candrabindu
+        {0x11d31, 0x11d36},  // Masaram Gondi Vowel Sign..Masaram Gondi Vowel Sign
+        {0x11d3a, 0x11d3a},  // Masaram Gondi Vowel Sign..Masaram Gondi Vowel Sign
+        {0x11d3c, 0x11d3d},  // Masaram Gondi Vowel Sign..Masaram Gondi Vowel Sign
+        {0x11d3f, 0x11d45},  // Masaram Gondi Vowel Sign..Masaram Gondi Virama
+        {0x11d47, 0x11d47},  // Masaram Gondi Ra-kara   ..Masaram Gondi Ra-kara
+        {0x11d90, 0x11d91},  // Gunjala Gondi Vowel Sign..Gunjala Gondi Vowel Sign
+        {0x11d95, 0x11d95},  // Gunjala Gondi Sign Anusv..Gunjala Gondi Sign Anusv
+        {0x11d97, 0x11d97},  // Gunjala Gondi Virama    ..Gunjala Gondi Virama
+        {0x11ef3, 0x11ef4},  // Makasar Vowel Sign I    ..Makasar Vowel Sign U
+        {0x11f00, 0x11f01},  // (nil)                   ..(nil)
+        {0x11f36, 0x11f3a},  // (nil)                   ..(nil)
+        {0x11f40, 0x11f40},  // (nil)                   ..(nil)
+        {0x11f42, 0x11f42},  // (nil)                   ..(nil)
+        {0x13440, 0x13440},  // (nil)                   ..(nil)
+        {0x13447, 0x13455},  // (nil)                   ..(nil)
+        {0x16af0, 0x16af4},  // Bassa Vah Combining High..Bassa Vah Combining High
+        {0x16b30, 0x16b36},  // Pahawh Hmong Mark Cim Tu..Pahawh Hmong Mark Cim Ta
+        {0x16f4f, 0x16f4f},  // Miao Sign Consonant Modi..Miao Sign Consonant Modi
+        {0x16f8f, 0x16f92},  // Miao Tone Right         ..Miao Tone Below
+        {0x16fe4, 0x16fe4},  // Khitan Small Script Fill..Khitan Small Script Fill
+        {0x1bc9d, 0x1bc9e},  // Duployan Thick Letter Se..Duployan Double Mark
+        {0x1cf00, 0x1cf2d},  // Znamenny Combining Mark ..Znamenny Combining Mark
+        {0x1cf30, 0x1cf46},  // Znamenny Combining Tonal..Znamenny Priznak Modifie
+        {0x1d167, 0x1d169},  // Musical Symbol Combining..Musical Symbol Combining
+        {0x1d17b, 0x1d182},  // Musical Symbol Combining..Musical Symbol Combining
+        {0x1d185, 0x1d18b},  // Musical Symbol Combining..Musical Symbol Combining
+        {0x1d1aa, 0x1d1ad},  // Musical Symbol Combining..Musical Symbol Combining
+        {0x1d242, 0x1d244},  // Combining Greek Musical ..Combining Greek Musical
+        {0x1da00, 0x1da36},  // Signwriting Head Rim    ..Signwriting Air Sucking
+        {0x1da3b, 0x1da6c},  // Signwriting Mouth Closed..Signwriting Excitement
+        {0x1da75, 0x1da75},  // Signwriting Upper Body T..Signwriting Upper Body T
+        {0x1da84, 0x1da84},  // Signwriting Location Hea..Signwriting Location Hea
+        {0x1da9b, 0x1da9f},  // Signwriting Fill Modifie..Signwriting Fill Modifie
+        {0x1daa1, 0x1daaf},  // Signwriting Rotation Mod..Signwriting Rotation Mod
+        {0x1e000, 0x1e006},  // Combining Glagolitic Let..Combining Glagolitic Let
+        {0x1e008, 0x1e018},  // Combining Glagolitic Let..Combining Glagolitic Let
+        {0x1e01b, 0x1e021},  // Combining Glagolitic Let..Combining Glagolitic Let
+        {0x1e023, 0x1e024},  // Combining Glagolitic Let..Combining Glagolitic Let
+        {0x1e026, 0x1e02a},  // Combining Glagolitic Let..Combining Glagolitic Let
+        {0x1e08f, 0x1e08f},  // (nil)                   ..(nil)
+        {0x1e130, 0x1e136},  // Nyiakeng Puachue Hmong T..Nyiakeng Puachue Hmong T
+        {0x1e2ae, 0x1e2ae},  // Toto Sign Rising Tone   ..Toto Sign Rising Tone
+        {0x1e2ec, 0x1e2ef},  // Wancho Tone Tup         ..Wancho Tone Koini
+        {0x1e4ec, 0x1e4ef},  // (nil)                   ..(nil)
+        {0x1e8d0, 0x1e8d6},  // Mende Kikakui Combining ..Mende Kikakui Combining
+        {0x1e944, 0x1e94a},  // Adlam Alif Lengthener   ..Adlam Nukta
+        {0xe0100, 0xe01ef},  // Variation Selector-17   ..Variation Selector-256
+    };
+
+    // https://github.com/jquast/wcwidth/blob/master/wcwidth/table_wide.py
+    // from https://github.com/jquast/wcwidth/pull/64
+    // at commit 1b9b6585b0080ea5cb88dc9815796505724793fe (2022-12-16):
+    private static final int[][] WIDE_EASTASIAN = {
+        {0x01100, 0x0115f},  // Hangul Choseong Kiyeok  ..Hangul Choseong Filler
+        {0x0231a, 0x0231b},  // Watch                   ..Hourglass
+        {0x02329, 0x0232a},  // Left-pointing Angle Brac..Right-pointing Angle Bra
+        {0x023e9, 0x023ec},  // Black Right-pointing Dou..Black Down-pointing Doub
+        {0x023f0, 0x023f0},  // Alarm Clock             ..Alarm Clock
+        {0x023f3, 0x023f3},  // Hourglass With Flowing S..Hourglass With Flowing S
+        {0x025fd, 0x025fe},  // White Medium Small Squar..Black Medium Small Squar
+        {0x02614, 0x02615},  // Umbrella With Rain Drops..Hot Beverage
+        {0x02648, 0x02653},  // Aries                   ..Pisces
+        {0x0267f, 0x0267f},  // Wheelchair Symbol       ..Wheelchair Symbol
+        {0x02693, 0x02693},  // Anchor                  ..Anchor
+        {0x026a1, 0x026a1},  // High Voltage Sign       ..High Voltage Sign
+        {0x026aa, 0x026ab},  // Medium White Circle     ..Medium Black Circle
+        {0x026bd, 0x026be},  // Soccer Ball             ..Baseball
+        {0x026c4, 0x026c5},  // Snowman Without Snow    ..Sun Behind Cloud
+        {0x026ce, 0x026ce},  // Ophiuchus               ..Ophiuchus
+        {0x026d4, 0x026d4},  // No Entry                ..No Entry
+        {0x026ea, 0x026ea},  // Church                  ..Church
+        {0x026f2, 0x026f3},  // Fountain                ..Flag In Hole
+        {0x026f5, 0x026f5},  // Sailboat                ..Sailboat
+        {0x026fa, 0x026fa},  // Tent                    ..Tent
+        {0x026fd, 0x026fd},  // Fuel Pump               ..Fuel Pump
+        {0x02705, 0x02705},  // White Heavy Check Mark  ..White Heavy Check Mark
+        {0x0270a, 0x0270b},  // Raised Fist             ..Raised Hand
+        {0x02728, 0x02728},  // Sparkles                ..Sparkles
+        {0x0274c, 0x0274c},  // Cross Mark              ..Cross Mark
+        {0x0274e, 0x0274e},  // Negative Squared Cross M..Negative Squared Cross M
+        {0x02753, 0x02755},  // Black Question Mark Orna..White Exclamation Mark O
+        {0x02757, 0x02757},  // Heavy Exclamation Mark S..Heavy Exclamation Mark S
+        {0x02795, 0x02797},  // Heavy Plus Sign         ..Heavy Division Sign
+        {0x027b0, 0x027b0},  // Curly Loop              ..Curly Loop
+        {0x027bf, 0x027bf},  // Double Curly Loop       ..Double Curly Loop
+        {0x02b1b, 0x02b1c},  // Black Large Square      ..White Large Square
+        {0x02b50, 0x02b50},  // White Medium Star       ..White Medium Star
+        {0x02b55, 0x02b55},  // Heavy Large Circle      ..Heavy Large Circle
+        {0x02e80, 0x02e99},  // Cjk Radical Repeat      ..Cjk Radical Rap
+        {0x02e9b, 0x02ef3},  // Cjk Radical Choke       ..Cjk Radical C-simplified
+        {0x02f00, 0x02fd5},  // Kangxi Radical One      ..Kangxi Radical Flute
+        {0x02ff0, 0x02ffb},  // Ideographic Description ..Ideographic Description
+        {0x03000, 0x0303e},  // Ideographic Space       ..Ideographic Variation In
+        {0x03041, 0x03096},  // Hiragana Letter Small A ..Hiragana Letter Small Ke
+        {0x03099, 0x030ff},  // Combining Katakana-hirag..Katakana Digraph Koto
+        {0x03105, 0x0312f},  // Bopomofo Letter B       ..Bopomofo Letter Nn
+        {0x03131, 0x0318e},  // Hangul Letter Kiyeok    ..Hangul Letter Araeae
+        {0x03190, 0x031e3},  // Ideographic Annotation L..Cjk Stroke Q
+        {0x031f0, 0x0321e},  // Katakana Letter Small Ku..Parenthesized Korean Cha
+        {0x03220, 0x03247},  // Parenthesized Ideograph ..Circled Ideograph Koto
+        {0x03250, 0x04dbf},  // Partnership Sign        ..Cjk Unified Ideograph-4d
+        {0x04e00, 0x0a48c},  // Cjk Unified Ideograph-4e..Yi Syllable Yyr
+        {0x0a490, 0x0a4c6},  // Yi Radical Qot          ..Yi Radical Ke
+        {0x0a960, 0x0a97c},  // Hangul Choseong Tikeut-m..Hangul Choseong Ssangyeo
+        {0x0ac00, 0x0d7a3},  // Hangul Syllable Ga      ..Hangul Syllable Hih
+        {0x0f900, 0x0faff},  // Cjk Compatibility Ideogr..(nil)
+        {0x0fe10, 0x0fe19},  // Presentation Form For Ve..Presentation Form For Ve
+        {0x0fe30, 0x0fe52},  // Presentation Form For Ve..Small Full Stop
+        {0x0fe54, 0x0fe66},  // Small Semicolon         ..Small Equals Sign
+        {0x0fe68, 0x0fe6b},  // Small Reverse Solidus   ..Small Commercial At
+        {0x0ff01, 0x0ff60},  // Fullwidth Exclamation Ma..Fullwidth Right White Pa
+        {0x0ffe0, 0x0ffe6},  // Fullwidth Cent Sign     ..Fullwidth Won Sign
+        {0x16fe0, 0x16fe4},  // Tangut Iteration Mark   ..Khitan Small Script Fill
+        {0x16ff0, 0x16ff1},  // Vietnamese Alternate Rea..Vietnamese Alternate Rea
+        {0x17000, 0x187f7},  // (nil)                   ..(nil)
+        {0x18800, 0x18cd5},  // Tangut Component-001    ..Khitan Small Script Char
+        {0x18d00, 0x18d08},  // (nil)                   ..(nil)
+        {0x1aff0, 0x1aff3},  // Katakana Letter Minnan T..Katakana Letter Minnan T
+        {0x1aff5, 0x1affb},  // Katakana Letter Minnan T..Katakana Letter Minnan N
+        {0x1affd, 0x1affe},  // Katakana Letter Minnan N..Katakana Letter Minnan N
+        {0x1b000, 0x1b122},  // Katakana Letter Archaic ..Katakana Letter Archaic
+        {0x1b132, 0x1b132},  // (nil)                   ..(nil)
+        {0x1b150, 0x1b152},  // Hiragana Letter Small Wi..Hiragana Letter Small Wo
+        {0x1b155, 0x1b155},  // (nil)                   ..(nil)
+        {0x1b164, 0x1b167},  // Katakana Letter Small Wi..Katakana Letter Small N
+        {0x1b170, 0x1b2fb},  // Nushu Character-1b170   ..Nushu Character-1b2fb
+        {0x1f004, 0x1f004},  // Mahjong Tile Red Dragon ..Mahjong Tile Red Dragon
+        {0x1f0cf, 0x1f0cf},  // Playing Card Black Joker..Playing Card Black Joker
+        {0x1f18e, 0x1f18e},  // Negative Squared Ab     ..Negative Squared Ab
+        {0x1f191, 0x1f19a},  // Squared Cl              ..Squared Vs
+        {0x1f200, 0x1f202},  // Square Hiragana Hoka    ..Squared Katakana Sa
+        {0x1f210, 0x1f23b},  // Squared Cjk Unified Ideo..Squared Cjk Unified Ideo
+        {0x1f240, 0x1f248},  // Tortoise Shell Bracketed..Tortoise Shell Bracketed
+        {0x1f250, 0x1f251},  // Circled Ideograph Advant..Circled Ideograph Accept
+        {0x1f260, 0x1f265},  // Rounded Symbol For Fu   ..Rounded Symbol For Cai
+        {0x1f300, 0x1f320},  // Cyclone                 ..Shooting Star
+        {0x1f32d, 0x1f335},  // Hot Dog                 ..Cactus
+        {0x1f337, 0x1f37c},  // Tulip                   ..Baby Bottle
+        {0x1f37e, 0x1f393},  // Bottle With Popping Cork..Graduation Cap
+        {0x1f3a0, 0x1f3ca},  // Carousel Horse          ..Swimmer
+        {0x1f3cf, 0x1f3d3},  // Cricket Bat And Ball    ..Table Tennis Paddle And
+        {0x1f3e0, 0x1f3f0},  // House Building          ..European Castle
+        {0x1f3f4, 0x1f3f4},  // Waving Black Flag       ..Waving Black Flag
+        {0x1f3f8, 0x1f43e},  // Badminton Racquet And Sh..Paw Prints
+        {0x1f440, 0x1f440},  // Eyes                    ..Eyes
+        {0x1f442, 0x1f4fc},  // Ear                     ..Videocassette
+        {0x1f4ff, 0x1f53d},  // Prayer Beads            ..Down-pointing Small Red
+        {0x1f54b, 0x1f54e},  // Kaaba                   ..Menorah With Nine Branch
+        {0x1f550, 0x1f567},  // Clock Face One Oclock   ..Clock Face Twelve-thirty
+        {0x1f57a, 0x1f57a},  // Man Dancing             ..Man Dancing
+        {0x1f595, 0x1f596},  // Reversed Hand With Middl..Raised Hand With Part Be
+        {0x1f5a4, 0x1f5a4},  // Black Heart             ..Black Heart
+        {0x1f5fb, 0x1f64f},  // Mount Fuji              ..Person With Folded Hands
+        {0x1f680, 0x1f6c5},  // Rocket                  ..Left Luggage
+        {0x1f6cc, 0x1f6cc},  // Sleeping Accommodation  ..Sleeping Accommodation
+        {0x1f6d0, 0x1f6d2},  // Place Of Worship        ..Shopping Trolley
+        {0x1f6d5, 0x1f6d7},  // Hindu Temple            ..Elevator
+        {0x1f6dc, 0x1f6df},  // (nil)                   ..Ring Buoy
+        {0x1f6eb, 0x1f6ec},  // Airplane Departure      ..Airplane Arriving
+        {0x1f6f4, 0x1f6fc},  // Scooter                 ..Roller Skate
+        {0x1f7e0, 0x1f7eb},  // Large Orange Circle     ..Large Brown Square
+        {0x1f7f0, 0x1f7f0},  // Heavy Equals Sign       ..Heavy Equals Sign
+        {0x1f90c, 0x1f93a},  // Pinched Fingers         ..Fencer
+        {0x1f93c, 0x1f945},  // Wrestlers               ..Goal Net
+        {0x1f947, 0x1f9ff},  // First Place Medal       ..Nazar Amulet
+        {0x1fa70, 0x1fa7c},  // Ballet Shoes            ..Crutch
+        {0x1fa80, 0x1fa88},  // Yo-yo                   ..(nil)
+        {0x1fa90, 0x1fabd},  // Ringed Planet           ..(nil)
+        {0x1fabf, 0x1fac5},  // (nil)                   ..Person With Crown
+        {0x1face, 0x1fadb},  // (nil)                   ..(nil)
+        {0x1fae0, 0x1fae8},  // Melting Face            ..(nil)
+        {0x1faf0, 0x1faf8},  // Hand With Index Finger A..(nil)
+        {0x20000, 0x2fffd},  // Cjk Unified Ideograph-20..(nil)
+        {0x30000, 0x3fffd},  // Cjk Unified Ideograph-30..(nil)
+    };
+
+
+    private static boolean intable(int[][] table, int c) {
+        // First quick check f|| Latin1 etc. characters.
+        if (c < table[0][0]) return false;
+
+        // Binary search in table.
+        int bot = 0;
+        int top = table.length - 1; // (int)(size / sizeof(struct interval) - 1);
+        while (top >= bot) {
+            int mid = (bot + top) / 2;
+            if (table[mid][1] < c) {
+                bot = mid + 1;
+            } else if (table[mid][0] > c) {
+                top = mid - 1;
+            } else {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /** Return the terminal display width of a code point: 0, 1 || 2. */
+    public static int width(int ucs) {
+        if (ucs == 0 ||
+            ucs == 0x034F ||
+            (0x200B <= ucs && ucs <= 0x200F) ||
+            ucs == 0x2028 ||
+            ucs == 0x2029 ||
+            (0x202A <= ucs && ucs <= 0x202E) ||
+            (0x2060 <= ucs && ucs <= 0x2063)) {
+            return 0;
+        }
+
+        // C0/C1 control characters
+        // Termux change: Return 0 instead of -1.
+        if (ucs < 32 || (0x07F <= ucs && ucs < 0x0A0)) return 0;
+
+        // combining characters with zero width
+        if (intable(ZERO_WIDTH, ucs)) return 0;
+
+        return intable(WIDE_EASTASIAN, ucs) ? 2 : 1;
+    }
+
+    /** The width at an index position in a java char array. */
+    public static int width(char[] chars, int index) {
+        char c = chars[index];
+        return Character.isHighSurrogate(c) ? width(Character.toCodePoint(c, chars[index + 1])) : width(c);
+    }
+
+    /**
+     * The zero width characters count like combining characters in the `chars` array from start
+     * index to end index (exclusive).
+     */
+    public static int zeroWidthCharsCount(char[] chars, int start, int end) {
+        if (start < 0 || start >= chars.length)
+            return 0;
+
+        int count = 0;
+        for (int i = start; i < end && i < chars.length;) {
+            if (Character.isHighSurrogate(chars[i])) {
+                if (width(Character.toCodePoint(chars[i], chars[i + 1])) <= 0) {
+                    count++;
+                }
+                i += 2;
+            } else {
+                if (width(chars[i]) <= 0) {
+                    count++;
+                }
+                i++;
+            }
+        }
+        return count;
+    }
+
+}

terminal-emulator/src/main/jni/Android.mk

@@ -0,0 +1,5 @@
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+LOCAL_MODULE:= libtermux
+LOCAL_SRC_FILES:= termux.c
+include $(BUILD_SHARED_LIBRARY)

