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//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// 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)
{
sx = src[2] - src[0];
shy = src[3] - src[1];
shx = src[4] - src[0];
sy = src[5] - src[1];
tx = src[0];
ty = 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 = sx * m.sx + shy * m.shx;
double t2 = shx * m.sx + sy * m.shx;
double t4 = tx * m.sx + ty * m.shx + m.tx;
shy = sx * m.shy + shy * m.sy;
sy = shx * m.shy + sy * m.sy;
ty = tx * m.shy + ty * m.sy + m.ty;
sx = t0;
shx = t2;
tx = t4;
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::invert()
{
double d = determinant_reciprocal();
double t0 = sy * d;
sy = sx * d;
shy = -shy * d;
shx = -shx * d;
double t4 = -tx * t0 - ty * shx;
ty = -tx * shy - ty * sy;
sx = t0;
tx = t4;
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::flip_x()
{
sx = -sx;
shy = -shy;
tx = -tx;
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::flip_y()
{
shx = -shx;
sy = -sy;
ty = -ty;
return *this;
}
//------------------------------------------------------------------------
const trans_affine& trans_affine::reset()
{
sx = sy = 1.0;
shy = shx = tx = ty = 0.0;
return *this;
}
//------------------------------------------------------------------------
bool trans_affine::is_identity(double epsilon) const
{
return is_equal_eps(sx, 1.0, epsilon) &&
is_equal_eps(shy, 0.0, epsilon) &&
is_equal_eps(shx, 0.0, epsilon) &&
is_equal_eps(sy, 1.0, epsilon) &&
is_equal_eps(tx, 0.0, epsilon) &&
is_equal_eps(ty, 0.0, epsilon);
}
//------------------------------------------------------------------------
bool trans_affine::is_valid(double epsilon) const
{
return fabs(sx) > epsilon && fabs(sy) > epsilon;
}
//------------------------------------------------------------------------
bool trans_affine::is_equal(const trans_affine& m, double epsilon) const
{
return is_equal_eps(sx, m.sx, epsilon) &&
is_equal_eps(shy, m.shy, epsilon) &&
is_equal_eps(shx, m.shx, epsilon) &&
is_equal_eps(sy, m.sy, epsilon) &&
is_equal_eps(tx, m.tx, epsilon) &&
is_equal_eps(ty, m.ty, 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
{
*dx = tx;
*dy = ty;
}
//------------------------------------------------------------------------
void trans_affine::scaling(double* x, double* y) 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);
*x = x2 - x1;
*y = y2 - y1;
}
}
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