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/*************************************************************************
* Copyright (C) 2009-2010 Tavian Barnes <tavianator@tavianator.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension Library is free software; you can redistribute it and/ *
* or modify it under the terms of the GNU Lesser General Public License *
* as published by the Free Software Foundation; either version 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension 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 *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
/**
* @file
* Color-related types and operations.
*/
#include <stdbool.h>
/** A color value. */
typedef struct {
double R; /**< sRGB red value. */
double G; /**< sRGB green value. */
double B; /**< sRGB blue value. */
/** Filtered transparency. */
double filter;
/** Unfiltered transparency; <tt>filter + trans</tt> should be <= 1. */
double trans;
} dmnsn_color;
/* Standard colors */
extern const dmnsn_color dmnsn_black; /**< Black. */
extern const dmnsn_color dmnsn_white; /**< White. */
extern const dmnsn_color dmnsn_clear; /**< Clear. */
extern const dmnsn_color dmnsn_red; /**< Red. */
extern const dmnsn_color dmnsn_green; /**< Green. */
extern const dmnsn_color dmnsn_blue; /**< Blue. */
extern const dmnsn_color dmnsn_magenta; /**< Magenta. */
extern const dmnsn_color dmnsn_orange; /**< Orange. */
extern const dmnsn_color dmnsn_yellow; /**< Yellow. */
extern const dmnsn_color dmnsn_cyan; /**< Cyan. */
/* Color construction */
/** Construct a new color. */
DMNSN_INLINE dmnsn_color
dmnsn_new_color(double R, double G, double B)
{
dmnsn_color ret = { R, G, B, 0.0, 0.0 };
return ret;
}
/** Construct a new color with transparent components. */
DMNSN_INLINE dmnsn_color
dmnsn_new_color5(double R, double G, double B, double filter, double trans)
{
dmnsn_color ret = { R, G, B, filter, trans };
return ret;
}
/** Is this color black? */
DMNSN_INLINE bool
dmnsn_color_is_black(dmnsn_color color)
{
return fabs(color.R) < dmnsn_epsilon
&& fabs(color.G) < dmnsn_epsilon
&& fabs(color.B) < dmnsn_epsilon
&& fabs(color.trans) < dmnsn_epsilon;
}
/* Perceptual color manipulation */
/** Greyscale color intensity. */
double dmnsn_color_intensity(dmnsn_color color);
/** Add two colors together. */
dmnsn_color dmnsn_color_add(dmnsn_color color1, dmnsn_color color2);
/** Multiply a color's intensity by \p n. */
dmnsn_color dmnsn_color_mul(double n, dmnsn_color color);
/** Return the color at \p n on a gradient from \p c1 at 0 to \p c2 at 1. */
dmnsn_color dmnsn_color_gradient(dmnsn_color c1, dmnsn_color c2, double n);
/** Filter \p light through \p filter. */
dmnsn_color dmnsn_filter_light(dmnsn_color light, dmnsn_color filter);
/** Add the background contribution \p filtered to \p filter. */
dmnsn_color dmnsn_apply_translucency(dmnsn_color filtered, dmnsn_color filter);
/** Add the background contribution of \p color to \p filter. */
dmnsn_color dmnsn_apply_filter(dmnsn_color color, dmnsn_color filter);
/** Illuminate \p color with \p light. */
dmnsn_color dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color);
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