terminal-emulator/src/main/jni/termux.c

@@ -0,0 +1,218 @@
+#include <dirent.h>
+#include <fcntl.h>
+#include <jni.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <termios.h>
+#include <unistd.h>
+
+#define TERMUX_UNUSED(x) x __attribute__((__unused__))
+#ifdef __APPLE__
+# define LACKS_PTSNAME_R
+#endif
+
+static int throw_runtime_exception(JNIEnv* env, char const* message)
+{
+    jclass exClass = (*env)->FindClass(env, "java/lang/RuntimeException");
+    (*env)->ThrowNew(env, exClass, message);
+    return -1;
+}
+
+static int create_subprocess(JNIEnv* env,
+        char const* cmd,
+        char const* cwd,
+        char* const argv[],
+        char** envp,
+        int* pProcessId,
+        jint rows,
+        jint columns,
+        jint cell_width,
+        jint cell_height)
+{
+    int ptm = open("/dev/ptmx", O_RDWR | O_CLOEXEC);
+    if (ptm < 0) return throw_runtime_exception(env, "Cannot open /dev/ptmx");
+
+#ifdef LACKS_PTSNAME_R
+    char* devname;
+#else
+    char devname[64];
+#endif
+    if (grantpt(ptm) || unlockpt(ptm) ||
+#ifdef LACKS_PTSNAME_R
+            (devname = ptsname(ptm)) == NULL
+#else
+            ptsname_r(ptm, devname, sizeof(devname))
+#endif
+       ) {
+        return throw_runtime_exception(env, "Cannot grantpt()/unlockpt()/ptsname_r() on /dev/ptmx");
+    }
+
+    // Enable UTF-8 mode and disable flow control to prevent Ctrl+S from locking up the display.
+    struct termios tios;
+    tcgetattr(ptm, &tios);
+    tios.c_iflag |= IUTF8;
+    tios.c_iflag &= ~(IXON | IXOFF);
+    tcsetattr(ptm, TCSANOW, &tios);
+
+    /** Set initial winsize. */
+    struct winsize sz = { .ws_row = (unsigned short) rows, .ws_col = (unsigned short) columns, .ws_xpixel = (unsigned short) (columns * cell_width), .ws_ypixel = (unsigned short) (rows * cell_height)};
+    ioctl(ptm, TIOCSWINSZ, &sz);
+
+    pid_t pid = fork();
+    if (pid < 0) {
+        return throw_runtime_exception(env, "Fork failed");
+    } else if (pid > 0) {
+        *pProcessId = (int) pid;
+        return ptm;
+    } else {
+        // Clear signals which the Android java process may have blocked:
+        sigset_t signals_to_unblock;
+        sigfillset(&signals_to_unblock);
+        sigprocmask(SIG_UNBLOCK, &signals_to_unblock, 0);
+
+        close(ptm);
+        setsid();
+
+        int pts = open(devname, O_RDWR);
+        if (pts < 0) exit(-1);
+
+        dup2(pts, 0);
+        dup2(pts, 1);
+        dup2(pts, 2);
+
+        DIR* self_dir = opendir("/proc/self/fd");
+        if (self_dir != NULL) {
+            int self_dir_fd = dirfd(self_dir);
+            struct dirent* entry;
+            while ((entry = readdir(self_dir)) != NULL) {
+                int fd = atoi(entry->d_name);
+                if (fd > 2 && fd != self_dir_fd) close(fd);
+            }
+            closedir(self_dir);
+        }
+
+        clearenv();
+        if (envp) for (; *envp; ++envp) putenv(*envp);
+
+        if (chdir(cwd) != 0) {
+            char* error_message;
+            // No need to free asprintf()-allocated memory since doing execvp() or exit() below.
+            if (asprintf(&error_message, "chdir(\"%s\")", cwd) == -1) error_message = "chdir()";
+            perror(error_message);
+            fflush(stderr);
+        }
+        execvp(cmd, argv);
+        // Show terminal output about failing exec() call:
+        char* error_message;
+        if (asprintf(&error_message, "exec(\"%s\")", cmd) == -1) error_message = "exec()";
+        perror(error_message);
+        _exit(1);
+    }
+}
+
+JNIEXPORT jint JNICALL Java_com_termux_terminal_JNI_createSubprocess(
+        JNIEnv* env,
+        jclass TERMUX_UNUSED(clazz),
+        jstring cmd,
+        jstring cwd,
+        jobjectArray args,
+        jobjectArray envVars,
+        jintArray processIdArray,
+        jint rows,
+        jint columns,
+        jint cell_width,
+        jint cell_height)
+{
+    jsize size = args ? (*env)->GetArrayLength(env, args) : 0;
+    char** argv = NULL;
+    if (size > 0) {
+        argv = (char**) malloc((size + 1) * sizeof(char*));
+        if (!argv) return throw_runtime_exception(env, "Couldn't allocate argv array");
+        for (int i = 0; i < size; ++i) {
+            jstring arg_java_string = (jstring) (*env)->GetObjectArrayElement(env, args, i);
+            char const* arg_utf8 = (*env)->GetStringUTFChars(env, arg_java_string, NULL);
+            if (!arg_utf8) return throw_runtime_exception(env, "GetStringUTFChars() failed for argv");
+            argv[i] = strdup(arg_utf8);
+            (*env)->ReleaseStringUTFChars(env, arg_java_string, arg_utf8);
+        }
+        argv[size] = NULL;
+    }
+
+    size = envVars ? (*env)->GetArrayLength(env, envVars) : 0;
+    char** envp = NULL;
+    if (size > 0) {
+        envp = (char**) malloc((size + 1) * sizeof(char *));
+        if (!envp) return throw_runtime_exception(env, "malloc() for envp array failed");
+        for (int i = 0; i < size; ++i) {
+            jstring env_java_string = (jstring) (*env)->GetObjectArrayElement(env, envVars, i);
+            char const* env_utf8 = (*env)->GetStringUTFChars(env, env_java_string, 0);
+            if (!env_utf8) return throw_runtime_exception(env, "GetStringUTFChars() failed for env");
+            envp[i] = strdup(env_utf8);
+            (*env)->ReleaseStringUTFChars(env, env_java_string, env_utf8);
+        }
+        envp[size] = NULL;
+    }
+
+    int procId = 0;
+    char const* cmd_cwd = (*env)->GetStringUTFChars(env, cwd, NULL);
+    char const* cmd_utf8 = (*env)->GetStringUTFChars(env, cmd, NULL);
+    int ptm = create_subprocess(env, cmd_utf8, cmd_cwd, argv, envp, &procId, rows, columns, cell_width, cell_height);
+    (*env)->ReleaseStringUTFChars(env, cmd, cmd_utf8);
+    (*env)->ReleaseStringUTFChars(env, cmd, cmd_cwd);
+
+    if (argv) {
+        for (char** tmp = argv; *tmp; ++tmp) free(*tmp);
+        free(argv);
+    }
+    if (envp) {
+        for (char** tmp = envp; *tmp; ++tmp) free(*tmp);
+        free(envp);
+    }
+
+    int* pProcId = (int*) (*env)->GetPrimitiveArrayCritical(env, processIdArray, NULL);
+    if (!pProcId) return throw_runtime_exception(env, "JNI call GetPrimitiveArrayCritical(processIdArray, &isCopy) failed");
+
+    *pProcId = procId;
+    (*env)->ReleasePrimitiveArrayCritical(env, processIdArray, pProcId, 0);
+
+    return ptm;
+}
+
+JNIEXPORT void JNICALL Java_com_termux_terminal_JNI_setPtyWindowSize(JNIEnv* TERMUX_UNUSED(env), jclass TERMUX_UNUSED(clazz), jint fd, jint rows, jint cols, jint cell_width, jint cell_height)
+{
+    struct winsize sz = { .ws_row = (unsigned short) rows, .ws_col = (unsigned short) cols, .ws_xpixel = (unsigned short) (cols * cell_width), .ws_ypixel = (unsigned short) (rows * cell_height) };
+    ioctl(fd, TIOCSWINSZ, &sz);
+}
+
+JNIEXPORT void JNICALL Java_com_termux_terminal_JNI_setPtyUTF8Mode(JNIEnv* TERMUX_UNUSED(env), jclass TERMUX_UNUSED(clazz), jint fd)
+{
+    struct termios tios;
+    tcgetattr(fd, &tios);
+    if ((tios.c_iflag & IUTF8) == 0) {
+        tios.c_iflag |= IUTF8;
+        tcsetattr(fd, TCSANOW, &tios);
+    }
+}
+
+JNIEXPORT jint JNICALL Java_com_termux_terminal_JNI_waitFor(JNIEnv* TERMUX_UNUSED(env), jclass TERMUX_UNUSED(clazz), jint pid)
+{
+    int status;
+    waitpid(pid, &status, 0);
+    if (WIFEXITED(status)) {
+        return WEXITSTATUS(status);
+    } else if (WIFSIGNALED(status)) {
+        return -WTERMSIG(status);
+    } else {
+        // Should never happen - waitpid(2) says "One of the first three macros will evaluate to a non-zero (true) value".
+        return 0;
+    }
+}
+
+JNIEXPORT void JNICALL Java_com_termux_terminal_JNI_close(JNIEnv* TERMUX_UNUSED(env), jclass TERMUX_UNUSED(clazz), jint fileDescriptor)
+{
+    close(fileDescriptor);
+}

terminal-emulator/src/test/java/com/termux/terminal/ApcTest.java

@@ -0,0 +1,21 @@
+package com.termux.terminal;
+
+public class ApcTest extends TerminalTestCase {
+
+    public void testApcConsumed() {
+        // At time of writing this is part of what yazi sends for probing for kitty graphics protocol support:
+        // https://github.com/sxyazi/yazi/blob/0cdaff98d0b3723caff63eebf1974e7907a43a2c/yazi-adapter/src/emulator.rs#L129
+        // This should not result in anything being written to the screen: If kitty graphics protocol support
+        // is implemented it should instead result in an error code on stdin, and if not it should be consumed
+        // silently just as xterm does. See https://sw.kovidgoyal.net/kitty/graphics-protocol/.
+        withTerminalSized(2, 2)
+            .enterString("\033_Gi=31,s=1,v=1,a=q,t=d,f=24;AAAA\033\\")
+            .assertLinesAre("  ", "  ");
+
+        // It is ok for the APC content to be non printable characters:
+        withTerminalSized(12, 2)
+            .enterString("hello \033_some\023\033_\\apc#end\033\\ world")
+            .assertLinesAre("hello  world", "            ");
+    }
+
+}

terminal-emulator/src/test/java/com/termux/terminal/ByteQueueTest.java

@@ -0,0 +1,54 @@
+package com.termux.terminal;
+
+import junit.framework.TestCase;
+
+public class ByteQueueTest extends TestCase {
+
+	private static void assertArrayEquals(byte[] expected, byte[] actual) {
+		if (expected.length != actual.length) {
+			fail("Difference array length");
+		}
+		for (int i = 0; i < expected.length; i++) {
+			if (expected[i] != actual[i]) {
+				fail("Inequals at index=" + i + ", expected=" + (int) expected[i] + ", actual=" + (int) actual[i]);
+			}
+		}
+	}
+
+	public void testCompleteWrites() throws Exception {
+		ByteQueue q = new ByteQueue(10);
+		assertTrue(q.write(new byte[]{1, 2, 3}, 0, 3));
+
+		byte[] arr = new byte[10];
+		assertEquals(3, q.read(arr, true));
+		assertArrayEquals(new byte[]{1, 2, 3}, new byte[]{arr[0], arr[1], arr[2]});
+
+		assertTrue(q.write(new byte[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, 0, 10));
+		assertEquals(10, q.read(arr, true));
+		assertArrayEquals(new byte[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, arr);
+	}
+
+	public void testQueueWraparound() throws Exception {
+		ByteQueue q = new ByteQueue(10);
+
+		byte[] origArray = new byte[]{1, 2, 3, 4, 5, 6};
+		byte[] readArray = new byte[origArray.length];
+		for (int i = 0; i < 20; i++) {
+			q.write(origArray, 0, origArray.length);
+			assertEquals(origArray.length, q.read(readArray, true));
+			assertArrayEquals(origArray, readArray);
+		}
+	}
+
+	public void testWriteNotesClosing() throws Exception {
+		ByteQueue q = new ByteQueue(10);
+		q.close();
+		assertFalse(q.write(new byte[]{1, 2, 3}, 0, 3));
+	}
+
+	public void testReadNonBlocking() throws Exception {
+		ByteQueue q = new ByteQueue(10);
+		assertEquals(0, q.read(new byte[128], false));
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/ControlSequenceIntroducerTest.java

@@ -0,0 +1,131 @@
+package com.termux.terminal;
+
+import java.util.List;
+
+/** "\033[" is the Control Sequence Introducer char sequence (CSI). */
+public class ControlSequenceIntroducerTest extends TerminalTestCase {
+
+	/** CSI Ps P Scroll down Ps lines (default = 1) (SD). */
+	public void testCsiT() {
+		withTerminalSized(4, 6).enterString("1\r\n2\r\n3\r\nhi\033[2Tyo\r\nA\r\nB").assertLinesAre("    ", "    ", "1   ", "2 yo", "A   ",
+				"Bi  ");
+		// Default value (1):
+		withTerminalSized(4, 6).enterString("1\r\n2\r\n3\r\nhi\033[Tyo\r\nA\r\nB").assertLinesAre("    ", "1   ", "2   ", "3 yo", "Ai  ",
+				"B   ");
+	}
+
+	/** CSI Ps S Scroll up Ps lines (default = 1) (SU). */
+	public void testCsiS() {
+		// The behaviour here is a bit inconsistent between terminals - this is how the OS X Terminal.app does it:
+		withTerminalSized(3, 4).enterString("1\r\n2\r\n3\r\nhi\033[2Sy").assertLinesAre("3  ", "hi ", "   ", "  y");
+		// Default value (1):
+		withTerminalSized(3, 4).enterString("1\r\n2\r\n3\r\nhi\033[Sy").assertLinesAre("2  ", "3  ", "hi ", "  y");
+	}
+
+	/** CSI Ps X  Erase Ps Character(s) (default = 1) (ECH). */
+	public void testCsiX() {
+		// See https://code.google.com/p/chromium/issues/detail?id=212712 where test was extraced from.
+		withTerminalSized(13, 2).enterString("abcdefghijkl\b\b\b\b\b\033[X").assertLinesAre("abcdefg ijkl ", "             ");
+		withTerminalSized(13, 2).enterString("abcdefghijkl\b\b\b\b\b\033[1X").assertLinesAre("abcdefg ijkl ", "             ");
+		withTerminalSized(13, 2).enterString("abcdefghijkl\b\b\b\b\b\033[2X").assertLinesAre("abcdefg  jkl ", "             ");
+		withTerminalSized(13, 2).enterString("abcdefghijkl\b\b\b\b\b\033[20X").assertLinesAre("abcdefg      ", "             ");
+	}
+
+	/** CSI Pm m  Set SGR parameter(s) from semicolon-separated list Pm. */
+	public void testCsiSGRParameters() {
+		// Set more parameters (19) than supported (16).  Additional parameters should be silently consumed.
+		withTerminalSized(3, 2).enterString("\033[0;38;2;255;255;255;48;2;0;0;0;1;2;3;4;5;7;8;9mabc").assertLinesAre("abc", "   ");
+	}
+
+	/** CSI Ps b  Repeat the preceding graphic character Ps times (REP). */
+	public void testRepeat() {
+		withTerminalSized(3, 2).enterString("a\033[b").assertLinesAre("aa ", "   ");
+		withTerminalSized(3, 2).enterString("a\033[2b").assertLinesAre("aaa", "   ");
+		// When no char has been output we ignore REP:
+		withTerminalSized(3, 2).enterString("\033[b").assertLinesAre("   ", "   ");
+		// This shows that REP outputs the last emitted code point and not the one relative to the
+		// current cursor position:
+		withTerminalSized(5, 2).enterString("abcde\033[2G\033[2b\n").assertLinesAre("aeede", "     ");
+	}
+
+	/** CSI 3 J  Clear scrollback (xterm, libvte; non-standard). */
+	public void testCsi3J() {
+		withTerminalSized(3, 2).enterString("a\r\nb\r\nc\r\nd");
+		assertEquals("a\nb\nc\nd", mTerminal.getScreen().getTranscriptText());
+		enterString("\033[3J");
+		assertEquals("c\nd", mTerminal.getScreen().getTranscriptText());
+
+		withTerminalSized(3, 2).enterString("Lorem_ipsum");
+		assertEquals("Lorem_ipsum", mTerminal.getScreen().getTranscriptText());
+		enterString("\033[3J");
+		assertEquals("ipsum", mTerminal.getScreen().getTranscriptText());
+
+		withTerminalSized(3, 2).enterString("w\r\nx\r\ny\r\nz\033[?1049h\033[3J\033[?1049l");
+		assertEquals("y\nz", mTerminal.getScreen().getTranscriptText());
+	}
+
+    public void testReportPixelSize() {
+        int columns = 3;
+        int rows = 3;
+        withTerminalSized(columns, rows);
+        int cellWidth = TerminalTest.INITIAL_CELL_WIDTH_PIXELS;
+        int cellHeight = TerminalTest.INITIAL_CELL_HEIGHT_PIXELS;
+        assertEnteringStringGivesResponse("\033[14t", "\033[4;" + (rows*cellHeight) + ";" + (columns*cellWidth) + "t");
+        assertEnteringStringGivesResponse("\033[16t", "\033[6;" + cellHeight + ";" + cellWidth + "t");
+        columns = 23;
+        rows = 33;
+        resize(columns, rows);
+        assertEnteringStringGivesResponse("\033[14t", "\033[4;" + (rows*cellHeight) + ";" + (columns*cellWidth) + "t");
+        assertEnteringStringGivesResponse("\033[16t", "\033[6;" + cellHeight + ";" + cellWidth + "t");
+        cellWidth = 8;
+        cellHeight = 18;
+        mTerminal.resize(columns, rows, cellWidth, cellHeight);
+        assertEnteringStringGivesResponse("\033[14t", "\033[4;" + (rows*cellHeight) + ";" + (columns*cellWidth) + "t");
+        assertEnteringStringGivesResponse("\033[16t", "\033[6;" + cellHeight + ";" + cellWidth + "t");
+    }
+
+    /**
+     * See <a href="https://sw.kovidgoyal.net/kitty/underlines/">Colored and styled underlines</a>:
+     *
+     * <pre>
+     *  <ESC>[4:0m  # no underline
+     *  <ESC>[4:1m  # straight underline
+     *  <ESC>[4:2m  # double underline
+     *  <ESC>[4:3m  # curly underline
+     *  <ESC>[4:4m  # dotted underline
+     *  <ESC>[4:5m  # dashed underline
+     *  <ESC>[4m    # straight underline (for backwards compat)
+     *  <ESC>[24m   # no underline (for backwards compat)
+     * </pre>
+     * <p>
+     * We currently parse the variants, but map them to normal/no underlines as appropriate
+     */
+    public void testUnderlineVariants() {
+        for (String suffix : List.of("", ":1", ":2", ":3", ":4", ":5")) {
+            for (String stop : List.of("24", "4:0")) {
+                withTerminalSized(3, 3);
+                enterString("\033[4" + suffix + "m").assertLinesAre("   ", "   ", "   ");
+                assertEquals(TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE, mTerminal.mEffect);
+                enterString("\033[4;1m").assertLinesAre("   ", "   ", "   ");
+                assertEquals(TextStyle.CHARACTER_ATTRIBUTE_BOLD | TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE, mTerminal.mEffect);
+                enterString("\033[" + stop + "m").assertLinesAre("   ", "   ", "   ");
+                assertEquals(TextStyle.CHARACTER_ATTRIBUTE_BOLD, mTerminal.mEffect);
+            }
+        }
+    }
+
+    public void testManyParameters() {
+        StringBuilder b = new StringBuilder("\033[");
+        for (int i = 0; i < 30; i++) {
+            b.append("0;");
+        }
+        b.append("4:2");
+        // This clearing of underline should be ignored as the parameters pass the threshold for too many parameters:
+        b.append("4:0m");
+        withTerminalSized(3, 3)
+            .enterString(b.toString())
+            .assertLinesAre("   ", "   ", "   ");
+        assertEquals(TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE, mTerminal.mEffect);
+    }
+
+}

