1 files changed, 70 insertions, 0 deletions
diff --git a/krita/core/kis_perspective_math.h b/krita/core/kis_perspective_math.h
new file mode 100644
index 000000000..047e571ef
--- /dev/null
+++ b/krita/core/kis_perspective_math.h
@@ -0,0 +1,70 @@
+/*
+ * This file is part of Krita
+ *
+ *  Copyright (c) 2006 Cyrille Berger <cberger@cberger.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; version 2 of the License.
+ *
+ *  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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef _KIS_PERSPECTVE_MATH_H_
+#define _KIS_PERSPECTVE_MATH_H_
+
+#include "kis_point.h"
+
+class QRect;
+
+class KisPerspectiveMath {
+    private:
+        KisPerspectiveMath() { }
+    public:
+        static double* computeMatrixTransfo( const KisPoint& topLeft1, const KisPoint& topRight1, const KisPoint& bottomLeft1, const KisPoint& bottomRight1 , const KisPoint& topLeft2, const KisPoint& topRight2, const KisPoint& bottomLeft2, const KisPoint& bottomRight2);
+      static double* computeMatrixTransfoToPerspective(const KisPoint& topLeft, const KisPoint& topRight, const KisPoint& bottomLeft, const KisPoint& bottomRight, const QRect& r);
+      static double* computeMatrixTransfoFromPerspective(const QRect& r, const KisPoint& topLeft, const KisPoint& topRight, const KisPoint& bottomLeft, const KisPoint& bottomRight);
+      struct LineEquation {
+            // y = a*x + b
+      double a, b;
+    };
+    /// TODO: get ride of this in 2.0
+    inline static KisPoint matProd(const double (&m)[3][3], const KisPoint& p)
+    {
+        double s = ( p.x() * m[2][0] + p.y() * m[2][1] + 1.0);
+        s = (s == 0.) ? 1. : 1./s;
+        return KisPoint( (p.x() * m[0][0] + p.y() * m[0][1] + m[0][2] ) * s,
+                         (p.x() * m[1][0] + p.y() * m[1][1] + m[1][2] ) * s );
+    }
+    static inline LineEquation computeLineEquation(const KisPoint* p1, const KisPoint* p2)
+    {
+      LineEquation eq;
+      double x1 = p1->x(); double x2 = p2->x();
+      if( fabs(x1 - x2) < 0.000001 )
+      {
+        x1 += 0.0001; // Introduce a small perturbation
+      }
+      eq.a = (p2->y() - p1->y()) / (double)( x2 - x1 );
+      eq.b = -eq.a * x1 + p1->y();
+      return eq;
+    }
+    static inline KisPoint computeIntersection(const LineEquation& d1, const LineEquation& d2)
+    {
+      double a1 = d1.a; double a2 = d2.a;
+      if( fabs(a1 - a2) < 0.000001 )
+      {
+        a1 += 0.0001; // Introduce a small perturbation
+      }
+      double x = (d1.b - d2.b) / (a2 - a1);
+      return KisPoint(x, a2 * x + d2.b);
+    }
+};
+
+#endif