X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fgui%2FSeqCanvas.java;h=b3fcc542f3c0f6f7d2fc3899b172bf0fe3b551b3;hb=a3ca1aac6c00fc2240fa21be9df43adcc1b964ff;hp=2a370c4713a2f433c11dec2f911f0f59a712cdfa;hpb=cc52d6f3b8199cb3e9eab962feeab735c5bdc310;p=jalview.git

diff --git a/src/jalview/gui/SeqCanvas.java b/src/jalview/gui/SeqCanvas.java
index 2a370c4..b3fcc54 100755
--- a/src/jalview/gui/SeqCanvas.java
+++ b/src/jalview/gui/SeqCanvas.java
@@ -1655,7 +1655,7 @@ public class SeqCanvas extends JComponent implements ViewportListenerI
       }
       ViewportRanges vpRanges = av.getRanges();
 
-      int range = vpRanges.getEndRes() - vpRanges.getStartRes();
+      int range = vpRanges.getEndRes() - vpRanges.getStartRes() + 1;
       if (scrollX > range)
       {
         scrollX = range;
@@ -1724,10 +1724,10 @@ public class SeqCanvas extends JComponent implements ViewportListenerI
   {
     ViewportRanges ranges = av.getRanges();
 
-    if (Math.abs(scrollX) > ranges.getViewportWidth())
+    if (Math.abs(scrollX) >= ranges.getViewportWidth())
     {
       /*
-       * shift of more than one view width is 
+       * shift of one view width or more is 
        * overcomplicated to handle in this method
        */
       fastPaint = false;
@@ -1918,10 +1918,17 @@ public class SeqCanvas extends JComponent implements ViewportListenerI
 
       while (y >= 0)
       {
+        /*
+         * shift 'widthToCopy' residues by 'positions' places to the right
+         */
         gg.copyArea(copyFromLeftStart, y, widthToCopy, heightToCopy,
                 positions * charWidth, 0);
         if (y > 0)
         {
+          /*
+           * copy 'positions' residue from the row above (right hand end)
+           * to this row's left hand end
+           */
           gg.copyArea(copyFromRightStart, y - wrappedRepeatHeightPx,
                   positions * charWidth, heightToCopy, -widthToCopy,
                   wrappedRepeatHeightPx);