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tdegraphics/ksvg/impl/svgpathparser.cc

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/* This file is part of the KDE project
Copyright (C) 2002, 2003 The Karbon Developers
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "svgpathparser.h"
#include <tqstring.h>
#include <math.h>
// parses the number into parameter number
const char *
KSVG::getNumber( const char *ptr, double &number )
{
int integer, exponent;
double decimal, frac;
int sign, expsign;
exponent = 0;
integer = 0;
frac = 1.0;
decimal = 0;
sign = 1;
expsign = 1;
// read the sign
if(*ptr == '+')
ptr++;
else if(*ptr == '-')
{
ptr++;
sign = -1;
}
// read the integer part
while(*ptr != '\0' && *ptr >= '0' && *ptr <= '9')
integer = (integer * 10) + *(ptr++) - '0';
if(*ptr == '.') // read the decimals
{
ptr++;
while(*ptr != '\0' && *ptr >= '0' && *ptr <= '9')
decimal += (*(ptr++) - '0') * (frac *= 0.1);
}
if(*ptr == 'e' || *ptr == 'E') // read the exponent part
{
ptr++;
// read the sign of the exponent
if(*ptr == '+')
ptr++;
else if(*ptr == '-')
{
ptr++;
expsign = -1;
}
exponent = 0;
while(*ptr != '\0' && *ptr >= '0' && *ptr <= '9')
{
exponent *= 10;
exponent += *ptr - '0';
ptr++;
}
}
number = integer + decimal;
number *= sign * pow( (double)10, double( expsign * exponent ) );
return ptr;
}
// parses the coord into parameter number and forwards to the next coord in the path data
const char *
SVGPathParser::getCoord( const char *ptr, double &number )
{
ptr = KSVG::getNumber( ptr, number );
// skip the following space
if(*ptr == ' ')
ptr++;
return ptr;
}
void
SVGPathParser::parseSVG( const TQString &s, bool process )
{
if(!s.isEmpty())
{
TQString d = s;
d = d.replace(',', ' ');
d = d.simplifyWhiteSpace();
const char *ptr = d.latin1();
const char *end = d.latin1() + d.length() + 1;
double contrlx, contrly, curx, cury, subpathx, subpathy, tox, toy, x1, y1, x2, y2, xc, yc;
double px1, py1, px2, py2, px3, py3;
bool relative, closed = true;
char command = *(ptr++), lastCommand = ' ';
subpathx = subpathy = curx = cury = contrlx = contrly = 0.0;
while( ptr < end )
{
if( *ptr == ' ' )
ptr++;
relative = false;
//std::cout << "Command : " << command << std::endl;
switch( command )
{
case 'm':
relative = true;
case 'M':
{
ptr = getCoord( ptr, tox );
ptr = getCoord( ptr, toy );
if( process )
{
subpathx = curx = relative ? curx + tox : tox;
subpathy = cury = relative ? cury + toy : toy;
svgMoveTo( curx, cury, closed );
}
else
svgMoveTo( tox, toy, closed, !relative );
closed = false;
break;
}
case 'l':
relative = true;
case 'L':
{
ptr = getCoord( ptr, tox );
ptr = getCoord( ptr, toy );
if( process )
{
curx = relative ? curx + tox : tox;
cury = relative ? cury + toy : toy;
svgLineTo( curx, cury );
}
else
svgLineTo( tox, toy, !relative );
break;
}
case 'h':
{
ptr = getCoord( ptr, tox );
if( process )
{
curx = curx + tox;
svgLineTo( curx, cury );
}
else
svgLineToHorizontal( tox, false );
break;
}
case 'H':
{
ptr = getCoord( ptr, tox );
if( process )
{
curx = tox;
svgLineTo( curx, cury );
}
else
svgLineToHorizontal( tox );
break;
}
case 'v':
{
ptr = getCoord( ptr, toy );
if( process )
{
cury = cury + toy;
svgLineTo( curx, cury );
}
else
svgLineToVertical( toy, false );
break;
}
case 'V':
{
ptr = getCoord( ptr, toy );
if( process )
{
cury = toy;
svgLineTo( curx, cury );
}
else
svgLineToVertical( toy );
break;
}
case 'z':
case 'Z':
{
// reset curx, cury for next path
if( process )
{
curx = subpathx;
cury = subpathy;
}
closed = true;
svgClosePath();
break;
}
case 'c':
relative = true;
case 'C':
{
ptr = getCoord( ptr, x1 );
ptr = getCoord( ptr, y1 );
ptr = getCoord( ptr, x2 );
ptr = getCoord( ptr, y2 );
ptr = getCoord( ptr, tox );
ptr = getCoord( ptr, toy );
if( process )
{
