[gtk] iconhelper: Don't snapshot 0 sized icons

[Timm Bäder <baedert src gnome org>]

commit 21123a12640b141ca6df822d76beb5a4bcac34c2
Author: Timm Bäder <mail baedert org>
Date:   Fri Aug 9 15:55:38 2019 +0200

    iconhelper: Don't snapshot 0 sized icons
    
    This is happening for me when snapshotting small thumbnails in the file
    chooser. The GtkScaler will scale the 1px height/width by 2, resulting
    in nothing being drawn at all.

 gtk/gtkiconhelper.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/gtk/gtkiconhelper.c b/gtk/gtkiconhelper.c
index a7cf18220f..5e96bb8e64 100644
--- a/gtk/gtkiconhelper.c
+++ b/gtk/gtkiconhelper.c
@@ -219,7 +219,7 @@ gtk_icon_helper_paintable_snapshot (GdkPaintable *paintable,
     case GTK_IMAGE_GICON:
       {
         double x, y, w, h;
-    
+
         /* Never scale up icons. */
         w = gdk_paintable_get_intrinsic_width (self->paintable);
         h = gdk_paintable_get_intrinsic_height (self->paintable);
@@ -228,6 +228,9 @@ gtk_icon_helper_paintable_snapshot (GdkPaintable *paintable,
         x = (width - w) / 2;
         y = (height - h) / 2;
 
+        if (w == 0 || h == 0)
+          return;
+
         if (x  != 0 || y != 0)
           {
             gtk_snapshot_save (snapshot);