From b636f0007e76155876da1dd75310a4cb153815d7 Mon Sep 17 00:00:00 2001
From: Jim Procter <jprocter@issues.jalview.org>
Date: Fri, 6 May 2016 15:03:24 +0100
Subject: [PATCH] JAL-192 JAL-2099 factored out calculation from rendering
 code #2

---
 src/jalview/gui/ScalePanel.java |   83 +++++++++++++++++++++++----------------
 1 file changed, 49 insertions(+), 34 deletions(-)

diff --git a/src/jalview/gui/ScalePanel.java b/src/jalview/gui/ScalePanel.java
index 14ce3fe..8a3138d 100755
--- a/src/jalview/gui/ScalePanel.java
+++ b/src/jalview/gui/ScalePanel.java
@@ -526,6 +526,54 @@ public class ScalePanel extends JPanel implements MouseMotionListener,
     // Draw the scale numbers
     gg.setColor(Color.black);
 
+    List<Object[]> marks = calculateMarks(startx, endx);
+    int maxX = 0;
+    for (Object[] mark : marks)
+    {
+      boolean major = Boolean.valueOf((Boolean) mark[0]);
+      int mpos = ((Integer) mark[1]).intValue(); // (i - startx - 1)
+      String mstring = (String) mark[2];
+      if (mstring != null)
+      {
+        if (mpos * avCharWidth > maxX)
+        {
+          gg.drawString(mstring, mpos * avCharWidth, y);
+          maxX = (mpos + 2) * avCharWidth + fm.stringWidth(mstring);
+        }
+      }
+      if (major)
+      {
+        gg.drawLine((mpos * avCharWidth) + (avCharWidth / 2), y + 2,
+                (mpos * avCharWidth) + (avCharWidth / 2), y + (yOf * 2));
+      }
+      else
+      {
+        gg.drawLine((mpos * avCharWidth) + (avCharWidth / 2), y + yOf,
+                (mpos * avCharWidth) + (avCharWidth / 2), y + (yOf * 2));
+      }
+    }
+    if (av.hasHiddenColumns())
+    {
+      if (reveal != null && reveal[0] > startx && reveal[0] < endx)
+      {
+        gg.drawString(MessageManager.getString("label.reveal_columns"),
+                reveal[0] * avCharWidth, 0);
+      }
+    }
+
+  }
+
+  /**
+   * calculate positions markers on the alignment ruler
+   * 
+   * @return List { Object { .. } } Boolean: true/false for major/minor mark,
+   *         Integer: marker position in alignment column coords, String: null
+   *         or a String to be rendered at the position.
+   */
+  public List<Object[]> calculateMarks(int startx, int endx)
+  {
+    new ArrayList<Object[]>();
+
     int scalestartx = (startx / 10) * 10;
 
     SequenceI refSeq = av.getAlignment().getSeqrep();
@@ -598,39 +646,6 @@ public class ScalePanel extends JPanel implements MouseMotionListener,
       }
       marks.add(amark);
     }
-    maxX=0;
-    for (Object[] mark : marks)
-    {
-      boolean major = Boolean.valueOf((Boolean) mark[0]);
-      int mpos = ((Integer) mark[1]).intValue(); // (i - startx - 1)
-      String mstring = (String) mark[2];
-      if (mstring != null)
-      {
-        if (mpos * avCharWidth > maxX)
-        {
-          gg.drawString(mstring, mpos * avCharWidth, y);
-          maxX = (mpos + 2) * avCharWidth + fm.stringWidth(mstring);
-        }
-      }
-      if (major)
-      {
-        gg.drawLine((mpos * avCharWidth) + (avCharWidth / 2), y + 2,
-                (mpos * avCharWidth) + (avCharWidth / 2), y + (yOf * 2));
-      }
-      else
-      {
-        gg.drawLine((mpos * avCharWidth) + (avCharWidth / 2), y + yOf,
-                (mpos * avCharWidth) + (avCharWidth / 2), y + (yOf * 2));
-      }
-    }
-    if (av.hasHiddenColumns())
-    {
-      if (reveal != null && reveal[0] > startx && reveal[0] < endx)
-      {
-        gg.drawString(MessageManager.getString("label.reveal_columns"),
-                reveal[0] * avCharWidth, 0);
-      }
-    }
-
+    return marks;
   }
 }
-- 
1.7.10.2