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/***********************************************************************/
/* */
/* Objective Caml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 1996 Institut National de Recherche en Informatique et */
/* Automatique. Distributed only by permission. */
/* */
/***********************************************************************/
/* $Id$ */
#include "libgraph.h"
/* Cache to speed up the translation rgb -> pixel value. */
struct color_cache_entry {
int rgb; /* RGB value with format 0xRRGGBB */
unsigned long pixel; /* Pixel value */
};
#define Color_cache_size 64
static struct color_cache_entry color_cache[Color_cache_size];
#define Empty (-1)
#define Hash_rgb(r,g,b) \
((((r) & 0xC0) >> 2) + (((g) & 0xC0) >> 4) + (((b) & 0xC0) >> 6))
void gr_init_color_cache()
{
int i;
for (i = 0; i < Color_cache_size; i++) color_cache[i].rgb = Empty;
i = Hash_rgb(0, 0, 0);
color_cache[i].rgb = 0;
color_cache[i].pixel = grblack;
i = Hash_rgb(0xFF, 0xFF, 0xFF);
color_cache[i].rgb = 0xFFFFFF;
color_cache[i].pixel = grwhite;
}
unsigned long gr_pixel_rgb(rgb)
int rgb;
{
unsigned int r, g, b;
int h, i;
XColor color;
r = (rgb >> 16) & 0xFF;
g = (rgb >> 8) & 0xFF;
b = rgb & 0xFF;
h = Hash_rgb(r, g, b);
i = h;
while(1) {
if (color_cache[i].rgb == Empty) break;
if (color_cache[i].rgb == rgb) return color_cache[i].pixel;
i = (i + 1) & (Color_cache_size - 1);
if (i == h) break;
}
color.red = r * 0x101;
color.green = g * 0x101;
color.blue = b * 0x101;
XAllocColor(grdisplay, grcolormap, &color);
color_cache[i].rgb = rgb;
color_cache[i].pixel = color.pixel;
return color.pixel;
}
int gr_rgb_pixel(pixel)
unsigned long pixel;
{
XColor color;
int i;
if (pixel == grblack) return 0;
if (pixel == grwhite) return 0xFFFFFF;
/* Probably faster to do a linear search than to query the X server. */
for (i = 0; i < Color_cache_size; i++) {
if (color_cache[i].rgb != Empty && color_cache[i].pixel == pixel)
return color_cache[i].rgb;
}
color.pixel = pixel;
XQueryColor(grdisplay, grcolormap, &color);
return
((color.red >> 8) << 16) + ((color.green >> 8) << 8) + (color.blue >> 8);
}
value gr_set_color(vrgb)
value vrgb;
{
gr_check_open();
grcolor = gr_pixel_rgb(Int_val(vrgb));
XSetForeground(grdisplay, grwindow.gc, grcolor);
XSetForeground(grdisplay, grbstore.gc, grcolor);
return Val_unit;
}
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