--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Scene2D/ScenePoint2D.h	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,179 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#pragma once
+
+#include "../Toolbox/AffineTransform2D.h"
+#include "../Toolbox/LinearAlgebra.h"
+
+namespace OrthancStone
+{
+  class ScenePoint2D
+  {
+  private:
+    double  x_;
+    double  y_;
+
+  public:
+    ScenePoint2D() :
+      x_(0),
+      y_(0)
+    {
+    }
+
+    ScenePoint2D(double x,
+      double y) :
+      x_(x),
+      y_(y)
+    {
+    }
+
+    double GetX() const
+    {
+      return x_;
+    }
+
+    double GetY() const
+    {
+      return y_;
+    }
+
+    ScenePoint2D Apply(const AffineTransform2D& t) const
+    {
+      double x = x_;
+      double y = y_;
+      t.Apply(x, y);
+      return ScenePoint2D(x, y);
+    }
+
+    const ScenePoint2D operator-(const ScenePoint2D& a) const
+    {
+      ScenePoint2D v;
+      v.x_ = x_ - a.x_;
+      v.y_ = y_ - a.y_;
+
+      return v;
+    }
+
+    const ScenePoint2D operator+(const ScenePoint2D& a) const
+    {
+      ScenePoint2D v;
+      v.x_ = x_ + a.x_;
+      v.y_ = y_ + a.y_;
+
+      return v;
+    }
+
+    const ScenePoint2D operator*(double a) const
+    {
+      ScenePoint2D v;
+      v.x_ = x_ * a;
+      v.y_ = y_ * a;
+
+      return v;
+    }
+
+    const ScenePoint2D operator/(double a) const
+    {
+      ScenePoint2D v;
+      v.x_ = x_ / a;
+      v.y_ = y_ / a;
+
+      return v;
+    }
+
+    static void MidPoint(ScenePoint2D& result, const ScenePoint2D& a, const ScenePoint2D& b)
+    {
+      result.x_ = 0.5 * (a.x_ + b.x_);
+      result.y_ = 0.5 * (a.y_ + b.y_);
+    }
+
+    static double Dot(const ScenePoint2D& a, const ScenePoint2D& b)
+    {
+      return a.x_ * b.x_ + a.y_ * b.y_;
+    }
+
+    static double SquaredMagnitude(const ScenePoint2D& v)
+    {
+      return v.x_ * v.x_ + v.y_ * v.y_;
+    }
+
+    static double Magnitude(const ScenePoint2D& v)
+    {
+      double squaredMagnitude = SquaredMagnitude(v);
+      if (LinearAlgebra::IsCloseToZero(squaredMagnitude))
+        return 0.0;
+      return sqrt(squaredMagnitude);
+    }
+
+    static double SquaredDistancePtPt(const ScenePoint2D& a, const ScenePoint2D& b)
+    {
+      ScenePoint2D n = b - a;
+      return Dot(n, n);
+    }
+
+    static double DistancePtPt(const ScenePoint2D& a, const ScenePoint2D& b)
+    {
+      double squaredDist = SquaredDistancePtPt(a, b);
+      return sqrt(squaredDist);
+    }
+
+    /**
+    Distance from point p to [a,b] segment
+
+    Rewritten from https://www.randygaul.net/2014/07/23/distance-point-to-line-segment/
+    */
+    static double SquaredDistancePtSegment(const ScenePoint2D& a, const ScenePoint2D& b, const ScenePoint2D& p)
+    {
+      ScenePoint2D n = b - a;
+      ScenePoint2D pa = a - p;
+
+      double c = Dot(n, pa);
+
+      // Closest point is a
+      if (c > 0.0)
+        return Dot(pa, pa);
+
+      ScenePoint2D bp = p - b;
+
+      // Closest point is b
+      if (Dot(n, bp) > 0.0)
+        return Dot(bp, bp);
+
+      // if segment length is very short, we approximate distance to the
+      // distance with a
+      double nq = Dot(n, n);
+      if (LinearAlgebra::IsCloseToZero(nq))
+      {
+        // segment is very small: approximate distance from point to segment
+        // with distance from p to a
+        return Dot(pa, pa);
+      }
+      else
+      {
+        // Closest point is between a and b
+        ScenePoint2D e = pa - n * (c / nq);
+        return Dot(e, e);
+      }
+    }
+  };
+}
+