terminal-emulator/src/test/java/com/termux/terminal/CursorAndScreenTest.java

@@ -0,0 +1,266 @@
+package com.termux.terminal;
+
+import org.junit.Assert;
+
+public class CursorAndScreenTest extends TerminalTestCase {
+
+	public void testDeleteLinesKeepsStyles() {
+		int cols = 5, rows = 5;
+		withTerminalSized(cols, rows);
+		for (int row = 0; row < 5; row++) {
+			for (int col = 0; col < 5; col++) {
+				// Foreground color to col, background to row:
+				enterString("\033[38;5;" + col + "m");
+				enterString("\033[48;5;" + row + "m");
+				enterString(Character.toString((char) ('A' + col + row * 5)));
+			}
+		}
+		assertLinesAre("ABCDE", "FGHIJ", "KLMNO", "PQRST", "UVWXY");
+		for (int row = 0; row < 5; row++) {
+			for (int col = 0; col < 5; col++) {
+				long s = getStyleAt(row, col);
+				Assert.assertEquals(col, TextStyle.decodeForeColor(s));
+				Assert.assertEquals(row, TextStyle.decodeBackColor(s));
+			}
+		}
+		// "${CSI}H" - place cursor at 1,1, then "${CSI}2M" to delete two lines.
+		enterString("\033[H\033[2M");
+		assertLinesAre("KLMNO", "PQRST", "UVWXY", "     ", "     ");
+		for (int row = 0; row < 3; row++) {
+			for (int col = 0; col < 5; col++) {
+				long s = getStyleAt(row, col);
+				Assert.assertEquals(col, TextStyle.decodeForeColor(s));
+				Assert.assertEquals(row + 2, TextStyle.decodeBackColor(s));
+			}
+		}
+		// Set default fg and background for the new blank lines:
+		enterString("\033[38;5;98m");
+		enterString("\033[48;5;99m");
+		// "${CSI}B" to go down one line, then "${CSI}2L" to insert two lines:
+		enterString("\033[B\033[2L");
+		assertLinesAre("KLMNO", "     ", "     ", "PQRST", "UVWXY");
+		for (int row = 0; row < 5; row++) {
+			for (int col = 0; col < 5; col++) {
+				int wantedForeground = (row == 1 || row == 2) ? 98 : col;
+				int wantedBackground = (row == 1 || row == 2) ? 99 : (row == 0 ? 2 : row);
+				long s = getStyleAt(row, col);
+				Assert.assertEquals(wantedForeground, TextStyle.decodeForeColor(s));
+				Assert.assertEquals(wantedBackground, TextStyle.decodeBackColor(s));
+			}
+		}
+	}
+
+	public void testDeleteCharacters() {
+		withTerminalSized(5, 2).enterString("枝ce").assertLinesAre("枝ce ", "     ");
+		withTerminalSized(5, 2).enterString("a枝ce").assertLinesAre("a枝ce", "     ");
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[G\033[P").assertLinesAre("ice  ", "     ");
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[G\033[2P").assertLinesAre("ce   ", "     ");
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[2G\033[2P").assertLinesAre("ne   ", "     ");
+		// "${CSI}${n}P, the delete characters (DCH) sequence should cap characters to delete.
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[G\033[99P").assertLinesAre("     ", "     ");
+		// With combining char U+0302.
+		withTerminalSized(5, 2).enterString("n\u0302ice").enterString("\033[G\033[2P").assertLinesAre("ce   ", "     ");
+		withTerminalSized(5, 2).enterString("n\u0302ice").enterString("\033[G\033[P").assertLinesAre("ice  ", "     ");
+		withTerminalSized(5, 2).enterString("n\u0302ice").enterString("\033[2G\033[2P").assertLinesAre("n\u0302e   ", "     ");
+		// With wide 枝 char, checking that putting char at part replaces other with whitespace:
+		withTerminalSized(5, 2).enterString("枝ce").enterString("\033[Ga").assertLinesAre("a ce ", "     ");
+		withTerminalSized(5, 2).enterString("枝ce").enterString("\033[2Ga").assertLinesAre(" ace ", "     ");
+		// With wide 枝 char, deleting either part replaces other with whitespace:
+		withTerminalSized(5, 2).enterString("枝ce").enterString("\033[G\033[P").assertLinesAre(" ce  ", "     ");
+		withTerminalSized(5, 2).enterString("枝ce").enterString("\033[2G\033[P").assertLinesAre(" ce  ", "     ");
+		withTerminalSized(5, 2).enterString("枝ce").enterString("\033[2G\033[2P").assertLinesAre(" e   ", "     ");
+		withTerminalSized(5, 2).enterString("枝ce").enterString("\033[G\033[2P").assertLinesAre("ce   ", "     ");
+		withTerminalSized(5, 2).enterString("a枝ce").enterString("\033[G\033[P").assertLinesAre("枝ce ", "     ");
+	}
+
+	public void testInsertMode() {
+		// "${CSI}4h" enables insert mode.
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[G\033[4hA").assertLinesAre("Anice", "     ");
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[2G\033[4hA").assertLinesAre("nAice", "     ");
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[G\033[4hABC").assertLinesAre("ABCni", "     ");
+		// With combining char U+0302.
+		withTerminalSized(5, 2).enterString("n\u0302ice").enterString("\033[G\033[4hA").assertLinesAre("An\u0302ice", "     ");
+		withTerminalSized(5, 2).enterString("n\u0302ice").enterString("\033[G\033[4hAB").assertLinesAre("ABn\u0302ic", "     ");
+		withTerminalSized(5, 2).enterString("n\u0302ic\u0302e").enterString("\033[2G\033[4hA").assertLinesAre("n\u0302Aic\u0302e", "     ");
+		// ... but without insert mode, combining char should be overwritten:
+		withTerminalSized(5, 2).enterString("n\u0302ice").enterString("\033[GA").assertLinesAre("Aice ", "     ");
+		// ... also with two combining:
+		withTerminalSized(5, 2).enterString("n\u0302\u0302i\u0302ce").enterString("\033[GA").assertLinesAre("Ai\u0302ce ", "     ");
+		// ... and in last column:
+		withTerminalSized(5, 2).enterString("n\u0302\u0302ice!\u0302").enterString("\033[5GA").assertLinesAre("n\u0302\u0302iceA", "     ");
+		withTerminalSized(5, 2).enterString("nic\u0302e!\u0302").enterString("\033[4G枝").assertLinesAre("nic\u0302枝", "     ");
+		withTerminalSized(5, 2).enterString("nic枝\u0302").enterString("\033[3GA").assertLinesAre("niA枝\u0302", "     ");
+		withTerminalSized(5, 2).enterString("nic枝\u0302").enterString("\033[3GA").assertLinesAre("niA枝\u0302", "     ");
+		// With wide 枝 char.
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[G\033[4h枝").assertLinesAre("枝nic", "     ");
+		withTerminalSized(5, 2).enterString("nice").enterString("\033[2G\033[4h枝").assertLinesAre("n枝ic", "     ");
+		withTerminalSized(5, 2).enterString("n枝ce").enterString("\033[G\033[4ha").assertLinesAre("an枝c", "     ");
+	}
+
+	/** HPA—Horizontal Position Absolute (http://www.vt100.net/docs/vt510-rm/HPA) */
+	public void testCursorHorizontalPositionAbsolute() {
+		withTerminalSized(4, 4).enterString("ABC\033[`").assertCursorAt(0, 0);
+		enterString("\033[1`").assertCursorAt(0, 0).enterString("\033[2`").assertCursorAt(0, 1);
+		enterString("\r\n\033[3`").assertCursorAt(1, 2).enterString("\033[22`").assertCursorAt(1, 3);
+		// Enable and configure right and left margins, first without origin mode:
+		enterString("\033[?69h\033[2;3s\033[`").assertCursorAt(0, 0).enterString("\033[22`").assertCursorAt(0, 3);
+		// .. now with origin mode:
+		enterString("\033[?6h\033[`").assertCursorAt(0, 1).enterString("\033[22`").assertCursorAt(0, 2);
+	}
+
+	public void testCursorForward() {
+		// "${CSI}${N:=1}C" moves cursor forward N columns:
+		withTerminalSized(6, 2).enterString("A\033[CB\033[2CC").assertLinesAre("A B  C", "      ");
+		// If an attempt is made to move the cursor to the right of the right margin, the cursor stops at the right margin:
+		withTerminalSized(6, 2).enterString("A\033[44CB").assertLinesAre("A    B", "      ");
+		// Enable right margin and verify that CUF ends at the set right margin:
+		withTerminalSized(6, 2).enterString("\033[?69h\033[1;3s\033[44CAB").assertLinesAre("  A   ", "B     ");
+	}
+
+	public void testCursorBack() {
+		// "${CSI}${N:=1}D" moves cursor back N columns:
+		withTerminalSized(3, 2).enterString("A\033[DB").assertLinesAre("B  ", "   ");
+		withTerminalSized(3, 2).enterString("AB\033[2DC").assertLinesAre("CB ", "   ");
+		// If an attempt is made to move the cursor to the left of the left margin, the cursor stops at the left margin:
+		withTerminalSized(3, 2).enterString("AB\033[44DC").assertLinesAre("CB ", "   ");
+		// Enable left margin and verify that CUB ends at the set left margin:
+		withTerminalSized(6, 2).enterString("ABCD\033[?69h\033[2;6s\033[44DE").assertLinesAre("AECD  ", "      ");
+	}
+
+	public void testCursorUp() {
+		// "${CSI}${N:=1}A" moves cursor up N rows:
+		withTerminalSized(3, 3).enterString("ABCDEFG\033[AH").assertLinesAre("ABC", "DHF", "G  ");
+		withTerminalSized(3, 3).enterString("ABCDEFG\033[2AH").assertLinesAre("AHC", "DEF", "G  ");
+		// If an attempt is made to move the cursor above the top margin, the cursor stops at the top margin:
+		withTerminalSized(3, 3).enterString("ABCDEFG\033[44AH").assertLinesAre("AHC", "DEF", "G  ");
+	}
+
+	public void testCursorDown() {
+		// "${CSI}${N:=1}B" moves cursor down N rows:
+		withTerminalSized(3, 3).enterString("AB\033[BC").assertLinesAre("AB ", "  C", "   ");
+		withTerminalSized(3, 3).enterString("AB\033[2BC").assertLinesAre("AB ", "   ", "  C");
+		// If an attempt is made to move the cursor below the bottom margin, the cursor stops at the bottom margin:
+		withTerminalSized(3, 3).enterString("AB\033[44BC").assertLinesAre("AB ", "   ", "  C");
+	}
+
+	public void testReportCursorPosition() {
+		withTerminalSized(10, 10);
+		for (int i = 0; i < 10; i++) {
+			for (int j = 0; j < 10; j++) {
+				enterString("\033[" + (i + 1) + ";" + (j + 1) + "H"); // CUP cursor position.
+				assertCursorAt(i, j);
+				// Device Status Report (DSR):
+				assertEnteringStringGivesResponse("\033[6n", "\033[" + (i + 1) + ";" + (j + 1) + "R");
+				// DECXCPR — Extended Cursor Position. Note that http://www.vt100.net/docs/vt510-rm/DECXCPR says
+				// the response is "${CSI}${LINE};${COLUMN};${PAGE}R" while xterm (http://invisible-island.net/xterm/ctlseqs/ctlseqs.html)
+				// drops the question mark. Expect xterm behaviour here.
+				assertEnteringStringGivesResponse("\033[?6n", "\033[?" + (i + 1) + ";" + (j + 1) + ";1R");
+			}
+		}
+	}
+
+	/**
+	 * See comments on horizontal tab handling in TerminalEmulator.java.
+	 * <p/>
+	 * We do not want to color already written cells when tabbing over them.
+	 */
+	public void DISABLED_testHorizontalTabColorsBackground() {
+		withTerminalSized(10, 3).enterString("\033[48;5;15m").enterString("\t");
+		assertCursorAt(0, 8);
+		for (int i = 0; i < 10; i++) {
+			int expectedColor = i < 8 ? 15 : TextStyle.COLOR_INDEX_BACKGROUND;
+			assertEquals(expectedColor, TextStyle.decodeBackColor(getStyleAt(0, i)));
+		}
+	}
+
+	/**
+	 * Test interactions between the cursor overflow bit and various escape sequences.
+	 * <p/>
+	 * Adapted from hterm:
+	 * https://chromium.googlesource.com/chromiumos/platform/assets/+/2337afa5c063127d5ce40ec7fec9b602d096df86%5E%21/#F2
+	 */
+	public void testClearingOfAutowrap() {
+		// Fill a row with the last hyphen wrong, then run a command that
+		// modifies the screen, then add a hyphen. The wrap bit should be
+		// cleared, so the extra hyphen can fix the row.
+		withTerminalSized(15, 6);
+
+		enterString("-----  1  ----X");
+		enterString("\033[K-");  // EL
+
+		enterString("-----  2  ----X");
+		enterString("\033[J-");  // ED
+
+		enterString("-----  3  ----X");
+		enterString("\033[@-");  // ICH
+
+		enterString("-----  4  ----X");
+		enterString("\033[P-");  // DCH
+
+		enterString("-----  5  ----X");
+		enterString("\033[X-");  // ECH
+
+		// DL will delete the entire line but clear the wrap bit, so we
+		// expect a hyphen at the end and nothing else.
+		enterString("XXXXXXXXXXXXXXX");
+		enterString("\033[M-");  // DL
+
+		assertLinesAre(
+				"-----  1  -----",
+				"-----  2  -----",
+				"-----  3  -----",
+				"-----  4  -----",
+				"-----  5  -----",
+				"              -");
+	}
+
+	public void testBackspaceAcrossWrappedLines() {
+		// Backspace should not go to previous line if not auto-wrapped:
+		withTerminalSized(3, 3).enterString("hi\r\n\b\byou").assertLinesAre("hi ", "you", "   ");
+		// Backspace should go to previous line if auto-wrapped:
+		withTerminalSized(3, 3).enterString("hi y").assertLinesAre("hi ", "y  ", "   ").enterString("\b\b#").assertLinesAre("hi#", "y  ", "   ");
+		// Initial backspace should do nothing:
+		withTerminalSized(3, 3).enterString("\b\b\b\bhi").assertLinesAre("hi ", "   ", "   ");
+	}
+
+	public void testCursorSaveRestoreLocation() {
+		// DEC save/restore
+		withTerminalSized(4, 2).enterString("t\0337est\r\nme\0338ry ").assertLinesAre("try ", "me  ");
+		// ANSI.SYS save/restore
+		withTerminalSized(4, 2).enterString("t\033[sest\r\nme\033[ury ").assertLinesAre("try ", "me  ");
+		// Alternate screen enter/exit
+		withTerminalSized(4, 2).enterString("t\033[?1049h\033[Hest\r\nme").assertLinesAre("est ", "me  ").enterString("\033[?1049lry").assertLinesAre("try ", "    ");
+	}
+
+	public void testCursorSaveRestoreTextStyle() {
+		long s;
+
+		// DEC save/restore
+		withTerminalSized(4, 2).enterString("\033[31;42;4m..\0337\033[36;47;24m\0338..");
+		s = getStyleAt(0, 3);
+		Assert.assertEquals(1, TextStyle.decodeForeColor(s));
+		Assert.assertEquals(2, TextStyle.decodeBackColor(s));
+		Assert.assertEquals(TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE, TextStyle.decodeEffect(s));
+
+		// ANSI.SYS save/restore
+		withTerminalSized(4, 2).enterString("\033[31;42;4m..\033[s\033[36;47;24m\033[u..");
+		s = getStyleAt(0, 3);
+		Assert.assertEquals(1, TextStyle.decodeForeColor(s));
+		Assert.assertEquals(2, TextStyle.decodeBackColor(s));
+		Assert.assertEquals(TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE, TextStyle.decodeEffect(s));
+
+		// Alternate screen enter/exit
+		withTerminalSized(4, 2);
+		enterString("\033[31;42;4m..\033[?1049h\033[H\033[36;47;24m.");
+		s = getStyleAt(0, 0);
+		Assert.assertEquals(6, TextStyle.decodeForeColor(s));
+		Assert.assertEquals(7, TextStyle.decodeBackColor(s));
+		Assert.assertEquals(0, TextStyle.decodeEffect(s));
+		enterString("\033[?1049l..");
+		s = getStyleAt(0, 3);
+		Assert.assertEquals(1, TextStyle.decodeForeColor(s));
+		Assert.assertEquals(2, TextStyle.decodeBackColor(s));
+		Assert.assertEquals(TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE, TextStyle.decodeEffect(s));
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/DecSetTest.java

@@ -0,0 +1,78 @@
+package com.termux.terminal;
+
+/**
+ * <pre>
+ * "CSI ? Pm h", DEC Private Mode Set (DECSET)
+ * </pre>
+ * <p/>
+ * and
+ * <p/>
+ * <pre>
+ * "CSI ? Pm l", DEC Private Mode Reset (DECRST)
+ * </pre>
+ * <p/>
+ * controls various aspects of the terminal
+ */
+public class DecSetTest extends TerminalTestCase {
+
+	/** DECSET 25, DECTCEM, controls visibility of the cursor. */
+	public void testEnableDisableCursor() {
+		withTerminalSized(3, 3);
+		assertTrue("Initially the cursor should be enabled", mTerminal.isCursorEnabled());
+		enterString("\033[?25l"); // Disable Cursor (DECTCEM).
+		assertFalse(mTerminal.isCursorEnabled());
+		enterString("\033[?25h"); // Enable Cursor (DECTCEM).
+		assertTrue(mTerminal.isCursorEnabled());
+
+		enterString("\033[?25l"); // Disable Cursor (DECTCEM), again.
+		assertFalse(mTerminal.isCursorEnabled());
+		mTerminal.reset();
+		assertTrue("Resetting the terminal should enable the cursor", mTerminal.isCursorEnabled());
+
+		enterString("\033[?25l");
+		assertFalse(mTerminal.isCursorEnabled());
+		enterString("\033c"); // RIS resetting should enabled cursor.
+		assertTrue(mTerminal.isCursorEnabled());
+	}
+
+	/** DECSET 2004, controls bracketed paste mode. */
+	public void testBracketedPasteMode() {
+		withTerminalSized(3, 3);
+
+		mTerminal.paste("a");
+		assertEquals("Pasting 'a' should output 'a' when bracketed paste mode is disabled", "a", mOutput.getOutputAndClear());
+
+		enterString("\033[?2004h"); // Enable bracketed paste mode.
+		mTerminal.paste("a");
+		assertEquals("Pasting when in bracketed paste mode should be bracketed", "\033[200~a\033[201~", mOutput.getOutputAndClear());
+
+		enterString("\033[?2004l"); // Disable bracketed paste mode.
+		mTerminal.paste("a");
+		assertEquals("Pasting 'a' should output 'a' when bracketed paste mode is disabled", "a", mOutput.getOutputAndClear());
+
+		enterString("\033[?2004h"); // Enable bracketed paste mode, again.
+		mTerminal.paste("a");
+		assertEquals("Pasting when in bracketed paste mode again should be bracketed", "\033[200~a\033[201~", mOutput.getOutputAndClear());
+
+		mTerminal.paste("\033ab\033cd\033");
+		assertEquals("Pasting an escape character should not input it", "\033[200~abcd\033[201~", mOutput.getOutputAndClear());
+		mTerminal.paste("\u0081ab\u0081cd\u009F");
+		assertEquals("Pasting C1 control codes should not input it", "\033[200~abcd\033[201~", mOutput.getOutputAndClear());
+
+		mTerminal.reset();
+		mTerminal.paste("a");
+		assertEquals("Terminal reset() should disable bracketed paste mode", "a", mOutput.getOutputAndClear());
+	}
+
+	/** DECSET 7, DECAWM, controls wraparound mode. */
+	public void testWrapAroundMode() {
+		// Default with wraparound:
+		withTerminalSized(3, 3).enterString("abcd").assertLinesAre("abc", "d  ", "   ");
+		// With wraparound disabled:
+		withTerminalSized(3, 3).enterString("\033[?7labcd").assertLinesAre("abd", "   ", "   ");
+		enterString("efg").assertLinesAre("abg", "   ", "   ");
+		// Re-enabling wraparound:
+		enterString("\033[?7hhij").assertLinesAre("abh", "ij ", "   ");
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/DeviceControlStringTest.java

@@ -0,0 +1,53 @@
+package com.termux.terminal;
+
+/**
+ * "\033P" is a device control string.
+ */
+public class DeviceControlStringTest extends TerminalTestCase {
+
+	private static String hexEncode(String s) {
+		StringBuilder result = new StringBuilder();
+		for (int i = 0; i < s.length(); i++)
+			result.append(String.format("%02X", (int) s.charAt(i)));
+		return result.toString();
+	}
+
+	private void assertCapabilityResponse(String cap, String expectedResponse) {
+		String input = "\033P+q" + hexEncode(cap) + "\033\\";
+		assertEnteringStringGivesResponse(input, "\033P1+r" + hexEncode(cap) + "=" + hexEncode(expectedResponse) + "\033\\");
+	}
+
+	public void testReportColorsAndName() {
+		// Request Termcap/Terminfo String. The string following the "q" is a list of names encoded in
+		// hexadecimal (2 digits per character) separated by ; which correspond to termcap or terminfo key
+		// names.
+		// Two special features are also recognized, which are not key names: Co for termcap colors (or colors
+		// for terminfo colors), and TN for termcap name (or name for terminfo name).
+		// xterm responds with DCS 1 + r P t ST for valid requests, adding to P t an = , and the value of the
+		// corresponding string that xterm would send, or DCS 0 + r P t ST for invalid requests. The strings are
+		// encoded in hexadecimal (2 digits per character).
+		withTerminalSized(3, 3).enterString("A");
+		assertCapabilityResponse("Co", "256");
+		assertCapabilityResponse("colors", "256");
+		assertCapabilityResponse("TN", "xterm");
+		assertCapabilityResponse("name", "xterm");
+		enterString("B").assertLinesAre("AB ", "   ", "   ");
+	}
+
+	public void testReportKeys() {
+		withTerminalSized(3, 3);
+		assertCapabilityResponse("kB", "\033[Z");
+	}
+
+	public void testReallyLongDeviceControlString() {
+		withTerminalSized(3, 3).enterString("\033P");
+		for (int i = 0; i < 10000; i++) {
+			enterString("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
+		}
+		// The terminal should ignore the overlong DCS sequence and continue printing "aaa." and fill at least the first two lines with
+		// them:
+		assertLineIs(0, "aaa");
+		assertLineIs(1, "aaa");
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/HistoryTest.java

@@ -0,0 +1,33 @@
+package com.termux.terminal;
+
+
+public class HistoryTest extends TerminalTestCase {
+
+	public void testHistory() {
+		final int rows = 3;
+		final int cols = 3;
+		withTerminalSized(cols, rows).enterString("111222333444555666777888999");
+		assertCursorAt(2, 2);
+		assertLinesAre("777", "888", "999");
+		assertHistoryStartsWith("666", "555");
+
+		resize(cols, 2);
+		assertHistoryStartsWith("777", "666", "555");
+
+		resize(cols, 3);
+		assertHistoryStartsWith("666", "555");
+	}
+
+	public void testHistoryWithScrollRegion() {
+		// "CSI P_s ; P_s r" - set Scrolling Region [top;bottom] (default = full size of window) (DECSTBM).
+		withTerminalSized(3, 4).enterString("111222333444");
+		assertLinesAre("111", "222", "333", "444");
+		enterString("\033[2;3r");
+		// NOTE: "DECSTBM moves the cursor to column 1, line 1 of the page."
+		assertCursorAt(0, 0);
+		enterString("\nCDEFGH").assertLinesAre("111", "CDE", "FGH", "444");
+		enterString("IJK").assertLinesAre("111", "FGH", "IJK", "444").assertHistoryStartsWith("CDE");
+		enterString("LMN").assertLinesAre("111", "IJK", "LMN", "444").assertHistoryStartsWith("FGH", "CDE");
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/KeyHandlerTest.java

@@ -0,0 +1,203 @@
+package com.termux.terminal;
+
+import android.view.KeyEvent;
+
+import junit.framework.TestCase;
+
+public class KeyHandlerTest extends TestCase {
+
+	private static String stringToHex(String s) {
+		if (s == null) return null;
+		StringBuilder buffer = new StringBuilder();
+		for (int i = 0; i < s.length(); i++) {
+			if (buffer.length() > 0) {
+				buffer.append(" ");
+			}
+			buffer.append("0x");
+			buffer.append(Integer.toHexString(s.charAt(i)));
+		}
+		return buffer.toString();
+	}
+
+	private static void assertKeysEquals(String expected, String actual) {
+		if (!expected.equals(actual)) {
+			assertEquals(stringToHex(expected), stringToHex(actual));
+		}
+	}
+
+	/** See http://pubs.opengroup.org/onlinepubs/7990989799/xcurses/terminfo.html */
+	public void testTermCaps() {
+		// Backspace.
+		assertKeysEquals("\u007f", KeyHandler.getCodeFromTermcap("kb", false, false));
+
+		// Back tab.
+		assertKeysEquals("\033[Z", KeyHandler.getCodeFromTermcap("kB", false, false));
+
+		// Arrow keys (up/down/right/left):
+		assertKeysEquals("\033[A", KeyHandler.getCodeFromTermcap("ku", false, false));
+		assertKeysEquals("\033[B", KeyHandler.getCodeFromTermcap("kd", false, false));
+		assertKeysEquals("\033[C", KeyHandler.getCodeFromTermcap("kr", false, false));
+		assertKeysEquals("\033[D", KeyHandler.getCodeFromTermcap("kl", false, false));
+		// .. shifted:
+		assertKeysEquals("\033[1;2A", KeyHandler.getCodeFromTermcap("kUP", false, false));
+		assertKeysEquals("\033[1;2B", KeyHandler.getCodeFromTermcap("kDN", false, false));
+		assertKeysEquals("\033[1;2C", KeyHandler.getCodeFromTermcap("%i", false, false));
+		assertKeysEquals("\033[1;2D", KeyHandler.getCodeFromTermcap("#4", false, false));
+
+		// Home/end keys:
+		assertKeysEquals("\033[H", KeyHandler.getCodeFromTermcap("kh", false, false));
+		assertKeysEquals("\033[F", KeyHandler.getCodeFromTermcap("@7", false, false));
+		// ... shifted:
+		assertKeysEquals("\033[1;2H", KeyHandler.getCodeFromTermcap("#2", false, false));
+		assertKeysEquals("\033[1;2F", KeyHandler.getCodeFromTermcap("*7", false, false));
+
+		// The traditional keyboard keypad:
+		// [Insert] [Home] [Page Up ]
+		// [Delete] [End] [Page Down]
+		//
+		// Termcap names (with xterm response in parenthesis):
+		// K1=Upper left of keypad (xterm sends same "<ESC>[H" = Home).
+		// K2=Center of keypad (xterm sends invalid response).
+		// K3=Upper right of keypad (xterm sends "<ESC>[5~" = Page Up).
+		// K4=Lower left of keypad (xterm sends "<ESC>[F" = End key).
+		// K5=Lower right of keypad (xterm sends "<ESC>[6~" = Page Down).
+		//
+		// vim/neovim (runtime/doc/term.txt):
+		// t_K1 <kHome> keypad home key
+		// t_K3 <kPageUp> keypad page-up key
+		// t_K4 <kEnd> keypad end key
+		// t_K5 <kPageDown> keypad page-down key
+		//
+		assertKeysEquals("\033[H", KeyHandler.getCodeFromTermcap("K1", false, false));
+		assertKeysEquals("\033OH", KeyHandler.getCodeFromTermcap("K1", true, false));
+		assertKeysEquals("\033[5~", KeyHandler.getCodeFromTermcap("K3", false, false));
+		assertKeysEquals("\033[F", KeyHandler.getCodeFromTermcap("K4", false, false));
+		assertKeysEquals("\033OF", KeyHandler.getCodeFromTermcap("K4", true, false));
+		assertKeysEquals("\033[6~", KeyHandler.getCodeFromTermcap("K5", false, false));
+
+		// Function keys F1-F12:
+		assertKeysEquals("\033OP", KeyHandler.getCodeFromTermcap("k1", false, false));
+		assertKeysEquals("\033OQ", KeyHandler.getCodeFromTermcap("k2", false, false));
+		assertKeysEquals("\033OR", KeyHandler.getCodeFromTermcap("k3", false, false));
+		assertKeysEquals("\033OS", KeyHandler.getCodeFromTermcap("k4", false, false));
+		assertKeysEquals("\033[15~", KeyHandler.getCodeFromTermcap("k5", false, false));
+		assertKeysEquals("\033[17~", KeyHandler.getCodeFromTermcap("k6", false, false));
+		assertKeysEquals("\033[18~", KeyHandler.getCodeFromTermcap("k7", false, false));
+		assertKeysEquals("\033[19~", KeyHandler.getCodeFromTermcap("k8", false, false));
+		assertKeysEquals("\033[20~", KeyHandler.getCodeFromTermcap("k9", false, false));
+		assertKeysEquals("\033[21~", KeyHandler.getCodeFromTermcap("k;", false, false));
+		assertKeysEquals("\033[23~", KeyHandler.getCodeFromTermcap("F1", false, false));
+		assertKeysEquals("\033[24~", KeyHandler.getCodeFromTermcap("F2", false, false));
+		// Function keys F13-F24 (same as shifted F1-F12):
+		assertKeysEquals("\033[1;2P", KeyHandler.getCodeFromTermcap("F3", false, false));
+		assertKeysEquals("\033[1;2Q", KeyHandler.getCodeFromTermcap("F4", false, false));
+		assertKeysEquals("\033[1;2R", KeyHandler.getCodeFromTermcap("F5", false, false));
+		assertKeysEquals("\033[1;2S", KeyHandler.getCodeFromTermcap("F6", false, false));
+		assertKeysEquals("\033[15;2~", KeyHandler.getCodeFromTermcap("F7", false, false));
+		assertKeysEquals("\033[17;2~", KeyHandler.getCodeFromTermcap("F8", false, false));
+		assertKeysEquals("\033[18;2~", KeyHandler.getCodeFromTermcap("F9", false, false));
+		assertKeysEquals("\033[19;2~", KeyHandler.getCodeFromTermcap("FA", false, false));
+		assertKeysEquals("\033[20;2~", KeyHandler.getCodeFromTermcap("FB", false, false));
+		assertKeysEquals("\033[21;2~", KeyHandler.getCodeFromTermcap("FC", false, false));
+		assertKeysEquals("\033[23;2~", KeyHandler.getCodeFromTermcap("FD", false, false));
+		assertKeysEquals("\033[24;2~", KeyHandler.getCodeFromTermcap("FE", false, false));
+	}
+
+	public void testKeyCodes() {
+		// Return sends carriage return (\r), which normally gets translated by the device driver to newline (\n) unless the ICRNL termios
+		// flag has been set.
+		assertKeysEquals("\r", KeyHandler.getCode(KeyEvent.KEYCODE_ENTER, 0, false, false));
+
+		// Backspace.
+		assertKeysEquals("\u007f", KeyHandler.getCode(KeyEvent.KEYCODE_DEL, 0, false, false));
+
+		// Space.
+		assertNull(KeyHandler.getCode(KeyEvent.KEYCODE_SPACE, 0, false, false));
+		assertKeysEquals("\u0000", KeyHandler.getCode(KeyEvent.KEYCODE_SPACE, KeyHandler.KEYMOD_CTRL, false, false));
+
+		// Back tab.
+		assertKeysEquals("\033[Z", KeyHandler.getCode(KeyEvent.KEYCODE_TAB, KeyHandler.KEYMOD_SHIFT, false, false));
+
+		// Arrow keys (up/down/right/left):
+		assertKeysEquals("\033[A", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_UP, 0, false, false));
+		assertKeysEquals("\033[B", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_DOWN, 0, false, false));
+		assertKeysEquals("\033[C", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_RIGHT, 0, false, false));
+		assertKeysEquals("\033[D", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_LEFT, 0, false, false));
+		// .. shifted:
+		assertKeysEquals("\033[1;2A", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_UP, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[1;2B", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_DOWN, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[1;2C", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_RIGHT, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[1;2D", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_LEFT, KeyHandler.KEYMOD_SHIFT, false, false));
+		// .. ctrl:ed:
+		assertKeysEquals("\033[1;5A", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_UP, KeyHandler.KEYMOD_CTRL, false, false));
+		assertKeysEquals("\033[1;5B", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_DOWN, KeyHandler.KEYMOD_CTRL, false, false));
+		assertKeysEquals("\033[1;5C", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_RIGHT, KeyHandler.KEYMOD_CTRL, false, false));
+		assertKeysEquals("\033[1;5D", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_LEFT, KeyHandler.KEYMOD_CTRL, false, false));
+		// .. ctrl:ed and shifted:
+		int mod = KeyHandler.KEYMOD_CTRL | KeyHandler.KEYMOD_SHIFT;
+		assertKeysEquals("\033[1;6A", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_UP, mod, false, false));
+		assertKeysEquals("\033[1;6B", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_DOWN, mod, false, false));
+		assertKeysEquals("\033[1;6C", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_RIGHT, mod, false, false));
+		assertKeysEquals("\033[1;6D", KeyHandler.getCode(KeyEvent.KEYCODE_DPAD_LEFT, mod, false, false));
+
+		// Home/end keys:
+		assertKeysEquals("\033[H", KeyHandler.getCode(KeyEvent.KEYCODE_MOVE_HOME, 0, false, false));
+		assertKeysEquals("\033[F", KeyHandler.getCode(KeyEvent.KEYCODE_MOVE_END, 0, false, false));
+		// ... shifted:
+		assertKeysEquals("\033[1;2H", KeyHandler.getCode(KeyEvent.KEYCODE_MOVE_HOME, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[1;2F", KeyHandler.getCode(KeyEvent.KEYCODE_MOVE_END, KeyHandler.KEYMOD_SHIFT, false, false));
+
+		// Function keys F1-F12:
+		assertKeysEquals("\033OP", KeyHandler.getCode(KeyEvent.KEYCODE_F1, 0, false, false));
+		assertKeysEquals("\033OQ", KeyHandler.getCode(KeyEvent.KEYCODE_F2, 0, false, false));
+		assertKeysEquals("\033OR", KeyHandler.getCode(KeyEvent.KEYCODE_F3, 0, false, false));
+		assertKeysEquals("\033OS", KeyHandler.getCode(KeyEvent.KEYCODE_F4, 0, false, false));
+		assertKeysEquals("\033[15~", KeyHandler.getCode(KeyEvent.KEYCODE_F5, 0, false, false));
+		assertKeysEquals("\033[17~", KeyHandler.getCode(KeyEvent.KEYCODE_F6, 0, false, false));
+		assertKeysEquals("\033[18~", KeyHandler.getCode(KeyEvent.KEYCODE_F7, 0, false, false));
+		assertKeysEquals("\033[19~", KeyHandler.getCode(KeyEvent.KEYCODE_F8, 0, false, false));
+		assertKeysEquals("\033[20~", KeyHandler.getCode(KeyEvent.KEYCODE_F9, 0, false, false));
+		assertKeysEquals("\033[21~", KeyHandler.getCode(KeyEvent.KEYCODE_F10, 0, false, false));
+		assertKeysEquals("\033[23~", KeyHandler.getCode(KeyEvent.KEYCODE_F11, 0, false, false));
+		assertKeysEquals("\033[24~", KeyHandler.getCode(KeyEvent.KEYCODE_F12, 0, false, false));
+		// Function keys F13-F24 (same as shifted F1-F12):
+		assertKeysEquals("\033[1;2P", KeyHandler.getCode(KeyEvent.KEYCODE_F1, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[1;2Q", KeyHandler.getCode(KeyEvent.KEYCODE_F2, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[1;2R", KeyHandler.getCode(KeyEvent.KEYCODE_F3, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[1;2S", KeyHandler.getCode(KeyEvent.KEYCODE_F4, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[15;2~", KeyHandler.getCode(KeyEvent.KEYCODE_F5, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[17;2~", KeyHandler.getCode(KeyEvent.KEYCODE_F6, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[18;2~", KeyHandler.getCode(KeyEvent.KEYCODE_F7, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[19;2~", KeyHandler.getCode(KeyEvent.KEYCODE_F8, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[20;2~", KeyHandler.getCode(KeyEvent.KEYCODE_F9, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[21;2~", KeyHandler.getCode(KeyEvent.KEYCODE_F10, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[23;2~", KeyHandler.getCode(KeyEvent.KEYCODE_F11, KeyHandler.KEYMOD_SHIFT, false, false));
+		assertKeysEquals("\033[24;2~", KeyHandler.getCode(KeyEvent.KEYCODE_F12, KeyHandler.KEYMOD_SHIFT, false, false));
+
+		assertKeysEquals("0", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_0, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("1", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_1, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("2", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_2, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("3", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_3, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("4", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_4, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("5", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_5, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("6", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_6, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("7", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_7, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("8", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_8, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals("9", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_9, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals(",", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_COMMA, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+		assertKeysEquals(".", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_DOT, KeyHandler.KEYMOD_NUM_LOCK, false, false));
+
+        assertKeysEquals("\033[2~", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_0, 0, false, false));
+        assertKeysEquals("\033[F", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_1, 0, false, false));
+        assertKeysEquals("\033[B", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_2, 0, false, false));
+        assertKeysEquals("\033[6~", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_3, 0, false, false));
+        assertKeysEquals("\033[D", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_4, 0, false, false));
+        assertKeysEquals("5", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_5, 0, false, false));
+        assertKeysEquals("\033[C", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_6, 0, false, false));
+        assertKeysEquals("\033[H", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_7, 0, false, false));
+        assertKeysEquals("\033[A", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_8, 0, false, false));
+        assertKeysEquals("\033[5~", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_9, 0, false, false));
+        assertKeysEquals("\033[3~", KeyHandler.getCode(KeyEvent.KEYCODE_NUMPAD_DOT, 0, false, false));
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/OperatingSystemControlTest.java

