Improve 'clear' performance (only clear overlays if possible).

src/main/org/insa/graphics/MainWindow.java

@@ -104,6 +104,9 @@ public class MainWindow extends JFrame {
     private final MapViewDrawing mapViewDrawing;
     private final BasicDrawing basicDrawing;
 
+    private final GraphPalette basicPalette, blackAndWhitePalette;
+    private GraphPalette currentPalette;
+
     // Main panel.
     private final JSplitPane mainPanel;
 
@@ -150,9 +153,13 @@ public class MainWindow extends JFrame {
         // Create drawing and action listeners...
         this.basicDrawing = new BasicDrawing();
         this.mapViewDrawing = new MapViewDrawing();
-
         this.drawing = this.basicDrawing;
 
+        // Createa palettes
+        this.basicPalette = new BasicGraphPalette();
+        this.blackAndWhitePalette = new BlackAndWhiteGraphPalette();
+        this.currentPalette = this.basicPalette;
+
         wccPanel = new AlgorithmPanel(this, WeaklyConnectedComponentsAlgorithm.class,
                 "Weakly-Connected Components", new String[] {}, false, false);
         wccPanel.addStartActionListener(new ActionListener() {
@@ -452,8 +459,13 @@ public class MainWindow extends JFrame {
             }
 
             // 2. We draw the graph.
+            if (isNewGraph) {
                 drawing.clear();
                 ((MapViewDrawing) drawing).drawGraph(mfile);
+            }
+            else {
+                drawing.clearOverlays();
+            }
             notifyRedrawRequest();
 
         }
@@ -465,8 +477,14 @@ public class MainWindow extends JFrame {
                 mainPanel.setDividerLocation(oldLocation);
                 notifyDrawingLoaded(mapViewDrawing, basicDrawing);
             }
+            if (isNewGraph || palette != this.currentPalette) {
+                this.currentPalette = palette;
                 drawing.clear();
                 drawing.drawGraph(graph, palette);
+            }
+            else {
+                drawing.clearOverlays();
+            }
             notifyRedrawRequest();
         }
 
@@ -483,7 +501,7 @@ public class MainWindow extends JFrame {
      * 
      */
     private void drawGraph() {
-        drawGraph(null, new BasicGraphPalette());
+        drawGraph(null, this.currentPalette);
     }
 
     private void loadGraph(GraphReader reader) {
@@ -662,7 +680,7 @@ public class MainWindow extends JFrame {
                 launchThread(new Runnable() {
                     @Override
                     public void run() {
-                        drawGraph(BasicDrawing.class);
+                        drawGraph(BasicDrawing.class, basicPalette);
                     }
                 });
             }
@@ -676,7 +694,7 @@ public class MainWindow extends JFrame {
                 launchThread(new Runnable() {
                     @Override
                     public void run() {
-                        drawGraph(BasicDrawing.class, new BlackAndWhiteGraphPalette());
+                        drawGraph(BasicDrawing.class, blackAndWhitePalette);
                     }
                 });
             }

src/main/org/insa/graphics/drawing/Drawing.java

@@ -30,6 +30,11 @@ public interface Drawing {
      */
     public void clear();
 
+    /**
+     * Remove overlays from the drawing.
+     */
+    public void clearOverlays();
+
     /**
      * Draw the given point with the given color.
      * 

src/main/org/insa/graphics/drawing/components/BasicDrawing.java

@@ -392,6 +392,35 @@ public class BasicDrawing extends JPanel implements Drawing {
 
     }
 
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.insa.graphics.drawing.Drawing#clear()
+     */
+    @Override
+    public void clear() {
+        if (this.graphGraphics != null) {
+            this.graphGraphics.clearRect(0, 0, this.width, this.height);
+        }
+        synchronized (overlays) {
+            this.overlays.clear();
+        }
+        this.repaint();
+    }
+
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.insa.graphics.drawing.Drawing#clearOverlays()
+     */
+    @Override
+    public void clearOverlays() {
+        synchronized (overlays) {
+            this.overlays.clear();
+        }
+        this.repaint();
+    }
+
     /**
      * @param lon
      * @return
@@ -433,26 +462,29 @@ public class BasicDrawing extends JPanel implements Drawing {
         return new Point((float) lon, (float) lat);
     }
 
+    /*
+     * (non-Javadoc)
+     * 
+     * @see
+     * org.insa.graphics.drawing.Drawing#addDrawingClickListener(org.insa.graphics.
+     * drawing.DrawingClickListener)
+     */
     @Override
     public void addDrawingClickListener(DrawingClickListener listener) {
         this.drawingClickListeners.add(listener);
     }
 
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.insa.graphics.drawing.Drawing#removeDrawingClickListener(org.insa.
+     * graphics.drawing.DrawingClickListener)
+     */
     @Override
     public void removeDrawingClickListener(DrawingClickListener listener) {
         this.drawingClickListeners.remove(listener);
     }
 
-    @Override
-    public void clear() {
-        if (this.graphGraphics != null) {
-            this.graphGraphics.clearRect(0, 0, this.width, this.height);
-        }
-        synchronized (overlays) {
-            this.overlays.clear();
-        }
-    }
-
     public BasicMarkerOverlay createMarker(Point point, Color color) {
         return new BasicMarkerOverlay(point, color);
     }

src/main/org/insa/graphics/drawing/components/MapViewDrawing.java

@@ -270,6 +270,11 @@ public class MapViewDrawing extends MapView implements Drawing {
         }
     }
 
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.mapsforge.map.awt.view.MapView#paint(java.awt.Graphics)
+     */
     @Override
     public void paint(Graphics graphics) {
         super.paint(graphics);
@@ -282,6 +287,33 @@ public class MapViewDrawing extends MapView implements Drawing {
 
     }
 
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.insa.graphics.drawing.Drawing#clear()
+     */
+    @Override
+    public void clear() {
+        getLayerManager().getLayers().clear();
+        repaint();
+    }
+
+    /*
+     * (non-Javadoc)
+     * 
+     * @see org.insa.graphics.drawing.Drawing#clearOverlays()
+     */
+    @Override
+    public void clearOverlays() {
+        Layers layers = getLayerManager().getLayers();
+        for (Layer layer: layers) {
+            if (layer instanceof PolylineAutoScaling || layer instanceof MarkerAutoScaling) {
+                getLayerManager().getLayers().remove(layer, false);
+            }
+        }
+        repaint();
+    }
+
     protected LatLong convertPoint(Point point) {
         return new LatLong(point.getLatitude(), point.getLongitude());
     }
@@ -319,12 +351,6 @@ public class MapViewDrawing extends MapView implements Drawing {
         this.drawingClickListeners.remove(listener);
     }
 
-    @Override
-    public void clear() {
-        getLayerManager().getLayers().clear();
-        repaint();
-    }
-
     protected MarkerAutoScaling createMarker(Point point, Color color) {
         Image image = MarkerUtils.getMarkerForColor(color);
         return new MarkerAutoScaling(convertPoint(point), image);