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diff --git a/libdimension/color.c b/libdimension/color.c
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-/*************************************************************************
- * Copyright (C) 2009-2011 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 handling.
- */
-
-#include "dimension.h"
-
-/* Standard colors */
-const dmnsn_color dmnsn_black = {
- .R = 0.0,
- .G = 0.0,
- .B = 0.0,
- .trans = 0.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_white = {
- .R = 1.0,
- .G = 1.0,
- .B = 1.0,
- .trans = 0.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_clear = {
- .R = 0.0,
- .G = 0.0,
- .B = 0.0,
- .trans = 1.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_red = {
- .R = 1.0,
- .G = 0.0,
- .B = 0.0,
- .trans = 0.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_green = {
- .R = 0.0,
- .G = 1.0,
- .B = 0.0,
- .trans = 0.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_blue = {
- .R = 0.0,
- .G = 0.0,
- .B = 1.0,
- .trans = 0.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_magenta = {
- .R = 1.0,
- .G = 0.0,
- .B = 1.0,
- .trans = 0.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_orange = {
- .R = 1.0,
- .G = 0.21404114048223255,
- .B = 0.0,
- .trans = 0.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_yellow = {
- .R = 1.0,
- .G = 1.0,
- .B = 0.0,
- .trans = 0.0,
- .filter = 0.0,
-};
-const dmnsn_color dmnsn_cyan = {
- .R = 0.0,
- .G = 1.0,
- .B = 1.0,
- .filter = 0.0,
- .trans = 0.0,
-};
-
-/* sRGB's `C' function. */
-static inline double
-dmnsn_sRGB_C(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;
- }
-}
-
-/* Export dmnsn_sRGB_C */
-double
-dmnsn_sRGB_gamma(double Clinear)
-{
- return dmnsn_sRGB_C(Clinear);
-}
-
-/* Convert to sRGB space */
-dmnsn_color
-dmnsn_color_to_sRGB(dmnsn_color color)
-{
- dmnsn_color ret = {
- .R = dmnsn_sRGB_C(color.R),
- .G = dmnsn_sRGB_C(color.G),
- .B = dmnsn_sRGB_C(color.B),
- .trans = color.trans,
- .filter = color.filter,
- };
- return ret;
-}
-
-/* Inverse function of sRGB's `C' function, for the reverse conversion. */
-double
-dmnsn_sRGB_C_inv(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 = { 1/2.4
- * { ((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);
- }
-}
-
-/* Export dmnsn_sRGB_C_inv */
-double
-dmnsn_sRGB_inverse_gamma(double CsRGB)
-{
- return dmnsn_sRGB_C_inv(CsRGB);
-}
-
-/* Convert from sRGB space */
-dmnsn_color
-dmnsn_color_from_sRGB(dmnsn_color color)
-{
- dmnsn_color ret = {
- .R = dmnsn_sRGB_C_inv(color.R),
- .G = dmnsn_sRGB_C_inv(color.G),
- .B = dmnsn_sRGB_C_inv(color.B),
- .trans = color.trans,
- .filter = color.filter,
- };
- return ret;
-}
-
-/* Greyscale color intensity */
-double
-dmnsn_color_intensity(dmnsn_color color)
-{
- return 0.2126*color.R + 0.7152*color.G + 0.0722*color.B;
-}
-
-/* Add two colors */
-dmnsn_color
-dmnsn_color_add(dmnsn_color c1, dmnsn_color c2)
-{
- dmnsn_color ret = dmnsn_new_color(c1.R + c2.R, c1.G + c2.G, c1.B + c2.B);
-
- /* Switch into absolute filter and transmittance space */
- double n1 = dmnsn_color_intensity(c1), n2 = dmnsn_color_intensity(c2);
- double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans;
- double t1 = c1.trans - f1, t2 = c2.trans - f2;
- double f = 0.0;
- if (n1 + n2 >= dmnsn_epsilon)
- f = (n1*f1 + n2*f2)/(n1 + n2);
- double t = t1 + t2;
-
- /* Switch back */
- ret.trans = f + t;
- if (ret.trans >= dmnsn_epsilon)
- ret.filter = f/ret.trans;
-
- return ret;
-}
-
-/* Subtract two colors */
-dmnsn_color
