Bug 327874. Fix _cairo_xlib_surface_create_similar to create surfaces with the same depth as the input surface. r=vlad

gfx/cairo/README

@@ -20,7 +20,7 @@ if cairo is enabled.  Please upgrade to VC7.1/8.
 
 ==== Patches ====
 
-Last update: 15 Feb 2006
+Last update: 21 Feb 2006
 
 mozilla-misc.patch
   - Misc compilation fixes for pixman (submitted upstream)
@@ -84,3 +84,8 @@ cairo-win32-expose-dc-and-dib.patch
 cairo-win32-creation-format.patch
   - Have cairo_win32_surface_create inspect the DC and set up the appropriate
     cairo_format_t
+
+cairo-xlib-create-similar.patch (Updated 21 Feb 06)
+  - _cairo_xlib_surface_create_similar should not create a 24-bit
+    surface for a 16-bit target; fix it to emulate the target surface
+    as closely as possible

gfx/cairo/cairo-xlib-create-similar.patch

@@ -0,0 +1,94 @@
+Index: gfx/cairo/cairo/src/cairo-xlib-surface.c
+===================================================================
+RCS file: /home/rocallahan/mozilla-cvs-mirror/mozilla/gfx/cairo/cairo/src/cairo-xlib-surface.c,v
+retrieving revision 1.4
+diff -u -t -p -1 -2 -r1.4 cairo-xlib-surface.c
+--- gfx/cairo/cairo/src/cairo-xlib-surface.c	10 Jan 2006 22:56:38 -0000	1.4
++++ gfx/cairo/cairo/src/cairo-xlib-surface.c	19 Feb 2006 23:59:56 -0000
+@@ -224,35 +224,83 @@ _cairo_xlib_surface_create_similar_with_
+                                                        xrender_format,
+                                                        width, height);
+     if (surface->base.status != CAIRO_STATUS_SUCCESS) {
+         _cairo_error (CAIRO_STATUS_NO_MEMORY);
+         return (cairo_surface_t*) &_cairo_surface_nil;
+     }
+                                  
+     surface->owns_pixmap = TRUE;
+ 
+     return &surface->base;
+ }
+ 
++static cairo_bool_t
++_xrender_format_matches_content (XRenderPictFormat *format,
++                                 cairo_content_t   content)
++{
++    cairo_bool_t has_alpha = format->direct.alpha != 0;
++    cairo_bool_t has_color = format->direct.red != 0 ||
++        format->direct.green != 0 || format->direct.blue != 0;
++    if (has_alpha != (content == CAIRO_CONTENT_ALPHA ||
++                      content == CAIRO_CONTENT_COLOR_ALPHA))
++        return False;
++    if (has_color != (content == CAIRO_CONTENT_COLOR ||
++                      content == CAIRO_CONTENT_COLOR_ALPHA))
++        return False;
++    return True;
++}
++
+ static cairo_surface_t *
+ _cairo_xlib_surface_create_similar (void               *abstract_src,
+                                     cairo_content_t     content,
+                                     int                 width,
+                                     int                 height)
+ {
+     cairo_format_t format = _cairo_format_from_content (content);
++    cairo_xlib_surface_t *src = abstract_src;
++
++    /* Try to create a surface with the same visual and depth as the
++       existing surface.
++       Don't bother if the X server doesn't have COMPOSITE, because we prefer
++       to just fall back to image surfaces in that case. */
++    if (src->visual != NULL && CAIRO_SURFACE_RENDER_HAS_COMPOSITE(src)) {
++        Display *dpy = src->dpy;
++        XRenderPictFormat *xrender_format =
++            XRenderFindVisualFormat (dpy, src->visual);
++        /* Give up if the requested content type isn't compatible with the
++           visual format */
++        if (xrender_format != NULL &&
++            _xrender_format_matches_content (xrender_format, content)) {
++            Pixmap pix = XCreatePixmap (dpy, RootWindowOfScreen (src->screen),
++               width <= 0 ? 1 : width, height <= 0 ? 1 : height,
++               xrender_format->depth);
++    
++            cairo_xlib_surface_t *surface = (cairo_xlib_surface_t *)
++                cairo_xlib_surface_create_with_xrender_format (dpy, pix, src->screen,
++                                                               xrender_format,
++                                                               width, height);
++            if (surface->base.status != CAIRO_STATUS_SUCCESS) {
++                 _cairo_error (CAIRO_STATUS_NO_MEMORY);
++                 return (cairo_surface_t*) &_cairo_surface_nil;
++            }
++         
++            surface->owns_pixmap = TRUE;
++            surface->visual = src->visual;
++
++            return &surface->base;
++        }
++    }
++
+     return _cairo_xlib_surface_create_similar_with_format (abstract_src,
+-                                                           format,
+-                                                           width,
+-                                                           height);
++                                                           format, width, height);
+ }
+ 
+ static cairo_status_t
+ _cairo_xlib_surface_finish (void *abstract_surface)
+ {
+     cairo_xlib_surface_t *surface = abstract_surface;
+     if (surface->dst_picture != None)
+         XRenderFreePicture (surface->dpy, surface->dst_picture);
+     
+     if (surface->src_picture != None)
+         XRenderFreePicture (surface->dpy, surface->src_picture);
+ 

