[gtk+/wip/matthiasc/gsk-renderer: 5/6] Allow selective debug spew

[Matthias Clasen <matthiasc src gnome org>]

commit 2adece369b201b8307c5c8c39dd269a30035d49a
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Aug 6 10:24:05 2016 -0400

    Allow selective debug spew
    
    I don't think this should stay in the code long-term, but it
    is useful for debugging. It helped me track down some suspicious
    placements of render nodes.

 gsk/gskrendernode.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/gsk/gskrendernode.c b/gsk/gskrendernode.c
index a58b071..a37620e 100644
--- a/gsk/gskrendernode.c
+++ b/gsk/gskrendernode.c
@@ -1372,12 +1372,16 @@ gsk_render_node_get_draw_context (GskRenderNode *node)
 
   if (GSK_DEBUG_CHECK (SURFACE))
     {
+      const char *prefix;
       cairo_save (res);
       cairo_rectangle (res,
                        node->bounds.origin.x + 1, node->bounds.origin.y + 1,
                        node->bounds.size.width - 2, node->bounds.size.height - 2);
-      cairo_set_source_rgba (res, 1, 0, 0, 0.5);
-      cairo_stroke (res);
+      cairo_set_line_width (res, 2);
+      cairo_set_source_rgb (res, 1, 0, 0);
+      prefix = g_getenv ("GSK_DEBUG_PREFIX");
+      if (!prefix || g_str_has_prefix (node->name, prefix))
+        cairo_stroke (res);
       cairo_restore (res);
     }