@@ -0,0 +1,196 @@
+package com.termux.terminal;
+
+import android.util.Base64;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+/** "ESC ]" is the Operating System Command. */
+public class OperatingSystemControlTest extends TerminalTestCase {
+
+	public void testSetTitle() throws Exception {
+		List<ChangedTitle> expectedTitleChanges = new ArrayList<>();
+
+		withTerminalSized(10, 10);
+		enterString("\033]0;Hello, world\007");
+		assertEquals("Hello, world", mTerminal.getTitle());
+		expectedTitleChanges.add(new ChangedTitle(null, "Hello, world"));
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+
+		enterString("\033]0;Goodbye, world\007");
+		assertEquals("Goodbye, world", mTerminal.getTitle());
+		expectedTitleChanges.add(new ChangedTitle("Hello, world", "Goodbye, world"));
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+
+		enterString("\033]0;Goodbye, \u00F1 world\007");
+		assertEquals("Goodbye, \uu00F1 world", mTerminal.getTitle());
+		expectedTitleChanges.add(new ChangedTitle("Goodbye, world", "Goodbye, \uu00F1 world"));
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+
+		// 2 should work as well (0 sets both title and icon).
+		enterString("\033]2;Updated\007");
+		assertEquals("Updated", mTerminal.getTitle());
+		expectedTitleChanges.add(new ChangedTitle("Goodbye, \uu00F1 world", "Updated"));
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+
+		enterString("\033[22;0t");
+		enterString("\033]0;FIRST\007");
+		expectedTitleChanges.add(new ChangedTitle("Updated", "FIRST"));
+		assertEquals("FIRST", mTerminal.getTitle());
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+
+		enterString("\033[22;0t");
+		enterString("\033]0;SECOND\007");
+		assertEquals("SECOND", mTerminal.getTitle());
+
+		expectedTitleChanges.add(new ChangedTitle("FIRST", "SECOND"));
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+
+		enterString("\033[23;0t");
+		assertEquals("FIRST", mTerminal.getTitle());
+
+		expectedTitleChanges.add(new ChangedTitle("SECOND", "FIRST"));
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+
+		enterString("\033[23;0t");
+		expectedTitleChanges.add(new ChangedTitle("FIRST", "Updated"));
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+
+		enterString("\033[22;0t");
+		enterString("\033[22;0t");
+		enterString("\033[22;0t");
+		// Popping to same title should not cause changes.
+		enterString("\033[23;0t");
+		enterString("\033[23;0t");
+		enterString("\033[23;0t");
+		assertEquals(expectedTitleChanges, mOutput.titleChanges);
+	}
+
+	public void testTitleStack() throws Exception {
+		// echo -ne '\e]0;BEFORE\007' # set title
+		// echo -ne '\e[22t' # push to stack
+		// echo -ne '\e]0;AFTER\007' # set new title
+		// echo -ne '\e[23t' # retrieve from stack
+
+		withTerminalSized(10, 10);
+		enterString("\033]0;InitialTitle\007");
+		assertEquals("InitialTitle", mTerminal.getTitle());
+		enterString("\033[22t");
+		assertEquals("InitialTitle", mTerminal.getTitle());
+		enterString("\033]0;UpdatedTitle\007");
+		assertEquals("UpdatedTitle", mTerminal.getTitle());
+		enterString("\033[23t");
+		assertEquals("InitialTitle", mTerminal.getTitle());
+		enterString("\033[23t\033[23t\033[23t");
+		assertEquals("InitialTitle", mTerminal.getTitle());
+	}
+
+	public void testSetColor() throws Exception {
+		// "OSC 4; $INDEX; $COLORSPEC BEL" => Change color $INDEX to the color specified by $COLORSPEC.
+		withTerminalSized(4, 4).enterString("\033]4;5;#00FF00\007");
+		assertEquals(Integer.toHexString(0xFF00FF00), Integer.toHexString(mTerminal.mColors.mCurrentColors[5]));
+		enterString("\033]4;5;#00FFAB\007");
+		assertEquals(mTerminal.mColors.mCurrentColors[5], 0xFF00FFAB);
+		enterString("\033]4;255;#ABFFAB\007");
+		assertEquals(mTerminal.mColors.mCurrentColors[255], 0xFFABFFAB);
+		// Two indexed colors at once:
+		enterString("\033]4;7;#00FF00;8;#0000FF\007");
+		assertEquals(mTerminal.mColors.mCurrentColors[7], 0xFF00FF00);
+		assertEquals(mTerminal.mColors.mCurrentColors[8], 0xFF0000FF);
+	}
+
+	void assertIndexColorsMatch(int[] expected) {
+		for (int i = 0; i < 255; i++)
+			assertEquals("index=" + i, expected[i], mTerminal.mColors.mCurrentColors[i]);
+	}
+
+	public void testResetColor() throws Exception {
+		withTerminalSized(4, 4);
+		int[] initialColors = new int[TextStyle.NUM_INDEXED_COLORS];
+		System.arraycopy(mTerminal.mColors.mCurrentColors, 0, initialColors, 0, initialColors.length);
+		int[] expectedColors = new int[initialColors.length];
+		System.arraycopy(mTerminal.mColors.mCurrentColors, 0, expectedColors, 0, expectedColors.length);
+		Random rand = new Random();
+		for (int endType = 0; endType < 3; endType++) {
+			// Both BEL (7) and ST (ESC \) can end an OSC sequence.
+			String ender = (endType == 0) ? "\007" : "\033\\";
+			for (int i = 0; i < 255; i++) {
+				expectedColors[i] = 0xFF000000 + (rand.nextInt() & 0xFFFFFF);
+				int r = (expectedColors[i] >> 16) & 0xFF;
+				int g = (expectedColors[i] >> 8) & 0xFF;
+				int b = expectedColors[i] & 0xFF;
+				String rgbHex = String.format("%02x", r) + String.format("%02x", g) + String.format("%02x", b);
+				enterString("\033]4;" + i + ";#" + rgbHex + ender);
+				assertEquals(expectedColors[i], mTerminal.mColors.mCurrentColors[i]);
+			}
+		}
+
+		enterString("\033]104;0\007");
+		expectedColors[0] = TerminalColors.COLOR_SCHEME.mDefaultColors[0];
+		assertIndexColorsMatch(expectedColors);
+		enterString("\033]104;1;2\007");
+		expectedColors[1] = TerminalColors.COLOR_SCHEME.mDefaultColors[1];
+		expectedColors[2] = TerminalColors.COLOR_SCHEME.mDefaultColors[2];
+		assertIndexColorsMatch(expectedColors);
+		enterString("\033]104\007"); // Reset all colors.
+		assertIndexColorsMatch(TerminalColors.COLOR_SCHEME.mDefaultColors);
+	}
+
+	public void disabledTestSetClipboard() {
+		// Cannot run this as a unit test since Base64 is a android.util class.
+		enterString("\033]52;c;" + Base64.encodeToString("Hello, world".getBytes(), 0) + "\007");
+	}
+
+	public void testResettingTerminalResetsColor() throws Exception {
+		// "OSC 4; $INDEX; $COLORSPEC BEL" => Change color $INDEX to the color specified by $COLORSPEC.
+		withTerminalSized(4, 4).enterString("\033]4;5;#00FF00\007");
+		enterString("\033]4;5;#00FFAB\007").assertColor(5, 0xFF00FFAB);
+		enterString("\033]4;255;#ABFFAB\007").assertColor(255, 0xFFABFFAB);
+		mTerminal.reset();
+		assertIndexColorsMatch(TerminalColors.COLOR_SCHEME.mDefaultColors);
+	}
+
+	public void testSettingDynamicColors() {
+		// "${OSC}${DYNAMIC};${COLORSPEC}${BEL_OR_STRINGTERMINATOR}" => Change ${DYNAMIC} color to the color specified by $COLORSPEC where:
+		// DYNAMIC=10: Text foreground color.
+		// DYNAMIC=11: Text background color.
+		// DYNAMIC=12: Text cursor color.
+		withTerminalSized(3, 3).enterString("\033]10;#ABCD00\007").assertColor(TextStyle.COLOR_INDEX_FOREGROUND, 0xFFABCD00);
+		enterString("\033]11;#0ABCD0\007").assertColor(TextStyle.COLOR_INDEX_BACKGROUND, 0xFF0ABCD0);
+		enterString("\033]12;#00ABCD\007").assertColor(TextStyle.COLOR_INDEX_CURSOR, 0xFF00ABCD);
+		// Two special colors at once
+		// ("Each successive parameter changes the next color in the list. The value of P s tells the starting point in the list"):
+		enterString("\033]10;#FF0000;#00FF00\007").assertColor(TextStyle.COLOR_INDEX_FOREGROUND, 0xFFFF0000);
+		assertColor(TextStyle.COLOR_INDEX_BACKGROUND, 0xFF00FF00);
+		// Three at once:
+		enterString("\033]10;#0000FF;#00FF00;#FF0000\007").assertColor(TextStyle.COLOR_INDEX_FOREGROUND, 0xFF0000FF);
+		assertColor(TextStyle.COLOR_INDEX_BACKGROUND, 0xFF00FF00).assertColor(TextStyle.COLOR_INDEX_CURSOR, 0xFFFF0000);
+
+		// Without ending semicolon:
+		enterString("\033]10;#FF0000\007").assertColor(TextStyle.COLOR_INDEX_FOREGROUND, 0xFFFF0000);
+		// For background and cursor:
+		enterString("\033]11;#FFFF00;\007").assertColor(TextStyle.COLOR_INDEX_BACKGROUND, 0xFFFFFF00);
+		enterString("\033]12;#00FFFF;\007").assertColor(TextStyle.COLOR_INDEX_CURSOR, 0xFF00FFFF);
+
+		// Using string terminator:
+		String stringTerminator = "\033\\";
+		enterString("\033]10;#FF0000" + stringTerminator).assertColor(TextStyle.COLOR_INDEX_FOREGROUND, 0xFFFF0000);
+		// For background and cursor:
+		enterString("\033]11;#FFFF00;" + stringTerminator).assertColor(TextStyle.COLOR_INDEX_BACKGROUND, 0xFFFFFF00);
+		enterString("\033]12;#00FFFF;" + stringTerminator).assertColor(TextStyle.COLOR_INDEX_CURSOR, 0xFF00FFFF);
+	}
+
+	public void testReportSpecialColors() {
+		// "${OSC}${DYNAMIC};?${BEL}" => Terminal responds with the control sequence which would set the current color.
+		// Both xterm and libvte (gnome-terminal and others) use the longest color representation, which means that
+		// the response is "${OSC}rgb:RRRR/GGGG/BBBB"
+		withTerminalSized(3, 3).enterString("\033]10;#ABCD00\007").assertColor(TextStyle.COLOR_INDEX_FOREGROUND, 0xFFABCD00);
+		assertEnteringStringGivesResponse("\033]10;?\007", "\033]10;rgb:abab/cdcd/0000\007");
+		// Same as above but with string terminator. xterm uses the same string terminator in the response, which
+		// e.g. script posted at http://superuser.com/questions/157563/programmatic-access-to-current-xterm-background-color
+		// relies on:
+		assertEnteringStringGivesResponse("\033]10;?\033\\", "\033]10;rgb:abab/cdcd/0000\033\\");
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/RectangularAreasTest.java

@@ -0,0 +1,117 @@
+package com.termux.terminal;
+
+public class RectangularAreasTest extends TerminalTestCase {
+
+	/** http://www.vt100.net/docs/vt510-rm/DECFRA */
+	public void testFillRectangularArea() {
+		withTerminalSized(3, 3).enterString("\033[88$x").assertLinesAre("XXX", "XXX", "XXX");
+		withTerminalSized(3, 3).enterString("\033[88;1;1;2;10$x").assertLinesAre("XXX", "XXX", "   ");
+		withTerminalSized(3, 3).enterString("\033[88;2;1;3;10$x").assertLinesAre("   ", "XXX", "XXX");
+		withTerminalSized(3, 3).enterString("\033[88;1;1;100;1$x").assertLinesAre("X  ", "X  ", "X  ");
+		withTerminalSized(3, 3).enterString("\033[88;1;1;100;2$x").assertLinesAre("XX ", "XX ", "XX ");
+		withTerminalSized(3, 3).enterString("\033[88;100;1;100;2$x").assertLinesAre("   ", "   ", "   ");
+	}
+
+	/** http://www.vt100.net/docs/vt510-rm/DECERA */
+	public void testEraseRectangularArea() {
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[$z").assertLinesAre("   ", "   ", "   ");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[1;1;2;10$z").assertLinesAre("   ", "   ", "GHI");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[2;1;3;10$z").assertLinesAre("ABC", "   ", "   ");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[1;1;100;1$z").assertLinesAre(" BC", " EF", " HI");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[1;1;100;2$z").assertLinesAre("  C", "  F", "  I");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[100;1;100;2$z").assertLinesAre("ABC", "DEF", "GHI");
+
+		withTerminalSized(3, 3).enterString("A\033[$zBC").assertLinesAre(" BC", "   ", "   ");
+	}
+
+	/** http://www.vt100.net/docs/vt510-rm/DECSED */
+	public void testSelectiveEraseInDisplay() {
+		// ${CSI}1"q enables protection, ${CSI}0"q disables it.
+		// ${CSI}?${0,1,2}J" erases (0=cursor to end, 1=start to cursor, 2=complete display).
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[?2J").assertLinesAre("   ", "   ", "   ");
+		withTerminalSized(3, 3).enterString("ABC\033[1\"qDE\033[0\"qFGHI\033[?2J").assertLinesAre("   ", "DE ", "   ");
+		withTerminalSized(3, 3).enterString("\033[1\"qABCDE\033[0\"qFGHI\033[?2J").assertLinesAre("ABC", "DE ", "   ");
+	}
+
+	/** http://vt100.net/docs/vt510-rm/DECSEL */
+	public void testSelectiveEraseInLine() {
+		// ${CSI}1"q enables protection, ${CSI}0"q disables it.
+		// ${CSI}?${0,1,2}K" erases (0=cursor to end, 1=start to cursor, 2=complete line).
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[?2K").assertLinesAre("ABC", "DEF", "   ");
+		withTerminalSized(3, 3).enterString("ABCDE\033[?0KFGHI").assertLinesAre("ABC", "DEF", "GHI");
+		withTerminalSized(3, 3).enterString("ABCDE\033[?1KFGHI").assertLinesAre("ABC", "  F", "GHI");
+		withTerminalSized(3, 3).enterString("ABCDE\033[?2KFGHI").assertLinesAre("ABC", "  F", "GHI");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[2;2H\033[?0K").assertLinesAre("ABC", "D  ", "GHI");
+		withTerminalSized(3, 3).enterString("ABC\033[1\"qD\033[0\"qE\033[?2KFGHI").assertLinesAre("ABC", "D F", "GHI");
+	}
+
+	/** http://www.vt100.net/docs/vt510-rm/DECSERA */
+	public void testSelectiveEraseInRectangle() {
+		// ${CSI}1"q enables protection, ${CSI}0"q disables it.
+		// ${CSI}?${TOP};${LEFT};${BOTTOM};${RIGHT}${" erases.
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[${").assertLinesAre("   ", "   ", "   ");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[1;1;2;10${").assertLinesAre("   ", "   ", "GHI");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[2;1;3;10${").assertLinesAre("ABC", "   ", "   ");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[1;1;100;1${").assertLinesAre(" BC", " EF", " HI");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[1;1;100;2${").assertLinesAre("  C", "  F", "  I");
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[100;1;100;2${").assertLinesAre("ABC", "DEF", "GHI");
+
+		withTerminalSized(3, 3).enterString("ABCD\033[1\"qE\033[0\"qFGHI\033[${").assertLinesAre("   ", " E ", "   ");
+		withTerminalSized(3, 3).enterString("ABCD\033[1\"qE\033[0\"qFGHI\033[1;1;2;10${").assertLinesAre("   ", " E ", "GHI");
+	}
+
+	/** http://vt100.net/docs/vt510-rm/DECCRA */
+	public void testRectangularCopy() {
+		// "${CSI}${SRC_TOP};${SRC_LEFT};${SRC_BOTTOM};${SRC_RIGHT};${SRC_PAGE};${DST_TOP};${DST_LEFT};${DST_PAGE}\$v"
+		withTerminalSized(7, 3).enterString("ABC\r\nDEF\r\nGHI\033[1;1;2;2;1;2;5;1$v").assertLinesAre("ABC    ", "DEF AB ", "GHI DE ");
+		withTerminalSized(7, 3).enterString("ABC\r\nDEF\r\nGHI\033[1;1;3;3;1;1;4;1$v").assertLinesAre("ABCABC ", "DEFDEF ", "GHIGHI ");
+		withTerminalSized(7, 3).enterString("ABC\r\nDEF\r\nGHI\033[1;1;3;3;1;1;3;1$v").assertLinesAre("ABABC  ", "DEDEF  ", "GHGHI  ");
+		withTerminalSized(7, 3).enterString("   ABC\r\n   DEF\r\n   GHI\033[1;4;3;6;1;1;1;1$v").assertLinesAre("ABCABC ", "DEFDEF ",
+				"GHIGHI ");
+		withTerminalSized(7, 3).enterString("   ABC\r\n   DEF\r\n   GHI\033[1;4;3;6;1;1;2;1$v").assertLinesAre(" ABCBC ", " DEFEF ",
+				" GHIHI ");
+		withTerminalSized(3, 3).enterString("ABC\r\nDEF\r\nGHI\033[1;1;2;2;1;2;2;1$v").assertLinesAre("ABC", "DAB", "GDE");
+
+		// Enable ${CSI}?6h origin mode (DECOM) and ${CSI}?69h for left/right margin (DECLRMM) enabling, ${CSI}${LEFTMARGIN};${RIGHTMARGIN}s
+		// for DECSLRM margin setting.
+		withTerminalSized(5, 5).enterString("\033[?6h\033[?69h\033[2;4s");
+		enterString("ABCDEFGHIJK").assertLinesAre(" ABC ", " DEF ", " GHI ", " JK  ", "     ");
+		enterString("\033[1;1;2;2;1;2;2;1$v").assertLinesAre(" ABC ", " DAB ", " GDE ", " JK  ", "     ");
+	}
+
+	/** http://vt100.net/docs/vt510-rm/DECCARA */
+	public void testChangeAttributesInRectangularArea() {
+		final int b = TextStyle.CHARACTER_ATTRIBUTE_BOLD;
+		// "${CSI}${TOP};${LEFT};${BOTTOM};${RIGHT};${ATTRIBUTES}\$r"
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[1;1;2;2;1$r").assertLinesAre("ABC", "DEF", "GHI");
+		assertEffectAttributesSet(effectLine(b, b, b), effectLine(b, b, 0), effectLine(0, 0, 0));
+
+		// Now with http://www.vt100.net/docs/vt510-rm/DECSACE ("${CSI}2*x") specifying rectangle:
+		withTerminalSized(3, 3).enterString("\033[2*xABCDEFGHI\033[1;1;2;2;1$r").assertLinesAre("ABC", "DEF", "GHI");
+		assertEffectAttributesSet(effectLine(b, b, 0), effectLine(b, b, 0), effectLine(0, 0, 0));
+	}
+
+	/** http://vt100.net/docs/vt510-rm/DECCARA */
+	public void testReverseAttributesInRectangularArea() {
+		final int b = TextStyle.CHARACTER_ATTRIBUTE_BOLD;
+		final int u = TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE;
+		final int bu = TextStyle.CHARACTER_ATTRIBUTE_BOLD | TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE;
+		// "${CSI}${TOP};${LEFT};${BOTTOM};${RIGHT};${ATTRIBUTES}\$t"
+		withTerminalSized(3, 3).enterString("ABCDEFGHI\033[1;1;2;2;1$t").assertLinesAre("ABC", "DEF", "GHI");
+		assertEffectAttributesSet(effectLine(b, b, b), effectLine(b, b, 0), effectLine(0, 0, 0));
+
+		// Now with http://www.vt100.net/docs/vt510-rm/DECSACE ("${CSI}2*x") specifying rectangle:
+		withTerminalSized(3, 3).enterString("\033[2*xABCDEFGHI\033[1;1;2;2;1$t").assertLinesAre("ABC", "DEF", "GHI");
+		assertEffectAttributesSet(effectLine(b, b, 0), effectLine(b, b, 0), effectLine(0, 0, 0));
+
+		// Check reversal by initially bolding the B:
+		withTerminalSized(3, 3).enterString("\033[2*xA\033[1mB\033[0mCDEFGHI\033[1;1;2;2;1$t").assertLinesAre("ABC", "DEF", "GHI");
+		assertEffectAttributesSet(effectLine(b, 0, 0), effectLine(b, b, 0), effectLine(0, 0, 0));
+
+		// Check reversal by initially underlining A, bolding B, then reversing both bold and underline:
+		withTerminalSized(3, 3).enterString("\033[2*x\033[4mA\033[0m\033[1mB\033[0mCDEFGHI\033[1;1;2;2;1;4$t").assertLinesAre("ABC", "DEF",
+				"GHI");
+		assertEffectAttributesSet(effectLine(b, u, 0), effectLine(bu, bu, 0), effectLine(0, 0, 0));
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/ResizeTest.java

