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// -*- related-file-name: "../include/lcdf/transform.hh" -*-
/* transform.{cc,hh} -- planar affine transformations
*
* Copyright (c) 2000-2011 Eddie Kohler
*
* 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; either version 2 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 General
* Public License for more details.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <lcdf/transform.hh>
#include <lcdf/straccum.hh>
#include <math.h>
Transform::Transform()
{
_m[0] = _m[3] = 1;
_m[1] = _m[2] = _m[4] = _m[5] = 0;
_null = true;
}
Transform::Transform(const double m[6])
{
_m[0] = m[0];
_m[1] = m[1];
_m[2] = m[2];
_m[3] = m[3];
_m[4] = m[4];
_m[5] = m[5];
check_null(0);
}
Transform::Transform(double m0, double m1, double m2,
double m3, double m4, double m5)
{
_m[0] = m0;
_m[1] = m1;
_m[2] = m2;
_m[3] = m3;
_m[4] = m4;
_m[5] = m5;
check_null(0);
}
void
Transform::check_null(double tolerance)
{
_null = (fabs(_m[0] - 1) < tolerance && fabs(_m[1]) < tolerance
&& fabs(_m[2]) < tolerance && fabs(_m[3] - 1) < tolerance
&& fabs(_m[4]) < tolerance && fabs(_m[5]) < tolerance);
}
void
Transform::scale(double x, double y)
{
_m[0] *= x;
_m[1] *= x;
_m[2] *= y;
_m[3] *= y;
if (x != 1 || y != 1)
_null = false;
}
void
Transform::rotate(double r)
{
double c = cos(r);
double s = sin(r);
double a = _m[0], b = _m[2];
_m[0] = a*c + b*s;
_m[2] = b*c - a*s;
a = _m[1], b = _m[3];
_m[1] = a*c + b*s;
_m[3] = b*c - a*s;
if (r != 0)
_null = false;
}
void
Transform::translate(double x, double y)
{
_m[4] += _m[0]*x + _m[2]*y;
_m[5] += _m[1]*x + _m[3]*y;
if (x != 0 || y != 0)
_null = false;
}
void
Transform::shear(double s)
{
*this *= Transform(1, 0, s, 1, 0, 0);
}
Transform
Transform::transformed(const Transform &t) const
{
return Transform(_m[0] * t._m[0] + _m[2] * t._m[1],
_m[1] * t._m[0] + _m[3] * t._m[1],
_m[0] * t._m[2] + _m[2] * t._m[3],
_m[1] * t._m[2] + _m[3] * t._m[3],
_m[0] * t._m[4] + _m[2] * t._m[5] + _m[4],
_m[1] * t._m[4] + _m[3] * t._m[5] + _m[5]);
}
void
Transform::real_apply_to(Point &p) const
{
double x = p.x;
p.x = x*_m[0] + p.y*_m[2] + _m[4];
p.y = x*_m[1] + p.y*_m[3] + _m[5];
}
Point
Transform::real_apply(const Point &p) const
{
return Point(p.x*_m[0] + p.y*_m[2] + _m[4],
p.x*_m[1] + p.y*_m[3] + _m[5]);
}
Bezier &
operator*=(Bezier &b, const Transform &t)
{
if (!t.null()) {
b.mpoint(0) *= t;
b.mpoint(1) *= t;
b.mpoint(2) *= t;
b.mpoint(3) *= t;
}
return b;
}
Bezier
operator*(const Bezier &b, const Transform &t)
{
return (t.null()
? b
: Bezier(b.point(0) * t, b.point(1) * t, b.point(2) * t, b.point(3) * t));
}
String
Transform::unparse() const
{
StringAccum sa;
sa << '[';
for (int i = 0; i < 6; i++) {
if (i)
sa << ',' << ' ';
sa << _m[i];
}
sa << ']';
return sa.take_string();
}
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