commit dbba0d51bfcf549c3d9f3f5a49465abab6e01c1f
Author: Carl Worth <cworth@cworth.org>
Date:   Wed Jul 26 15:48:56 2006 -0700

    Don't call XRenderAddGlyphs for zero-sized surfaces (bug #7494)
    
    The bug in 7494 is really an X server bug, and this is perhaps only
    a partial workaround. There's probably a better place this workaround
    could be implemented in cairo since with this patch cairo still
    attempts to render glyphs even after not adding them to the server-
    side glyph cache. So I'm not sure if this might not cause strange
    things to happen.
    
    A very minimal bit of testing suggests that this patch does help,
    (firefox stops having disappearing text for example).

diff --git a/src/cairo-xlib-surface.c b/src/cairo-xlib-surface.c
index cac6787..fc50a07 100644
--- a/src/cairo-xlib-surface.c
+++ b/src/cairo-xlib-surface.c
@@ -2455,10 +2455,12 @@ _cairo_xlib_surface_add_glyph (Display *
 
     glyph_index = _cairo_scaled_glyph_index (scaled_glyph);
 
-    XRenderAddGlyphs (dpy, font_private->glyphset,
-		      &glyph_index, &(glyph_info), 1,
-		      (char *) data,
-		      glyph_surface->stride * glyph_surface->height);
+    if (glyph_surface->width || glyph_surface->height) {
+	XRenderAddGlyphs (dpy, font_private->glyphset,
+			  &glyph_index, &(glyph_info), 1,
+			  (char *) data,
+			  glyph_surface->stride * glyph_surface->height);
+    }
 
     if (data != glyph_surface->data)
 	free (data);