@@ -0,0 +1,212 @@
+package com.termux.terminal;
+
+public class ResizeTest extends TerminalTestCase {
+
+	public void testResizeWhenHasHistory() {
+		final int cols = 3;
+		withTerminalSized(cols, 3).enterString("111222333444555666777888999").assertCursorAt(2, 2).assertLinesAre("777", "888", "999");
+		resize(cols, 5).assertCursorAt(4, 2).assertLinesAre("555", "666", "777", "888", "999");
+		resize(cols, 3).assertCursorAt(2, 2).assertLinesAre("777", "888", "999");
+	}
+
+	public void testResizeWhenInAltBuffer() {
+		final int rows = 3, cols = 3;
+		withTerminalSized(cols, rows).enterString("a\r\ndef$").assertLinesAre("a  ", "def", "$  ").assertCursorAt(2, 1);
+
+		// Resize and back again while in main buffer:
+		resize(cols, 5).assertLinesAre("a  ", "def", "$  ", "   ", "   ").assertCursorAt(2, 1);
+		resize(cols, rows).assertLinesAre("a  ", "def", "$  ").assertCursorAt(2, 1);
+
+		// Switch to alt buffer:
+		enterString("\033[?1049h").assertLinesAre("   ", "   ", "   ").assertCursorAt(2, 1);
+		enterString("h").assertLinesAre("   ", "   ", " h ").assertCursorAt(2, 2);
+
+		resize(cols, 5).resize(cols, rows);
+
+		// Switch from alt buffer:
+		enterString("\033[?1049l").assertLinesAre("a  ", "def", "$  ").assertCursorAt(2, 1);
+	}
+
+	public void testShrinkingInAltBuffer() {
+		final int rows = 5;
+		final int cols = 3;
+		withTerminalSized(cols, rows).enterString("A\r\nB\r\nC\r\nD\r\nE").assertLinesAre("A  ", "B  ", "C  ", "D  ", "E  ");
+		enterString("\033[?1049h").assertLinesAre("   ", "   ", "   ", "   ", "   ");
+		resize(3, 3).enterString("\033[?1049lF").assertLinesAre("C  ", "D  ", "EF ");
+	}
+
+	public void testResizeAfterNewlineWhenInAltBuffer() {
+		final int rows = 3;
+		final int cols = 3;
+		withTerminalSized(cols, rows);
+		enterString("a\r\nb\r\nc\r\nd\r\ne\r\nf\r\n").assertLinesAre("e  ", "f  ", "   ").assertCursorAt(2, 0);
+		assertLineWraps(false, false, false);
+
+		// Switch to alt buffer:
+		enterString("\033[?1049h").assertLinesAre("   ", "   ", "   ").assertCursorAt(2, 0);
+		enterString("h").assertLinesAre("   ", "   ", "h  ").assertCursorAt(2, 1);
+
+		// Grow by two rows:
+		resize(cols, 5).assertLinesAre("   ", "   ", "h  ", "   ", "   ").assertCursorAt(2, 1);
+		resize(cols, rows).assertLinesAre("   ", "   ", "h  ").assertCursorAt(2, 1);
+
+		// Switch from alt buffer:
+		enterString("\033[?1049l").assertLinesAre("e  ", "f  ", "   ").assertCursorAt(2, 0);
+	}
+
+	public void testResizeAfterHistoryWraparound() {
+		final int rows = 3;
+		final int cols = 10;
+		withTerminalSized(cols, rows);
+		StringBuilder buffer = new StringBuilder();
+		for (int i = 0; i < 1000; i++) {
+			String s = Integer.toString(i);
+			enterString(s);
+			buffer.setLength(0);
+			buffer.append(s);
+			while (buffer.length() < cols)
+				buffer.append(' ');
+			if (i > rows) {
+				assertLineIs(rows - 1, buffer.toString());
+			}
+			enterString("\r\n");
+		}
+		assertLinesAre("998       ", "999       ", "          ");
+		resize(cols, 2);
+		assertLinesAre("999       ", "          ");
+		resize(cols, 5);
+		assertLinesAre("996       ", "997       ", "998       ", "999       ", "          ");
+		resize(cols, rows);
+		assertLinesAre("998       ", "999       ", "          ");
+	}
+
+	public void testVerticalResize() {
+		final int rows = 5;
+		final int cols = 3;
+
+		withTerminalSized(cols, rows);
+		// Foreground color to 119:
+		enterString("\033[38;5;119m");
+		// Background color to 129:
+		enterString("\033[48;5;129m");
+		// Clear with ED, Erase in Display:
+		enterString("\033[2J");
+		for (int r = 0; r < rows; r++) {
+			for (int c = 0; c < cols; c++) {
+				long style = getStyleAt(r, c);
+				assertEquals(119, TextStyle.decodeForeColor(style));
+				assertEquals(129, TextStyle.decodeBackColor(style));
+			}
+		}
+		enterString("11\r\n22");
+		assertLinesAre("11 ", "22 ", "   ", "   ", "   ").assertLineWraps(false, false, false, false, false);
+		resize(cols, rows - 2).assertLinesAre("11 ", "22 ", "   ");
+
+		// After resize, screen should still be same color:
+		for (int r = 0; r < rows - 2; r++) {
+			for (int c = 0; c < cols; c++) {
+				long style = getStyleAt(r, c);
+				assertEquals(119, TextStyle.decodeForeColor(style));
+				assertEquals(129, TextStyle.decodeBackColor(style));
+			}
+		}
+
+		// Background color to 200 and grow back size (which should be cleared to the new background color):
+		enterString("\033[48;5;200m");
+		resize(cols, rows);
+		for (int r = 0; r < rows; r++) {
+			for (int c = 0; c < cols; c++) {
+                long style = getStyleAt(r, c);
+				assertEquals(119, TextStyle.decodeForeColor(style));
+				assertEquals("wrong at row=" + r, r >= 3 ? 200 : 129, TextStyle.decodeBackColor(style));
+			}
+		}
+	}
+
+	public void testHorizontalResize() {
+		final int rows = 5;
+		final int cols = 5;
+
+		withTerminalSized(cols, rows);
+		// Background color to 129:
+		// enterString("\033[48;5;129m").assertLinesAre(" ", " ", " ", " ", " ");
+		enterString("1111\r\n2222\r\n3333\r\n4444\r\n5555").assertCursorAt(4, 4);
+		// assertEquals(129, TextStyle.decodeBackColor(getStyleAt(2, 2)));
+		assertLinesAre("1111 ", "2222 ", "3333 ", "4444 ", "5555 ").assertLineWraps(false, false, false, false, false);
+		resize(cols + 2, rows).assertLinesAre("1111   ", "2222   ", "3333   ", "4444   ", "5555   ").assertCursorAt(4, 4);
+		assertLineWraps(false, false, false, false, false);
+		resize(cols, rows).assertLinesAre("1111 ", "2222 ", "3333 ", "4444 ", "5555 ").assertCursorAt(4, 4);
+		assertLineWraps(false, false, false, false, false);
+		resize(cols - 1, rows).assertLinesAre("2222", "3333", "4444", "5555", "    ").assertCursorAt(4, 0);
+		assertLineWraps(false, false, false, true, false);
+		resize(cols - 2, rows).assertLinesAre("3  ", "444", "4  ", "555", "5  ").assertCursorAt(4, 1);
+		assertLineWraps(false, true, false, true, false);
+		// Back to original size:
+		resize(cols, rows).assertLinesAre("1111 ", "2222 ", "3333 ", "4444 ", "5555 ").assertCursorAt(4, 4);
+		assertLineWraps(false, false, false, false, false);
+	}
+
+	public void testLineWrap() {
+		final int rows = 3, cols = 5;
+		withTerminalSized(cols, rows).enterString("111111").assertLinesAre("11111", "1    ", "     ");
+		assertCursorAt(1, 1).assertLineWraps(true, false, false);
+
+		resize(7, rows).assertCursorAt(0, 6).assertLinesAre("111111 ", "       ", "       ").assertLineWraps(false, false, false);
+		resize(cols, rows).assertCursorAt(1, 1).assertLinesAre("11111", "1    ", "     ").assertLineWraps(true, false, false);
+
+		enterString("2").assertLinesAre("11111", "12   ", "     ").assertLineWraps(true, false, false);
+		enterString("123").assertLinesAre("11111", "12123", "     ").assertLineWraps(true, false, false);
+		enterString("W").assertLinesAre("11111", "12123", "W    ").assertLineWraps(true, true, false);
+
+		withTerminalSized(cols, rows).enterString("1234512345");
+		assertLinesAre("12345", "12345", "     ").assertLineWraps(true, false, false);
+		enterString("W").assertLinesAre("12345", "12345", "W    ").assertLineWraps(true, true, false);
+	}
+
+	public void testCursorPositionWhenShrinking() {
+		final int rows = 5, cols = 3;
+		withTerminalSized(cols, rows).enterString("$ ").assertLinesAre("$  ", "   ", "   ", "   ", "   ").assertCursorAt(0, 2);
+		resize(3, 3).assertLinesAre("$  ", "   ", "   ").assertCursorAt(0, 2);
+		resize(cols, rows).assertLinesAre("$  ", "   ", "   ", "   ", "   ").assertCursorAt(0, 2);
+	}
+
+	public void testResizeWithCombiningCharInLastColumn() {
+		withTerminalSized(3, 3).enterString("ABC\u0302DEF").assertLinesAre("ABC\u0302", "DEF", "   ");
+		resize(4, 3).assertLinesAre("ABC\u0302D", "EF  ", "    ");
+
+		// Same as above but with colors:
+		withTerminalSized(3, 3).enterString("\033[37mA\033[35mB\033[33mC\u0302\033[32mD\033[31mE\033[34mF").assertLinesAre("ABC\u0302",
+				"DEF", "   ");
+		resize(4, 3).assertLinesAre("ABC\u0302D", "EF  ", "    ");
+		assertForegroundIndices(effectLine(7, 5, 3, 2), effectLine(1, 4, 4, 4), effectLine(4, 4, 4, 4));
+	}
+
+	public void testResizeWithLineWrappingContinuing() {
+		withTerminalSized(5, 3).enterString("\r\nAB DE").assertLinesAre("     ", "AB DE", "     ");
+		resize(4, 3).assertLinesAre("AB D", "E   ", "    ");
+		resize(3, 3).assertLinesAre("AB ", "DE ", "   ");
+		resize(5, 3).assertLinesAre("     ", "AB DE", "     ");
+	}
+
+	public void testResizeWithWideChars() {
+		final int rows = 3, cols = 4;
+		String twoCharsWidthOne = new String(Character.toChars(TerminalRowTest.TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1));
+		withTerminalSized(cols, rows).enterString(twoCharsWidthOne).enterString("\r\n");
+		enterString(twoCharsWidthOne).assertLinesAre(twoCharsWidthOne + "   ", twoCharsWidthOne + "   ", "    ");
+		resize(3, 3).assertLinesAre(twoCharsWidthOne + "  ", twoCharsWidthOne + "  ", "   ");
+		enterString(twoCharsWidthOne).assertLinesAre(twoCharsWidthOne + "  ", twoCharsWidthOne + twoCharsWidthOne + " ", "   ");
+	}
+
+	public void testResizeWithMoreWideChars() {
+		final int rows = 4, cols = 5;
+
+		withTerminalSized(cols, rows).enterString("qqrr").assertLinesAre("qqrr ", "     ", "     ", "     ");
+		resize(2, rows).assertLinesAre("qq", "rr", "  ", "  ");
+		resize(5, rows).assertLinesAre("qqrr ", "     ", "     ", "     ");
+
+		withTerminalSized(cols, rows).enterString("ＱＲ").assertLinesAre("ＱＲ ", "     ", "     ", "     ");
+		resize(2, rows).assertLinesAre("Ｑ", "Ｒ", "  ", "  ");
+		resize(5, rows).assertLinesAre("ＱＲ ", "     ", "     ", "     ");
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/ScreenBufferTest.java

@@ -0,0 +1,65 @@
+package com.termux.terminal;
+
+public class ScreenBufferTest extends TerminalTestCase {
+
+	public void testBasics() {
+		TerminalBuffer screen = new TerminalBuffer(5, 3, 3);
+		assertEquals("", screen.getTranscriptText());
+		screen.setChar(0, 0, 'a', 0);
+		assertEquals("a", screen.getTranscriptText());
+		screen.setChar(0, 0, 'b', 0);
+		assertEquals("b", screen.getTranscriptText());
+		screen.setChar(2, 0, 'c', 0);
+		assertEquals("b c", screen.getTranscriptText());
+		screen.setChar(2, 2, 'f', 0);
+		assertEquals("b c\n\n  f", screen.getTranscriptText());
+		screen.blockSet(0, 0, 2, 2, 'X', 0);
+	}
+
+	public void testBlockSet() {
+		TerminalBuffer screen = new TerminalBuffer(5, 3, 3);
+		screen.blockSet(0, 0, 2, 2, 'X', 0);
+		assertEquals("XX\nXX", screen.getTranscriptText());
+		screen.blockSet(1, 1, 2, 2, 'Y', 0);
+		assertEquals("XX\nXYY\n YY", screen.getTranscriptText());
+	}
+
+	public void testGetSelectedText() {
+		withTerminalSized(5, 3).enterString("ABCDEFGHIJ").assertLinesAre("ABCDE", "FGHIJ", "     ");
+		assertEquals("AB", mTerminal.getSelectedText(0, 0, 1, 0));
+		assertEquals("BC", mTerminal.getSelectedText(1, 0, 2, 0));
+		assertEquals("CDE", mTerminal.getSelectedText(2, 0, 4, 0));
+		assertEquals("FG", mTerminal.getSelectedText(0, 1, 1, 1));
+		assertEquals("GH", mTerminal.getSelectedText(1, 1, 2, 1));
+		assertEquals("HIJ", mTerminal.getSelectedText(2, 1, 4, 1));
+
+		assertEquals("ABCDEFG", mTerminal.getSelectedText(0, 0, 1, 1));
+		withTerminalSized(5, 3).enterString("ABCDE\r\nFGHIJ").assertLinesAre("ABCDE", "FGHIJ", "     ");
+		assertEquals("ABCDE\nFG", mTerminal.getSelectedText(0, 0, 1, 1));
+	}
+
+	public void testGetSelectedTextJoinFullLines() {
+		withTerminalSized(5, 3).enterString("ABCDE\r\nFG");
+		assertEquals("ABCDEFG", mTerminal.getScreen().getSelectedText(0, 0, 1, 1, true, true));
+
+		withTerminalSized(5, 3).enterString("ABC\r\nFG");
+		assertEquals("ABC\nFG", mTerminal.getScreen().getSelectedText(0, 0, 1, 1, true, true));
+	}
+
+	public void testGetWordAtLocation() {
+		withTerminalSized(5, 3).enterString("ABCDEFGHIJ\r\nKLMNO");
+		assertEquals("ABCDEFGHIJKLMNO", mTerminal.getScreen().getWordAtLocation(0, 0));
+		assertEquals("ABCDEFGHIJKLMNO", mTerminal.getScreen().getWordAtLocation(4, 1));
+		assertEquals("ABCDEFGHIJKLMNO", mTerminal.getScreen().getWordAtLocation(4, 2));
+
+		withTerminalSized(5, 3).enterString("ABC DEF GHI ");
+		assertEquals("ABC", mTerminal.getScreen().getWordAtLocation(0, 0));
+		assertEquals("", mTerminal.getScreen().getWordAtLocation(3, 0));
+		assertEquals("DEF", mTerminal.getScreen().getWordAtLocation(4, 0));
+		assertEquals("DEF", mTerminal.getScreen().getWordAtLocation(0, 1));
+		assertEquals("DEF", mTerminal.getScreen().getWordAtLocation(1, 1));
+		assertEquals("GHI", mTerminal.getScreen().getWordAtLocation(0, 2));
+		assertEquals("", mTerminal.getScreen().getWordAtLocation(1, 2));
+		assertEquals("", mTerminal.getScreen().getWordAtLocation(2, 2));
+	}
+}

