/* 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 <cworth@cworth.org>
*/
#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;
}
}
/* 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)
{
if (color_a == color_b)
return TRUE;
return color_a->alpha_short == color_b->alpha_short &&
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_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;
}