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Diffstat (limited to 'libdimension/dimension/color/color.h')
| -rw-r--r-- | libdimension/dimension/color/color.h | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/libdimension/dimension/color/color.h b/libdimension/dimension/color/color.h new file mode 100644 index 0000000..84e66ea --- /dev/null +++ b/libdimension/dimension/color/color.h @@ -0,0 +1,198 @@ +/************************************************************************* + * Copyright (C) 2009-2014 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 + * Colors. + */ + +#ifndef DMNSN_COLOR_H +#error "Please include <dimension/color.h> instead of this header directly." +#endif + +#include <math.h> +#include <stdbool.h> + +/** A color value. */ +typedef struct { + double R; /**< Red component. */ + double G; /**< Green component. */ + double B; /**< Blue component. */ +} dmnsn_color; + +/** A standard format string for colors. */ +#define DMNSN_COLOR_FORMAT "Color<%g, %g, %g>" +/** The appropriate arguements to printf() a color. */ +#define DMNSN_COLOR_PRINTF(c) (c).R, (c).G, (c).B + +/** Construct a new color. */ +DMNSN_INLINE dmnsn_color +dmnsn_new_color(double R, double G, double B) +{ + dmnsn_color ret = { R, G, B }; + return ret; +} + +/** Apply sRGB gamma */ +DMNSN_INLINE double +dmnsn_sRGB_gamma(double Clinear) +{ + /* + * If C represents R, G, and B, then the sRGB values are now found as follows: + * + * { 12.92*Clinear, Clinear <= 0.0031308 + * Csrgb = { 1/2.4 + * { (1.055)*Clinear - 0.055, Clinear > 0.0031308 + */ + if (Clinear == 1.0) { + return 1.0; /* Map 1.0 to 1.0 instead of 0.9999999999999999 */ + } else if (Clinear > 0.0031308) { + return 1.055*pow(Clinear, 1.0/2.4) - 0.055; + } else { + return 12.92*Clinear; + } +} + +/** Convert to sRGB space. */ +DMNSN_INLINE dmnsn_color +dmnsn_color_to_sRGB(dmnsn_color color) +{ + return dmnsn_new_color( + dmnsn_sRGB_gamma(color.R), + dmnsn_sRGB_gamma(color.G), + dmnsn_sRGB_gamma(color.B) + ); +} + +/** Remove sRGB gamma */ +DMNSN_INLINE double +dmnsn_sRGB_inverse_gamma(double CsRGB) +{ + /* + * If C represents R, G, and B, then the Clinear values are now found as + * follows: + * + * { Csrgb/12.92, Csrgb <= 0.04045 + * Clinear = { 2.4 + * { ((Csrgb + 0.055)/1.055) , Csrgb > 0.04045 + */ + if (CsRGB == 1.0) { + return 1.0; /* Map 1.0 to 1.0 instead of 0.9999999999999999 */ + } else if (CsRGB <= 0.040449936) { + return CsRGB/12.92; + } else { + return pow((CsRGB + 0.055)/1.055, 2.4); + } +} + +/** Convert from sRGB space. */ +DMNSN_INLINE dmnsn_color +dmnsn_color_from_sRGB(dmnsn_color color) +{ + return dmnsn_new_color( + dmnsn_sRGB_inverse_gamma(color.R), + dmnsn_sRGB_inverse_gamma(color.G), + dmnsn_sRGB_inverse_gamma(color.B) + ); +} + +/** Greyscale color intensity. */ +DMNSN_INLINE double +dmnsn_color_intensity(dmnsn_color color) +{ + return 0.2126*color.R + 0.7152*color.G + 0.0722*color.B; +} + +/** Add two colors together. */ +DMNSN_INLINE dmnsn_color +dmnsn_color_add(dmnsn_color lhs, dmnsn_color rhs) +{ + return dmnsn_new_color(lhs.R + rhs.R, lhs.G + rhs.G, lhs.B + rhs.B); +} + +/** Subtract two colors. */ +DMNSN_INLINE dmnsn_color +dmnsn_color_sub(dmnsn_color lhs, dmnsn_color rhs) +{ + return dmnsn_new_color(lhs.R - rhs.R, lhs.G - rhs.G, lhs.B - rhs.B); +} + +/** Scale a color's intensity. */ +DMNSN_INLINE dmnsn_color +dmnsn_color_mul(double n, dmnsn_color color) +{ + return dmnsn_new_color(n*color.R, n*color.G, n*color.B); +} + +/** Return the color at \p n on a gradient from \p c1 at 0 to \p c2 at 1. */ +DMNSN_INLINE dmnsn_color +dmnsn_color_gradient(dmnsn_color c1, dmnsn_color c2, double n) +{ + return dmnsn_new_color( + n*(c2.R - c1.R) + c1.R, + n*(c2.G - c1.G) + c1.G, + n*(c2.B - c1.B) + c1.B + ); +} + +/** Illuminate \p color with \p light. */ +DMNSN_INLINE dmnsn_color +dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color) +{ + return dmnsn_new_color(light.R*color.R, light.G*color.G, light.B*color.B); +} + +/** Saturate the color components to [0.0, 1.0]. */ +DMNSN_INLINE dmnsn_color +dmnsn_color_clamp(dmnsn_color color) +{ + color.R = dmnsn_clamp(color.R, 0.0, 1.0); + color.G = dmnsn_clamp(color.G, 0.0, 1.0); + color.B = dmnsn_clamp(color.B, 0.0, 1.0); + return color; +} + +/** Return whether a color contains any NaN components. */ +DMNSN_INLINE bool +dmnsn_color_isnan(dmnsn_color color) +{ + return dmnsn_isnan(color.R) || dmnsn_isnan(color.G) || dmnsn_isnan(color.B); +} + +/* Standard colors */ + +/** Black. */ +#define dmnsn_black dmnsn_new_color(0.0, 0.0, 0.0) +/** White. */ +#define dmnsn_white dmnsn_new_color(1.0, 1.0, 1.0) +/** Red. */ +#define dmnsn_red dmnsn_new_color(1.0, 0.0, 0.0) +/** Green. */ +#define dmnsn_green dmnsn_new_color(0.0, 1.0, 0.0) +/** Blue. */ +#define dmnsn_blue dmnsn_new_color(0.0, 0.0, 1.0) +/** Magenta. */ +#define dmnsn_magenta dmnsn_new_color(1.0, 0.0, 1.0) +/** Orange. */ +#define dmnsn_orange dmnsn_new_color(1.0, 0.21404114048223255, 0.0) +/** Yellow. */ +#define dmnsn_yellow dmnsn_new_color(1.0, 1.0, 0.0) +/** Cyan. */ +#define dmnsn_cyan dmnsn_new_color(0.0, 1.0, 1.0) |