terminal-emulator/src/test/java/com/termux/terminal/ScrollRegionTest.java

@@ -0,0 +1,167 @@
+package com.termux.terminal;
+
+/**
+ * ${CSI}${top};${bottom}r" - set Scrolling Region [top;bottom] (default = full size of window) (DECSTBM).
+ * <p/>
+ * "DECSTBM moves the cursor to column 1, line 1 of the page" (http://www.vt100.net/docs/vt510-rm/DECSTBM).
+ */
+public class ScrollRegionTest extends TerminalTestCase {
+
+	public void testScrollRegionTop() {
+		withTerminalSized(3, 4).enterString("111222333444").assertLinesAre("111", "222", "333", "444");
+		enterString("\033[2r").assertCursorAt(0, 0);
+		enterString("\r\n\r\n\r\n\r\nCDEFGH").assertLinesAre("111", "444", "CDE", "FGH").assertHistoryStartsWith("333");
+		enterString("IJK").assertLinesAre("111", "CDE", "FGH", "IJK").assertHistoryStartsWith("444");
+		// Reset scroll region and enter line:
+		enterString("\033[r").enterString("\r\n\r\n\r\n").enterString("LMNOPQ").assertLinesAre("CDE", "FGH", "LMN", "OPQ");
+	}
+
+	public void testScrollRegionBottom() {
+		withTerminalSized(3, 4).enterString("111222333444");
+		assertLinesAre("111", "222", "333", "444");
+		enterString("\033[1;3r").assertCursorAt(0, 0);
+		enterString("\r\n\r\nCDEFGH").assertLinesAre("222", "CDE", "FGH", "444").assertHistoryStartsWith("111");
+		// Reset scroll region and enter line:
+		enterString("\033[r").enterString("\r\n\r\n\r\n").enterString("IJKLMN").assertLinesAre("CDE", "FGH", "IJK", "LMN");
+	}
+
+	public void testScrollRegionResetWithOriginMode() {
+		withTerminalSized(3, 4).enterString("111222333444");
+		assertLinesAre("111", "222", "333", "444");
+		// "\033[?6h" sets origin mode, so that the later DECSTBM resets cursor to below margin:
+		enterString("\033[?6h\033[2r").assertCursorAt(1, 0);
+	}
+
+	public void testScrollRegionLeft() {
+		// ${CSI}?69h for DECLRMM enabling, ${CSI}${LEFTMARGIN};${RIGHTMARGIN}s for DECSLRM margin setting.
+		withTerminalSized(3, 3).enterString("\033[?69h\033[2sABCDEFG").assertLinesAre("ABC", " DE", " FG");
+		enterString("HI").assertLinesAre("ADE", " FG", " HI").enterString("JK").assertLinesAre("AFG", " HI", " JK");
+		enterString("\n").assertLinesAre("AHI", " JK", "   ");
+	}
+
+	public void testScrollRegionRight() {
+		// ${CSI}?69h for DECLRMM enabling, ${CSI}${LEFTMARGIN};${RIGHTMARGIN}s for DECSLRM margin setting.
+		withTerminalSized(3, 3).enterString("YYY\033[?69h\033[1;2sABCDEF").assertLinesAre("ABY", "CD ", "EF ");
+		enterString("GH").assertLinesAre("CDY", "EF ", "GH ").enterString("IJ").assertLinesAre("EFY", "GH ", "IJ ");
+		enterString("\n").assertLinesAre("GHY", "IJ ", "   ");
+	}
+
+	public void testScrollRegionOnAllSides() {
+		// ${CSI}?69h for DECLRMM enabling, ${CSI}${LEFTMARGIN};${RIGHTMARGIN}s for DECSLRM margin setting.
+		withTerminalSized(4, 4).enterString("ABCDEFGHIJKLMNOP").assertLinesAre("ABCD", "EFGH", "IJKL", "MNOP");
+		// http://www.vt100.net/docs/vt510-rm/DECOM
+		enterString("\033[?6h\033[2;3r").assertCursorAt(1, 0);
+		enterString("\033[?69h\033[2;3s").assertCursorAt(1, 1);
+		enterString("QRST").assertLinesAre("ABCD", "EQRH", "ISTL", "MNOP");
+		enterString("UV").assertLinesAre("ABCD", "ESTH", "IUVL", "MNOP");
+	}
+
+	public void testDECCOLMResetsScrollMargin() {
+		// DECCOLM — Select 80 or 132 Columns per Page (http://www.vt100.net/docs/vt510-rm/DECCOLM) has the important
+		// side effect to clear scroll margins, which is useful for e.g. the "reset" utility to clear scroll margins.
+		withTerminalSized(3, 4).enterString("111222333444").assertLinesAre("111", "222", "333", "444");
+		enterString("\033[2r\033[?3h\r\nABCDEFGHIJKL").assertLinesAre("ABC", "DEF", "GHI", "JKL");
+	}
+
+	public void testScrollOutsideVerticalRegion() {
+		withTerminalSized(3, 4).enterString("\033[0;2rhi\033[4;0Hyou").assertLinesAre("hi ", "   ", "   ", "you");
+		//enterString("see").assertLinesAre("hi ", "   ", "   ", "see");
+	}
+
+	public void testNELRespectsLeftMargin() {
+		// vttest "Menu 11.3.2: VT420 Cursor-Movement Test", select "10. Test other movement (CR/HT/LF/FF) within margins".
+		// The NEL (ESC E) sequence moves cursor to first position on next line, where first position depends on origin mode and margin.
+		withTerminalSized(3, 3).enterString("\033[?69h\033[2sABC\033ED").assertLinesAre("ABC", "D  ", "   ");
+		withTerminalSized(3, 3).enterString("\033[?69h\033[2sABC\033[?6h\033ED").assertLinesAre("ABC", " D ", "   ");
+	}
+
+	public void testRiRespectsLeftMargin() {
+		// Reverse Index (RI), ${ESC}M, should respect horizontal margins:
+		withTerminalSized(4, 3).enterString("ABCD\033[?69h\033[2;3s\033[?6h\033M").assertLinesAre("A  D", " BC ", "    ");
+	}
+
+	public void testSdRespectsLeftMargin() {
+		// Scroll Down (SD), ${CSI}${N}T, should respect horizontal margins:
+		withTerminalSized(4, 3).enterString("ABCD\033[?69h\033[2;3s\033[?6h\033[2T").assertLinesAre("A  D", "    ", " BC ");
+	}
+
+	public void testBackwardIndex() {
+		// vttest "Menu 11.3.2: VT420 Cursor-Movement Test", test 7.
+		// Without margins:
+		withTerminalSized(3, 3).enterString("ABCDEF\0336H").assertLinesAre("ABC", "DHF", "   ");
+		enterString("\0336\0336I").assertLinesAre("ABC", "IHF", "   ");
+		enterString("\0336\0336").assertLinesAre(" AB", " IH", "   ");
+		// With left margin:
+		withTerminalSized(3, 3).enterString("\033[?69h\033[2sABCDEF\0336\0336").assertLinesAre("A B", "  D", "  F");
+	}
+
+	public void testForwardIndex() {
+		// vttest "Menu 11.3.2: VT420 Cursor-Movement Test", test 8.
+		// Without margins:
+		withTerminalSized(3, 3).enterString("ABCD\0339E").assertLinesAre("ABC", "D E", "   ");
+		enterString("\0339").assertLinesAre("BC ", " E ", "   ");
+		// With right margin:
+		withTerminalSized(3, 3).enterString("\033[?69h\033[0;2sABCD\0339").assertLinesAre("B  ", "D  ", "   ");
+	}
+
+	public void testScrollDownWithScrollRegion() {
+		withTerminalSized(2, 5).enterString("1\r\n2\r\n3\r\n4\r\n5").assertLinesAre("1 ", "2 ", "3 ", "4 ", "5 ");
+		enterString("\033[3r").enterString("\033[2T").assertLinesAre("1 ", "2 ", "  ", "  ", "3 ");
+	}
+
+	public void testScrollDownBelowScrollRegion() {
+		withTerminalSized(2, 5).enterString("1\r\n2\r\n3\r\n4\r\n5").assertLinesAre("1 ", "2 ", "3 ", "4 ", "5 ");
+		enterString("\033[1;3r"); // DECSTBM margins.
+		enterString("\033[4;1H"); // Place cursor just below bottom margin.
+		enterString("QQ\r\nRR\r\n\r\n\r\nYY");
+		assertLinesAre("1 ", "2 ", "3 ", "QQ", "YY");
+	}
+
+	/** See https://github.com/termux/termux-app/issues/1340 */
+	public void testScrollRegionDoesNotLimitCursorMovement() {
+		withTerminalSized(6, 4)
+			.enterString("\033[4;7r\033[3;1Haaa\033[Axxx")
+			.assertLinesAre(
+				"      ",
+				"   xxx",
+				"aaa   ",
+				"      "
+			);
+
+		withTerminalSized(6, 4)
+			.enterString("\033[1;3r\033[3;1Haaa\033[Bxxx")
+			.assertLinesAre(
+				"      ",
+				"      ",
+				"aaa   ",
+				"   xxx"
+			);
+	}
+
+	/**
+	 * See <a href="https://github.com/termux/termux-packages/issues/12556">reported issue</a>.
+	 */
+	public void testClearingWhenScrollingWithMargins() {
+		int newForeground = 2;
+		int newBackground = 3;
+		int size = 3;
+		TerminalTestCase terminal = withTerminalSized(size, size)
+			// Enable horizontal margin and set left margin to 1:
+			.enterString("\033[?69h\033[2s")
+			// Set foreground and background color:
+			.enterString("\033[" + (30 + newForeground) + ";" + (40 + newBackground) + "m")
+			// Enter newlines to scroll down:
+			.enterString("\r\n\r\n\r\n\r\n\r\n");
+		for (int row = 0; row < size; row++) {
+			for (int col = 0; col < size; col++) {
+				// The first column (outside of the scrolling area, due to us setting a left scroll
+				// margin of 1) should be unmodified, the others should use the current style:
+				int expectedForeground = col == 0 ? TextStyle.COLOR_INDEX_FOREGROUND : newForeground;
+				int expectedBackground = col == 0 ? TextStyle.COLOR_INDEX_BACKGROUND : newBackground;
+				terminal.assertForegroundColorAt(row, col, expectedForeground);
+				terminal.assertBackgroundColorAt(row, col, expectedBackground);
+			}
+		}
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/TerminalRowTest.java

@@ -0,0 +1,432 @@
+package com.termux.terminal;
+
+import junit.framework.TestCase;
+
+import java.util.Arrays;
+import java.util.Random;
+
+public class TerminalRowTest extends TestCase {
+
+	/** The properties of these code points are validated in {@link #testStaticConstants()}. */
+	private static final int ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1 = 0x679C;
+	private static final int ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2 = 0x679D;
+	private static final int TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_1 = 0x2070E;
+	private static final int TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_2 = 0x20731;
+
+	/** Unicode Character 'MUSICAL SYMBOL G CLEF' (U+1D11E). Two java chars required for this. */
+	static final int TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1 = 0x1D11E;
+	/** Unicode Character 'MUSICAL SYMBOL G CLEF OTTAVA ALTA' (U+1D11F). Two java chars required for this. */
+	private static final int TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_2 = 0x1D11F;
+
+	private final int COLUMNS = 80;
+
+	/** A combining character. */
+	private static final int DIARESIS_CODEPOINT = 0x0308;
+
+	private TerminalRow row;
+
+	@Override
+	protected void setUp() throws Exception {
+		super.setUp();
+		row = new TerminalRow(COLUMNS, TextStyle.NORMAL);
+	}
+
+	private void assertLineStartsWith(int... codePoints) {
+		char[] chars = row.mText;
+		int charIndex = 0;
+		for (int i = 0; i < codePoints.length; i++) {
+			int lineCodePoint = chars[charIndex++];
+			if (Character.isHighSurrogate((char) lineCodePoint)) {
+				lineCodePoint = Character.toCodePoint((char) lineCodePoint, chars[charIndex++]);
+			}
+			assertEquals("Differing a code point index=" + i, codePoints[i], lineCodePoint);
+		}
+	}
+
+	private void assertColumnCharIndicesStartsWith(int... indices) {
+		for (int i = 0; i < indices.length; i++) {
+			int expected = indices[i];
+			int actual = row.findStartOfColumn(i);
+			assertEquals("At index=" + i, expected, actual);
+		}
+	}
+
+	public void testSimpleDiaresis() {
+		row.setChar(0, DIARESIS_CODEPOINT, 0);
+		assertEquals(81, row.getSpaceUsed());
+		row.setChar(0, DIARESIS_CODEPOINT, 0);
+		assertEquals(82, row.getSpaceUsed());
+		assertLineStartsWith(' ', DIARESIS_CODEPOINT, DIARESIS_CODEPOINT, ' ');
+	}
+
+	public void testStaticConstants() {
+		assertEquals(1, Character.charCount(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1));
+		assertEquals(1, Character.charCount(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2));
+		assertEquals(2, WcWidth.width(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1));
+		assertEquals(2, WcWidth.width(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2));
+
+		assertEquals(2, Character.charCount(TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1));
+		assertEquals(2, Character.charCount(TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_2));
+		assertEquals(1, WcWidth.width(TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1));
+		assertEquals(1, WcWidth.width(TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_2));
+
+		assertEquals(2, Character.charCount(TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_1));
+		assertEquals(2, Character.charCount(TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_2));
+		assertEquals(2, WcWidth.width(TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_1));
+		assertEquals(2, WcWidth.width(TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_2));
+
+		assertEquals(1, Character.charCount(DIARESIS_CODEPOINT));
+		assertEquals(0, WcWidth.width(DIARESIS_CODEPOINT));
+	}
+
+	public void testOneColumn() {
+		assertEquals(0, row.findStartOfColumn(0));
+		row.setChar(0, 'a', 0);
+		assertEquals(0, row.findStartOfColumn(0));
+	}
+
+	public void testAscii() {
+		assertEquals(0, row.findStartOfColumn(0));
+		row.setChar(0, 'a', 0);
+		assertLineStartsWith('a', ' ', ' ');
+		assertEquals(1, row.findStartOfColumn(1));
+		assertEquals(80, row.getSpaceUsed());
+		row.setChar(0, 'b', 0);
+		assertEquals(1, row.findStartOfColumn(1));
+		assertEquals(2, row.findStartOfColumn(2));
+		assertEquals(80, row.getSpaceUsed());
+		assertColumnCharIndicesStartsWith(0, 1, 2, 3);
+
+		char[] someChars = new char[]{'a', 'c', 'e', '4', '5', '6', '7', '8'};
+
+		char[] rawLine = new char[80];
+		Arrays.fill(rawLine, ' ');
+		Random random = new Random();
+		for (int i = 0; i < 1000; i++) {
+			int lineIndex = random.nextInt(rawLine.length);
+			int charIndex = random.nextInt(someChars.length);
+			rawLine[lineIndex] = someChars[charIndex];
+			row.setChar(lineIndex, someChars[charIndex], 0);
+		}
+		char[] lineChars = row.mText;
+		for (int i = 0; i < rawLine.length; i++) {
+			assertEquals(rawLine[i], lineChars[i]);
+		}
+	}
+
+	public void testUnicode() {
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(80, row.getSpaceUsed());
+
+		row.setChar(0, TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1, 0);
+		assertEquals(81, row.getSpaceUsed());
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(2, row.findStartOfColumn(1));
+		assertLineStartsWith(TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1, ' ', ' ');
+		assertColumnCharIndicesStartsWith(0, 2, 3, 4);
+
+		row.setChar(0, 'a', 0);
+		assertEquals(80, row.getSpaceUsed());
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(1, row.findStartOfColumn(1));
+		assertLineStartsWith('a', ' ', ' ');
+		assertColumnCharIndicesStartsWith(0, 1, 2, 3);
+
+		row.setChar(0, TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1, 0);
+		row.setChar(1, 'a', 0);
+		assertLineStartsWith(TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1, 'a', ' ');
+
+		row.setChar(0, TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1, 0);
+		row.setChar(1, TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_2, 0);
+		assertLineStartsWith(TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_1, TWO_JAVA_CHARS_DISPLAY_WIDTH_ONE_2, ' ');
+		assertColumnCharIndicesStartsWith(0, 2, 4, 5);
+		assertEquals(82, row.getSpaceUsed());
+	}
+
+	public void testDoubleWidth() {
+		row.setChar(0, 'a', 0);
+		row.setChar(1, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2, 0);
+		assertLineStartsWith('a', ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2, ' ');
+		assertColumnCharIndicesStartsWith(0, 1, 1, 2);
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		assertLineStartsWith(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, ' ', ' ');
+		assertColumnCharIndicesStartsWith(0, 0, 1, 2);
+
+		row.setChar(0, ' ', 0);
+		assertLineStartsWith(' ', ' ', ' ', ' ');
+		assertColumnCharIndicesStartsWith(0, 1, 2, 3, 4);
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		row.setChar(2, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2, 0);
+		assertLineStartsWith(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2);
+		assertColumnCharIndicesStartsWith(0, 0, 1, 1, 2);
+		row.setChar(0, 'a', 0);
+		assertLineStartsWith('a', ' ', ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2, ' ');
+	}
+
+	/** Just as {@link #testDoubleWidth()} but requires a surrogate pair. */
+	public void testDoubleWidthSurrogage() {
+		row.setChar(0, 'a', 0);
+		assertColumnCharIndicesStartsWith(0, 1, 2, 3, 4);
+
+		row.setChar(1, TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_2, 0);
+		assertColumnCharIndicesStartsWith(0, 1, 1, 3, 4);
+		assertLineStartsWith('a', TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_2, ' ');
+		row.setChar(0, TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_1, 0);
+		assertColumnCharIndicesStartsWith(0, 0, 2, 3, 4);
+		assertLineStartsWith(TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_1, ' ', ' ', ' ');
+
+		row.setChar(0, ' ', 0);
+		assertLineStartsWith(' ', ' ', ' ', ' ');
+		row.setChar(0, TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_1, 0);
+		row.setChar(1, TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_2, 0);
+		assertLineStartsWith(' ', TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_2, ' ');
+		row.setChar(0, 'a', 0);
+		assertLineStartsWith('a', TWO_JAVA_CHARS_DISPLAY_WIDTH_TWO_2, ' ');
+	}
+
+	public void testReplacementChar() {
+		row.setChar(0, TerminalEmulator.UNICODE_REPLACEMENT_CHAR, 0);
+		row.setChar(1, 'Y', 0);
+		assertLineStartsWith(TerminalEmulator.UNICODE_REPLACEMENT_CHAR, 'Y', ' ', ' ');
+	}
+
+	public void testSurrogateCharsWithNormalDisplayWidth() {
+		// These requires a UTF-16 surrogate pair, and has a display width of one.
+		int first = 0x1D306;
+		int second = 0x1D307;
+		// Assert the above statement:
+		assertEquals(2, Character.toChars(first).length);
+		assertEquals(2, Character.toChars(second).length);
+
+		row.setChar(0, second, 0);
+		assertEquals(second, Character.toCodePoint(row.mText[0], row.mText[1]));
+		assertEquals(' ', row.mText[2]);
+		assertEquals(2, row.findStartOfColumn(1));
+
+		row.setChar(0, first, 0);
+		assertEquals(first, Character.toCodePoint(row.mText[0], row.mText[1]));
+		assertEquals(' ', row.mText[2]);
+		assertEquals(2, row.findStartOfColumn(1));
+
+		row.setChar(1, second, 0);
+		row.setChar(2, 'a', 0);
+		assertEquals(first, Character.toCodePoint(row.mText[0], row.mText[1]));
+		assertEquals(second, Character.toCodePoint(row.mText[2], row.mText[3]));
+		assertEquals('a', row.mText[4]);
+		assertEquals(' ', row.mText[5]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(2, row.findStartOfColumn(1));
+		assertEquals(4, row.findStartOfColumn(2));
+		assertEquals(5, row.findStartOfColumn(3));
+		assertEquals(6, row.findStartOfColumn(4));
+
+		row.setChar(0, ' ', 0);
+		assertEquals(' ', row.mText[0]);
+		assertEquals(second, Character.toCodePoint(row.mText[1], row.mText[2]));
+		assertEquals('a', row.mText[3]);
+		assertEquals(' ', row.mText[4]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(1, row.findStartOfColumn(1));
+		assertEquals(3, row.findStartOfColumn(2));
+		assertEquals(4, row.findStartOfColumn(3));
+		assertEquals(5, row.findStartOfColumn(4));
+
+		for (int i = 0; i < 80; i++) {
+			row.setChar(i, i % 2 == 0 ? first : second, 0);
+		}
+		for (int i = 0; i < 80; i++) {
+			int idx = row.findStartOfColumn(i);
+			assertEquals(i % 2 == 0 ? first : second, Character.toCodePoint(row.mText[idx], row.mText[idx + 1]));
+		}
+		for (int i = 0; i < 80; i++) {
+			row.setChar(i, i % 2 == 0 ? 'a' : 'b', 0);
+		}
+		for (int i = 0; i < 80; i++) {
+			int idx = row.findStartOfColumn(i);
+			assertEquals(i, idx);
+			assertEquals(i % 2 == 0 ? 'a' : 'b', row.mText[i]);
+		}
+	}
+
+	public void testOverwritingDoubleDisplayWidthWithNormalDisplayWidth() {
+		// Initial "OO "
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, row.mText[0]);
+		assertEquals(' ', row.mText[1]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(0, row.findStartOfColumn(1));
+		assertEquals(1, row.findStartOfColumn(2));
+
+		// Setting first column to a clears second: "a  "
+		row.setChar(0, 'a', 0);
+		assertEquals('a', row.mText[0]);
+		assertEquals(' ', row.mText[1]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(1, row.findStartOfColumn(1));
+		assertEquals(2, row.findStartOfColumn(2));
+
+		// Back to initial "OO "
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, row.mText[0]);
+		assertEquals(' ', row.mText[1]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(0, row.findStartOfColumn(1));
+		assertEquals(1, row.findStartOfColumn(2));
+
+		// Setting first column to a clears first: " a "
+		row.setChar(1, 'a', 0);
+		assertEquals(' ', row.mText[0]);
+		assertEquals('a', row.mText[1]);
+		assertEquals(' ', row.mText[2]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(1, row.findStartOfColumn(1));
+		assertEquals(2, row.findStartOfColumn(2));
+	}
+
+	public void testOverwritingDoubleDisplayWidthWithSelf() {
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, row.mText[0]);
+		assertEquals(' ', row.mText[1]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(0, row.findStartOfColumn(1));
+		assertEquals(1, row.findStartOfColumn(2));
+	}
+
+	public void testNormalCharsWithDoubleDisplayWidth() {
+		// These fit in one java char, and has a display width of two.
+		assertTrue(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1 != ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2);
+		assertEquals(1, Character.charCount(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1));
+		assertEquals(1, Character.charCount(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2));
+		assertEquals(2, WcWidth.width(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1));
+		assertEquals(2, WcWidth.width(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2));
+
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, row.mText[0]);
+		assertEquals(0, row.findStartOfColumn(1));
+		assertEquals(' ', row.mText[1]);
+
+		row.setChar(0, 'a', 0);
+		assertEquals('a', row.mText[0]);
+		assertEquals(' ', row.mText[1]);
+		assertEquals(1, row.findStartOfColumn(1));
+
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, row.mText[0]);
+		// The first character fills both first columns.
+		assertEquals(0, row.findStartOfColumn(1));
+		row.setChar(2, 'a', 0);
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, row.mText[0]);
+		assertEquals('a', row.mText[1]);
+		assertEquals(1, row.findStartOfColumn(2));
+
+		row.setChar(0, 'c', 0);
+		assertEquals('c', row.mText[0]);
+		assertEquals(' ', row.mText[1]);
+		assertEquals('a', row.mText[2]);
+		assertEquals(' ', row.mText[3]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(1, row.findStartOfColumn(1));
+		assertEquals(2, row.findStartOfColumn(2));
+	}
+
+	public void testNormalCharsWithDoubleDisplayWidthOverlapping() {
+		// These fit in one java char, and has a display width of two.
+		row.setChar(0, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, 0);
+		row.setChar(2, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2, 0);
+		row.setChar(4, 'a', 0);
+		// O = ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO
+		// A = ANOTHER_JAVA_CHAR_DISPLAY_WIDTH_TWO
+		// "OOAAa    "
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(0, row.findStartOfColumn(1));
+		assertEquals(1, row.findStartOfColumn(2));
+		assertEquals(1, row.findStartOfColumn(3));
+		assertEquals(2, row.findStartOfColumn(4));
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1, row.mText[0]);
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2, row.mText[1]);
+		assertEquals('a', row.mText[2]);
+		assertEquals(' ', row.mText[3]);
+
+		row.setChar(1, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2, 0);
+		// " AA a    "
+		assertEquals(' ', row.mText[0]);
+		assertEquals(ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_2, row.mText[1]);
+		assertEquals(' ', row.mText[2]);
+		assertEquals('a', row.mText[3]);
+		assertEquals(' ', row.mText[4]);
+		assertEquals(0, row.findStartOfColumn(0));
+		assertEquals(1, row.findStartOfColumn(1));
+		assertEquals(1, row.findStartOfColumn(2));
+		assertEquals(2, row.findStartOfColumn(3));
+		assertEquals(3, row.findStartOfColumn(4));
+	}
+
+	// https://github.com/jackpal/Android-Terminal-Emulator/issues/145
+	public void testCrashATE145() {
+		// 0xC2541 is unassigned, use display width 1 for UNICODE_REPLACEMENT_CHAR.
+		// assertEquals(1, WcWidth.width(0xC2541));
+		assertEquals(2, Character.charCount(0xC2541));
+
+		assertEquals(2, WcWidth.width(0x73EE));
+		assertEquals(1, Character.charCount(0x73EE));
+
+		assertEquals(0, WcWidth.width(0x009F));
+		assertEquals(1, Character.charCount(0x009F));
+
+		int[] points = new int[]{0xC2541, 'a', '8', 0x73EE, 0x009F, 0x881F, 0x8324, 0xD4C9, 0xFFFD, 'B', 0x009B, 0x61C9, 'Z'};
+		// int[] expected = new int[] { TerminalEmulator.UNICODE_REPLACEMENT_CHAR, 'a', '8', 0x73EE, 0x009F, 0x881F, 0x8324, 0xD4C9, 0xFFFD,
+		// 'B', 0x009B, 0x61C9, 'Z' };
+		int currentColumn = 0;
+		for (int point : points) {
+			row.setChar(currentColumn, point, 0);
+			currentColumn += WcWidth.width(point);
+		}
+		// assertLineStartsWith(points);
+		// assertEquals(Character.highSurrogate(0xC2541), line.mText[0]);
+		// assertEquals(Character.lowSurrogate(0xC2541), line.mText[1]);
+		// assertEquals('a', line.mText[2]);
+		// assertEquals('8', line.mText[3]);
+		// assertEquals(Character.highSurrogate(0x73EE), line.mText[4]);
+		// assertEquals(Character.lowSurrogate(0x73EE), line.mText[5]);
+		//
+		// char[] chars = line.mText;
+		// int charIndex = 0;
+		// for (int i = 0; i < points.length; i++) {
+		// char c = chars[charIndex];
+		// charIndex++;
+		// int thisPoint = (int) c;
+		// if (Character.isHighSurrogate(c)) {
+		// thisPoint = Character.toCodePoint(c, chars[charIndex]);
+		// charIndex++;
+		// }
+		// assertEquals("At index=" + i + ", charIndex=" + charIndex + ", char=" + (char) thisPoint, points[i], thisPoint);
+		// }
+	}
+
+	public void testNormalization() {
+		// int lowerCaseN = 0x006E;
+		// int combiningTilde = 0x0303;
+		// int combined = 0x00F1;
+		row.setChar(0, 0x006E, 0);
+		assertEquals(80, row.getSpaceUsed());
+		row.setChar(0, 0x0303, 0);
+		assertEquals(81, row.getSpaceUsed());
+		// assertEquals("\u00F1  ", new String(term.getScreen().getLine(0)));
+		assertLineStartsWith(0x006E, 0x0303, ' ');
+	}
+
+	public void testInsertWideAtLastColumn() {
+		row.setChar(COLUMNS - 2, 'Z', 0);
+		row.setChar(COLUMNS - 1, 'a', 0);
+		assertEquals('Z', row.mText[row.findStartOfColumn(COLUMNS - 2)]);
+		assertEquals('a', row.mText[row.findStartOfColumn(COLUMNS - 1)]);
+		row.setChar(COLUMNS - 1, 'ö', 0);
+		assertEquals('Z', row.mText[row.findStartOfColumn(COLUMNS - 2)]);
+		assertEquals('ö', row.mText[row.findStartOfColumn(COLUMNS - 1)]);
+		// line.setChar(COLUMNS - 1, ONE_JAVA_CHAR_DISPLAY_WIDTH_TWO_1);
+		// assertEquals('Z', line.mText[line.findStartOfColumn(COLUMNS - 2)]);
+		// assertEquals(' ', line.mText[line.findStartOfColumn(COLUMNS - 1)]);
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/TerminalTest.java

