Repo created

3party/agg/agg_shorten_path.h

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+//----------------------------------------------------------------------------
+// Anti-Grain Geometry - Version 2.4
+// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
+//
+// Permission to copy, use, modify, sell and distribute this software 
+// is granted provided this copyright notice appears in all copies. 
+// This software is provided "as is" without express or implied
+// warranty, and with no claim as to its suitability for any purpose.
+//
+//----------------------------------------------------------------------------
+// Contact: mcseem@antigrain.com
+//          mcseemagg@yahoo.com
+//          http://www.antigrain.com
+//----------------------------------------------------------------------------
+
+#ifndef AGG_SHORTEN_PATH_INCLUDED
+#define AGG_SHORTEN_PATH_INCLUDED
+
+#include "agg_basics.h"
+#include "agg_vertex_sequence.h"
+
+namespace agg
+{
+
+    //===========================================================shorten_path
+    template<class VertexSequence> 
+    void shorten_path(VertexSequence& vs, double s, unsigned closed = 0)
+    {
+        typedef typename VertexSequence::value_type vertex_type;
+
+        if(s > 0.0 && vs.size() > 1)
+        {
+            double d;
+            int n = int(vs.size() - 2);
+            while(n)
+            {
+                d = vs[n].dist;
+                if(d > s) break;
+                vs.remove_last();
+                s -= d;
+                --n;
+            }
+            if(vs.size() < 2)
+            {
+                vs.remove_all();
+            }
+            else
+            {
+                n = vs.size() - 1;
+                vertex_type& prev = vs[n-1];
+                vertex_type& last = vs[n];
+                d = (prev.dist - s) / prev.dist;
+                double x = prev.x + (last.x - prev.x) * d;
+                double y = prev.y + (last.y - prev.y) * d;
+                last.x = x;
+                last.y = y;
+                if(!prev(last)) vs.remove_last();
+                vs.close(closed != 0);
+            }
+        }
+    }
+
+
+}
+
+#endif