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/*************************************************************************
* Copyright (C) 2009-2010 Tavian Barnes <tavianator@gmail.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.
*/
#ifndef DIMENSION_COLOR_H
#define DIMENSION_COLOR_H
#include <stdbool.h>
/** A color value. */
typedef struct {
/** Filtered transparency. */
double filter;
/** Unfiltered transparency; <tt>filter + trans</tt> should be <= 1. */
double trans;
/* Internally we use sRGB color. */
double R; /**< @internal sRGB red value. */
double G; /**< @internal sRGB green value. */
double B; /**< @internal sRGB blue value. */
} dmnsn_color;
/** sRGB color. */
typedef struct {
double R; /**< sRGB red value. */
double G; /**< sRGB green value. */
double B; /**< sRGB blue value. */
} dmnsn_sRGB;
/** CIE XYZ color. */
typedef struct {
double X; /**< X component. */
double Y; /**< Y (luminance) component. */
double Z; /**< Z component. */
} dmnsn_CIE_XYZ;
/** CIE xyY color. */
typedef struct {
double x; /**< x chromaticity coordinate (in [0, 1]). */
double y; /**< y chromaticity coordinate (in [0, 1]). */
double Y; /**< Luminance, unbounded >= 0; 1 is diffuse white. */
} dmnsn_CIE_xyY;
/** CIE 1976 (L*, a*, b*) color. */
typedef struct {
double L; /**< Luminance (100 is diffuse white). */
double a; /**< Red/greed color-opponent value. */
double b; /**< Yellow/blue color-opponent value. */
} dmnsn_CIE_Lab;
/** CIE 1976 (L*, u*, v*) color. */
typedef struct {
double L; /**< Luminance (same L* as CIE L*, a*, b*). */
double u; /**< u* coordinate. */
double v; /**< v* coordinate. */
} dmnsn_CIE_Luv;
/* Standard colors */
extern const dmnsn_color dmnsn_black; /**< Black. */
extern const dmnsn_color dmnsn_white; /**< White. */
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. */
/** Standard whitepoint, determined by the conversion of sRGB white to
CIE XYZ */
extern const dmnsn_CIE_XYZ dmnsn_whitepoint;
/** Is this color black?. */
bool dmnsn_color_is_black(dmnsn_color color);
/* Color conversions */
/** Convert an sRGB color to a Dimension color. */
dmnsn_color dmnsn_color_from_sRGB(dmnsn_sRGB sRGB);
/** Convert a CIE XYZ color to a Dimension color. */
dmnsn_color dmnsn_color_from_XYZ(dmnsn_CIE_XYZ XYZ);
/** Convert a CIE xyY color to a Dimension color. */
dmnsn_color dmnsn_color_from_xyY(dmnsn_CIE_xyY xyY);
/** Convert a CIE L*, a*, b* color to a Dimension color. */
dmnsn_color dmnsn_color_from_Lab(dmnsn_CIE_Lab Lab, dmnsn_CIE_XYZ white);
/** Convert a CIE L*, u*, v* color to a Dimension color. */
dmnsn_color dmnsn_color_from_Luv(dmnsn_CIE_Luv Luv, dmnsn_CIE_XYZ white);
/** Convert a Dimension color to sRGB. */
dmnsn_sRGB dmnsn_sRGB_from_color(dmnsn_color color);
/** Convert a Dimension color to CIE XYZ. */
dmnsn_CIE_XYZ dmnsn_XYZ_from_color(dmnsn_color color);
/** Convert a Dimension color to CIE xyY. */
dmnsn_CIE_xyY dmnsn_xyY_from_color(dmnsn_color color);
/** Convert a Dimension color to CIE L*, a*, b*. */
dmnsn_CIE_Lab dmnsn_Lab_from_color(dmnsn_color color, dmnsn_CIE_XYZ white);
/** Convert a Dimension color to CIE L*, u*, v*. */
dmnsn_CIE_Luv dmnsn_Luv_from_color(dmnsn_color color, dmnsn_CIE_XYZ white);
/* Perceptual color manipulation */
/** 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 color through \p filter. */
dmnsn_color dmnsn_color_filter(dmnsn_color color, dmnsn_color filter);
/** Illuminate \p color with \p light. */
dmnsn_color dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color);
/** Return the perceptual difference between two colors. */
double dmnsn_color_difference(dmnsn_color color1, dmnsn_color color2);
#endif /* DIMENSION_COLOR_H */
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