//+----------------------------------------------------------------------------+
//| Description:  Magic Set Editor - Program to make Magic (tm) cards          |
//| Copyright:    (C) 2001 - 2006 Twan van Laarhoven                           |
//| License:      GNU General Public License 2 or later (see file COPYING)     |
//+----------------------------------------------------------------------------+

// ----------------------------------------------------------------------------- : Includes

#include <gfx/gfx.hpp>

// ----------------------------------------------------------------------------- : Color utility functions

Color lerp(const Color& a, const Color& b, double t) {
	return Color(a.Red()   + (b.Red()   - a.Red()  ) * t,
	             a.Green() + (b.Green() - a.Green()) * t,
	             a.Blue()  + (b.Blue()  - a.Blue() ) * t);
}


int hsl2rgbp(double t1, double t2, double t3) {
	// adjust t3 to [0...1)
	if      (t3 < 0.0) t3 += 1;
	else if (t3 > 1.0) t3 -= 1;
	// determine color
	if (6.0 * t3 < 1) return (int)(255 * (t1 + (t2-t1) * 6.0 * t3)             );
	if (2.0 * t3 < 1) return (int)(255 * (t2)                                  );
	if (3.0 * t3 < 2) return (int)(255 * (t1 + (t2-t1) * 6.0 * (2.0/3.0 - t3)) );
	else              return (int)(255 * (t1)                                  );
}
Color hsl2rgb(double h, double s, double l) {
	double t2 = l < 0.5 ? l * (1.0 + s) :
	                      l * (1.0 - s) + s;
	double t1 = 2.0 * l - t2;
	return Color(
		hsl2rgbp(t1, t2, h + 1.0/3.0),
		hsl2rgbp(t1, t2, h)          ,
		hsl2rgbp(t1, t2, h - 1.0/3.0)
	);
}


Color darken(const Color& c) {
	return Color(
		c.Red()   * 8 / 10,
		c.Green() * 8 / 10,
		c.Blue()  * 8 / 10
	);
}

Color saturate(const Color& c, double amount) {
	int r = c.Red(), g = c.Green(), b = c.Blue();
	double l = (r + g + b) / 3;
	return Color(
		col((r - amount * l) / (1 - amount)),
		col((g - amount * l) / (1 - amount)),
		col((b - amount * l) / (1 - amount))
	);
}