/*************************************************************************
** Color.cpp                                                            **
**                                                                      **
** This file is part of dvisvgm -- the DVI to SVG converter             **
** Copyright (C) 2005-2011 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);
}