Expand the in-app-editor with saturation, contrast, brightness, vignette, sharpen

[natrius]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one feature request.
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Feature description

When editing a picture with the gallery editor there are 3 tabs on the bottom, beautify, crop, draw - add a fourth one with "Adjust" where the stuff i mentioned in the title is possible - contrast, saturation, brightness, vignette, sharpen.

Why do you want this feature?

It should be common and is pretty useful when someone wants to share a nice picture to make it even a bit more pop but without the predefined settings.

Additional information

I tried to search another app in f-droid with the capability for that but i was not really able to find one, so it would be nice if this one would offer this possibility.

[Aga-C]

The most basic and also easiest to implement should be saturation, contrast and brightness, so I think it should be the first to implement. Sharpen could be the next feature. I would consider a vignette as a nice-to-have, but not very important.

Generally we could use Simple Gallery's advanced editor (which we had to remove) as a basis, what should be in such tab, as there were more options, also useful.

[Pawwwle]

These options was in the Gallery of Simple Mobile Tool. It was called Advanced Editor.