From 70724a44b37a79c072a03963749464dc97331dda Mon Sep 17 00:00:00 2001
From: JosefNevrly <jnevrly@alps.cz>
Date: Sun, 16 Mar 2014 15:13:43 +0100
Subject: [PATCH] Added check for zero ViewBox width when calculating automatic
 downsampling ratio. (Prevents zero-division when downsampling is set before
 Plot is properly created and drawn within a container).

---
 pyqtgraph/graphicsItems/PlotDataItem.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pyqtgraph/graphicsItems/PlotDataItem.py b/pyqtgraph/graphicsItems/PlotDataItem.py
index d2d18fd9..14a39dba 100644
--- a/pyqtgraph/graphicsItems/PlotDataItem.py
+++ b/pyqtgraph/graphicsItems/PlotDataItem.py
@@ -532,7 +532,8 @@ class PlotDataItem(GraphicsObject):
                     x0 = (range.left()-x[0]) / dx
                     x1 = (range.right()-x[0]) / dx
                     width = self.getViewBox().width()
-                    ds = int(max(1, int(0.2 * (x1-x0) / width)))
+                    if width != 0.0:
+                        ds = int(max(1, int(0.2 * (x1-x0) / width)))
                     ## downsampling is expensive; delay until after clipping.
             
             if self.opts['clipToView']: