Bitmap.compress() function has bugs about PNG file

 

Normally in Android, a developer uses Bitmap.compress() function for saving an image file as JPEG and PNG.

However, if some pixels of ARGB_8888 typed bitmap are not 0 or 255, for example 137 or 230, etc., unwanted value is saved when compress by Bitmap.compress() function.

Currently I don’t know how to solve the problem. Moreover I have found another problem (or maybe bug?).

It’s that when a bitmap image constructed by OpenCV, especially bitmapToMat(), Android didn’t assume that bitmap created by PNG format.