Add double-buffering to GridWorld view

examples/blocks-world/BlocksEnv/WorldModel.java

@@ -7,6 +7,7 @@
 import java.util.List;
 import java.util.Stack;
 import java.util.logging.Logger;
+import javax.swing.SwingUtilities;
 
 public class WorldModel extends GridWorldModel {
 
@@ -91,7 +92,9 @@ boolean move(String a, String b, List<String> adds, List<String> dels) throws Ex
         }
         modelToGrid();
         if (view != null)
-            view.update();
+            SwingUtilities.invokeLater(() -> {
+                view.update();
+            });
 
         return true;
     }
@@ -155,16 +158,16 @@ static WorldModel world4() throws Exception {
     void modelToGrid() {
         for (int i=0; i<GWidth; i++) {
             for (int j=0; j<GHeight-1; j++) {
-                model.data[i][j] = 0;
+                model.set(0, i, j);
                 model.names[i][j] = "";
             }
-            model.data[i][GHeight-1] = TABLE;
+            model.set(TABLE, i, GHeight-1);
             model.names[i][GHeight-1] = "table";
         }
         int i=0;
         for (Stack<String> s : stackList) {
             for (int j=1; j<s.size(); j++) {
-                model.data[i*2+1][GHeight-j-1] = BLOCK;
+                model.set(BLOCK, i*2+1, GHeight-j-1);
                 model.names[i*2+1][GHeight-j-1] = s.get(j);
             }
             i++;

jason-interpreter/src/main/java/jason/environment/grid/GridWorldModel.java

@@ -1,5 +1,6 @@
 package jason.environment.grid;
 
+import javax.swing.*;
 import java.util.Random;
 
 
@@ -110,7 +111,10 @@ public int countObjects(int obj) {
 
     public void set(int value, int x, int y) {
         data[x][y] = value;
-        if (view != null) view.update(x,y);
+        if (view != null) {
+            final int ux = x, uy = y;
+            SwingUtilities.invokeLater(() -> view.update(ux, uy));
+        }
     }
 
     public void add(int value, Location l) {
@@ -119,7 +123,10 @@ public void add(int value, Location l) {
 
     public void add(int value, int x, int y) {
         data[x][y] |= value;
-        if (view != null) view.update(x,y);
+        if (view != null) {
+            final int ux = x, uy = y;
+            SwingUtilities.invokeLater(() -> view.update(ux, uy));
+        }
     }
 
     public void addWall(int x1, int y1, int x2, int y2) {
@@ -130,13 +137,16 @@ public void addWall(int x1, int y1, int x2, int y2) {
         }
     }
 
-    public void remove(int value, Location l) {
+        public void remove(int value, Location l) {
         remove(value, l.x, l.y);
     }
 
     public void remove(int value, int x, int y) {
         data[x][y] &= ~value;
-        if (view != null) view.update(x,y);
+        if (view != null) {
+            final int ux = x, uy = y;
+            SwingUtilities.invokeLater(() -> view.update(ux, uy));
+        }
     }
 
     public void removeAll(int value) {

jason-interpreter/src/main/java/jason/environment/grid/GridWorldView.java

@@ -1,13 +1,9 @@
 package jason.environment.grid;
 
-import java.awt.BorderLayout;
-import java.awt.Canvas;
-import java.awt.Color;
-import java.awt.Font;
-import java.awt.FontMetrics;
-import java.awt.Graphics;
+import java.awt.*;
+import java.awt.image.BufferedImage;
 
-import javax.swing.JFrame;
+import javax.swing.*;
 
 /**
  * View component for a GirdWorldModel.
@@ -23,6 +19,8 @@ public class GridWorldView extends JFrame {
 
     protected GridCanvas     drawArea;
     protected GridWorldModel model;
+    protected BufferedImage backBuffer;
+    private Graphics2D backG;
 
     protected Font defaultFont = new Font("Arial", Font.BOLD, 10);
 
@@ -46,20 +44,25 @@ public void repaint() {
         cellSizeW = drawArea.getWidth() / model.getWidth();
         cellSizeH = drawArea.getHeight() / model.getHeight();
         super.repaint();
-        drawArea.repaint();
     }
 
     /** updates all the frame */
     public void update() {
+        ensureBackBuffer();
         repaint();
     }
 
     /** updates only one position of the grid */
     public void update(int x, int y) {
-        Graphics g = drawArea.getGraphics();
-        if (g == null) return;
-        drawEmpty(g, x, y);
-        draw(g, x, y);
+        if (!SwingUtilities.isEventDispatchThread()) {
+            // Only the event dispatch thread can update the GUI
+            SwingUtilities.invokeLater(this::update);
+            return;
+        }
+
+        ensureBackBuffer();
+        renderAllToBackBuffer();
+        drawArea.repaint();
     }
 
     public void drawObstacle(Graphics g, int x, int y) {
@@ -100,25 +103,7 @@ public void draw(Graphics g, int x, int y, int object) {
         //drawString(g,x,y,defaultFont,String.valueOf(object));
     }
 
