Merge pull request #696 from campagnola/scatter-stepmode

Fix error when using PlotDataItem with both stepMode and symbol

pyqtgraph/graphicsItems/PlotDataItem.py

@@ -490,6 +490,9 @@ class PlotDataItem(GraphicsObject):
             self.curve.hide()
         
         if scatterArgs['symbol'] is not None:
+            
+            if self.opts.get('stepMode', False) is True:
+                x = 0.5 * (x[:-1] + x[1:])                
             self.scatter.setData(x=x, y=y, **scatterArgs)
             self.scatter.show()
         else: