Commit e019878d authored by Gerd Moellmann's avatar Gerd Moellmann
Browse files

(lookup_rgb_color): Handle TrueColor visuals specially.

parent 17139abc
2003-08-29 Gerd Moellmann <gerd@gnu.org>
* xfns.c (lookup_rgb_color): Handle TrueColor visuals specially.
2003-08-28 David Abrahams <dave@boost-consulting.com> (tiny change)
* coding.c (decode_coding_iso2022): Initialized local variable c2.
......
......@@ -6755,7 +6755,43 @@ lookup_rgb_color (f, r, g, b)
unsigned hash = CT_HASH_RGB (r, g, b);
int i = hash % CT_SIZE;
struct ct_color *p;
Visual *visual;
/* Handle TrueColor visuals specially, which improves performance by
two orders of magnitude. Freeing colors on TrueColor visuals is
a nop, and pixel colors specify RGB values directly. See also
the Xlib spec, chapter 3.1. */
visual = FRAME_X_DISPLAY_INFO (f)->visual;
if (visual->class == TrueColor)
{
int bits = visual->bits_per_rgb;
unsigned long pr, pg, pb;
/* Apply gamma-correction like normal color allocation does. */
if (f->gamma)
{
XColor color;
color.red = r, color.green = g, color.blue = b;
gamma_correct (f, &color);
r = color.red, g = color.green, b = color.blue;
}
/* Scale down RGB values to the visual's bits per RGB, and shift
them to the right position in the pixel color. Note that the
original RGB values are 16-bit values, as usual in X. */
pr = (r >> (16 - bits)) << 2 * bits;
pg = (g >> (16 - bits)) << 1 * bits;
pb = (b >> (16 - bits)) << 0 * bits;
/* Apply RGB masks of the visual. */
pr &= visual->red_mask;
pg &= visual->green_mask;
pb &= visual->blue_mask;
/* Assemble the pixel color. */
return pr | pg | pb;
}
for (p = ct_table[i]; p; p = p->next)
if (p->r == r && p->g == g && p->b == b)
break;
......
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