Reduce color allocation/query traffic in the TrueColor case.

When working with an X visual with TrueColor class, pixel values can
be generated from the RGB values according to mask value provided by
the server on connection.  Some of the image-handling code was already
doing this.

* src/xterm.h (x_make_truecolor_pixel): New function; code taken from
lookup_rgb_color.
(x_mutable_colormap): New function.
* src/image.c (lookup_rgb_color): Move pixel composition code to
x_make_truecolor_pixel.
(x_kill_gs_process): Call x_mutable_colormap.
* src/xfaces.c (x_free_colors, x_free_dpy_colors): Call
x_mutable_colormap.
* src/xftfont.c (xftfont_get_colors): Call x_query_colors.
* src/xterm.c (x_query_colors): For a TrueColor display, decompose the
pixel value into RGB values directly, and don't send a request to the
server.
(x_alloc_nearest_color): For a TrueColor display, construct the pixel
value with x_make_truecolor_pixel.
(x_copy_color): For an immutable color map, just return the provided
pixel value.

1 files changed, 2 insertions, 12 deletions

diff --git a/src/image.c b/src/image.c
index 79bf21e8865..401689e940a 100644
--- a/src/image.c
+++ b/src/image.c
@@ -4442,15 +4442,7 @@ lookup_rgb_color (struct frame *f, int r, int g, int b)
           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 - dpyinfo->red_bits))   << dpyinfo->red_offset;
-      pg = (g >> (16 - dpyinfo->green_bits)) << dpyinfo->green_offset;
-      pb = (b >> (16 - dpyinfo->blue_bits))  << dpyinfo->blue_offset;
-
-      /* Assemble the pixel color.  */
-      return pr | pg | pb;
+      return x_make_truecolor_pixel (dpyinfo, r, g, b);
     }
 
   for (p = ct_table[i]; p; p = p->next)
@@ -9542,7 +9534,6 @@ void
 x_kill_gs_process (Pixmap pixmap, struct frame *f)
 {
   struct image_cache *c = FRAME_IMAGE_CACHE (f);
-  int class;
   ptrdiff_t i;
   struct image *img;
 
@@ -9568,8 +9559,7 @@ x_kill_gs_process (Pixmap pixmap, struct frame *f)
   /* On displays with a mutable colormap, figure out the colors
      allocated for the image by looking at the pixels of an XImage for
      img->pixmap.  */
-  class = FRAME_X_VISUAL (f)->class;
-  if (class != StaticColor && class != StaticGray && class != TrueColor)
+  if (x_mutable_colormap (FRAME_X_VISUAL (f)))
     {
       XImagePtr ximg;