X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fviewmodel%2FViewportRanges.java;h=c2bcf3f5b8539c5e96f9daf211f5d394f4638fa1;hb=52298f6987c5807b9f672e33f416dee9e14e1952;hp=56c1d39e789a7eb02e63252dfbdd5ca9b0bd1b38;hpb=2b2c9e1a88930585de0b5c205e4ae6f0174440d2;p=jalview.git

diff --git a/src/jalview/viewmodel/ViewportRanges.java b/src/jalview/viewmodel/ViewportRanges.java
index 56c1d39..c2bcf3f 100644
--- a/src/jalview/viewmodel/ViewportRanges.java
+++ b/src/jalview/viewmodel/ViewportRanges.java
@@ -32,6 +32,14 @@ import jalview.datamodel.HiddenColumns;
  */
 public class ViewportRanges extends ViewportProperties
 {
+  public static final String STARTRES = "startres";
+
+  public static final String ENDRES = "endres";
+
+  public static final String STARTSEQ = "startseq";
+
+  public static final String ENDSEQ = "endseq";
+
   // start residue of viewport
   private int startRes;
 
@@ -123,7 +131,7 @@ public class ViewportRanges extends ViewportProperties
     int oldstartres = this.startRes;
     if (start > getVisibleAlignmentWidth() - 1)
     {
-      startRes = getVisibleAlignmentWidth() - 1;
+      startRes = Math.max(getVisibleAlignmentWidth() - 1, 0);
     }
     else if (start < 0)
     {
@@ -139,17 +147,21 @@ public class ViewportRanges extends ViewportProperties
     {
       endRes = 0;
     }
+    else if (end > getVisibleAlignmentWidth() - 1)
+    {
+      endRes = Math.max(getVisibleAlignmentWidth() - 1, 0);
+    }
     else
     {
       endRes = end;
     }
 
-    changeSupport.firePropertyChange("startres", oldstartres, startRes);
+    changeSupport.firePropertyChange(STARTRES, oldstartres, startRes);
     if (oldstartres == startRes)
     {
       // event won't be fired if start positions are same
       // fire an event for the end positions in case they changed
-      changeSupport.firePropertyChange("endres", oldendres, endRes);
+      changeSupport.firePropertyChange(ENDRES, oldendres, endRes);
     }
   }
 
@@ -204,7 +216,7 @@ public class ViewportRanges extends ViewportProperties
     int oldstartseq = this.startSeq;
     if (start > getVisibleAlignmentHeight() - 1)
     {
-      startSeq = getVisibleAlignmentHeight() - 1;
+      startSeq = Math.max(getVisibleAlignmentHeight() - 1, 0);
     }
     else if (start < 0)
     {
@@ -218,7 +230,7 @@ public class ViewportRanges extends ViewportProperties
     int oldendseq = this.endSeq;
     if (end >= getVisibleAlignmentHeight())
     {
-      endSeq = getVisibleAlignmentHeight() - 1;
+      endSeq = Math.max(getVisibleAlignmentHeight() - 1, 0);
     }
     else if (end < 0)
     {
@@ -229,12 +241,12 @@ public class ViewportRanges extends ViewportProperties
       endSeq = end;
     }
 
-    changeSupport.firePropertyChange("startseq", oldstartseq, startSeq);
+    changeSupport.firePropertyChange(STARTSEQ, oldstartseq, startSeq);
     if (oldstartseq == startSeq)
     {
       // event won't be fired if start positions are the same
       // fire in case the end positions changed
-      changeSupport.firePropertyChange("endseq", oldendseq, endSeq);
+      changeSupport.firePropertyChange(ENDSEQ, oldendseq, endSeq);
     }
   }
 
@@ -326,9 +338,12 @@ public class ViewportRanges extends ViewportProperties
     {
       vpstart = 0;
     }
-    else if (vpstart + w - 1 > getVisibleAlignmentWidth() - 1)
+    else if ((w <= getVisibleAlignmentWidth())
+            && (vpstart + w - 1 > getVisibleAlignmentWidth() - 1))
+    // viewport width is less than the full alignment and we are running off the
+    // RHS edge
     {
-      vpstart = getVisibleAlignmentWidth() - 1;
+      vpstart = getVisibleAlignmentWidth() - w;
     }
     setStartEndRes(vpstart, vpstart + w - 1);
   }
@@ -350,7 +365,10 @@ public class ViewportRanges extends ViewportProperties
     {
       vpstart = 0;
     }
-    else if (vpstart + h - 1 > getVisibleAlignmentHeight() - 1)
+    else if ((h <= getVisibleAlignmentHeight())
+            && (vpstart + h - 1 > getVisibleAlignmentHeight() - 1))
+    // viewport height is less than the full alignment and we are running off
+    // the bottom
     {
       vpstart = getVisibleAlignmentHeight() - h;
     }
@@ -429,7 +447,7 @@ public class ViewportRanges extends ViewportProperties
     }
     else
     {
-      if (endRes > getVisibleAlignmentWidth() - 1)
+      if (endRes >= getVisibleAlignmentWidth() - 1)
       {
         return false;
       }