gtk: check NULL before unref

diff --git a/modules/highgui/src/window_gtk.cpp b/modules/highgui/src/window_gtk.cpp
index e97ea2f..07b4c96 100644 (file)
--- a/modules/highgui/src/window_gtk.cpp
+++ b/modules/highgui/src/window_gtk.cpp
@@ -951,7 +951,8 @@ static gboolean cvImageWidget_draw(GtkWidget* widget, cairo_t *cr, gpointer data
   }
 
   cairo_paint(cr);
-  g_object_unref(pixbuf);
+  if(pixbuf)
+      g_object_unref(pixbuf);
   return TRUE;
 }
 
@@ -1005,7 +1006,8 @@ static gboolean cvImageWidget_expose(GtkWidget* widget, GdkEventExpose* event, g
   }
 
   cairo_paint(cr);
-  g_object_unref(pixbuf);
+  if(pixbuf)
+      g_object_unref(pixbuf);
   cairo_destroy(cr);
   return TRUE;
 }