90 lines
2.1 KiB
C
90 lines
2.1 KiB
C
#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 64
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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) & 0xC0) >> 2) + (((g) & 0xC0) >> 4) + (((b) & 0xC0) >> 6))
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void gr_init_color_cache()
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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(rgb)
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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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r = (rgb >> 16) & 0xFF;
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g = (rgb >> 8) & 0xFF;
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b = rgb & 0xFF;
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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) break;
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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(pixel)
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unsigned long 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(vrgb)
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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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