[gtk+/rendering-cleanup: 133/140] x11: Set background color bypassing colormaps

[Benjamin Otte <otte src gnome org>]

commit 458f51058e51ed6deeb2a1ea5c0c978dc1d6d5b5
Author: Benjamin Otte <otte redhat com>
Date:   Sun Aug 29 11:52:29 2010 +0200

    x11: Set background color bypassing colormaps
    
    Direct and TrueColor visuals don't alloc colors, so they don't need to
    fiddle with colormaps. Just copy the code that computes the pixel value
    from gdkcolor-x11.c and use it. For other visual types, don't set the
    background color and fallback to background = None.

 gdk/x11/gdkwindow-x11.c |   67 ++++++++++++++++++++++++++++++++++++----------
 1 files changed, 52 insertions(+), 15 deletions(-)
---
diff --git a/gdk/x11/gdkwindow-x11.c b/gdk/x11/gdkwindow-x11.c
index 0048379..5e1c9b5 100644
--- a/gdk/x11/gdkwindow-x11.c
+++ b/gdk/x11/gdkwindow-x11.c
@@ -2621,21 +2621,59 @@ gdk_window_set_transient_for (GdkWindow *window,
 			  GDK_WINDOW_XID (parent));
 }
 
-static void
+static gboolean
 gdk_window_x11_set_back_color (GdkWindow *window,
-                               GdkColor *color)
+                               double     alpha,
+                               double     red,
+                               double     green,
+                               double     blue)
 {
-  GdkColor allocated = *color;
+  GdkVisual *visual = gdk_window_get_visual (window);
 
-  if (!gdk_colormap_alloc_color (gdk_drawable_get_colormap (window),
-                                 &allocated,
-                                 TRUE, TRUE))
-    return;
+  /* I suppose we could handle these, but that'd require fiddling with 
+   * xrender formats... */
+  if (alpha != 1.0)
+    return FALSE;
 
-  XSetWindowBackground (GDK_WINDOW_XDISPLAY (window),
-			GDK_WINDOW_XID (window), allocated.pixel);
+  switch (visual->type)
+    {
+    case GDK_VISUAL_DIRECT_COLOR:
+    case GDK_VISUAL_TRUE_COLOR:
+	{
+	  /* If bits not used for color are used for something other than padding,
+	   * it's likely alpha, so we set them to 1s.
+	   */
+	  guint padding, pixel;
+
+	  /* Shifting by >= width-of-type isn't defined in C */
+	  if (visual->depth >= 32)
+	    padding = 0;
+	  else
+	    padding = ((~(guint32)0)) << visual->depth;
+	  
+	  pixel = ~ (visual->red_mask | visual->green_mask | visual->blue_mask | padding);
+	  
+	  pixel += (((int) (red   * ((1 << visual->red_prec  ) - 1))) << visual->red_shift  ) +
+		   (((int) (green * ((1 << visual->green_prec) - 1))) << visual->green_shift) +
+		   (((int) (blue  * ((1 << visual->blue_prec ) - 1))) << visual->blue_shift );
 
-  gdk_colormap_free_colors (gdk_drawable_get_colormap (window), &allocated, 1);
+          XSetWindowBackground (GDK_WINDOW_XDISPLAY (window),
+                                GDK_WINDOW_XID (window), pixel);
+	}
+      return TRUE;
+
+    /* These require fiddling with the colormap, and as they're essentially unused
+     * we're just gonna skip them for now.
+     */
+    case GDK_VISUAL_PSEUDO_COLOR:
+    case GDK_VISUAL_GRAYSCALE:
+    case GDK_VISUAL_STATIC_GRAY:
+    case GDK_VISUAL_STATIC_COLOR:
+    default:
+      break;
+    }
+
+  return FALSE;
 }
 
 static gboolean
@@ -2650,7 +2688,6 @@ static void
 gdk_window_x11_set_background (GdkWindow      *window,
                                cairo_pattern_t *pattern)
 {
-  GdkColor color = { 0, };
   double r, g, b, a;
   cairo_surface_t *surface;
   cairo_matrix_t matrix;
@@ -2669,9 +2706,8 @@ gdk_window_x11_set_background (GdkWindow      *window,
     {
     case CAIRO_PATTERN_TYPE_SOLID:
       cairo_pattern_get_rgba (pattern, &r, &g, &b, &a);
-      color.red = r * 65535;
-      color.green = g * 65535;
-      color.blue = b * 65535;
+      if (gdk_window_x11_set_back_color (window, r, g, b, a))
+        return;
       break;
     case CAIRO_PATTERN_TYPE_SURFACE:
       cairo_pattern_get_matrix (pattern, &matrix);
@@ -2701,7 +2737,8 @@ gdk_window_x11_set_background (GdkWindow      *window,
       break;
     }
 
-  gdk_window_x11_set_back_color (window, &color);
+  XSetWindowBackgroundPixmap (GDK_WINDOW_XDISPLAY (window),
+                              GDK_WINDOW_XID (window), None);
 }
 
 static void