@@ -0,0 +1,350 @@
+package com.termux.terminal;
+
+import java.io.UnsupportedEncodingException;
+
+public class TerminalTest extends TerminalTestCase {
+
+	public void testCursorPositioning() throws Exception {
+		withTerminalSized(10, 10).placeCursorAndAssert(1, 2).placeCursorAndAssert(3, 5).placeCursorAndAssert(2, 2).enterString("A")
+				.assertCursorAt(2, 3);
+	}
+
+	public void testScreen() throws UnsupportedEncodingException {
+		withTerminalSized(3, 3);
+		assertLinesAre("   ", "   ", "   ");
+
+		assertEquals("", mTerminal.getScreen().getTranscriptText());
+		enterString("hi").assertLinesAre("hi ", "   ", "   ");
+		assertEquals("hi", mTerminal.getScreen().getTranscriptText());
+		enterString("\r\nu");
+		assertEquals("hi\nu", mTerminal.getScreen().getTranscriptText());
+		mTerminal.reset();
+		assertEquals("hi\nu", mTerminal.getScreen().getTranscriptText());
+
+		withTerminalSized(3, 3).enterString("hello");
+		assertEquals("hello", mTerminal.getScreen().getTranscriptText());
+		enterString("\r\nworld");
+		assertEquals("hello\nworld", mTerminal.getScreen().getTranscriptText());
+	}
+
+	public void testScrollDownInAltBuffer() {
+		withTerminalSized(3, 3).enterString("\033[?1049h");
+		enterString("\033[38;5;111m1\r\n");
+		enterString("\033[38;5;112m2\r\n");
+		enterString("\033[38;5;113m3\r\n");
+		enterString("\033[38;5;114m4\r\n");
+		enterString("\033[38;5;115m5");
+		assertLinesAre("3  ", "4  ", "5  ");
+		assertForegroundColorAt(0, 0, 113);
+		assertForegroundColorAt(1, 0, 114);
+		assertForegroundColorAt(2, 0, 115);
+	}
+
+	public void testMouseClick() throws Exception {
+		withTerminalSized(10, 10);
+		assertFalse(mTerminal.isMouseTrackingActive());
+		enterString("\033[?1000h");
+		assertTrue(mTerminal.isMouseTrackingActive());
+		enterString("\033[?1000l");
+		assertFalse(mTerminal.isMouseTrackingActive());
+		enterString("\033[?1000h");
+		assertTrue(mTerminal.isMouseTrackingActive());
+
+		enterString("\033[?1006h");
+		mTerminal.sendMouseEvent(TerminalEmulator.MOUSE_LEFT_BUTTON, 3, 4, true);
+		assertEquals("\033[<0;3;4M", mOutput.getOutputAndClear());
+		mTerminal.sendMouseEvent(TerminalEmulator.MOUSE_LEFT_BUTTON, 3, 4, false);
+		assertEquals("\033[<0;3;4m", mOutput.getOutputAndClear());
+
+		// When the client says that a click is outside (which could happen when pixels are outside
+		// the terminal area, see https://github.com/termux/termux-app/issues/501) the terminal
+		// sends a click at the edge.
+		mTerminal.sendMouseEvent(TerminalEmulator.MOUSE_LEFT_BUTTON, 0, 0, true);
+		assertEquals("\033[<0;1;1M", mOutput.getOutputAndClear());
+		mTerminal.sendMouseEvent(TerminalEmulator.MOUSE_LEFT_BUTTON, 11, 11, false);
+		assertEquals("\033[<0;10;10m", mOutput.getOutputAndClear());
+	}
+
+	public void testNormalization() throws UnsupportedEncodingException {
+		// int lowerCaseN = 0x006E;
+		// int combiningTilde = 0x0303;
+		// int combined = 0x00F1;
+		withTerminalSized(3, 3).assertLinesAre("   ", "   ", "   ");
+		enterString("\u006E\u0303");
+		assertEquals(1, WcWidth.width("\u006E\u0303".toCharArray(), 0));
+		// assertEquals("\u00F1  ", new String(mTerminal.getScreen().getLine(0)));
+		assertLinesAre("\u006E\u0303  ", "   ", "   ");
+	}
+
+	/** On "\e[18t" xterm replies with "\e[8;${HEIGHT};${WIDTH}t" */
+	public void testReportTerminalSize() throws Exception {
+		withTerminalSized(5, 5);
+		assertEnteringStringGivesResponse("\033[18t", "\033[8;5;5t");
+		for (int width = 3; width < 12; width++) {
+			for (int height = 3; height < 12; height++) {
+				resize(width, height);
+				assertEnteringStringGivesResponse("\033[18t", "\033[8;" + height + ";" + width + "t");
+			}
+		}
+	}
+
+	/** Device Status Report (DSR) and Report Cursor Position (CPR). */
+	public void testDeviceStatusReport() throws Exception {
+		withTerminalSized(5, 5);
+		assertEnteringStringGivesResponse("\033[5n", "\033[0n");
+
+		assertEnteringStringGivesResponse("\033[6n", "\033[1;1R");
+		enterString("AB");
+		assertEnteringStringGivesResponse("\033[6n", "\033[1;3R");
+		enterString("\r\n");
+		assertEnteringStringGivesResponse("\033[6n", "\033[2;1R");
+	}
+
+	/** Test the cursor shape changes using DECSCUSR. */
+	public void testSetCursorStyle() throws Exception {
+		withTerminalSized(5, 5);
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_BLOCK, mTerminal.getCursorStyle());
+		enterString("\033[3 q");
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_UNDERLINE, mTerminal.getCursorStyle());
+		enterString("\033[5 q");
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_BAR, mTerminal.getCursorStyle());
+		enterString("\033[0 q");
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_BLOCK, mTerminal.getCursorStyle());
+		enterString("\033[6 q");
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_BAR, mTerminal.getCursorStyle());
+		enterString("\033[4 q");
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_UNDERLINE, mTerminal.getCursorStyle());
+		enterString("\033[1 q");
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_BLOCK, mTerminal.getCursorStyle());
+		enterString("\033[4 q");
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_UNDERLINE, mTerminal.getCursorStyle());
+		enterString("\033[2 q");
+		assertEquals(TerminalEmulator.TERMINAL_CURSOR_STYLE_BLOCK, mTerminal.getCursorStyle());
+	}
+
+	public void testPaste() {
+		withTerminalSized(5, 5);
+		mTerminal.paste("hi");
+		assertEquals("hi", mOutput.getOutputAndClear());
+
+		enterString("\033[?2004h");
+		mTerminal.paste("hi");
+		assertEquals("\033[200~" + "hi" + "\033[201~", mOutput.getOutputAndClear());
+
+		enterString("\033[?2004l");
+		mTerminal.paste("hi");
+		assertEquals("hi", mOutput.getOutputAndClear());
+	}
+
+	public void testSelectGraphics() {
+		selectGraphicsTestRun(';');
+		selectGraphicsTestRun(':');
+	}
+
+	public void selectGraphicsTestRun(char separator) {
+		withTerminalSized(5, 5);
+		enterString("\033[31m");
+		assertEquals(mTerminal.mForeColor, 1);
+		enterString("\033[32m");
+		assertEquals(mTerminal.mForeColor, 2);
+		enterString("\033[43m");
+		assertEquals(2, mTerminal.mForeColor);
+		assertEquals(3, mTerminal.mBackColor);
+
+		// SGR 0 should reset both foreground and background color.
+		enterString("\033[0m");
+		assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+		assertEquals(TextStyle.COLOR_INDEX_BACKGROUND, mTerminal.mBackColor);
+
+		// Test CSI resetting to default if sequence starts with ; or has sequential ;;
+        // Check TerminalEmulator.parseArg()
+        enterString("\033[31m\033[m");
+        assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+        enterString("\033[31m\033[;m".replace(';', separator));
+        assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+        enterString("\033[31m\033[0m");
+        assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+        enterString("\033[31m\033[0;m".replace(';', separator));
+        assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+        enterString("\033[31;;m");
+        assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+        enterString("\033[31::m");
+        assertEquals(1, mTerminal.mForeColor);
+        enterString("\033[31;m");
+        assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+        enterString("\033[31:m");
+        assertEquals(1, mTerminal.mForeColor);
+        enterString("\033[31;;41m");
+        assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+        assertEquals(1, mTerminal.mBackColor);
+        enterString("\033[0m");
+        assertEquals(TextStyle.COLOR_INDEX_BACKGROUND, mTerminal.mBackColor);
+
+		// 256 colors:
+		enterString("\033[38;5;119m".replace(';', separator));
+		assertEquals(119, mTerminal.mForeColor);
+		assertEquals(TextStyle.COLOR_INDEX_BACKGROUND, mTerminal.mBackColor);
+		enterString("\033[48;5;129m".replace(';', separator));
+		assertEquals(119, mTerminal.mForeColor);
+		assertEquals(129, mTerminal.mBackColor);
+
+		// Invalid parameter:
+		enterString("\033[48;8;129m".replace(';', separator));
+		assertEquals(119, mTerminal.mForeColor);
+		assertEquals(129, mTerminal.mBackColor);
+
+		// Multiple parameters at once:
+		enterString("\033[38;5;178".replace(';', separator) + ";" + "48;5;179m".replace(';', separator));
+		assertEquals(178, mTerminal.mForeColor);
+		assertEquals(179, mTerminal.mBackColor);
+
+		// Omitted parameter means zero:
+		enterString("\033[38;5;m".replace(';', separator));
+		assertEquals(0, mTerminal.mForeColor);
+		assertEquals(179, mTerminal.mBackColor);
+		enterString("\033[48;5;m".replace(';', separator));
+		assertEquals(0, mTerminal.mForeColor);
+		assertEquals(0, mTerminal.mBackColor);
+
+		// 24 bit colors:
+		enterString(("\033[0m")); // Reset fg and bg colors.
+		enterString("\033[38;2;255;127;2m".replace(';', separator));
+		int expectedForeground = 0xff000000 | (255 << 16) | (127 << 8) | 2;
+		assertEquals(expectedForeground, mTerminal.mForeColor);
+		assertEquals(TextStyle.COLOR_INDEX_BACKGROUND, mTerminal.mBackColor);
+		enterString("\033[48;2;1;2;254m".replace(';', separator));
+		int expectedBackground = 0xff000000 | (1 << 16) | (2 << 8) | 254;
+		assertEquals(expectedForeground, mTerminal.mForeColor);
+		assertEquals(expectedBackground, mTerminal.mBackColor);
+
+		// 24 bit colors, set fg and bg at once:
+		enterString(("\033[0m")); // Reset fg and bg colors.
+		assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, mTerminal.mForeColor);
+		assertEquals(TextStyle.COLOR_INDEX_BACKGROUND, mTerminal.mBackColor);
+		enterString("\033[38;2;255;127;2".replace(';', separator) + ";" + "48;2;1;2;254m".replace(';', separator));
+		assertEquals(expectedForeground, mTerminal.mForeColor);
+		assertEquals(expectedBackground, mTerminal.mBackColor);
+
+		// 24 bit colors, invalid input:
+		enterString("\033[38;2;300;127;2;48;2;1;300;254m".replace(';', separator));
+		assertEquals(expectedForeground, mTerminal.mForeColor);
+		assertEquals(expectedBackground, mTerminal.mBackColor);
+
+		// 24 bit colors, omitted parameter means zero:
+		enterString("\033[38;2;255;127;m".replace(';', separator));
+		expectedForeground = 0xff000000 | (255 << 16) | (127 << 8);
+		assertEquals(expectedForeground, mTerminal.mForeColor);
+		assertEquals(expectedBackground, mTerminal.mBackColor);
+		enterString("\033[38;2;123;;77m".replace(';', separator));
+		expectedForeground = 0xff000000 | (123 << 16) | 77;
+		assertEquals(expectedForeground, mTerminal.mForeColor);
+		assertEquals(expectedBackground, mTerminal.mBackColor);
+
+		// 24 bit colors, extra sub-parameters are skipped:
+		expectedForeground = 0xff000000 | (255 << 16) | (127 << 8) | 2;
+		enterString("\033[0;38:2:255:127:2:48:2:1:2:254m");
+		assertEquals(expectedForeground, mTerminal.mForeColor);
+		assertEquals(TextStyle.COLOR_INDEX_BACKGROUND, mTerminal.mBackColor);
+	}
+
+	public void testBackgroundColorErase() {
+		final int rows = 3;
+		final int cols = 3;
+		withTerminalSized(cols, rows);
+		for (int r = 0; r < rows; r++) {
+			for (int c = 0; c < cols; c++) {
+				long style = getStyleAt(r, c);
+				assertEquals(TextStyle.COLOR_INDEX_FOREGROUND, TextStyle.decodeForeColor(style));
+				assertEquals(TextStyle.COLOR_INDEX_BACKGROUND, TextStyle.decodeBackColor(style));
+			}
+		}
+		// Foreground color to 119:
+		enterString("\033[38;5;119m");
+		// Background color to 129:
+		enterString("\033[48;5;129m");
+		// Clear with ED, Erase in Display:
+		enterString("\033[2J");
+		for (int r = 0; r < rows; r++) {
+			for (int c = 0; c < cols; c++) {
+				long style = getStyleAt(r, c);
+				assertEquals(119, TextStyle.decodeForeColor(style));
+				assertEquals(129, TextStyle.decodeBackColor(style));
+			}
+		}
+		// Background color to 139:
+		enterString("\033[48;5;139m");
+		// Insert two blank lines.
+		enterString("\033[2L");
+		for (int r = 0; r < rows; r++) {
+			for (int c = 0; c < cols; c++) {
+				long style = getStyleAt(r, c);
+				assertEquals((r == 0 || r == 1) ? 139 : 129, TextStyle.decodeBackColor(style));
+			}
+		}
+
+		withTerminalSized(cols, rows);
+		// Background color to 129:
+		enterString("\033[48;5;129m");
+		// Erase two characters, filling them with background color:
+		enterString("\033[2X");
+		assertEquals(129, TextStyle.decodeBackColor(getStyleAt(0, 0)));
+		assertEquals(129, TextStyle.decodeBackColor(getStyleAt(0, 1)));
+		assertEquals(TextStyle.COLOR_INDEX_BACKGROUND, TextStyle.decodeBackColor(getStyleAt(0, 2)));
+	}
+
+	public void testParseColor() {
+		assertEquals(0xFF0000FA, TerminalColors.parse("#0000FA"));
+		assertEquals(0xFF000000, TerminalColors.parse("#000000"));
+		assertEquals(0xFF000000, TerminalColors.parse("#000"));
+		assertEquals(0xFF000000, TerminalColors.parse("#000000000"));
+		assertEquals(0xFF53186f, TerminalColors.parse("#53186f"));
+
+		assertEquals(0xFFFF00FF, TerminalColors.parse("rgb:F/0/F"));
+		assertEquals(0xFF0000FA, TerminalColors.parse("rgb:00/00/FA"));
+		assertEquals(0xFF53186f, TerminalColors.parse("rgb:53/18/6f"));
+
+		assertEquals(0, TerminalColors.parse("invalid_0000FA"));
+		assertEquals(0, TerminalColors.parse("#3456"));
+	}
+
+	/** The ncurses library still uses this. */
+	public void testLineDrawing() {
+		// 016 - shift out / G1. 017 - shift in / G0. "ESC ) 0" - use line drawing for G1
+		withTerminalSized(4, 2).enterString("q\033)0q\016q\017q").assertLinesAre("qq─q", "    ");
+		// "\0337", saving cursor should save G0, G1 and invoked charset and "ESC 8" should restore.
+		withTerminalSized(4, 2).enterString("\033)0\016qqq\0337\017\0338q").assertLinesAre("────", "    ");
+	}
+
+	public void testSoftTerminalReset() {
+		// See http://vt100.net/docs/vt510-rm/DECSTR and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=650304
+		// "\033[?7l" is DECRST to disable wrap-around, and DECSTR ("\033[!p") should reset it.
+		withTerminalSized(3, 3).enterString("\033[?7lABCD").assertLinesAre("ABD", "   ", "   ");
+		enterString("\033[!pEF").assertLinesAre("ABE", "F  ", "   ");
+	}
+
+	public void testBel() {
+		withTerminalSized(3, 3);
+		assertEquals(0, mOutput.bellsRung);
+		enterString("\07");
+		assertEquals(1, mOutput.bellsRung);
+		enterString("hello\07");
+		assertEquals(2, mOutput.bellsRung);
+		enterString("\07hello");
+		assertEquals(3, mOutput.bellsRung);
+		enterString("hello\07world");
+		assertEquals(4, mOutput.bellsRung);
+	}
+
+	public void testAutomargins() throws UnsupportedEncodingException {
+		withTerminalSized(3, 3).enterString("abc").assertLinesAre("abc", "   ", "   ").assertCursorAt(0, 2);
+		enterString("d").assertLinesAre("abc", "d  ", "   ").assertCursorAt(1, 1);
+
+		withTerminalSized(3, 3).enterString("abc\r ").assertLinesAre(" bc", "   ", "   ").assertCursorAt(0, 1);
+	}
+
+	public void testTab() {
+		withTerminalSized(11, 2).enterString("01234567890\r\tXX").assertLinesAre("01234567XX0", "           ");
+		withTerminalSized(11, 2).enterString("01234567890\033[44m\r\tXX").assertLinesAre("01234567XX0", "           ");
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/TerminalTestCase.java

