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/*************************************************************************
** Color.cpp **
** **
** This file is part of dvisvgm -- the DVI to SVG converter **
** Copyright (C) 2005-2010 Martin Gieseking <martin.gieseking@uos.de> **
** **
** 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 3 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. **
** **
** You should have received a copy of the GNU General Public License **
** along with this program; if not, see <http://www.gnu.org/licenses/>. **
*************************************************************************/
#include <cmath>
#include <iomanip>
#include <sstream>
#include "Color.h"
using namespace std;
const Color Color::BLACK(0);
const Color Color::WHITE(UInt8(255), UInt8(255), UInt8(255));
static inline UInt8 float_to_byte (float v) {
return (UInt8) (floor(255*v+0.5));
}
void Color::set (float r, float g, float b) {
set(float_to_byte(r), float_to_byte(g), float_to_byte(b));
}
void Color::setHSB (float h, float s, float b) {
vector<float> hsb(3), rgb(3);
hsb[0] = h;
hsb[1] = s;
hsb[2] = b;
HSB2RGB(hsb, rgb);
set(rgb[0], rgb[1], rgb[2]);
}
void Color::setCMYK (float c, float m, float y, float k) {
vector<float> cmyk(4), rgb(3);
cmyk[0] = c;
cmyk[1] = m;
cmyk[2] = y;
cmyk[3] = k;
CMYK2RGB(cmyk, rgb);
set(rgb[0], rgb[1], rgb[2]);
}
void Color::operator *= (double c) {
UInt32 rgb=0;
for (int i=0; i < 3; i++) {
rgb |= UInt32(floor((_rgb & 0xff)*c+0.5)) << (8*i);
_rgb >>= 8;
}
_rgb = rgb;
}
string Color::rgbString () const {
ostringstream oss;
oss << '#';
for (int i=2; i >= 0; i--) {
oss << setbase(16) << setfill('0') << setw(2)
<< (((_rgb >> (8*i)) & 0xff));
}
return oss.str();
}
/** Approximates a CMYK color by an RGB triple. The component values
* are expected to be normalized, i.e. 0 <= cmyk[i],rgb[j] <= 1.
* @param[in] cmyk color in CMYK space
* @param[out] rgb RGB approximation */
void Color::CMYK2RGB (const vector<float> &cmyk, vector<float> &rgb) {
for (int i=0; i < 3; i++)
rgb[i] = 1.0f-min(1.0f, cmyk[i]+cmyk[3]);
}
/** Converts a color given in HSB coordinates to RGB.
* @param[in] hsb color in HSB space
* @param[out] rgb color in RGB space */
void Color::HSB2RGB (const vector<float> &hsb, vector<float> &rgb) {
if (hsb[1] == 0)
rgb[0] = rgb[1] = rgb[2] = hsb[2];
else {
float h = hsb[0]-floor(hsb[0]);
int i = int(6*h);
float f = float(6.0*h-i);
float p = hsb[2]*(1-hsb[1]);
float q = hsb[2]*(1-hsb[1]*f);
float t = hsb[2]*(1-hsb[1]*(1-f));
switch (i) {
case 0 : rgb[0]=hsb[2]; rgb[1]=t; rgb[2]=p; break;
case 1 : rgb[0]=q; rgb[1]=hsb[2]; rgb[2]=p; break;
case 2 : rgb[0]=p; rgb[1]=hsb[2]; rgb[2]=t; break;
case 3 : rgb[0]=p; rgb[1]=q; rgb[2]=hsb[2]; break;
case 4 : rgb[0]=t; rgb[1]=p; rgb[2]=hsb[2]; break;
case 5 : rgb[0]=hsb[2]; rgb[1]=p; rgb[2]=q; break;
default: ; // prevent compiler warning
}
}
}
void Color::getRGB (float &r, float &g, float &b) const {
r = float(((_rgb >> 16) & 255) / 255.0);
g = float(((_rgb >> 8) & 255) / 255.0);
b = float((_rgb & 255) / 255.0);
}
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