Merge pull request #417 from termim/PlotDataItem_clear

In PlotDataItem.clear() use corresponding curve.clear() and scatter.clear()

pyqtgraph/graphicsItems/PlotDataItem.py

@@ -630,8 +630,8 @@ class PlotDataItem(GraphicsObject):
         #self.yClean = None
         self.xDisp = None
         self.yDisp = None
-        self.curve.setData([])
-        self.scatter.setData([])
+        self.curve.clear()
+        self.scatter.clear()
 
     def appendData(self, *args, **kargs):
         pass

pyqtgraph/graphicsItems/tests/test_PlotDataItem.py

@@ -58,3 +58,9 @@ def test_clear():
 
     assert pdi.xData == None
     assert pdi.yData == None
+
+def test_clear_in_step_mode():
+    w = pg.PlotWidget()
+    c = pg.PlotDataItem([1,4,2,3], [5,7,6], stepMode=True)
+    w.addItem(c)
+    c.clear()