/* Color utilities * * Copyright (C) 1999 The Free Software Foundation * * Authors: Simon Budig (original code) * Federico Mena-Quintero (cleanup for GTK+) * Jonathan Blandford (cleanup for GTK+) * * This 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 2 of the License, or (at your option) any later version. * * This 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 library. If not, see . */ /* * Modified by the GTK+ Team and others 1997-2000. See the AUTHORS * file for a list of people on the GTK+ Team. See the ChangeLog * files for a list of changes. These files are distributed with * GTK+ at ftp://ftp.gtk.org/pub/gtk/. */ #include "config.h" #include #include #include "gtkcolorutils.h" /* Converts from HSV to RGB */ static void hsv_to_rgb (gdouble *h, gdouble *s, gdouble *v) { gdouble hue, saturation, value; gdouble f, p, q, t; if (*s == 0.0) { *h = *v; *s = *v; *v = *v; /* heh */ } else { hue = *h * 6.0; saturation = *s; value = *v; if (hue == 6.0) hue = 0.0; f = hue - (int) hue; p = value * (1.0 - saturation); q = value * (1.0 - saturation * f); t = value * (1.0 - saturation * (1.0 - f)); switch ((int) hue) { case 0: *h = value; *s = t; *v = p; break; case 1: *h = q; *s = value; *v = p; break; case 2: *h = p; *s = value; *v = t; break; case 3: *h = p; *s = q; *v = value; break; case 4: *h = t; *s = p; *v = value; break; case 5: *h = value; *s = p; *v = q; break; default: g_assert_not_reached (); } } } /* Converts from RGB to HSV */ static void rgb_to_hsv (gdouble *r, gdouble *g, gdouble *b) { gdouble red, green, blue; gdouble h, s, v; gdouble min, max; gdouble delta; red = *r; green = *g; blue = *b; h = 0.0; if (red > green) { if (red > blue) max = red; else max = blue; if (green < blue) min = green; else min = blue; } else { if (green > blue) max = green; else max = blue; if (red < blue) min = red; else min = blue; } v = max; if (max != 0.0) s = (max - min) / max; else s = 0.0; if (s == 0.0) h = 0.0; else { delta = max - min; if (red == max) h = (green - blue) / delta; else if (green == max) h = 2 + (blue - red) / delta; else if (blue == max) h = 4 + (red - green) / delta; h /= 6.0; if (h < 0.0) h += 1.0; else if (h > 1.0) h -= 1.0; } *r = h; *g = s; *b = v; } /** * gtk_hsv_to_rgb: * @h: Hue * @s: Saturation * @v: Value * @r: (out): Return value for the red component * @g: (out): Return value for the green component * @b: (out): Return value for the blue component * * Converts a color from HSV space to RGB. * * Input values must be in the [0.0, 1.0] range; * output values will be in the same range. * * Since: 2.14 */ void gtk_hsv_to_rgb (gdouble h, gdouble s, gdouble v, gdouble *r, gdouble *g, gdouble *b) { g_return_if_fail (h >= 0.0 && h <= 1.0); g_return_if_fail (s >= 0.0 && s <= 1.0); g_return_if_fail (v >= 0.0 && v <= 1.0); hsv_to_rgb (&h, &s, &v); if (r) *r = h; if (g) *g = s; if (b) *b = v; } /** * gtk_rgb_to_hsv: * @r: Red * @g: Green * @b: Blue * @h: (out): Return value for the hue component * @s: (out): Return value for the saturation component * @v: (out): Return value for the value component * * Converts a color from RGB space to HSV. * * Input values must be in the [0.0, 1.0] range; * output values will be in the same range. * * Since: 2.14 */ void gtk_rgb_to_hsv (gdouble r, gdouble g, gdouble b, gdouble *h, gdouble *s, gdouble *v) { g_return_if_fail (r >= 0.0 && r <= 1.0); g_return_if_fail (g >= 0.0 && g <= 1.0); g_return_if_fail (b >= 0.0 && b <= 1.0); rgb_to_hsv (&r, &g, &b); if (h) *h = r; if (s) *s = g; if (v) *v = b; }