@@ -0,0 +1,319 @@
+package com.termux.terminal;
+
+import junit.framework.AssertionFailedError;
+import junit.framework.TestCase;
+
+import java.io.ByteArrayOutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+
+public abstract class TerminalTestCase extends TestCase {
+
+    public static final int INITIAL_CELL_WIDTH_PIXELS = 13;
+    public static final int INITIAL_CELL_HEIGHT_PIXELS = 15;
+
+    public static class MockTerminalOutput extends TerminalOutput {
+		final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		public final List<ChangedTitle> titleChanges = new ArrayList<>();
+		public final List<String> clipboardPuts = new ArrayList<>();
+		public int bellsRung = 0;
+		public int colorsChanged = 0;
+
+		@Override
+		public void write(byte[] data, int offset, int count) {
+			baos.write(data, offset, count);
+		}
+
+		public String getOutputAndClear() {
+			String result = new String(baos.toByteArray(), StandardCharsets.UTF_8);
+			baos.reset();
+			return result;
+		}
+
+		@Override
+		public void titleChanged(String oldTitle, String newTitle) {
+			titleChanges.add(new ChangedTitle(oldTitle, newTitle));
+		}
+
+		@Override
+		public void onCopyTextToClipboard(String text) {
+			clipboardPuts.add(text);
+		}
+
+        @Override
+        public void onPasteTextFromClipboard() {
+        }
+
+		@Override
+		public void onBell() {
+			bellsRung++;
+		}
+
+		@Override
+		public void onColorsChanged() {
+			colorsChanged++;
+		}
+	}
+
+	public TerminalEmulator mTerminal;
+	public MockTerminalOutput mOutput;
+
+	public static final class ChangedTitle {
+		final String oldTitle;
+		final String newTitle;
+
+		public ChangedTitle(String oldTitle, String newTitle) {
+			this.oldTitle = oldTitle;
+			this.newTitle = newTitle;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (!(o instanceof ChangedTitle)) return false;
+			ChangedTitle other = (ChangedTitle) o;
+			return Objects.equals(oldTitle, other.oldTitle) && Objects.equals(newTitle, other.newTitle);
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hash(oldTitle, newTitle);
+		}
+
+		@Override
+		public String toString() {
+			return "ChangedTitle[oldTitle=" + oldTitle + ", newTitle=" + newTitle + "]";
+		}
+
+	}
+
+	public TerminalTestCase enterString(String s) {
+		byte[] bytes = s.getBytes(StandardCharsets.UTF_8);
+		mTerminal.append(bytes, bytes.length);
+		assertInvariants();
+		return this;
+	}
+
+	public void assertEnteringStringGivesResponse(String input, String expectedResponse) {
+		enterString(input);
+		String response = mOutput.getOutputAndClear();
+		assertEquals(expectedResponse, response);
+	}
+
+	@Override
+	protected void setUp() throws Exception {
+		super.setUp();
+		mOutput = new MockTerminalOutput();
+	}
+
+	protected TerminalTestCase withTerminalSized(int columns, int rows) {
+	    // The tests aren't currently using the client, so a null client will suffice, a dummy client should be implemented if needed
+		mTerminal = new TerminalEmulator(mOutput, columns, rows, INITIAL_CELL_WIDTH_PIXELS, INITIAL_CELL_HEIGHT_PIXELS, rows * 2, null);
+		return this;
+	}
+
+	public void assertHistoryStartsWith(String... rows) {
+		assertTrue("About to check " + rows.length + " lines, but only " + mTerminal.getScreen().getActiveTranscriptRows() + " in history",
+				mTerminal.getScreen().getActiveTranscriptRows() >= rows.length);
+		for (int i = 0; i < rows.length; i++) {
+			assertLineIs(-i - 1, rows[i]);
+		}
+	}
+
+	private static final class LineWrapper {
+		final TerminalRow mLine;
+
+		public LineWrapper(TerminalRow line) {
+			mLine = line;
+		}
+
+		@Override
+		public int hashCode() {
+			return System.identityHashCode(mLine);
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			return o instanceof LineWrapper && ((LineWrapper) o).mLine == mLine;
+		}
+	}
+
+	protected TerminalTestCase assertInvariants() {
+		TerminalBuffer screen = mTerminal.getScreen();
+		TerminalRow[] lines = screen.mLines;
+
+		Set<LineWrapper> linesSet = new HashSet<>();
+		for (int i = 0; i < lines.length; i++) {
+			if (lines[i] == null) continue;
+			assertTrue("Line exists at multiple places: " + i, linesSet.add(new LineWrapper(lines[i])));
+			char[] text = lines[i].mText;
+			int usedChars = lines[i].getSpaceUsed();
+			int currentColumn = 0;
+			for (int j = 0; j < usedChars; j++) {
+				char c = text[j];
+				int codePoint;
+				if (Character.isHighSurrogate(c)) {
+					char lowSurrogate = text[++j];
+					assertTrue("High surrogate without following low surrogate", Character.isLowSurrogate(lowSurrogate));
+					codePoint = Character.toCodePoint(c, lowSurrogate);
+				} else {
+					assertFalse("Low surrogate without preceding high surrogate", Character.isLowSurrogate(c));
+					codePoint = c;
+				}
+				assertFalse("Screen should never contain unassigned characters", Character.getType(codePoint) == Character.UNASSIGNED);
+				int width = WcWidth.width(codePoint);
+				assertFalse("The first column should not start with combining character", currentColumn == 0 && width < 0);
+				if (width > 0) currentColumn += width;
+			}
+			assertEquals("Line whose width does not match screens. line=" + new String(lines[i].mText, 0, lines[i].getSpaceUsed()),
+					screen.mColumns, currentColumn);
+		}
+
+		assertEquals("The alt buffer should have have no history", mTerminal.mAltBuffer.mTotalRows, mTerminal.mAltBuffer.mScreenRows);
+		if (mTerminal.isAlternateBufferActive()) {
+			assertEquals("The alt buffer should be the same size as the screen", mTerminal.mRows, mTerminal.mAltBuffer.mTotalRows);
+		}
+
+		return this;
+	}
+
+	protected void assertLineIs(int line, String expected) {
+		TerminalRow l = mTerminal.getScreen().allocateFullLineIfNecessary(mTerminal.getScreen().externalToInternalRow(line));
+		char[] chars = l.mText;
+		int textLen = l.getSpaceUsed();
+		if (textLen != expected.length()) fail("Expected '" + expected + "' (len=" + expected.length() + "), was='"
+				+ new String(chars, 0, textLen) + "' (len=" + textLen + ")");
+		for (int i = 0; i < textLen; i++) {
+			if (expected.charAt(i) != chars[i])
+				fail("Expected '" + expected + "', was='" + new String(chars, 0, textLen) + "' - first different at index=" + i);
+		}
+	}
+
+	public TerminalTestCase assertLinesAre(String... lines) {
+		assertEquals(lines.length, mTerminal.getScreen().mScreenRows);
+		for (int i = 0; i < lines.length; i++)
+			try {
+				assertLineIs(i, lines[i]);
+			} catch (AssertionFailedError e) {
+				throw new AssertionFailedError("Line: " + i + " - " + e.getMessage());
+			}
+		return this;
+	}
+
+	public TerminalTestCase resize(int cols, int rows) {
+		mTerminal.resize(cols, rows, INITIAL_CELL_WIDTH_PIXELS, INITIAL_CELL_HEIGHT_PIXELS);
+		assertInvariants();
+		return this;
+	}
+
+	public TerminalTestCase assertLineWraps(boolean... lines) {
+		for (int i = 0; i < lines.length; i++)
+			assertEquals("line=" + i, lines[i], mTerminal.getScreen().mLines[mTerminal.getScreen().externalToInternalRow(i)].mLineWrap);
+		return this;
+	}
+
+	protected TerminalTestCase assertLineStartsWith(int line, int... codePoints) {
+		char[] chars = mTerminal.getScreen().mLines[mTerminal.getScreen().externalToInternalRow(line)].mText;
+		int charIndex = 0;
+		for (int i = 0; i < codePoints.length; i++) {
+			int lineCodePoint = chars[charIndex++];
+			if (Character.isHighSurrogate((char) lineCodePoint)) {
+				lineCodePoint = Character.toCodePoint((char) lineCodePoint, chars[charIndex++]);
+			}
+			assertEquals("Differing a code point index=" + i, codePoints[i], lineCodePoint);
+		}
+		return this;
+	}
+
+	protected TerminalTestCase placeCursorAndAssert(int row, int col) {
+		// +1 due to escape sequence being one based.
+		enterString("\033[" + (row + 1) + ";" + (col + 1) + "H");
+		assertCursorAt(row, col);
+		return this;
+	}
+
+	public TerminalTestCase assertCursorAt(int row, int col) {
+		int actualRow = mTerminal.getCursorRow();
+		int actualCol = mTerminal.getCursorCol();
+		if (!(row == actualRow && col == actualCol))
+			fail("Expected cursor at (row,col)=(" + row + ", " + col + ") but was (" + actualRow + ", " + actualCol + ")");
+		return this;
+	}
+
+	/** For testing only. Encoded style according to {@link TextStyle}. */
+	public long getStyleAt(int externalRow, int column) {
+		return mTerminal.getScreen().getStyleAt(externalRow, column);
+	}
+
+	public static class EffectLine {
+		final int[] styles;
+
+		public EffectLine(int[] styles) {
+			this.styles = styles;
+		}
+	}
+
+	protected EffectLine effectLine(int... bits) {
+		return new EffectLine(bits);
+	}
+
+	public TerminalTestCase assertEffectAttributesSet(EffectLine... lines) {
+		assertEquals(lines.length, mTerminal.getScreen().mScreenRows);
+		for (int i = 0; i < lines.length; i++) {
+			int[] line = lines[i].styles;
+			for (int j = 0; j < line.length; j++) {
+				int effectsAtCell = TextStyle.decodeEffect(getStyleAt(i, j));
+				int attributes = line[j];
+				if ((effectsAtCell & attributes) != attributes) fail("Line=" + i + ", column=" + j + ", expected "
+						+ describeStyle(attributes) + " set, was " + describeStyle(effectsAtCell));
+			}
+		}
+		return this;
+	}
+
+	public TerminalTestCase assertForegroundIndices(EffectLine... lines) {
+		assertEquals(lines.length, mTerminal.getScreen().mScreenRows);
+		for (int i = 0; i < lines.length; i++) {
+			int[] line = lines[i].styles;
+			for (int j = 0; j < line.length; j++) {
+				int actualColor = TextStyle.decodeForeColor(getStyleAt(i, j));
+				int expectedColor = line[j];
+				if (actualColor != expectedColor) fail("Line=" + i + ", column=" + j + ", expected color "
+						+ Integer.toHexString(expectedColor) + " set, was " + Integer.toHexString(actualColor));
+			}
+		}
+		return this;
+	}
+
+	private static String describeStyle(int styleBits) {
+		return "'" + ((styleBits & TextStyle.CHARACTER_ATTRIBUTE_BLINK) != 0 ? ":BLINK:" : "")
+				+ ((styleBits & TextStyle.CHARACTER_ATTRIBUTE_BOLD) != 0 ? ":BOLD:" : "")
+				+ ((styleBits & TextStyle.CHARACTER_ATTRIBUTE_INVERSE) != 0 ? ":INVERSE:" : "")
+				+ ((styleBits & TextStyle.CHARACTER_ATTRIBUTE_INVISIBLE) != 0 ? ":INVISIBLE:" : "")
+				+ ((styleBits & TextStyle.CHARACTER_ATTRIBUTE_ITALIC) != 0 ? ":ITALIC:" : "")
+				+ ((styleBits & TextStyle.CHARACTER_ATTRIBUTE_PROTECTED) != 0 ? ":PROTECTED:" : "")
+				+ ((styleBits & TextStyle.CHARACTER_ATTRIBUTE_STRIKETHROUGH) != 0 ? ":STRIKETHROUGH:" : "")
+				+ ((styleBits & TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE) != 0 ? ":UNDERLINE:" : "") + "'";
+	}
+
+	public void assertForegroundColorAt(int externalRow, int column, int color) {
+		long style = mTerminal.getScreen().mLines[mTerminal.getScreen().externalToInternalRow(externalRow)].getStyle(column);
+		assertEquals(color, TextStyle.decodeForeColor(style));
+	}
+
+	public void assertBackgroundColorAt(int externalRow, int column, int color) {
+		long style = mTerminal.getScreen().mLines[mTerminal.getScreen().externalToInternalRow(externalRow)].getStyle(column);
+		assertEquals(color, TextStyle.decodeBackColor(style));
+	}
+
+	public TerminalTestCase assertColor(int colorIndex, int expected) {
+		int actual = mTerminal.mColors.mCurrentColors[colorIndex];
+		if (expected != actual) {
+			fail("Color index=" + colorIndex + ", expected=" + Integer.toHexString(expected) + ", was=" + Integer.toHexString(actual));
+		}
+		return this;
+	}
+}

terminal-emulator/src/test/java/com/termux/terminal/TextStyleTest.java

@@ -0,0 +1,65 @@
+package com.termux.terminal;
+
+import junit.framework.TestCase;
+
+public class TextStyleTest extends TestCase {
+
+	private static final int[] ALL_EFFECTS = new int[]{0, TextStyle.CHARACTER_ATTRIBUTE_BOLD, TextStyle.CHARACTER_ATTRIBUTE_ITALIC,
+			TextStyle.CHARACTER_ATTRIBUTE_UNDERLINE, TextStyle.CHARACTER_ATTRIBUTE_BLINK, TextStyle.CHARACTER_ATTRIBUTE_INVERSE,
+			TextStyle.CHARACTER_ATTRIBUTE_INVISIBLE, TextStyle.CHARACTER_ATTRIBUTE_STRIKETHROUGH, TextStyle.CHARACTER_ATTRIBUTE_PROTECTED,
+			TextStyle.CHARACTER_ATTRIBUTE_DIM};
+
+	public void testEncodingSingle() {
+		for (int fx : ALL_EFFECTS) {
+			for (int fg = 0; fg < TextStyle.NUM_INDEXED_COLORS; fg++) {
+				for (int bg = 0; bg < TextStyle.NUM_INDEXED_COLORS; bg++) {
+					long encoded = TextStyle.encode(fg, bg, fx);
+					assertEquals(fg, TextStyle.decodeForeColor(encoded));
+					assertEquals(bg, TextStyle.decodeBackColor(encoded));
+					assertEquals(fx, TextStyle.decodeEffect(encoded));
+				}
+			}
+		}
+	}
+
+	public void testEncoding24Bit() {
+		int[] values = {255, 240, 127, 1, 0};
+		for (int red : values) {
+			for (int green : values) {
+				for (int blue : values) {
+					int argb = 0xFF000000 | (red << 16) | (green << 8) | blue;
+					long encoded = TextStyle.encode(argb, 0, 0);
+					assertEquals(argb, TextStyle.decodeForeColor(encoded));
+					encoded = TextStyle.encode(0, argb, 0);
+					assertEquals(argb, TextStyle.decodeBackColor(encoded));
+				}
+			}
+		}
+	}
+
+
+	public void testEncodingCombinations() {
+		for (int f1 : ALL_EFFECTS) {
+			for (int f2 : ALL_EFFECTS) {
+				int combined = f1 | f2;
+				assertEquals(combined, TextStyle.decodeEffect(TextStyle.encode(0, 0, combined)));
+			}
+		}
+	}
+
+	public void testEncodingStrikeThrough() {
+		long encoded = TextStyle.encode(TextStyle.COLOR_INDEX_FOREGROUND, TextStyle.COLOR_INDEX_BACKGROUND,
+				TextStyle.CHARACTER_ATTRIBUTE_STRIKETHROUGH);
+		assertTrue((TextStyle.decodeEffect(encoded) & TextStyle.CHARACTER_ATTRIBUTE_STRIKETHROUGH) != 0);
+	}
+
+	public void testEncodingProtected() {
+		long encoded = TextStyle.encode(TextStyle.COLOR_INDEX_FOREGROUND, TextStyle.COLOR_INDEX_BACKGROUND,
+				TextStyle.CHARACTER_ATTRIBUTE_STRIKETHROUGH);
+		assertEquals(0, (TextStyle.decodeEffect(encoded) & TextStyle.CHARACTER_ATTRIBUTE_PROTECTED));
+		encoded = TextStyle.encode(TextStyle.COLOR_INDEX_FOREGROUND, TextStyle.COLOR_INDEX_BACKGROUND,
+				TextStyle.CHARACTER_ATTRIBUTE_STRIKETHROUGH | TextStyle.CHARACTER_ATTRIBUTE_PROTECTED);
+		assertTrue((TextStyle.decodeEffect(encoded) & TextStyle.CHARACTER_ATTRIBUTE_PROTECTED) != 0);
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/UnicodeInputTest.java

@@ -0,0 +1,136 @@
+package com.termux.terminal;
+
+import java.io.UnsupportedEncodingException;
+
+public class UnicodeInputTest extends TerminalTestCase {
+
+	public void testIllFormedUtf8SuccessorByteNotConsumed() throws Exception {
+		// The Unicode Standard Version 6.2 – Core Specification (http://www.unicode.org/versions/Unicode6.2.0/ch03.pdf):
+		// "If the converter encounters an ill-formed UTF-8 code unit sequence which starts with a valid first byte, but which does not
+		// continue with valid successor bytes (see Table 3-7), it must not consume the successor bytes as part of the ill-formed
+		// subsequence whenever those successor bytes themselves constitute part of a well-formed UTF-8 code unit subsequence."
+		withTerminalSized(5, 5);
+		mTerminal.append(new byte[]{(byte) 0b11101111, (byte) 'a'}, 2);
+		assertLineIs(0, ((char) TerminalEmulator.UNICODE_REPLACEMENT_CHAR) + "a   ");
+
+		// https://code.google.com/p/chromium/issues/detail?id=212704
+		byte[] input = new byte[]{
+				(byte) 0x61, (byte) 0xF1,
+				(byte) 0x80, (byte) 0x80,
+				(byte) 0xe1, (byte) 0x80,
+				(byte) 0xc2, (byte) 0x62,
+				(byte) 0x80, (byte) 0x63,
+				(byte) 0x80, (byte) 0xbf,
+				(byte) 0x64
+		};
+		withTerminalSized(10, 2);
+		mTerminal.append(input, input.length);
+		assertLinesAre("a\uFFFD\uFFFD\uFFFDb\uFFFDc\uFFFD\uFFFDd", "          ");
+
+		// Surrogate pairs.
+		withTerminalSized(5, 2);
+		input = new byte[]{
+				(byte) 0xed, (byte) 0xa0,
+				(byte) 0x80, (byte) 0xed,
+				(byte) 0xad, (byte) 0xbf,
+				(byte) 0xed, (byte) 0xae,
+				(byte) 0x80, (byte) 0xed,
+				(byte) 0xbf, (byte) 0xbf
+		};
+		mTerminal.append(input, input.length);
+		assertLinesAre("\uFFFD\uFFFD\uFFFD\uFFFD ", "     ");
+
+		// https://bugzilla.mozilla.org/show_bug.cgi?id=746900: "with this patch 0xe0 0x80 is decoded as two U+FFFDs,
+		// but 0xe0 0xa0 is decoded as a single U+FFFD, and this is correct according to the "Best Practices", but IE
+		// and Chrome (Version 22.0.1229.94) decode both of them as two U+FFFDs. Opera 12.11 decodes both of them as
+		// one U+FFFD".
+		withTerminalSized(5, 2);
+		input = new byte[]{(byte) 0xe0, (byte) 0xa0, ' '};
+		mTerminal.append(input, input.length);
+		assertLinesAre("\uFFFD    ", "     ");
+
+		// withTerminalSized(5, 2);
+		// input = new byte[]{(byte) 0xe0, (byte) 0x80, 'a'};
+		// mTerminal.append(input, input.length);
+		// assertLinesAre("\uFFFD\uFFFDa  ", "     ");
+	}
+
+	public void testUnassignedCodePoint() throws UnsupportedEncodingException {
+		withTerminalSized(3, 3);
+		// UTF-8 for U+C2541, an unassigned code point:
+		byte[] b = new byte[]{(byte) 0xf3, (byte) 0x82, (byte) 0x95, (byte) 0x81};
+		mTerminal.append(b, b.length);
+		enterString("Y");
+		assertEquals(1, Character.charCount(TerminalEmulator.UNICODE_REPLACEMENT_CHAR));
+		assertLineStartsWith(0, TerminalEmulator.UNICODE_REPLACEMENT_CHAR, (int) 'Y', ' ');
+	}
+
+	public void testStuff() {
+		withTerminalSized(80, 24);
+		byte[] b = new byte[]{(byte) 0xf3, (byte) 0x82, (byte) 0x95, (byte) 0x81, (byte) 0x61, (byte) 0x38, (byte) 0xe7, (byte) 0x8f,
+				(byte) 0xae, (byte) 0xc2, (byte) 0x9f, (byte) 0xe8, (byte) 0xa0, (byte) 0x9f, (byte) 0xe8, (byte) 0x8c, (byte) 0xa4,
+				(byte) 0xed, (byte) 0x93, (byte) 0x89, (byte) 0xef, (byte) 0xbf, (byte) 0xbd, (byte) 0x42, (byte) 0xc2, (byte) 0x9b,
+				(byte) 0xe6, (byte) 0x87, (byte) 0x89, (byte) 0x5a};
+		mTerminal.append(b, b.length);
+	}
+
+	public void testSimpleCombining() throws Exception {
+		withTerminalSized(3, 2).enterString(" a\u0302 ").assertLinesAre(" a\u0302 ", "   ");
+	}
+
+	public void testCombiningCharacterInFirstColumn() throws Exception {
+		withTerminalSized(5, 3).enterString("test\r\nhi\r\n").assertLinesAre("test ", "hi   ", "     ");
+
+		// U+0302 is COMBINING CIRCUMFLEX ACCENT. Test case from mosh (http://mosh.mit.edu/).
+		withTerminalSized(5, 5).enterString("test\r\nabc\r\n\u0302\r\ndef\r\n");
+		assertLinesAre("test ", "abc  ", " \u0302    ", "def  ", "     ");
+	}
+
+	public void testCombiningCharacterInLastColumn() throws Exception {
+		withTerminalSized(3, 2).enterString("  a\u0302").assertLinesAre("  a\u0302", "   ");
+		withTerminalSized(3, 2).enterString("  à̲").assertLinesAre("  à̲", "   ");
+		withTerminalSized(3, 2).enterString("Aà̲F").assertLinesAre("Aà̲F", "   ");
+	}
+
+	public void testWideCharacterInLastColumn() throws Exception {
+		withTerminalSized(3, 2).enterString("  枝\u0302").assertLinesAre("   ", "枝\u0302 ");
+
+		withTerminalSized(3, 2).enterString(" 枝").assertLinesAre(" 枝", "   ").assertCursorAt(0, 2);
+		enterString("a").assertLinesAre(" 枝", "a  ");
+	}
+
+	public void testWideCharacterDeletion() throws Exception {
+		// CSI Ps D Cursor Backward Ps Times
+		withTerminalSized(3, 2).enterString("枝\033[Da").assertLinesAre(" a ", "   ");
+		withTerminalSized(3, 2).enterString("枝\033[2Da").assertLinesAre("a  ", "   ");
+		withTerminalSized(3, 2).enterString("枝\033[2D枝").assertLinesAre("枝 ", "   ");
+		withTerminalSized(3, 2).enterString("枝\033[1D枝").assertLinesAre(" 枝", "   ");
+		withTerminalSized(5, 2).enterString(" 枝 \033[Da").assertLinesAre(" 枝a ", "     ");
+		withTerminalSized(5, 2).enterString("a \033[D\u0302").assertLinesAre("a\u0302    ", "     ");
+		withTerminalSized(5, 2).enterString("枝 \033[D\u0302").assertLinesAre("枝\u0302   ", "     ");
+		enterString("Z").assertLinesAre("枝\u0302Z  ", "     ");
+		enterString("\033[D ").assertLinesAre("枝\u0302   ", "     ");
+		// Go back two columns, standing at the second half of the wide character:
+		enterString("\033[2DU").assertLinesAre(" U   ", "     ");
+	}
+
+	public void testWideCharOverwriting() {
+		withTerminalSized(3, 2).enterString("abc\033[3D枝").assertLinesAre("枝c", "   ");
+	}
+
+	public void testOverlongUtf8Encoding() throws Exception {
+		// U+0020 should be encoded as 0x20, 0xc0 0xa0 is an overlong encoding
+		// so should be replaced with the replacement char U+FFFD.
+		withTerminalSized(5, 5).mTerminal.append(new byte[]{(byte) 0xc0, (byte) 0xa0, 'Y'}, 3);
+		assertLineIs(0, "\uFFFDY   ");
+	}
+
+	public void testWideCharacterWithoutWrapping() throws Exception {
+		// With wraparound disabled. The behaviour when a wide character is output with cursor in
+		// the last column when autowrap is disabled is not obvious, but we expect the wide
+		// character to be ignored here.
+		withTerminalSized(3, 3).enterString("\033[?7l").enterString("枝枝枝").assertLinesAre("枝 ", "   ", "   ");
+		enterString("a枝").assertLinesAre("枝a", "   ", "   ");
+	}
+
+}

terminal-emulator/src/test/java/com/termux/terminal/WcWidthTest.java

@@ -0,0 +1,81 @@
+package com.termux.terminal;
+
+import junit.framework.TestCase;
+
+public class WcWidthTest extends TestCase {
+
+	private static void assertWidthIs(int expectedWidth, int codePoint) {
+		int wcWidth = WcWidth.width(codePoint);
+		assertEquals(expectedWidth, wcWidth);
+	}
+
+	public void testPrintableAscii() {
+		for (int i = 0x20; i <= 0x7E; i++) {
+			assertWidthIs(1, i);
+		}
+	}
+
+	public void testSomeWidthOne() {
+		assertWidthIs(1, 'å');
+		assertWidthIs(1, 'ä');
+		assertWidthIs(1, 'ö');
+		assertWidthIs(1, 0x23F2);
+	}
+
+	public void testSomeWide() {
+		assertWidthIs(2, 'Ａ');
+		assertWidthIs(2, 'Ｂ');
+		assertWidthIs(2, 'Ｃ');
+		assertWidthIs(2, '中');
+		assertWidthIs(2, '文');
+
+		assertWidthIs(2, 0x679C);
+		assertWidthIs(2, 0x679D);
+
+		assertWidthIs(2, 0x2070E);
+		assertWidthIs(2, 0x20731);
+
+		assertWidthIs(1, 0x1F781);
+	}
+
+	public void testSomeNonWide() {
+		assertWidthIs(1, 0x1D11E);
+		assertWidthIs(1, 0x1D11F);
+	}
+
+	public void testCombining() {
+		assertWidthIs(0, 0x0302);
+		assertWidthIs(0, 0x0308);
+		assertWidthIs(0, 0xFE0F);
+	}
+
+	public void testWordJoiner() {
+		// https://en.wikipedia.org/wiki/Word_joiner
+		// The word joiner (WJ) is a code point in Unicode used to separate words when using scripts
+		// that do not use explicit spacing. It is encoded since Unicode version 3.2
+		// (released in 2002) as U+2060 WORD JOINER (HTML &#8288;).
+		// The word joiner does not produce any space, and prohibits a line break at its position.
+		assertWidthIs(0, 0x2060);
+	}
+
+	public void testSofthyphen() {
+		// http://osdir.com/ml/internationalization.linux/2003-05/msg00006.html:
+		// "Existing implementation practice in terminals is that the SOFT HYPHEN is
+		// a spacing graphical character, and the purpose of my wcwidth() was to
+		// predict the advancement of the cursor position after a string is sent to
+		// a terminal. Hence, I have no choice but to keep wcwidth(SOFT HYPHEN) = 1.
+		// VT100-style terminals do not hyphenate."
+		assertWidthIs(1, 0x00AD);
+	}
+
+	public void testHangul() {
+		assertWidthIs(1, 0x11A3);
+	}
+
+	public void testEmojis() {
+		assertWidthIs(2, 0x1F428); // KOALA.
+		assertWidthIs(2, 0x231a);  // WATCH.
+		assertWidthIs(2, 0x1F643); // UPSIDE-DOWN FACE (Unicode 8).
+	}
+
+}