0,0 → 1,194 |
/* Cairo - a vector graphics library with display and print output |
* |
* Copyright © 2008 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 Red Hat, Inc. |
* |
* Contributor(s): |
* Carl D. Worth <cworth@cworth.org> |
*/ |
|
#include "cairoint.h" |
|
#if !CAIRO_HAS_XLIB_XCB_FUNCTIONS |
|
#include "cairo-xlib-private.h" |
|
#include "cairo-error-private.h" |
#include "cairo-list-inline.h" |
|
/* A perceptual distance metric between two colors. No sqrt needed |
* since the square of the distance is still a valid metric. */ |
|
/* XXX: This is currently using linear distance in RGB space which is |
* decidedly not perceptually linear. If someone cared a lot about the |
* quality, they might choose something else here. Then again, they |
* might also choose not to use a PseudoColor visual... */ |
static inline int |
_color_distance (unsigned short r1, unsigned short g1, unsigned short b1, |
unsigned short r2, unsigned short g2, unsigned short b2) |
{ |
r1 >>= 8; g1 >>= 8; b1 >>= 8; |
r2 >>= 8; g2 >>= 8; b2 >>= 8; |
|
return ((r2 - r1) * (r2 - r1) + |
(g2 - g1) * (g2 - g1) + |
(b2 - b1) * (b2 - b1)); |
} |
|
cairo_status_t |
_cairo_xlib_visual_info_create (Display *dpy, |
int screen, |
VisualID visualid, |
cairo_xlib_visual_info_t **out) |
{ |
cairo_xlib_visual_info_t *info; |
Colormap colormap = DefaultColormap (dpy, screen); |
XColor color; |
int gray, red, green, blue; |
int i, j, distance, min_distance = 0; |
XColor colors[256]; |
unsigned short cube_index_to_short[CUBE_SIZE]; |
unsigned short ramp_index_to_short[RAMP_SIZE]; |
unsigned char gray_to_pseudocolor[RAMP_SIZE]; |
|
for (i = 0; i < CUBE_SIZE; i++) |
cube_index_to_short[i] = (0xffff * i + ((CUBE_SIZE-1)>>1)) / (CUBE_SIZE-1); |
for (i = 0; i < RAMP_SIZE; i++) |
ramp_index_to_short[i] = (0xffff * i + ((RAMP_SIZE-1)>>1)) / (RAMP_SIZE-1); |
|
info = malloc (sizeof (cairo_xlib_visual_info_t)); |
if (unlikely (info == NULL)) |
return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
|
cairo_list_init (&info->link); |
info->visualid = visualid; |
|
/* Allocate a gray ramp and a color cube. |
* Give up as soon as failures start. */ |
|
for (gray = 0; gray < RAMP_SIZE; gray++) { |
color.red = color.green = color.blue = ramp_index_to_short[gray]; |
if (! XAllocColor (dpy, colormap, &color)) |
goto DONE_ALLOCATE; |
} |
|
/* XXX: Could do this in a more clever order to have the best |
* possible results from early failure. Could also choose a cube |
* uniformly distributed in a better space than RGB. */ |
for (red = 0; red < CUBE_SIZE; red++) { |
for (green = 0; green < CUBE_SIZE; green++) { |
for (blue = 0; blue < CUBE_SIZE; blue++) { |
color.red = cube_index_to_short[red]; |
color.green = cube_index_to_short[green]; |
color.blue = cube_index_to_short[blue]; |
color.pixel = 0; |
color.flags = 0; |
color.pad = 0; |
if (! XAllocColor (dpy, colormap, &color)) |
goto DONE_ALLOCATE; |
} |
} |
} |
DONE_ALLOCATE: |
|
for (i = 0; i < ARRAY_LENGTH (colors); i++) |
colors[i].pixel = i; |
XQueryColors (dpy, colormap, colors, ARRAY_LENGTH (colors)); |
|
/* Search for nearest colors within allocated colormap. */ |
for (gray = 0; gray < RAMP_SIZE; gray++) { |
for (i = 0; i < 256; i++) { |
distance = _color_distance (ramp_index_to_short[gray], |
ramp_index_to_short[gray], |
ramp_index_to_short[gray], |
colors[i].red, |
colors[i].green, |
colors[i].blue); |
if (i == 0 || distance < min_distance) { |
gray_to_pseudocolor[gray] = colors[i].pixel; |
min_distance = distance; |
if (!min_distance) |
break; |
} |
} |
} |
for (red = 0; red < CUBE_SIZE; red++) { |
for (green = 0; green < CUBE_SIZE; green++) { |
for (blue = 0; blue < CUBE_SIZE; blue++) { |
for (i = 0; i < 256; i++) { |
distance = _color_distance (cube_index_to_short[red], |
cube_index_to_short[green], |
cube_index_to_short[blue], |
colors[i].red, |
colors[i].green, |
colors[i].blue); |
if (i == 0 || distance < min_distance) { |
info->cube_to_pseudocolor[red][green][blue] = colors[i].pixel; |
min_distance = distance; |
if (!min_distance) |
break; |
} |
} |
} |
} |
} |
|
for (i = 0, j = 0; i < 256; i++) { |
if (j < CUBE_SIZE - 1 && (((i<<8)+i) - (int)cube_index_to_short[j]) > ((int)cube_index_to_short[j+1] - ((i<<8)+i))) |
j++; |
info->field8_to_cube[i] = j; |
|
info->dither8_to_cube[i] = ((int)i - 128) / (CUBE_SIZE - 1); |
} |
for (i = 0, j = 0; i < 256; i++) { |
if (j < RAMP_SIZE - 1 && (((i<<8)+i) - (int)ramp_index_to_short[j]) > ((int)ramp_index_to_short[j+1] - ((i<<8)+i))) |
j++; |
info->gray8_to_pseudocolor[i] = gray_to_pseudocolor[j]; |
} |
|
for (i = 0; i < 256; i++) { |
info->colors[i].a = 0xff; |
info->colors[i].r = colors[i].red >> 8; |
info->colors[i].g = colors[i].green >> 8; |
info->colors[i].b = colors[i].blue >> 8; |
} |
|
*out = info; |
return CAIRO_STATUS_SUCCESS; |
} |
|
void |
_cairo_xlib_visual_info_destroy (cairo_xlib_visual_info_t *info) |
{ |
/* No need for XFreeColors() whilst using DefaultColormap */ |
_cairo_list_del (&info->link); |
free (info); |
} |
|
#endif /* !CAIRO_HAS_XLIB_XCB_FUNCTIONS */ |