Android两种旋转Bitmap方法

方法1.利用Bitmap.createBitmap

   BitmapadjustPhotoRotation(Bitmap bm, final int orientationDegree){

           Matrix m = new Matrix();
           m.setRotate(orientationDegree, (float) bm.getWidth() / 2, (float)bm.getHeight() / 2);

           try {

           Bitmapbm1 = Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(),m, true);

              return bm1;

             } catch (OutOfMemoryError ex) {
                    }

               returnnull;

}

方法2.利用Canvas.drawBitmap

BitmapadjustPhotoRotation(Bitmap bm, final int orientationDegree){

       Matrix m = new Matrix();
       m.setRotate(orientationDegree, (float) bm.getWidth() / 2, (float)bm.getHeight() / 2);
        floattargetX, targetY;
       if (orientationDegree == 90) {
       targetX = bm.getHeight();
       targetY = 0;
       } else {
       targetX = bm.getHeight();
       targetY = bm.getWidth();
  }

    finalfloat[] values = new float[9];
   m.getValues(values);

    float x1 =values[Matrix.MTRANS_X];
    float y1 =values[Matrix.MTRANS_Y];

   m.postTranslate(targetX - x1, targetY - y1);

    Bitmap bm1 =Bitmap.createBitmap(bm.getHeight(), bm.getWidth(),Bitmap.Config.ARGB_8888);

Paint paint = new Paint();
    Canvascanvas = new Canvas(bm1);
   canvas.drawBitmap(bm, m, paint);

    returnbm1;
  }

 

性能测试：

1. 手机

CPU : MTK6575 ,1G Hz

MEM : 512MB

OS : andoid 2.3.7

2.图片尺寸1632 * 1224

 

结果：

1. 方法1在280 - 350毫秒间， 方法2在110毫秒左右。

2. 方法2优于方法1