- // Nothing to do for 15, 16, 24, 32 bit displays
- if (visual->depth > 8) return TRUE;
-
- // initialize color cube for 8-bit color reduction dithering
-
- GdkColormap *cmap = gtk_widget_get_default_colormap();
-
- m_colorCube = (unsigned char*)malloc(32 * 32 * 32);
-
- for (int r = 0; r < 32; r++)
- {
- for (int g = 0; g < 32; g++)
- {
- for (int b = 0; b < 32; b++)
- {
- int rr = (r << 3) | (r >> 2);
- int gg = (g << 3) | (g >> 2);
- int bb = (b << 3) | (b >> 2);
-
- int index = -1;
-
- GdkColor *colors = cmap->colors;
- if (colors)
- {
- int max = 3 * 65536;
-
- for (int i = 0; i < cmap->size; i++)
- {
- int rdiff = ((rr << 8) - colors[i].red);
- int gdiff = ((gg << 8) - colors[i].green);
- int bdiff = ((bb << 8) - colors[i].blue);
- int sum = ABS (rdiff) + ABS (gdiff) + ABS (bdiff);
- if (sum < max)
- {
- index = i; max = sum;
- }
- }
- }
- else
- {
- // assume 8-bit true or static colors. this really exists
- GdkVisual* vis = gdk_colormap_get_visual( cmap );
- index = (r >> (5 - vis->red_prec)) << vis->red_shift;
- index |= (g >> (5 - vis->green_prec)) << vis->green_shift;
- index |= (b >> (5 - vis->blue_prec)) << vis->blue_shift;
- }
- m_colorCube[ (r*1024) + (g*32) + b ] = index;
- }
- }
- }
-
- return TRUE;