[gegl-qt] NodeViewImplementation: Guard against malloc calls with invalid size

[Jon Nordby <jonnor src gnome org>]

commit b3ec857320b5adb5a3890c171ebc9d9913f9aa52
Author: Jon Nordby <jononor gmail com>
Date:   Sat Sep 24 18:17:09 2011 +0200

    NodeViewImplementation: Guard against malloc calls with invalid size

 gegl-qt/internal/nodeviewimplementation.cpp |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/gegl-qt/internal/nodeviewimplementation.cpp b/gegl-qt/internal/nodeviewimplementation.cpp
index 28c2c65..5c23ddb 100644
--- a/gegl-qt/internal/nodeviewimplementation.cpp
+++ b/gegl-qt/internal/nodeviewimplementation.cpp
@@ -297,13 +297,13 @@ NodeViewImplementation::paint(QPainter *painter, const QRectF & viewRect)
         return;
     }
 
-    if (!inputNode()) {
-        return;
-    }
-
     QRect modelRect = modelAreaFromViewArea(viewRect, options()).toRect();
     gegl_rectangle_set_from_qrect(&roi, modelRect);
 
+    if (!inputNode() || roi.width <= 0 || roi.height <= 0) {
+        return;
+    }
+
     buffer = (guchar *)g_malloc ((roi.width) * (roi.height) * 4);
 
     gegl_node_blit (inputNode(), 1.0, &roi,