Axis line can optionally stop at the last tick

pyqtgraph/graphicsItems/AxisItem.py

@@ -383,6 +383,7 @@ class AxisItem(GraphicsWidget):
                 picture = QtGui.QPicture()
                 painter = QtGui.QPainter(picture)
                 specs = self.generateDrawSpecs(painter)
+                if specs is not None:
                     self.drawPicture(painter, *specs)
             finally:
                 painter.end()
@@ -646,6 +647,10 @@ class AxisItem(GraphicsWidget):
         
         ## determine mapping between tick values and local coordinates
         dif = self.range[1] - self.range[0]
+        if dif == 0:
+            xscale = 1
+            offset = 0
+        else:
             if axis == 0:
                 xScale = -bounds.height() / dif
                 offset = self.range[0] * xScale - bounds.height()