Bitmap 处理圆形图片工具类

package com.view;


import java.io.IOException;
import java.io.InputStream;


import android.content.Context;
import android.content.res.AssetManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;


public class Util {
private static final int STROKE_WIDTH = 4;


public static  Bitmap toRoundBitmap(Context context,Bitmap bitmap) {  
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float roundPx;
    float left,top,right,bottom,dst_left,dst_top,dst_right,dst_bottom;
if (width <= height) {
     roundPx = width / 2;
     top = 0;
     left = 0;
     bottom = width;
         right = width;
         height = width;
     dst_left = 0;
     dst_top = 0;
     dst_right = width;
     dst_bottom = width;
 } else {
     roundPx = height / 2;
         float clip = (width - height) / 2;
     left = clip;
     right = width - clip;
     top = 0;
     bottom = height;
 width = height;
 dst_left = 0;
 dst_top = 0;
 dst_right = height;
 dst_bottom = height;
    }


       Bitmap output = Bitmap.createBitmap(width,
height, Config.ARGB_8888);
Canvas canvas = new Canvas(output);

   final int color = 0xff424242;
final Paint paint = new Paint();
final Rect src = new Rect((int)left, (int)top, (int)right, (int)bottom);
   final Rect dst = new Rect((int)dst_left, (int)dst_top, (int)dst_right, (int)dst_bottom);
final RectF rectF = new RectF(dst);


paint.setAntiAlias(true);


       canvas.drawARGB(0, 0, 0, 0);
   paint.setColor(Color.WHITE);
   paint.setStrokeWidth(4); 
       canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
       paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
   canvas.drawBitmap(bitmap, src, dst, paint);
   
   //画白色圆圿
   paint.reset();
   paint.setColor(Color.WHITE);
   paint.setStyle(Paint.Style.STROKE);
   paint.setStrokeWidth(STROKE_WIDTH);
   paint.setAntiAlias(true);
   canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG));
       canvas.drawCircle(width / 2, width / 2, width / 2 - STROKE_WIDTH / 2, paint);
       return output ; 
}

/*public static void drawImage(Canvas canvas, Bitmap blt, int x, int y, int w, int h, int bx, int by)
    {                                                        //x,y表示绘画的起点，
        Rect src = new Rect();// 图片
        Rect dst = new Rect();// 屏幕位置及尺寿
        //src 这个是表示绘画图片的大小
        src.left = bx;   //0,0  
        src.top = by;
        src.right = bx + w;// mBitDestTop.getWidth();,这个是桌面图的宽度，
        src.bottom = by + h;//mBitDestTop.getHeight()/2;// 这个是桌面图的高度的丿卿
        // 下面皿 dst 是表礿 绘画这个图片的位罿
        dst.left = x;    //miDTX,//这个是可以改变的，也就是绘图的起点X位置
        dst.top = y;    //mBitQQ.getHeight();//这个是QQ图片的高度㿿 也就相当亿 桌面图片绘画起点的Y坐标
        dst.right = x + w;    //miDTX + mBitDestTop.getWidth();// 表示霿绘画的图片的右上觿
        dst.bottom = y + h;    // mBitQQ.getHeight() + mBitDestTop.getHeight();//表示霿绘画的图片的右下觿
        canvas.drawBitmap(blt, src, dst, null);//这个方法  第一个参数是图片原来的大小，第二个参数是 绘画该图片需显示多少。也就是说你想绘画该图片的某丿些地方，而不是全部图片，第三个参数表示该图片绘画的位罿
        
        src = null;
        dst = null;
    }*/

}

Bitmap roundBitmap = Util.toRoundBitmap(RegisterActivity.this,
bitmap);