Android中按照固定长宽缩放图片

private Bitmap getMetadataBitmap(Bitmap bm){
        int width = bm.getWidth();
      int height = bm.getHeight();
      //固定的长宽
      int newWidth = 90;
      int newHeight = 130;

      float scaleWidth = ((float) newWidth) / width;
      float scaleHeight = ((float) newHeight) / height;

      Matrix matrix = new Matrix();
      matrix.postScale(scaleWidth, scaleHeight);
      Bitmap newbm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix,
        true);
      return newbm;
  }