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Diffstat (limited to 'libs/cairo-1.16.0/src/cairo-xlib-visual.c')
| -rw-r--r-- | libs/cairo-1.16.0/src/cairo-xlib-visual.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/libs/cairo-1.16.0/src/cairo-xlib-visual.c b/libs/cairo-1.16.0/src/cairo-xlib-visual.c new file mode 100644 index 0000000..979cd5b --- /dev/null +++ b/libs/cairo-1.16.0/src/cairo-xlib-visual.c @@ -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 = _cairo_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 */ |