[gtk+/gtk-3-4] Handle transparent colors better in GtkStyle emulation

[Matthew Barnes <mbarnes src gnome org>]

commit 72feb95edb6ab8c3fac27c0c32afeb2b2f61bd1c
Author: Alexander Larsson <alexl redhat com>
Date:   Thu Jun 28 21:30:24 2012 +0200

    Handle transparent colors better in GtkStyle emulation
    
    We can't expose colors with alpha in the GtkStyle colors, since
    GdkColor has no alpha. Currently we throw away alpha completely,
    which fails very badly for completely transparent backgrounds,
    which now is the default for most widgets, as it typically
    end up with black-on-black.
    
    We handle this by falling back on the default/previous colors for
    transparent colors. This is is simple and avoids complete failure.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=671437
    
    (cherry picked from commit 10423726709539724be0ea19bed76ba4331af774)

 gtk/deprecated/gtkstyle.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/deprecated/gtkstyle.c b/gtk/deprecated/gtkstyle.c
index 5266368..16e3ce4 100644
--- a/gtk/deprecated/gtkstyle.c
+++ b/gtk/deprecated/gtkstyle.c
@@ -673,7 +673,7 @@ set_color (GtkStyle        *style,
       break;
     }
 
-  if (color)
+  if (color && color->alpha > 0.01)
     {
       dest->pixel = 0;
       dest->red = CLAMP ((guint) (color->red * 65535), 0, 65535);