px1 = relative ? curx + x1 : x1;
py1 = relative ? cury + y1 : y1;
px2 = relative ? curx + x2 : x2;
py2 = relative ? cury + y2 : y2;
px3 = relative ? curx + tox : tox;
py3 = relative ? cury + toy : toy;
svgCurveToCubic( px1, py1, px2, py2, px3, py3 );
contrlx = relative ? curx + x2 : x2;
contrly = relative ? cury + y2 : y2;
curx = relative ? curx + tox : tox;
cury = relative ? cury + toy : toy;
}
else
svgCurveToCubic( x1, y1, x2, y2, tox, toy, !relative );
break;
}
case 's':
relative = true;
case 'S':
{
ptr = getCoord( ptr, x2 );
ptr = getCoord( ptr, y2 );
ptr = getCoord( ptr, tox );
ptr = getCoord( ptr, toy );
if( process )
{
px1 = 2 * curx - contrlx;
py1 = 2 * cury - contrly;
px2 = relative ? curx + x2 : x2;
py2 = relative ? cury + y2 : y2;
px3 = relative ? curx + tox : tox;
py3 = relative ? cury + toy : toy;
svgCurveToCubic( px1, py1, px2, py2, px3, py3 );
contrlx = relative ? curx + x2 : x2;
contrly = relative ? cury + y2 : y2;
curx = relative ? curx + tox : tox;
cury = relative ? cury + toy : toy;
}
else
svgCurveToCubicSmooth( x2, y2, tox, toy, !relative );
break;
}
case 'q':
relative = true;
case 'Q':
{
ptr = getCoord( ptr, x1 );
ptr = getCoord( ptr, y1 );
ptr = getCoord( ptr, tox );
ptr = getCoord( ptr, toy );
if( process )
{
px1 = relative ? (curx + 2 * (x1 + curx)) * (1.0 / 3.0) : (curx + 2 * x1) * (1.0 / 3.0);
py1 = relative ? (cury + 2 * (y1 + cury)) * (1.0 / 3.0) : (cury + 2 * y1) * (1.0 / 3.0);
px2 = relative ? ((curx + tox) + 2 * (x1 + curx)) * (1.0 / 3.0) : (tox + 2 * x1) * (1.0 / 3.0);
py2 = relative ? ((cury + toy) + 2 * (y1 + cury)) * (1.0 / 3.0) : (toy + 2 * y1) * (1.0 / 3.0);
px3 = relative ? curx + tox : tox;
py3 = relative ? cury + toy : toy;
svgCurveToCubic( px1, py1, px2, py2, px3, py3 );
contrlx = relative ? curx + x1 : (tox + 2 * x1) * (1.0 / 3.0);
contrly = relative ? cury + y1 : (toy + 2 * y1) * (1.0 / 3.0);
curx = relative ? curx + tox : tox;
cury = relative ? cury + toy : toy;
}
else
svgCurveToQuadratic( x1, y1, tox, toy, !relative );
break;
}
case 't':
relative = true;
case 'T':
{
ptr = getCoord(ptr, tox);
ptr = getCoord(ptr, toy);
if( process )
{
xc = 2 * curx - contrlx;
yc = 2 * cury - contrly;
px1 = (curx + 2 * xc) * (1.0 / 3.0);
py1 = (cury + 2 * yc) * (1.0 / 3.0);
px2 = relative ? ((curx + tox) + 2 * xc) * (1.0 / 3.0) : (tox + 2 * xc) * (1.0 / 3.0);
py2 = relative ? ((cury + toy) + 2 * yc) * (1.0 / 3.0) : (toy + 2 * yc) * (1.0 / 3.0);
px3 = relative ? curx + tox : tox;
py3 = relative ? cury + toy : toy;
svgCurveToCubic( px1, py1, px2, py2, px3, py3 );
contrlx = xc;
contrly = yc;
curx = relative ? curx + tox : tox;
cury = relative ? cury + toy : toy;
}
else
svgCurveToQuadraticSmooth( tox, toy, !relative );
break;
}
case 'a':
relative = true;
case 'A':
{
bool largeArc, sweep;
double angle, rx, ry;
ptr = getCoord( ptr, rx );
ptr = getCoord( ptr, ry );
ptr = getCoord( ptr, angle );
ptr = getCoord( ptr, tox );
largeArc = tox == 1;
ptr = getCoord( ptr, tox );
sweep = tox == 1;
ptr = getCoord( ptr, tox );
ptr = getCoord( ptr, toy );
// Spec: radii are nonnegative numbers
rx = fabs(rx);
ry = fabs(ry);
if( process )
calculateArc( relative, curx, cury, angle, tox, toy, rx, ry, largeArc, sweep );
else
svgArcTo( tox, toy, rx, ry, angle, largeArc, sweep, !relative );
}
}
lastCommand = command;
if(*ptr == '+' || *ptr == '-' || (*ptr >= '0' && *ptr <= '9'))
{
// there are still coords in this command
if(command == 'M')
command = 'L';
else if(command == 'm')
command = 'l';
}
else
command = *(ptr++);
if( lastCommand != 'C' && lastCommand != 'c' &&
lastCommand != 'S' && lastCommand != 's' &&
lastCommand != 'Q' && lastCommand != 'q' &&
lastCommand != 'T' && lastCommand != 't')
{
contrlx = curx;
contrly = cury;
}
}
}
}
// This works by converting the SVG arc to "simple" beziers.
