关于android处理大位图的有关问题

public static Bitmap preScaleBitmap(Bitmap temp, float drawScale) {        float scaleWidth = DataManager.deviceWidth - 20;        // float scaleHeight=(int)((DataManager.deviceWidth-20)*drawScale);        float scale = scaleWidth / temp.getWidth();        Matrix matrix = new Matrix();        matrix.postScale(scale, scale);        // matrix.postScale(0.5f, 0.5f);        Bitmap temp2 = Bitmap.createBitmap(temp, 0, 0, temp.getWidth(),                temp.getHeight(), matrix, true);        return temp2;    }