BitMap 压缩指定大小的文件

private Bitmap compressImage(Bitmap tempBitmap) {   final int IMAGE_SIZE = 255;//指定文件大小   boolean landscape = bitmap.getWidth() > bitmap.getHeight();   float scale_factor;   if (landscape) scale_factor = (float)IMAGE_SIZE / bitmap.getHeight();   else scale_factor = (float)IMAGE_SIZE / bitmap.getWidth();   Matrix matrix = new Matrix();   matrix.postScale(scale_factor, scale_factor);   Bitmap croppedBitmap;   if (landscape){      int start = (tempBitmap.getWidth() - tempBitmap.getHeight()) / 2;      croppedBitmap = Bitmap.createBitmap(tempBitmap, start, 0, tempBitmap.getHeight(), tempBitmap.getHeight(), matrix, true);   } else {      int start = (tempBitmap.getHeight() - tempBitmap.getWidth()) / 2;      croppedBitmap = Bitmap.createBitmap(tempBitmap, 0, start, tempBitmap.getWidth(), tempBitmap.getWidth(), matrix, true);   }   return croppedBitmap;}