Color of some pixels may be changed when alpha channel is 0 in PNG file.

[Leoongithub]

Although alpha channel is 0 means color is meaningless, is there an option to not change RGB channels' value?

[JayXon]

By default lossy_transparent option is enabled because there's no difference in the pixels we can see, it is possible to add an option to disable this, but I would like to know more about the use case, why do you need it to not change?

[Leoongithub]

I can use transparent area to record some hidden information. How do I use this option in CLI? Or I need modify the source code?

[JayXon]

Currently it's not exposed in CLI, but you can remove this line in the code

[doterax]

I have found the same behaviour. And in my opinion, by default, leanify should behave lossless. And only if user wants to squeeze more bytes, user should be able to add switch to enable lossy behavour in this case.

[doterax]

Hi @javiergutierrezchamorro, I have found that you updated leanify in https://sourceforge.net/p/nikkhokkho/code/1755/

So, please consider to handle additional parameter "--png-lossless-transparent" (Prohibit altering hidden colors of fully transparent pixels.) By default do not add anything, but user have to have ability to use it.