/* cairo - a vector graphics library with display and print output * * Copyright © 2002 University of Southern California * Copyright © 2005 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it either under the terms of the GNU Lesser General Public * License version 2.1 as published by the Free Software Foundation * (the "LGPL") or, at your option, under the terms of the Mozilla * Public License Version 1.1 (the "MPL"). If you do not alter this * notice, a recipient may use your version of this file under either * the MPL or the LGPL. * * You should have received a copy of the LGPL along with this library * in the file COPYING-LGPL-2.1; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA * You should have received a copy of the MPL along with this library * in the file COPYING-MPL-1.1 * * The contents of this file are subject to the Mozilla Public License * Version 1.1 (the "License"); you may not use this file except in * compliance with the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY * OF ANY KIND, either express or implied. See the LGPL or the MPL for * the specific language governing rights and limitations. * * The Original Code is the cairo graphics library. * * The Initial Developer of the Original Code is University of Southern * California. * * Contributor(s): * Carl D. Worth */ #include "cairoint.h" static cairo_color_t const cairo_color_white = { 1.0, 1.0, 1.0, 1.0, 0xffff, 0xffff, 0xffff, 0xffff }; static cairo_color_t const cairo_color_black = { 0.0, 0.0, 0.0, 1.0, 0x0, 0x0, 0x0, 0xffff }; static cairo_color_t const cairo_color_transparent = { 0.0, 0.0, 0.0, 0.0, 0x0, 0x0, 0x0, 0x0 }; static cairo_color_t const cairo_color_magenta = { 1.0, 0.0, 1.0, 1.0, 0xffff, 0x0, 0xffff, 0xffff }; const cairo_color_t * _cairo_stock_color (cairo_stock_t stock) { switch (stock) { case CAIRO_STOCK_WHITE: return &cairo_color_white; case CAIRO_STOCK_BLACK: return &cairo_color_black; case CAIRO_STOCK_TRANSPARENT: return &cairo_color_transparent; case CAIRO_STOCK_NUM_COLORS: default: ASSERT_NOT_REACHED; /* If the user can get here somehow, give a color that indicates a * problem. */ return &cairo_color_magenta; } } void _cairo_color_init (cairo_color_t *color) { *color = cairo_color_white; } void _cairo_color_init_rgb (cairo_color_t *color, double red, double green, double blue) { _cairo_color_init_rgba (color, red, green, blue, 1.0); } /* Convert a double in [0.0, 1.0] to an integer in [0, 65535] * The conversion is designed to divide the input range into 65536 * equally-sized regions. This is achieved by multiplying by 65536 and * then special-casing the result of an input value of 1.0 so that it * maps to 65535 instead of 65536. */ uint16_t _cairo_color_double_to_short (double d) { uint32_t i; i = (uint32_t) (d * 65536); i -= (i >> 16); return i; } static void _cairo_color_compute_shorts (cairo_color_t *color) { color->red_short = _cairo_color_double_to_short (color->red * color->alpha); color->green_short = _cairo_color_double_to_short (color->green * color->alpha); color->blue_short = _cairo_color_double_to_short (color->blue * color->alpha); color->alpha_short = _cairo_color_double_to_short (color->alpha); } void _cairo_color_init_rgba (cairo_color_t *color, double red, double green, double blue, double alpha) { color->red = red; color->green = green; color->blue = blue; color->alpha = alpha; _cairo_color_compute_shorts (color); } void _cairo_color_multiply_alpha (cairo_color_t *color, double alpha) { color->alpha *= alpha; _cairo_color_compute_shorts (color); } void _cairo_color_get_rgba (cairo_color_t *color, double *red, double *green, double *blue, double *alpha) { *red = color->red; *green = color->green; *blue = color->blue; *alpha = color->alpha; } void _cairo_color_get_rgba_premultiplied (cairo_color_t *color, double *red, double *green, double *blue, double *alpha) { *red = color->red * color->alpha; *green = color->green * color->alpha; *blue = color->blue * color->alpha; *alpha = color->alpha; } /* NB: This function works both for unmultiplied and premultiplied colors */ cairo_bool_t _cairo_color_equal (const cairo_color_t *color_a, const cairo_color_t *color_b) { if (color_a == color_b) return TRUE; if (color_a->alpha_short != color_b->alpha_short) return FALSE; if (color_a->alpha_short == 0) return TRUE; return color_a->red_short == color_b->red_short && color_a->green_short == color_b->green_short && color_a->blue_short == color_b->blue_short; } cairo_bool_t _cairo_color_stop_equal (const cairo_color_stop_t *color_a, const cairo_color_stop_t *color_b) { uint16_t a, b; if (color_a == color_b) return TRUE; if (color_a->alpha_short != color_b->alpha_short) return FALSE; a = _cairo_color_double_to_short (color_a->red * color_a->alpha); b = _cairo_color_double_to_short (color_b->red * color_b->alpha); if (a != b) return FALSE; a = _cairo_color_double_to_short (color_a->green * color_a->alpha); b = _cairo_color_double_to_short (color_b->green * color_b->alpha); if (a != b) return FALSE; a = _cairo_color_double_to_short (color_a->blue * color_a->alpha); b = _cairo_color_double_to_short (color_b->blue * color_b->alpha); if (a != b) return FALSE; return TRUE; } cairo_content_t _cairo_color_get_content (const cairo_color_t *color) { if (CAIRO_COLOR_IS_OPAQUE (color)) return CAIRO_CONTENT_COLOR; if (color->red_short == 0 && color->green_short == 0 && color->blue_short == 0) { return CAIRO_CONTENT_ALPHA; } return CAIRO_CONTENT_COLOR_ALPHA; }