把图片转换成圆形图片

调用：（bt是Bitmap）

head_portrait.setImageBitmap(ToRoundBitmap.toRoundBitmap(bt));

转换圆形的方法：

 1 package com.ghp.tools;
 2 
 3 import android.graphics.Bitmap;
 4 import android.graphics.Canvas;
 5 import android.graphics.Color;
 6 import android.graphics.Paint;
 7 import android.graphics.PorterDuffXfermode;
 8 import android.graphics.Rect;
 9 import android.graphics.Bitmap.Config;
10 
11 public class ToRoundBitmap {
12     /**
13      * 转成圆形图片
14      * 
15      * @param bitmap
16      * @return
17      */
18     public static Bitmap toRoundBitmap(Bitmap bitmap) {
19         int width = bitmap.getWidth();
20         int height = bitmap.getHeight();
21 
22         final int color = Color.parseColor("#00FF00");
23         // defaultWidth = width;
24         // defaultHeight = height;
25 
26         float roundPx;
27         float left, top, right, bottom, dst_left, dst_top, dst_right, dst_bottom;
28         if (width <= height) { // 高大于宽
29             roundPx = width / 2;
30             left = 0;
31             top = 0;
32             right = width;
33             bottom = width;
34             height = width;
35             dst_left = 0;
36             dst_top = 0;
37             dst_right = width;
38             dst_bottom = width;
39         } else { // 宽大于高
40             roundPx = height / 2;
41             float clip = (width - height) / 2;
42             left = clip;
43             right = width - clip;
44             top = 0;
45             bottom = height;
46             width = height;
47             dst_left = 0;
48             dst_top = 0;
49             dst_right = height;
50             dst_bottom = height;
51         }
52 
53         Bitmap output = Bitmap.createBitmap(width, height, Config.ARGB_8888);
54         Canvas canvas = new Canvas(output);
55 
56         final Paint paint = new Paint();
57         paint.setAntiAlias(true);// 设置画笔无锯齿
58 
59         final Rect src = new Rect((int) left, (int) top, (int) right,
60                 (int) bottom);
61         final Rect dst = new Rect((int) dst_left, (int) dst_top,
62                 (int) dst_right, (int) dst_bottom);
63         canvas.drawARGB(0, 0, 0, 0); // 填充整个Canvas
64         paint.setColor(color);
65         paint.setDither(true);
66 
67         canvas.drawCircle(roundPx, roundPx, roundPx, paint);// 画圆
68         paint.setXfermode(new PorterDuffXfermode(
69                 android.graphics.PorterDuff.Mode.SRC_IN));
70         canvas.drawBitmap(bitmap, src, dst, paint); // 以Mode.SRC_IN模式合并bitmap和已经draw了的Circle
71 
72         return output;
73     }
74 }