From 2ac76a67e4f3421b4dee3ffa8fbb5956692dfda5 Mon Sep 17 00:00:00 2001
From: kiramt <k.mourao@dundee.ac.uk>
Date: Mon, 4 Sep 2017 15:57:49 +0100
Subject: [PATCH] JAL-2673 Attempt to stop infinite scrolling etc

---
 src/jalview/gui/SeqPanel.java |   33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/src/jalview/gui/SeqPanel.java b/src/jalview/gui/SeqPanel.java
index 328dfdc..cb29c3f 100644
--- a/src/jalview/gui/SeqPanel.java
+++ b/src/jalview/gui/SeqPanel.java
@@ -1095,7 +1095,7 @@ public class SeqPanel extends JPanel
     }
 
     mouseDragging = true;
-    if (scrollThread != null)
+    if ((scrollThread != null) && (scrollThread.isRunning()))
     {
       scrollThread.setEvent(evt);
     }
@@ -1521,9 +1521,9 @@ public class SeqPanel extends JPanel
       oldSeq = 0;
     }
 
-    if (scrollThread != null)
+    if ((scrollThread != null) && (scrollThread.isRunning()))
     {
-      scrollThread.running = false;
+      scrollThread.stopScrolling();
       scrollThread = null;
     }
   }
@@ -1949,7 +1949,7 @@ public class SeqPanel extends JPanel
 
     mouseDragging = true;
 
-    if (scrollThread != null)
+    if ((scrollThread != null) && (scrollThread.isRunning()))
     {
       scrollThread.setEvent(evt);
     }
@@ -1959,9 +1959,9 @@ public class SeqPanel extends JPanel
   {
     if (evt == null)
     {
-      if (scrollThread != null)
+      if ((scrollThread != null) && (scrollThread.isRunning()))
       {
-        scrollThread.running = false;
+        scrollThread.stopScrolling();
         scrollThread = null;
       }
       mouseDragging = false;
@@ -1984,7 +1984,7 @@ public class SeqPanel extends JPanel
   {
     MouseEvent evt;
 
-    boolean running = false;
+    private volatile boolean threadRunning = true;
 
     public ScrollThread()
     {
@@ -1998,37 +1998,40 @@ public class SeqPanel extends JPanel
 
     public void stopScrolling()
     {
-      running = false;
+      threadRunning = false;
+    }
+
+    public boolean isRunning()
+    {
+      return threadRunning;
     }
 
     @Override
     public void run()
     {
-      running = true;
-
-      while (running)
+      while (threadRunning)
       {
         if (evt != null)
         {
           if (mouseDragging && (evt.getY() < 0)
                   && (av.getRanges().getStartSeq() > 0))
           {
-            running = av.getRanges().scrollUp(true);
+            av.getRanges().scrollUp(true);
           }
 
           if (mouseDragging && (evt.getY() >= getHeight()) && (av
                   .getAlignment().getHeight() > av.getRanges().getEndSeq()))
           {
-            running = av.getRanges().scrollUp(false);
+            av.getRanges().scrollUp(false);
           }
 
           if (mouseDragging && (evt.getX() < 0))
           {
-            running = av.getRanges().scrollRight(false);
+            av.getRanges().scrollRight(false);
           }
           else if (mouseDragging && (evt.getX() >= getWidth()))
           {
-            running = av.getRanges().scrollRight(true);
+            av.getRanges().scrollRight(true);
           }
         }
 
-- 
1.7.10.2