forked from KolibriOS/kolibrios
195 lines
6.3 KiB
C
195 lines
6.3 KiB
C
/* Cairo - a vector graphics library with display and print output
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*
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* Copyright © 2008 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it either under the terms of the GNU Lesser General Public
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* License version 2.1 as published by the Free Software Foundation
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* (the "LGPL") or, at your option, under the terms of the Mozilla
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* Public License Version 1.1 (the "MPL"). If you do not alter this
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* notice, a recipient may use your version of this file under either
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* the MPL or the LGPL.
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*
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* You should have received a copy of the LGPL along with this library
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* in the file COPYING-LGPL-2.1; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
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* You should have received a copy of the MPL along with this library
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* in the file COPYING-MPL-1.1
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.1 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
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* OF ANY KIND, either express or implied. See the LGPL or the MPL for
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* the specific language governing rights and limitations.
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*
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* The Original Code is the cairo graphics library.
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*
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* The Initial Developer of the Original Code is Red Hat, Inc.
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*
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* Contributor(s):
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* Carl D. Worth <cworth@cworth.org>
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*/
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#include "cairoint.h"
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#if !CAIRO_HAS_XLIB_XCB_FUNCTIONS
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#include "cairo-xlib-private.h"
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#include "cairo-error-private.h"
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#include "cairo-list-inline.h"
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/* A perceptual distance metric between two colors. No sqrt needed
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* since the square of the distance is still a valid metric. */
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/* XXX: This is currently using linear distance in RGB space which is
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* decidedly not perceptually linear. If someone cared a lot about the
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* quality, they might choose something else here. Then again, they
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* might also choose not to use a PseudoColor visual... */
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static inline int
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_color_distance (unsigned short r1, unsigned short g1, unsigned short b1,
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unsigned short r2, unsigned short g2, unsigned short b2)
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{
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r1 >>= 8; g1 >>= 8; b1 >>= 8;
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r2 >>= 8; g2 >>= 8; b2 >>= 8;
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return ((r2 - r1) * (r2 - r1) +
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(g2 - g1) * (g2 - g1) +
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(b2 - b1) * (b2 - b1));
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}
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cairo_status_t
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_cairo_xlib_visual_info_create (Display *dpy,
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int screen,
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VisualID visualid,
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cairo_xlib_visual_info_t **out)
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{
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cairo_xlib_visual_info_t *info;
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Colormap colormap = DefaultColormap (dpy, screen);
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XColor color;
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int gray, red, green, blue;
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int i, j, distance, min_distance = 0;
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XColor colors[256];
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unsigned short cube_index_to_short[CUBE_SIZE];
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unsigned short ramp_index_to_short[RAMP_SIZE];
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unsigned char gray_to_pseudocolor[RAMP_SIZE];
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for (i = 0; i < CUBE_SIZE; i++)
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cube_index_to_short[i] = (0xffff * i + ((CUBE_SIZE-1)>>1)) / (CUBE_SIZE-1);
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for (i = 0; i < RAMP_SIZE; i++)
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ramp_index_to_short[i] = (0xffff * i + ((RAMP_SIZE-1)>>1)) / (RAMP_SIZE-1);
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info = malloc (sizeof (cairo_xlib_visual_info_t));
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if (unlikely (info == NULL))
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return _cairo_error (CAIRO_STATUS_NO_MEMORY);
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cairo_list_init (&info->link);
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info->visualid = visualid;
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/* Allocate a gray ramp and a color cube.
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* Give up as soon as failures start. */
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for (gray = 0; gray < RAMP_SIZE; gray++) {
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color.red = color.green = color.blue = ramp_index_to_short[gray];
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if (! XAllocColor (dpy, colormap, &color))
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goto DONE_ALLOCATE;
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}
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/* XXX: Could do this in a more clever order to have the best
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* possible results from early failure. Could also choose a cube
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* uniformly distributed in a better space than RGB. */
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for (red = 0; red < CUBE_SIZE; red++) {
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for (green = 0; green < CUBE_SIZE; green++) {
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for (blue = 0; blue < CUBE_SIZE; blue++) {
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color.red = cube_index_to_short[red];
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color.green = cube_index_to_short[green];
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color.blue = cube_index_to_short[blue];
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color.pixel = 0;
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color.flags = 0;
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color.pad = 0;
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if (! XAllocColor (dpy, colormap, &color))
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goto DONE_ALLOCATE;
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}
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}
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}
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DONE_ALLOCATE:
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for (i = 0; i < ARRAY_LENGTH (colors); i++)
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colors[i].pixel = i;
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XQueryColors (dpy, colormap, colors, ARRAY_LENGTH (colors));
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/* Search for nearest colors within allocated colormap. */
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for (gray = 0; gray < RAMP_SIZE; gray++) {
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for (i = 0; i < 256; i++) {
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distance = _color_distance (ramp_index_to_short[gray],
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ramp_index_to_short[gray],
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ramp_index_to_short[gray],
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colors[i].red,
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colors[i].green,
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colors[i].blue);
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if (i == 0 || distance < min_distance) {
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gray_to_pseudocolor[gray] = colors[i].pixel;
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min_distance = distance;
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if (!min_distance)
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break;
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}
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}
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}
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for (red = 0; red < CUBE_SIZE; red++) {
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for (green = 0; green < CUBE_SIZE; green++) {
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for (blue = 0; blue < CUBE_SIZE; blue++) {
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for (i = 0; i < 256; i++) {
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distance = _color_distance (cube_index_to_short[red],
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cube_index_to_short[green],
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cube_index_to_short[blue],
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colors[i].red,
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colors[i].green,
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colors[i].blue);
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if (i == 0 || distance < min_distance) {
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info->cube_to_pseudocolor[red][green][blue] = colors[i].pixel;
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min_distance = distance;
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if (!min_distance)
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break;
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}
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}
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}
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}
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}
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for (i = 0, j = 0; i < 256; i++) {
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if (j < CUBE_SIZE - 1 && (((i<<8)+i) - (int)cube_index_to_short[j]) > ((int)cube_index_to_short[j+1] - ((i<<8)+i)))
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j++;
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info->field8_to_cube[i] = j;
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info->dither8_to_cube[i] = ((int)i - 128) / (CUBE_SIZE - 1);
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}
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for (i = 0, j = 0; i < 256; i++) {
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if (j < RAMP_SIZE - 1 && (((i<<8)+i) - (int)ramp_index_to_short[j]) > ((int)ramp_index_to_short[j+1] - ((i<<8)+i)))
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j++;
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info->gray8_to_pseudocolor[i] = gray_to_pseudocolor[j];
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}
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for (i = 0; i < 256; i++) {
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info->colors[i].a = 0xff;
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info->colors[i].r = colors[i].red >> 8;
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info->colors[i].g = colors[i].green >> 8;
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info->colors[i].b = colors[i].blue >> 8;
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}
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*out = info;
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return CAIRO_STATUS_SUCCESS;
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}
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void
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_cairo_xlib_visual_info_destroy (cairo_xlib_visual_info_t *info)
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{
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/* No need for XFreeColors() whilst using DefaultColormap */
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_cairo_list_del (&info->link);
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free (info);
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}
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#endif /* !CAIRO_HAS_XLIB_XCB_FUNCTIONS */
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