[gtk+] docs: Clarify gtk_render_icon()'s behaviour

[Emmanuele Bassi <ebassi src gnome org>]

commit f959b350640040f08fe91d4ac3dff449ae056502
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Wed Nov 4 11:45:41 2015 +0000

    docs: Clarify gtk_render_icon()'s behaviour
    
    A GdkPixbuf has no scaling factor, so drawing directly from it can only
    using a scale of 1, to avoid blurry, fuzzy icons.
    
    You should be using gtk_render_icon_surface() anyway.

 gtk/gtkrender.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkrender.c b/gtk/gtkrender.c
index 20c014d..4f986bb 100644
--- a/gtk/gtkrender.c
+++ b/gtk/gtkrender.c
@@ -1205,6 +1205,13 @@ gtk_render_icon_pixbuf (GtkStyleContext     *context,
  *
  * Renders the icon in @pixbuf at the specified @x and @y coordinates.
  *
+ * This function will render the icon in @pixbuf at exactly its size,
+ * regardless of scaling factors, which may not be appropriate when
+ * drawing on displays with high pixel densities.
+ *
+ * You probably want to use gtk_render_icon_surface() instead, if you
+ * already have a Cairo surface.
+ *
  * Since: 3.2
  **/
 void