explicitly test _drawRect against None

hmeine · hmeine · commit 1e73388678e1 · 2014-04-02T15:27:36.000+02:00
diff --git a/lib/matplotlib/backends/backend_qt4agg.py b/lib/matplotlib/backends/backend_qt4agg.py
@@ -113,7 +113,7 @@ def paintEvent(self, e):
             p.drawPixmap(QtCore.QPoint(0, 0), QtGui.QPixmap.fromImage(qImage))
 
             # draw the zoom rectangle to the QPainter
-            if self._drawRect:
+            if self._drawRect is not None:
                 p.setPen(QtGui.QPen(QtCore.Qt.black, 1, QtCore.Qt.DotLine))
                 x, y, w, h = self._drawRect
                 p.drawRect(x, y, w, h)
