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koffice/chalk/core/kis_perspective_math.h

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/*
* This file is part of Chalk
*
* 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 TQRect;
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 TQRect& r);
static double* computeMatrixTransfoFromPerspective(const TQRect& 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