Andriod 将图片截取为圆角图片

     Andriod 将图片截取为圆角图片

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;

方法：

  /**
      * 将图片截取为圆角图片
     * @param bitmap 原图片
     * @param ratio 截取比例，如果是8，则圆角半径是宽高的1/8，如果是2，则是圆形图片
     * @return 圆角矩形图片
     */
     public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float ratio) {
            
             Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
                             bitmap.getHeight(), Config.ARGB_8888);
             Canvas canvas = new Canvas(output);

             final Paint paint = new Paint();
             final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
             final RectF rectF = new RectF(rect);

             paint.setAntiAlias(true);
             canvas.drawARGB(0, 0, 0, 0);
             canvas.drawRoundRect(rectF, bitmap.getWidth()/ratio,
                             bitmap.getHeight()/ratio, paint);

             paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
             canvas.drawBitmap(bitmap, rect, rect, paint);
             return output;
     }