android clipPath切割画布

（转自：http://wallage.blog.163.com/blog/static/1738962420101012439991/）

[java] view plain copy

1. public class PictureTestActivity extends Activity {  
2.    
3.        @Override  
4.        public void onCreate(Bundle savedInstanceState){  
5.            super.onCreate(savedInstanceState);  
6.            setContentView(new SampleView(this));  
7.        }  
8.         private static class SampleView extends View {  
9.             private Paint mPaint;  
10.             private Path mPath;  
11.             public SampleView(Context context) {  
12.                 super(context);  
13.                 setFocusable(true);  
14.                   
15.                 mPaint = new Paint();  
16.                 mPaint.setAntiAlias(true);  
17.                 mPaint.setStrokeWidth(6);  
18.                 mPaint.setTextSize(16);  
19.                 mPaint.setTextAlign(Paint.Align.RIGHT);  
20.                   
21.                 mPath = new Path();  
22.             }  
23.               
24.             private void drawScene(Canvas canvas) {  
25.                 canvas.clipRect(0, 0, 100, 100);  
26.                   
27.                 canvas.drawColor(Color.WHITE);  
28.                   
29.                 mPaint.setColor(Color.RED);  
30.                 canvas.drawLine(0, 0, 100, 100, mPaint);  
31.                   
32.                 mPaint.setColor(Color.GREEN);  
33.                 canvas.drawCircle(30, 70, 30, mPaint);  
34.                   
35.                 mPaint.setColor(Color.BLUE);  
36.                 canvas.drawText("Clipping", 100, 30, mPaint);  
37.             }  
38.               
39.             @Override   
40.             protected void onDraw(Canvas canvas) {  
41.                 canvas.drawColor(Color.GRAY);              
42.                 canvas.save();  
43.                 canvas.translate(10, 10);  
44.                 drawScene(canvas);  
45.                 canvas.restore();  
46.                   
47.                 canvas.save();  
48.                 canvas.translate(160, 10);  
49.                 canvas.clipRect(10, 10, 90, 90);  
50.                 canvas.clipRect(30, 30, 70, 70, Region.Op.DIFFERENCE);  
51.                 drawScene(canvas);  
52.                 canvas.restore();  
53.                   
54.                 canvas.save();  
55.                 canvas.translate(10, 160);  
56.                 mPath.reset();  
57.                 canvas.clipPath(mPath); // makes the clip empty  
58.                 mPath.addCircle(50, 50, 50, Path.Direction.CCW);  
59.                 canvas.clipPath(mPath, Region.Op.REPLACE);  
60.                 drawScene(canvas);  
61.                 canvas.restore();  
62.                   
63.                 canvas.save();  
64.                 canvas.translate(160, 160);  
65.                 canvas.clipRect(0, 0, 60, 60);  
66.                 canvas.clipRect(40, 40, 100, 100, Region.Op.UNION);  
67.                 drawScene(canvas);  
68.                 canvas.restore();  
69.                   
70.                 canvas.save();  
71.                 canvas.translate(10, 310);  
72.                 canvas.clipRect(0, 0, 60, 60);  
73.                 canvas.clipRect(40, 40, 100, 100, Region.Op.XOR);  
74.                 drawScene(canvas);  
75.                 canvas.restore();  
76.                   
77.                 canvas.save();  
78.                 canvas.translate(160, 310);  
79.                 canvas.clipRect(0, 0, 60, 60);  
80.                 canvas.clipRect(40, 40, 100, 100, Region.Op.REVERSE_DIFFERENCE);  
81.                 drawScene(canvas);  
82.                 canvas.restore();  
83.             }  
84.         }  
85. }  

效果如图：

扫描二维码关注公众号，回复： 647537 查看本文章

canvas.clipRect(30, 30, 70, 70, Region.Op.XOR);最后一个参数有多个选择分别是：

            //DIFFERENCE是第一次不同于第二次的部分显示出来
            //REPLACE是显示第二次的
            //REVERSE_DIFFERENCE 是第二次不同于第一次的部分显示
            //INTERSECT交集显示
            //UNION全部显示
            //XOR补集 就是全集的减去交集生育部分显示