Repo created

libs/geometry/calipers_box.hpp

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "geometry/point2d.hpp"
+
+#include "base/visitor.hpp"
+
+#include <vector>
+
+namespace m2
+{
+// When the size of the convex hull over a set of |points| is less
+// than 3, stores convex hull explicitly, otherwise stores smallest
+// rectangle containing the hull. Note that at least one side of the
+// rectangle should contain a facet of the hull, and in general sides
+// of the rectangle may not be parallel to the axes. In any case,
+// CalipersBox stores points in counter-clockwise order.
+class CalipersBox
+{
+public:
+  // 1e-12 is used here because of we are going to use the box on
+  // Mercator plane, where the precision of all coords is 1e-5, so we
+  // are off by two orders of magnitude from the precision of data.
+  static double constexpr kEps = 1e-12;
+
+  CalipersBox() = default;
+  explicit CalipersBox(std::vector<PointD> const & points);
+
+  // Used in CitiesBoundariesDecoder. Faster than ctor.
+  void Deserialize(std::vector<PointD> && points);
+  // Remove useless points in case of degenerate box. Used in unit tests.
+  void Normalize();
+
+  bool TestValid() const;
+
+  std::vector<PointD> const & Points() const { return m_points; }
+
+  bool HasPoint(PointD const & p) const { return HasPoint(p, kEps); }
+  bool HasPoint(double x, double y) const { return HasPoint(m2::PointD(x, y)); }
+
+  bool HasPoint(PointD const & p, double eps) const;
+  bool HasPoint(double x, double y, double eps) const { return HasPoint(PointD(x, y), eps); }
+
+  bool operator==(CalipersBox const & rhs) const { return m_points == rhs.m_points; }
+
+  DECLARE_VISITOR(visitor(m_points, "points"))
+  DECLARE_DEBUG_PRINT(CalipersBox)
+
+private:
+  std::vector<PointD> m_points;
+};
+}  // namespace m2