Recalculate positions in error marker column on resize

Fixes #3619

java/src/processing/mode/java/MarkerColumn.java

@@ -89,6 +89,12 @@ public class MarkerColumn extends JPanel {
 	}
 
 
+	@Override
+	public void repaint() {
+	  recalculateMarkerPositions();
+	  super.repaint();
+	}
+
   public void paintComponent(Graphics g) {
     g.setColor(backgroundColor);
     g.fillRect(0, 0, getWidth(), getHeight());
@@ -117,14 +123,7 @@ public class MarkerColumn extends JPanel {
 	    new SwingWorker() {
 	      protected Object doInBackground() throws Exception {
 	        Sketch sketch = editor.getSketch();
-	        SketchCode code = sketch.getCurrentCode();
-	        int totalLines = 0;
 	        int currentTab = sketch.getCurrentCodeIndex();
-	        try {
-	          totalLines = Util.countLines(code.getDocumentText());
-	        } catch (BadLocationException e) {
-	          e.printStackTrace();
-	        }
 	        errorPoints = new ArrayList<>();
 
 	        // Each problem.getSourceLine() will have an extra line added because
@@ -132,14 +131,12 @@ public class MarkerColumn extends JPanel {
 	        synchronized (problems) {
 	          for (Problem problem : problems) {
 	            if (problem.getTabIndex() == currentTab) {
-	              // Ratio of error line to total lines
-	              float y = (problem.getLineNumber() + 1) / ((float) totalLines);
-	              // Ratio multiplied by height of the error bar
-	              y *= getHeight() - 15; // -15 is just a vertical offset
-	              errorPoints.add(new LineMarker(problem, (int) y, problem.isError()));
+	              errorPoints.add(new LineMarker(problem, problem.isError()));
 	            }
 	          }
 	        }
+
+	        recalculateMarkerPositions();
 	        return null;
 	      }
 
@@ -195,6 +192,31 @@ public class MarkerColumn extends JPanel {
 	}
 
 
+	private void recalculateMarkerPositions() {
+	  List<LineMarker> errorPoints = getErrorPoints();
+	  if (errorPoints != null && errorPoints.size() > 0) {
+	    Sketch sketch = editor.getSketch();
+	    SketchCode code = sketch.getCurrentCode();
+	    int totalLines;
+	    try {
+	      totalLines = Util.countLines(code.getDocumentText());
+	    } catch (BadLocationException e) {
+	      e.printStackTrace();
+	      totalLines = 1; // do not divide by zero
+	    }
+
+	    for (LineMarker m : errorPoints) {
+	      // Ratio of error line to total lines
+	      float y = (m.getLineNumber() + 1) / ((float) totalLines);
+	      // Ratio multiplied by height of the error bar
+	      y *= getHeight() - 15; // -15 is just a vertical offset
+
+	      m.setY((int) y);
+	    }
+	  }
+	}
+
+
 	private LineMarker findClosestMarker(final int y) {
 	  LineMarker closest = null;
 	  int closestDist = Integer.MAX_VALUE;

java/src/processing/mode/java/pdex/LineMarker.java

@@ -48,13 +48,20 @@ public class LineMarker {
   private Problem problem;
 
 
-  public LineMarker(Problem problem, int y, boolean error) {
+  public LineMarker(Problem problem, boolean error) {
     this.problem = problem;
-    this.y = y;
     this.type = error ? ERROR : WARNING;
   }
 
 
+  /**
+   * set y co-ordinate of the marker
+   */
+  public void setY(int y) {
+    this.y = y;
+  }
+
+
   /**
    * y co-ordinate of the marker
    */
@@ -63,6 +70,14 @@ public class LineMarker {
   }
 
 
+  /**
+   * line number of the marker
+   */
+  public int getLineNumber() {
+    return problem.getLineNumber();
+  }
+
+
   /**
    * Type of marker: ErrorMarker.Error or ErrorMarker.Warning?
    */