Android兩種旋轉Bitmap方法比較

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方法1. 利用Bitmap.createBitmap

    Bitmap adjustPhotoRotation(Bitmap bm, final int orientationDegree) {        Matrix m = new Matrix();        m.setRotate(orientationDegree, ( float ) bm.getWidth() / 2, ( float ) bm.getHeight() / 2);        try {            Bitmap bm1 = Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(), m, true);            return bm1;        } catch (OutOfMemoryError ex) {            ex.printStackTrace();        } catch (Exception e) {            e.printStackTrace();        }        return null;    }

 

方法2. 利用Canvas.drawBitmap

 

    Bitmap adjustPhotoRotation(Bitmap bm, final int orientationDegree) {        try {            int width = bm.getWidth();            int height = bm.getHeight();            Matrix matrix = new Matrix();            matrix.setRotate(orientationDegree, ( float ) width / 2, ( float ) height / 2);            float targetX = 0;            float targetY = 0;            if (orientationDegree == 90 || orientationDegree == 270) {                if (width > height) {                    targetX = ( float ) height / 2 - ( float ) width / 2;                    targetY = 0 - targetX;                } else {                    targetY = ( float ) width / 2 - ( float ) height / 2;                    targetX = 0 - targetY;                }            }            matrix.postTranslate(targetX, targetY);            Bitmap bm1 = Bitmap.createBitmap(bm.getHeight(), bm.getWidth(), Bitmap.Config.ARGB_8888);            Paint paint = new Paint();            Canvas canvas = new Canvas(bm1);            canvas.drawBitmap(bm, matrix, paint);            return bm1;        } catch (OutOfMemoryError e) {            e.printStackTrace();        } catch (Exception e) {            e.printStackTrace();        }    }

 

效能測試：

 1. 手機 

    CPU : MTK6575 ,1G Hz

    MEM : 512MB

    OS : andoid 2.3.7

 2.圖片尺寸1632 * 1224

 

結果： 

 1. 方法1在280 - 350毫秒間， 方法2在110毫秒左右。 

 2. 方法2優於方法1