From b13062f081464d6950990d7e3add969e43e7d934 Mon Sep 17 00:00:00 2001
From: Mikhail Terekhov <terekhov@emc.com>
Date: Wed, 14 Dec 2016 22:39:39 -0500
Subject: [PATCH] In PlotDataItem.clear() use corresponding curve.clear() and
 scatter.clear()

Otherwise when stepMode is True curve.setData([]) causes exception:
"len(X) must be len(Y)+1 ..."
---
 pyqtgraph/graphicsItems/PlotDataItem.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pyqtgraph/graphicsItems/PlotDataItem.py b/pyqtgraph/graphicsItems/PlotDataItem.py
index 2faa9ac1..1bf48f5d 100644
--- a/pyqtgraph/graphicsItems/PlotDataItem.py
+++ b/pyqtgraph/graphicsItems/PlotDataItem.py
@@ -627,9 +627,9 @@ 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