123 lines
3.6 KiB
C
123 lines
3.6 KiB
C
/***********************************************************************/
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/* */
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/* Objective Caml */
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/* */
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/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
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/* */
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/* Copyright 1996 Institut National de Recherche en Informatique et */
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/* en Automatique. All rights reserved. This file is distributed */
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/* under the terms of the GNU Library General Public License. */
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/* */
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/***********************************************************************/
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/* $Id$ */
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#include "libgraph.h"
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/* Cache to speed up the translation rgb -> pixel value. */
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struct color_cache_entry {
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int rgb; /* RGB value with format 0xRRGGBB */
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unsigned long pixel; /* Pixel value */
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};
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#define Color_cache_size 512
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static struct color_cache_entry color_cache[Color_cache_size];
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#define Empty (-1)
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#define Hash_rgb(r,g,b) \
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((((r) & 0xE0) << 1) + (((g) & 0xE0) >> 2) + (((b) & 0xE0) >> 5))
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#define Color_cache_slack 16
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static int num_overflows = 0;
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Bool direct_rgb = False;
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int byte_order;
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int bitmap_unit;
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int bits_per_pixel;
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void gr_init_color_cache(void)
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{
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int i;
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for (i = 0; i < Color_cache_size; i++) color_cache[i].rgb = Empty;
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i = Hash_rgb(0, 0, 0);
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color_cache[i].rgb = 0;
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color_cache[i].pixel = grblack;
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i = Hash_rgb(0xFF, 0xFF, 0xFF);
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color_cache[i].rgb = 0xFFFFFF;
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color_cache[i].pixel = grwhite;
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}
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unsigned long gr_pixel_rgb(int rgb)
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{
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unsigned int r, g, b;
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int h, i;
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XColor color;
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unsigned short tmp;
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r = (rgb >> 16) & 0xFF;
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g = (rgb >> 8) & 0xFF;
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b = rgb & 0xFF;
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if (direct_rgb){
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switch ( bits_per_pixel ){
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case 16:
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tmp = ((r >> 3) << 11) + ((g >> 2) << 5) + ((b >> 3) << 0);
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return (unsigned long) tmp;
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case 32:
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return (r << 16) + (g << 8) + (b << 0);
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}
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}
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h = Hash_rgb(r, g, b);
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i = h;
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while(1) {
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if (color_cache[i].rgb == Empty) break;
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if (color_cache[i].rgb == rgb) return color_cache[i].pixel;
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i = (i + 1) & (Color_cache_size - 1);
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if (i == h) {
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/* Cache is full. Instead of inserting at slot h, which causes
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thrashing if many colors hash to the same value,
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insert at h + n where n is pseudo-random and
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smaller than Color_cache_slack */
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int slack = num_overflows++ & (Color_cache_slack - 1);
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i = (i + slack) & (Color_cache_size - 1);
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break;
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}
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}
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color.red = r * 0x101;
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color.green = g * 0x101;
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color.blue = b * 0x101;
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XAllocColor(grdisplay, grcolormap, &color);
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color_cache[i].rgb = rgb;
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color_cache[i].pixel = color.pixel;
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return color.pixel;
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}
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int gr_rgb_pixel(long unsigned int pixel)
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{
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XColor color;
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int i;
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if (pixel == grblack) return 0;
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if (pixel == grwhite) return 0xFFFFFF;
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/* Probably faster to do a linear search than to query the X server. */
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for (i = 0; i < Color_cache_size; i++) {
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if (color_cache[i].rgb != Empty && color_cache[i].pixel == pixel)
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return color_cache[i].rgb;
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}
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color.pixel = pixel;
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XQueryColor(grdisplay, grcolormap, &color);
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return
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((color.red >> 8) << 16) + ((color.green >> 8) << 8) + (color.blue >> 8);
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}
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value gr_set_color(value vrgb)
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{
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gr_check_open();
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grcolor = gr_pixel_rgb(Int_val(vrgb));
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XSetForeground(grdisplay, grwindow.gc, grcolor);
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XSetForeground(grdisplay, grbstore.gc, grcolor);
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return Val_unit;
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}
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