可视区域应用-android游戏开发

主要方法：
               //----设置矩形可视区域
               canvas.save();
               canvas.clipRect(20,20,50,50);
               canvas.drawBitmap(bmp, 0, 0, paint);
               canvas.restore();
               //----利用Path设置可视区域
               canvas.save();
               Path path=new Path();
               path.addCircle(100+30, 100+30, 30, Direction.CCW);
               canvas.clipPath(path);
               canvas.drawBitmap(bmp, 100, 100, paint);
               canvas.restore();
               //----利用Region设置可视区域
               canvas.save();
               Region region = new Region();
               region.op(new Rect(20,20+300,100,100+300), Region.Op.XOR);
               region.op(new Rect(40,20+300,80,150+300), Region.Op.XOR);
               canvas.clipRegion(region);
               canvas.drawBitmap(bmp, 0, 300, paint);
               canvas.restore();

案例运行结果：

案例源码：

  1 package caicai.animation;
  2 
  3 import android.content.Context;
  4 import android.graphics.Bitmap;
  5 import android.graphics.BitmapFactory;
  6 import android.graphics.Canvas;
  7 import android.graphics.Color;
  8 import android.graphics.Matrix;
  9 import android.graphics.Paint;
 10 import android.graphics.PaintFlagsDrawFilter;
 11 import android.graphics.Path;
 12 import android.graphics.Path.Direction;
 13 import android.graphics.Rect;
 14 import android.graphics.RectF;
 15 import android.graphics.Region;
 16 import android.util.Log;
 17 import android.view.MotionEvent;
 18 import android.view.SurfaceHolder;
 19 import android.view.SurfaceHolder.Callback;
 20 import android.view.SurfaceView;
 21 
 22 public class clipView extends SurfaceView implements Callback, Runnable {
 23     private Paint paint;// 画布
 24     private SurfaceHolder sfh; // 用于控制SurfaceView
 25     private Canvas canvas;// 画布
 26     private boolean flag;// 关闭线程标志
 27     private Thread th;// 新建线程
 28     private Bitmap bmp;// 位图
 29 
 30     // 设置画布绘图无锯齿
 31     private PaintFlagsDrawFilter pfd = new PaintFlagsDrawFilter(0,
 32             Paint.ANTI_ALIAS_FLAG);
 33 
 34     public clipView(Context context) {
 35         super(context);
 36         sfh = this.getHolder();// 实例SurfaceHolder
 37         sfh.addCallback(this);// 为SurfaceView添加状态监听
 38         paint = new Paint();// 实例一个画笔
 39         paint.setColor(Color.WHITE);// 设置画笔颜色为白色
 40         setFocusable(true);// 设置焦点
 41         bmp = BitmapFactory.decodeResource(getResources(), R.drawable.tanke);
 42     }
 43 
 44     @Override
 45     public void surfaceCreated(SurfaceHolder holder) {
 46         flag = true;
 47         // 实例线程
 48         th = new Thread(this);
 49         // 启动线程
 50         th.start();
 51     }
 52 
 53     public void mydraw() {
 54         try {
 55             canvas = sfh.lockCanvas();// 锁定画布
 56             if (canvas != null) {
 57                 canvas.drawColor(Color.BLACK);
 58                 //----设置矩形可视区域
 59                 canvas.save();
 60                 canvas.clipRect(20,20,50,50);
 61                 canvas.drawBitmap(bmp, 0, 0, paint);
 62                 canvas.restore();
 63                 //----利用Path设置可视区域
 64                 canvas.save();
 65                 Path path=new Path();
 66                 path.addCircle(100+30, 100+30, 30, Direction.CCW);
 67                 canvas.clipPath(path);
 68                 canvas.drawBitmap(bmp, 100, 100, paint);
 69                 canvas.restore();
 70                 //----利用Region设置可视区域
 71                 canvas.save();
 72                 Region region = new Region();
 73                 region.op(new Rect(20,20+300,100,100+300), Region.Op.XOR);
 74                 region.op(new Rect(40,20+300,80,150+300), Region.Op.XOR);
 75                 canvas.clipRegion(region);
 76                 canvas.drawBitmap(bmp, 0, 300, paint);
 77                 canvas.restore();
 78                 canvas.drawBitmap(bmp, 200, 300, paint);
 79             } else {
 80                 Log.i("tt", "获取不到画布");// 释放画布
 81             }
 82         } catch (Exception e) {
 83 
 84         } finally {
 85             if (canvas != null)
 86                 sfh.unlockCanvasAndPost(canvas);
 87         }
 88     }
 89 
 90     /**
 91      * SurfaceView视图状态发生改变，响应此函数
 92      */
 93     @Override
 94     public void surfaceChanged(SurfaceHolder holder, int format, int width,
 95             int height) {
 96         // TODO Auto-generated method stub
 97 
 98     }
 99 
100     /**
101      * SurfaceView视图消亡时，响应此函数
102      */
103     @Override
104     public void surfaceDestroyed(SurfaceHolder holder) {
105         flag = false;// 结束游戏，设置线程关闭标志为false
106 
107     }
108 
109     public void logic() {
110 
111     };
112 
113     @Override
114     public void run() {
115         while (flag) {
116             long start = System.currentTimeMillis();
117             mydraw();
118             logic();
119             long end = System.currentTimeMillis();
120             try {
121                 if (end - start < 50) {
122                     Thread.sleep(50 - (end - start));
123                 }
124             } catch (InterruptedException e) {
125                 e.printStackTrace();
126             }
127         }
128     }
129 
130     // 获取点击坐标
131     @Override
132     public boolean onTouchEvent(MotionEvent event) {
133         return true;
134     }
135 
136 }

clipView

 1 package caicai.animation;
 2 
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.view.Window;
 6 import android.view.WindowManager;
 7 
 8 public class MainActivity extends Activity {
 9     /** Called when the activity is first created. */
10     @Override
11     public void onCreate(Bundle savedInstanceState) {
12         super.onCreate(savedInstanceState);
13         //设置全屏
14         this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
15         requestWindowFeature(Window.FEATURE_NO_TITLE);
16         //显示自定义的SurfaceView视图
17         setContentView(new clipView(this));
18 
19     }
20 }

MainActivity

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