Chapter 02 section 07 updated.

Author: liuyubobobo

02-Java-Swing-Basics/07-Animation-Basics/src/AlgoFrame.java

@@ -39,7 +39,7 @@ public AlgoFrame(String title){
 
     // data
     private Circle[] circles;
-    public void setCircles(Circle[] circles){
+    public void render(Circle[] circles){
         this.circles = circles;
         repaint();
     }
@@ -68,7 +68,7 @@ public void paintComponent(Graphics g) {
             AlgoVisHelper.setStrokeWidth(g2d,1);
             AlgoVisHelper.setColor(g2d, Color.RED);
             for(Circle circle: circles)
-                AlgoVisHelper.strokeCircle(g2d, circle.x, circle.y, circle.r);
+                AlgoVisHelper.strokeCircle(g2d, circle.x, circle.y, circle.getR());
         }
 
         @Override

02-Java-Swing-Basics/07-Animation-Basics/src/AlgoVisHelper.java

@@ -7,23 +7,23 @@ public class AlgoVisHelper {
 
     private AlgoVisHelper(){}
 
-    static public void strokeCircle(Graphics2D g, int x, int y, int r){
+    public static void strokeCircle(Graphics2D g, int x, int y, int r){
 
         Ellipse2D circle = new Ellipse2D.Double(x-r, y-r, 2*r, 2*r);
         g.draw(circle);
     }
 
-    static public void fillCircle(Graphics2D g, int x, int y, int r){
+    public static void fillCircle(Graphics2D g, int x, int y, int r){
 
         Ellipse2D circle = new Ellipse2D.Double(x-r, y-r, 2*r, 2*r);
         g.fill(circle);
     }
 
-    static public void setColor(Graphics2D g, Color color){
+    public static void setColor(Graphics2D g, Color color){
         g.setColor(color);
     }
 
-    static public void setStrokeWidth(Graphics2D g, int w){
+    public static void setStrokeWidth(Graphics2D g, int w){
         int strokeWidth = w;
         g.setStroke(new BasicStroke(strokeWidth, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
     }

02-Java-Swing-Basics/07-Animation-Basics/src/Circle.java

@@ -3,7 +3,8 @@ public class Circle {
 
     public int x;
     public int y;
-    public int r;
+    private int r;
+
     public int vx;
     public int vy;
 
@@ -15,9 +16,21 @@ public Circle(int x, int y, int r, int vx, int vy){
         this.vy = vy;
     }
 
-    public void move(){
+    public int getR(){return r;}
+
+    public void move(int minx, int miny, int maxx, int maxy){
         x += vx;
         y += vy;
+
+        checkCollision(minx, miny, maxx, maxy);
+    }
+
+    private void checkCollision(int minx, int miny, int maxx, int maxy){
+
+        if(x - r < minx) { x = r;        vx = -vx; }
+        if(x + r >= maxx){ x = maxx - r; vx = -vx; }
+        if(y - r < miny) { y = r;        vy = -vy; }
+        if(y + r >= maxy){ y = maxy - r; vy = -vy; }
     }
 
 }

02-Java-Swing-Basics/07-Animation-Basics/src/Main.java

@@ -8,31 +8,31 @@ public static void main(String[] args) {
         int sceneWidth = 800;
         int sceneHeight = 800;
 
+        // init data
+        int N = 10;
+        Circle[] circles = new Circle[N];
+        int R = 50;
+
+        for(int i = 0 ; i < N ; i ++ ) {
+            int x = (int)(Math.random()*(sceneWidth-2*R)) + R;
+            int y = (int)(Math.random()*(sceneHeight-2*R)) + R;
+            int vx = (int)(Math.random()*11) - 5;
+            int vy = (int)(Math.random()*11) - 5;
+            circles[i] = new Circle(x, y, R, vx, vy);
+        }
+
         EventQueue.invokeLater(() -> {
             AlgoFrame frame = new AlgoFrame("Welcome", sceneWidth,sceneHeight);
 
-            // init data
-            int N = 10;
-            Circle[] circles = new Circle[N];
-            int R = 50;
-
-            for(int i = 0 ; i < N ; i ++ ) {
-                int x = (int)(Math.random()*(sceneWidth-2*R)) + R;
-                int y = (int)(Math.random()*(sceneHeight-2*R)) + R;
-                int vx = (int)(Math.random()*11) - 5;
-                int vy = (int)(Math.random()*11) - 5;
-                circles[i] = new Circle(x, y, R, vx, vy);
-            }
-
             new Thread(() -> {
                 while(true) {
                     // 绘制数据
-                    frame.setCircles(circles);
+                    frame.render(circles);
                     AlgoVisHelper.pause(20);
 
                     // 更新数据
-                    for(Circle circle: circles)
-                        circle.move();
+                    for(Circle circle : circles)
+                        circle.move(0, 0, sceneWidth, sceneHeight);
                 }
             }).start();
         });

02-Java-Swing-Basics/08-MVC-in-Algorithm-Visualization/src/AlgoVisualizer.java

@@ -8,10 +8,11 @@ public class AlgoVisualizer {
     static private int R = 50;
     private AlgoFrame frame;
 
-    public AlgoVisualizer(int N, AlgoFrame frame){
-        this.N = N;
-        this.frame = frame;
+    public AlgoVisualizer(int sceneWidth, int sceneHeight, int N){
+
+        this.frame = new AlgoFrame("Welcome", sceneWidth, sceneHeight);
 
+        this.N = N;
         circles = new Circle[N];
 
         for(int i = 0 ; i < N ; i ++ ) {
@@ -40,12 +41,10 @@ public static void main(String[] args) {
 
         int sceneWidth = 800;
         int sceneHeight = 800;
+        int N = 10;
 
         EventQueue.invokeLater(() -> {
-            AlgoFrame frame = new AlgoFrame("Welcome", sceneWidth,sceneHeight);
-
-            int N = 10;
-            AlgoVisualizer vis = new AlgoVisualizer(N, frame);
+            AlgoVisualizer vis = new AlgoVisualizer(sceneWidth, sceneHeight, N);
             new Thread(() -> {
                 vis.run();
             }).start();