-    private static int limit = (int)Math.pow(2,14);
-
-    private void draw(Graphics g, int x, int y) {
-        if ((model.data[x][y] & GridWorldModel.OBSTACLE) != 0) {
-            drawObstacle(g, x, y);
-        }
-
-        int vl = GridWorldModel.OBSTACLE*2; // the next  object after OBSTACLE
-        while (vl < limit) {
-            if ((model.data[x][y] & vl) != 0) {
-                draw(g, x, y, vl);
-            }
-            vl *= 2;
-        }
-
-        if ((model.data[x][y] & GridWorldModel.AGENT) != 0) {
-            drawAgent(drawArea.getGraphics(), x, y, Color.blue, model.getAgAtPos(x, y));
-        }
-    }
+    private static final int limit = (int)Math.pow(2,14);
 
     public Canvas getCanvas() {
         return drawArea;
@@ -130,27 +115,73 @@ public GridWorldModel getModel() {
 
     class GridCanvas extends Canvas {
 
-        private static final long serialVersionUID = 1L;
+        private static final long serialVersionUID = 2L;
+
+        @Override
+        public void update(Graphics g) {
+            paint(g);
+        }
 
         public void paint(Graphics g) {
-            cellSizeW = drawArea.getWidth() / model.getWidth();
-            cellSizeH = drawArea.getHeight() / model.getHeight();
-            int mwidth = model.getWidth();
-            int mheight = model.getHeight();
-
-            g.setColor(Color.lightGray);
-            for (int l = 1; l <= mheight; l++) {
-                g.drawLine(0, l * cellSizeH, mwidth * cellSizeW, l * cellSizeH);
+            ensureBackBuffer();
+            g.drawImage(backBuffer, 0, 0, this);
+            Toolkit.getDefaultToolkit().sync();
+        }
+    }
+
+    private void ensureBackBuffer() {
+        int w = Math.max(1, drawArea.getWidth());
+        int h = Math.max(1, drawArea.getHeight());
+        if (backBuffer == null || backBuffer.getWidth() != w || backBuffer.getHeight() != h) {
+            if (backG != null) {
+                backG.dispose();
             }
-            for (int c = 1; c <= mwidth; c++) {
-                g.drawLine(c * cellSizeW, 0, c * cellSizeW, mheight * cellSizeH);
+            backBuffer = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
+            backG = backBuffer.createGraphics();
+            backG.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
+        }
+        renderAllToBackBuffer();
+    }
+
+    private void renderAllToBackBuffer() {
+        cellSizeW = Math.max(1, backBuffer.getWidth() / model.getWidth());
+        cellSizeH = Math.max(1, backBuffer.getHeight() / model.getHeight());
+
+        backG.setColor(Color.white);
+        backG.fillRect(0, 0, backBuffer.getWidth(), backBuffer.getHeight());
+
+        backG.setColor(Color.lightGray);
+        for (int l = 1; l <= backBuffer.getHeight(); l++) {
+            backG.drawLine(0, l * cellSizeH, model.getWidth() * cellSizeW, l * cellSizeH);
+        }
+        for (int c = 1; c <= backBuffer.getWidth(); c++) {
+            backG.drawLine(c * cellSizeW, 0, c * cellSizeW, model.getHeight() *  cellSizeH);
+        }
+
+        for (int x = 0; x < model.getWidth(); x++) {
+            for (int y = 0; y < model.getHeight(); y++) {
+                renderCell(backG, x, y);
             }
+        }
+    }
+
+    private void renderCell(Graphics2D g, int x, int y) {
+        drawEmpty(g, x, y);
 
-            for (int x = 0; x < mwidth; x++) {
-                for (int y = 0; y < mheight; y++) {
-                    draw(g,x,y);
-                }
+        if ((model.data[x][y] & GridWorldModel.OBSTACLE) != 0) {
+            drawObstacle(g, x, y);
+        }
+
+        int vl = GridWorldModel.OBSTACLE*2; // the next  object after OBSTACLE
+        while (vl < limit) {
+            if ((model.data[x][y] & vl) != 0) {
+                draw(g, x, y, vl);
             }
+            vl *= 2;
+        }
+
+        if ((model.data[x][y] & GridWorldModel.AGENT) != 0) {
+            drawAgent(g, x, y, Color.blue, model.getAgAtPos(x, y));
         }
     }
 }