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//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.3
// 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
//----------------------------------------------------------------------------
//
// Affine transformations
//
//----------------------------------------------------------------------------
#include "agg_trans_affine.h"
namespace agg
{
//------------------------------------------------------------------------
const trans_affine& trans_affine::parl_to_parl(const double* src,
const double* dst)
{
m0 = src[2] - src[0];
m1 = src[3] - src[1];
m2 = src[4] - src[0];
m3 = src[5] - src[1];
m4 = src[0];
m5 = src[1];
invert();
multiply(trans_affine(dst[2] - dst[0], dst[3] - dst[1],
dst[4] - dst[0], dst[5] - dst[1],
dst[0], dst[1]));
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::rect_to_parl(double x1, double y1,
double x2, double y2,
const double* parl)
{
double src[6];
src[0] = x1; src[1] = y1;
src[2] = x2; src[3] = y1;
src[4] = x2; src[5] = y2;
parl_to_parl(src, parl);
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::parl_to_rect(const double* parl,
double x1, double y1,
double x2, double y2)
{
double dst[6];
dst[0] = x1; dst[1] = y1;
dst[2] = x2; dst[3] = y1;
dst[4] = x2; dst[5] = y2;
parl_to_parl(parl, dst);
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::multiply(const trans_affine& m)
{
double t0 = m0 * m.m0 + m1 * m.m2;
double t2 = m2 * m.m0 + m3 * m.m2;
double t4 = m4 * m.m0 + m5 * m.m2 + m.m4;
m1 = m0 * m.m1 + m1 * m.m3;
m3 = m2 * m.m1 + m3 * m.m3;
m5 = m4 * m.m1 + m5 * m.m3 + m.m5;
m0 = t0;
m2 = t2;
m4 = t4;
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::invert()
{
double d = determinant();
double t0 = m3 * d;
m3 = m0 * d;
m1 = -m1 * d;
m2 = -m2 * d;
double t4 = -m4 * t0 - m5 * m2;
m5 = -m4 * m1 - m5 * m3;
m0 = t0;
m4 = t4;
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::flip_x()
{
m0 = -m0;
m1 = -m1;
m4 = -m4;
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::flip_y()
{
m2 = -m2;
m3 = -m3;
m5 = -m5;
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::reset()
{
m0 = m3 = 1.0;
m1 = m2 = m4 = m5 = 0.0;
return *this;
}
//------------------------------------------------------------------------
inline bool is_equal_eps(double v1, double v2, double epsilon)
{
return fabs(v1 - v2) < epsilon;
}
//------------------------------------------------------------------------
bool trans_affine::is_identity(double epsilon) const
{
return is_equal_eps(m0, 1.0, epsilon) &&
is_equal_eps(m1, 0.0, epsilon) &&
is_equal_eps(m2, 0.0, epsilon) &&
is_equal_eps(m3, 1.0, epsilon) &&
is_equal_eps(m4, 0.0, epsilon) &&
is_equal_eps(m5, 0.0, epsilon);
}
//------------------------------------------------------------------------
bool trans_affine::is_equal(const trans_affine& m, double epsilon) const
{
return is_equal_eps(m0, m.m0, epsilon) &&
is_equal_eps(m1, m.m1, epsilon) &&
is_equal_eps(m2, m.m2, epsilon) &&
is_equal_eps(m3, m.m3, epsilon) &&
is_equal_eps(m4, m.m4, epsilon) &&
is_equal_eps(m5, m.m5, epsilon);
}
//------------------------------------------------------------------------
double trans_affine::rotation() const
{
double x1 = 0.0;
double y1 = 0.0;
double x2 = 1.0;
double y2 = 0.0;
transform(&x1, &y1);
transform(&x2, &y2);
return atan2(y2-y1, x2-x1);
}
//------------------------------------------------------------------------
void trans_affine::translation(double* dx, double* dy) const
{
trans_affine t(*this);
t *= trans_affine_rotation(-rotation());
t.transform(dx, dy);
}
//------------------------------------------------------------------------
void trans_affine::scaling(double* sx, double* sy) const
{
double x1 = 0.0;
double y1 = 0.0;
double x2 = 1.0;
double y2 = 1.0;
trans_affine t(*this);
t *= trans_affine_rotation(-rotation());
t.transform(&x1, &y1);
t.transform(&x2, &y2);
*sx = x2 - x1;
*sy = y2 - y1;
}
}
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