gfx/cairo/cairo/src/cairo-xlib-surface.c

@@ -233,6 +233,22 @@ _cairo_xlib_surface_create_similar_with_format (void	       *abstract_src,
     return &surface->base;
 }
 
+static cairo_bool_t
+_xrender_format_matches_content (XRenderPictFormat *format,
+                                 cairo_content_t   content)
+{
+    cairo_bool_t has_alpha = format->direct.alpha != 0;
+    cairo_bool_t has_color = format->direct.red != 0 ||
+        format->direct.green != 0 || format->direct.blue != 0;
+    if (has_alpha != (content == CAIRO_CONTENT_ALPHA ||
+                      content == CAIRO_CONTENT_COLOR_ALPHA))
+        return False;
+    if (has_color != (content == CAIRO_CONTENT_COLOR ||
+                      content == CAIRO_CONTENT_COLOR_ALPHA))
+        return False;
+    return True;
+}
+
 static cairo_surface_t *
 _cairo_xlib_surface_create_similar (void	       *abstract_src,
 				    cairo_content_t	content,
@@ -240,10 +256,42 @@ _cairo_xlib_surface_create_similar (void	       *abstract_src,
 				    int			height)
 {
     cairo_format_t format = _cairo_format_from_content (content);
+    cairo_xlib_surface_t *src = abstract_src;
+
+    /* Try to create a surface with the same visual and depth as the
+       existing surface.
+       Don't bother if the X server doesn't have COMPOSITE, because we prefer
+       to just fall back to image surfaces in that case. */
+    if (src->visual != NULL && CAIRO_SURFACE_RENDER_HAS_COMPOSITE(src)) {
+        Display *dpy = src->dpy;
+        XRenderPictFormat *xrender_format =
+            XRenderFindVisualFormat (dpy, src->visual);
+        /* Give up if the requested content type isn't compatible with the
+           visual format */
+        if (xrender_format != NULL &&
+            _xrender_format_matches_content (xrender_format, content)) {
+            Pixmap pix = XCreatePixmap (dpy, RootWindowOfScreen (src->screen),
+               width <= 0 ? 1 : width, height <= 0 ? 1 : height,
+               xrender_format->depth);
+    
+            cairo_xlib_surface_t *surface = (cairo_xlib_surface_t *)
+                cairo_xlib_surface_create_with_xrender_format (dpy, pix, src->screen,
+                                                               xrender_format,
+                                                               width, height);
+            if (surface->base.status != CAIRO_STATUS_SUCCESS) {
+                 _cairo_error (CAIRO_STATUS_NO_MEMORY);
+                 return (cairo_surface_t*) &_cairo_surface_nil;
+            }
+         
+            surface->owns_pixmap = TRUE;
+            surface->visual = src->visual;
+
+            return &surface->base;
+        }
+    }
+
     return _cairo_xlib_surface_create_similar_with_format (abstract_src,
-							   format,
-							   width,
-							   height);
+                                                           format, width, height);
 }
 
 static cairo_status_t