Merge branch 'develop' into features/JAL-2446NCList

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

diff --git a/src/jalview/viewmodel/ViewportRanges.java b/src/jalview/viewmodel/ViewportRanges.java
index f8115a1..42d490e 100644 (file)
--- a/src/jalview/viewmodel/ViewportRanges.java
+++ b/src/jalview/viewmodel/ViewportRanges.java
@@ -456,18 +456,42 @@ public class ViewportRanges extends ViewportProperties
   }
 
   /**
-   * Scroll a wrapped alignment so that the specified residue is visible. Fires
-   * a property change event.
+   * Scroll a wrapped alignment so that the specified residue is in the first
+   * repeat of the wrapped view. Fires a property change event. Answers true if
+   * the startRes changed, else false.
    * 
    * @param res
    *          residue position to scroll to
+   * @return
    */
-  public void scrollToWrappedVisible(int res)
+  public boolean scrollToWrappedVisible(int res)
   {
-    // get the start residue of the wrapped row which res is in
-    // and set that as our start residue
+    int oldStartRes = startRes;
     int width = getViewportWidth();
-    setStartRes((res / width) * width);
+
+    if (res >= oldStartRes && res < oldStartRes + width)
+    {
+      return false;
+    }
+
+    boolean up = res < oldStartRes;
+    int widthsToScroll = Math.abs((res - oldStartRes) / width);
+    if (up)
+    {
+      widthsToScroll++;
+    }
+
+    int residuesToScroll = width * widthsToScroll;
+    int newStartRes = up ? oldStartRes - residuesToScroll : oldStartRes
+            + residuesToScroll;
+    if (newStartRes < 0)
+    {
+      newStartRes = 0;
+    }
+
+    setStartRes(newStartRes);
+
+    return true;
   }
 
   /**