X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fjalview%2Fviewmodel%2FViewportRanges.java;h=4bdaa815caec0d0cf561bb353452f178c10aaa45;hb=refs%2Fheads%2Fimp%2FJAL-2774;hp=b1d2c02dd02225d12c05c1d3041d9782f3202afe;hpb=53507580ea0d347514d4f5e092a4d3d815609b9e;p=jalview.git

diff --git a/src/jalview/viewmodel/ViewportRanges.java b/src/jalview/viewmodel/ViewportRanges.java
index b1d2c02..4bdaa81 100644
--- a/src/jalview/viewmodel/ViewportRanges.java
+++ b/src/jalview/viewmodel/ViewportRanges.java
@@ -292,7 +292,9 @@ public class ViewportRanges extends ViewportProperties
   }
 
   /**
-   * Set start residue and start sequence together (fires single event)
+   * Set start residue and start sequence together (fires single event). The
+   * event supplies a pair of old values and a pair of new values: [old start
+   * residue, old start sequence] and [new start residue, new start sequence]
    * 
    * @param res
    *          the start residue
@@ -465,23 +467,39 @@ public class ViewportRanges extends ViewportProperties
    */
   public boolean scrollUp(boolean up)
   {
+    /*
+     * if in unwrapped mode, scroll up or down one sequence row;
+     * if in wrapped mode, scroll by one visible width of columns
+     */
     if (up)
     {
-      if (startSeq < 1)
+      if (wrappedMode)
       {
-        return false;
+        pageUp();
+      }
+      else
+      {
+        if (startSeq < 1)
+        {
+          return false;
+        }
+        setStartSeq(startSeq - 1);
       }
-
-      setStartSeq(startSeq - 1);
     }
     else
     {
-      if (endSeq >= getVisibleAlignmentHeight() - 1)
+      if (wrappedMode)
       {
-        return false;
+        pageDown();
+      }
+      else
+      {
+        if (endSeq >= getVisibleAlignmentHeight() - 1)
+        {
+          return false;
+        }
+        setStartSeq(startSeq + 1);
       }
-
-      setStartSeq(startSeq + 1);
     }
     return true;
   }