JAL-2774 Added javadoc for new event parameters

[jalview.git] / src / jalview / viewmodel / ViewportRanges.java

diff --git a/src/jalview/viewmodel/ViewportRanges.java b/src/jalview/viewmodel/ViewportRanges.java
index b1d2c02..4bdaa81 100644 (file)
--- 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;
   }