// For each bezier found a svgToCurve call is done.
// Adapted from Niko's code in tdelibs/tdecore/svgicons.
// Maybe this can serve in some shared lib? (Rob)
void
SVGPathParser::calculateArc(bool relative, double &curx, double &cury, double angle, double x, double y, double r1, double r2, bool largeArcFlag, bool sweepFlag)
{
double sin_th, cos_th;
double a00, a01, a10, a11;
double x0, y0, x1, y1, xc, yc;
double d, sfactor, sfactor_sq;
double th0, th1, th_arc;
int i, n_segs;
sin_th = sin(angle * (M_PI / 180.0));
cos_th = cos(angle * (M_PI / 180.0));
double dx;
if(!relative)
dx = (curx - x) / 2.0;
else
dx = -x / 2.0;
double dy;
if(!relative)
dy = (cury - y) / 2.0;
else
dy = -y / 2.0;
double _x1 = cos_th * dx + sin_th * dy;
double _y1 = -sin_th * dx + cos_th * dy;
double Pr1 = r1 * r1;
double Pr2 = r2 * r2;
double Px = _x1 * _x1;
double Py = _y1 * _y1;
// Spec : check if radii are large enough
double check = Px / Pr1 + Py / Pr2;
if(check > 1)
{
r1 = r1 * sqrt(check);
r2 = r2 * sqrt(check);
}
a00 = cos_th / r1;
a01 = sin_th / r1;
a10 = -sin_th / r2;
a11 = cos_th / r2;
x0 = a00 * curx + a01 * cury;
y0 = a10 * curx + a11 * cury;
if(!relative)
x1 = a00 * x + a01 * y;
else
x1 = a00 * (curx + x) + a01 * (cury + y);
if(!relative)
y1 = a10 * x + a11 * y;
else
y1 = a10 * (curx + x) + a11 * (cury + y);
/* (x0, y0) is current point in transformed coordinate space.
(x1, y1) is new point in transformed coordinate space.
The arc fits a unit-radius circle in this space.
*/
d = (x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0);
sfactor_sq = 1.0 / d - 0.25;
if(sfactor_sq < 0)
sfactor_sq = 0;
sfactor = sqrt(sfactor_sq);
if(sweepFlag == largeArcFlag)
sfactor = -sfactor;
xc = 0.5 * (x0 + x1) - sfactor * (y1 - y0);
yc = 0.5 * (y0 + y1) + sfactor * (x1 - x0);
/* (xc, yc) is center of the circle. */
th0 = atan2(y0 - yc, x0 - xc);
th1 = atan2(y1 - yc, x1 - xc);
th_arc = th1 - th0;
if(th_arc < 0 && sweepFlag)
th_arc += 2 * M_PI;
else if(th_arc > 0 && !sweepFlag)
th_arc -= 2 * M_PI;
n_segs = (int) (int) ceil(fabs(th_arc / (M_PI * 0.5 + 0.001)));
for(i = 0; i < n_segs; i++)
{
{
double sin_th, cos_th;
double a00, a01, a10, a11;
double x1, y1, x2, y2, x3, y3;
double t;
double th_half;
double _th0 = th0 + i * th_arc / n_segs;
double _th1 = th0 + (i + 1) * th_arc / n_segs;
sin_th = sin(angle * (M_PI / 180.0));
cos_th = cos(angle * (M_PI / 180.0));
/* inverse transform compared with rsvg_path_arc */
a00 = cos_th * r1;
a01 = -sin_th * r2;
a10 = sin_th * r1;
a11 = cos_th * r2;
th_half = 0.5 * (_th1 - _th0);
t = (8.0 / 3.0) * sin(th_half * 0.5) * sin(th_half * 0.5) / sin(th_half);
x1 = xc + cos(_th0) - t * sin(_th0);
y1 = yc + sin(_th0) + t * cos(_th0);
x3 = xc + cos(_th1);
y3 = yc + sin(_th1);
x2 = x3 + t * sin(_th1);
y2 = y3 - t * cos(_th1);
svgCurveToCubic( a00 * x1 + a01 * y1, a10 * x1 + a11 * y1, a00 * x2 + a01 * y2, a10 * x2 + a11 * y2, a00 * x3 + a01 * y3, a10 * x3 + a11 * y3 );
}
}
if(!relative)
curx = x;
else
curx += x;
if(!relative)
cury = y;
else
cury += y;
}
void
SVGPathParser::svgLineToHorizontal( double, bool )
{
}
void
SVGPathParser::svgLineToVertical( double, bool )
{
}
void
SVGPathParser::svgCurveToCubicSmooth( double, double, double, double, bool )
{
}
void
SVGPathParser::svgCurveToQuadratic( double, double, double, double, bool )
{
}
void
SVGPathParser::svgCurveToQuadraticSmooth( double, double, bool )
{
}
void
SVGPathParser::svgArcTo( double, double, double, double, double, bool, bool, bool )
{
}