[gthumb] cairo scale: fixed error if the size is zero

[Paolo Bacchilega <paobac src gnome org>]

commit 5e72134a962cd1e9edce7513b632de1988c5b154
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Nov 3 18:20:34 2013 +0100

    cairo scale: fixed error if the size is zero

 gthumb/cairo-scale.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gthumb/cairo-scale.c b/gthumb/cairo-scale.c
index 28c482d..de90637 100644
--- a/gthumb/cairo-scale.c
+++ b/gthumb/cairo-scale.c
@@ -885,6 +885,9 @@ _cairo_image_surface_scale_bilinear (cairo_surface_t *image,
        cairo_surface_t *tmp2;
        double           w, h;
 
+       if ((new_width == 0) || (new_height == 0))
+               return NULL;
+
        scale = (double) new_width / cairo_image_surface_get_width (image);
        last_scale = 1.0;
        s = scale;