From caa660fc22a9d405034eb3ae2d23e2e8003dbf3d Mon Sep 17 00:00:00 2001
From: larsbrubaker <larsbrubaker@gmail.com>
Date: Thu, 20 Mar 2014 18:41:22 -0700
Subject: [PATCH] Don't redraw on auto rotation if we have not done a draw
 since last invalidate.

---
 PartPreviewWindow/View3DTransfromPart.cs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/PartPreviewWindow/View3DTransfromPart.cs b/PartPreviewWindow/View3DTransfromPart.cs
index e0b1fc40e..2053341f0 100644
--- a/PartPreviewWindow/View3DTransfromPart.cs
+++ b/PartPreviewWindow/View3DTransfromPart.cs
@@ -224,6 +224,7 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 
         public override void OnDraw(Graphics2D graphics2D)
         {
+            hasDrawn = true;
             base.OnDraw(graphics2D);
         }
 
@@ -439,6 +440,7 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
             UiThread.RunOnIdle(AutoSpin);
         }
 
+        bool hasDrawn = false;
         Stopwatch timeSinceLastSpin = new Stopwatch();
         void AutoSpin(object state)
         {
@@ -447,8 +449,10 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
                 // add it back in to keep it running.
                 UiThread.RunOnIdle(AutoSpin);
 
-                if (!timeSinceLastSpin.IsRunning || timeSinceLastSpin.ElapsedMilliseconds > 50)
+                if ((!timeSinceLastSpin.IsRunning || timeSinceLastSpin.ElapsedMilliseconds > 50)
+                    && hasDrawn)
                 {
+                    hasDrawn = false;
                     timeSinceLastSpin.Restart();
 
                     Quaternion currentRotation = meshViewerWidget.TrackballTumbleWidget.TrackBallController.CurrentRotation.GetRotation();