-dmnsn_color_sub(dmnsn_color c1, dmnsn_color c2)
-{
- dmnsn_color ret = dmnsn_new_color(c1.R - c2.R, c1.G - c2.G, c1.B - c2.B);
-
- /* Switch into absolute filter and transmittance space */
- double n1 = dmnsn_color_intensity(c1), n2 = dmnsn_color_intensity(c2);
- double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans;
- double t1 = c1.trans - f1, t2 = c2.trans - f2;
- double f = 0.0;
- if (n1 - n2 >= dmnsn_epsilon)
- f = (n1*f1 - n2*f2)/(n1 - n2);
- double t = t1 - t2;
-
- /* Switch back */
- ret.trans = f + t;
- if (ret.trans >= dmnsn_epsilon)
- ret.filter = f/ret.trans;
-
- return ret;
-}
-
-/* Multiply a color by a scalar */
-dmnsn_color
-dmnsn_color_mul(double n, dmnsn_color color)
-{
- color.R *= n;
- color.G *= n;
- color.B *= n;
- color.trans *= n;
- return color;
-}
-
-/* For n in [0, 1] get the color in a gradient between c1 and c2 */
-dmnsn_color
-dmnsn_color_gradient(dmnsn_color c1, dmnsn_color c2, double n)
-{
- dmnsn_color ret = dmnsn_new_color(
- n*(c2.R - c1.R) + c1.R,
- n*(c2.G - c1.G) + c1.G,
- n*(c2.B - c1.B) + c1.B
- );
-
- /* Switch into absolute filter and transmittance space */
- double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans;
- double t1 = c1.trans - f1, t2 = c2.trans - f2;
- double f = n*(f2 - f1) + f1;
- double t = n*(t2 - t1) + t1;
-
- /* Switch back */
- ret.trans = f + t;
- ret.filter = 0.0;
- if (ret.trans >= dmnsn_epsilon)
- ret.filter = f/ret.trans;
-
- return ret;
-}
-
-/* Filters `light' through `filter' */
-dmnsn_color
-dmnsn_filter_light(dmnsn_color light, dmnsn_color filter)
-{
- dmnsn_color transmitted = dmnsn_color_mul(
- (1.0 - filter.filter)*filter.trans,
- light
- );
- dmnsn_color filtered = dmnsn_color_mul(
- filter.filter*filter.trans,
- dmnsn_color_illuminate(filter, light)
- );
-
- dmnsn_color ret = dmnsn_new_color(
- transmitted.R + filtered.R,
- transmitted.G + filtered.G,
- transmitted.B + filtered.B
- );
-
- /* Switch into absolute filter and transmittance space */
- double lf = light.filter*light.trans, ff = filter.filter*filter.trans;
- double lt = light.trans - lf, ft = filter.trans - ff;
- double f = lf*(dmnsn_color_intensity(filtered) + ft) + lt*ff;
- double t = ft*lt;
-
- /* Switch back */
- ret.trans = f + t;
- if (ret.trans >= dmnsn_epsilon)
- ret.filter = f/ret.trans;
-
- return ret;
-}
-
-/* Adds the background contribution, `filtered', to `filter' */
-dmnsn_color
-dmnsn_apply_transparency(dmnsn_color filtered, dmnsn_color filter)
-{
- dmnsn_color ret = dmnsn_color_add(
- dmnsn_color_mul(1.0 - filter.trans, filter),
- filtered
- );
- ret.trans = filtered.trans;
- ret.filter = filtered.filter;
- return ret;
-}
-
-/* Adds the background contribution of `color' to `filter' */
-dmnsn_color
-dmnsn_apply_filter(dmnsn_color color, dmnsn_color filter)
-{
- return dmnsn_apply_transparency(dmnsn_filter_light(color, filter), filter);
-}
-
-/* Remove the filter channel */
-dmnsn_color
-dmnsn_remove_filter(dmnsn_color color)
-{
- double intensity = dmnsn_color_intensity(color);
- double newtrans = (1.0 - (1.0 - intensity)*color.filter)*color.trans;
- if (1.0 - newtrans >= dmnsn_epsilon)
- color = dmnsn_color_mul((1.0 - color.trans)/(1.0 - newtrans), color);
- color.trans = newtrans;
- color.filter = 0.0;
- return color;
-}
-
-/* Illuminates `color' with `light' */
-dmnsn_color
-dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color)
-{
- return dmnsn_new_color5(light.R*color.R, light.G*color.G, light.B*color.B,
- color.filter, color.trans);
-}
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