How to create a custom manipulation (or a workaround for that)?

[LMCom]

This package is using https://github.com/spatie/image which is using https://github.com/thephpleague/glide which is using https://github.com/intervention/image which is providing several image manipulation methods, one being trim(). The set of available methods in laravel-medialibrary, however, seems to ultimately be limited by thephpleague/glide, and that package does not have trim().

I need trim() and expected to be able to add it as a custom manipulation but, digging through the code, it does not seem to be possible to add custom manipulations.

If my assumption is true, how do I best work around that?
Ideas:

1. Manipulating the media model and the files via own code (dirty!).
2. I implement my own algorithm to find out how the image should be trimmed (including some color tolerance). Then I could pass the appropriate parameters to crop(), I guess. That would be tedious and the code likely slow.

I am using addMediaFromUrl, so I do not have the image file beforehand, so I would best listen to the event MediaHasBeenAdded and execute my code then, right?

[LMCom]

so I would best listen to the event MediaHasBeenAdded and execute my code then, right?

I just noticed that this does not work. After I somehow implemented trimming, I would have to regenerate the existing conversions with php artisan media-library:regenerate. But that does not fire MediaHasBeenAdded. And there's no other appropriate event.