Thank you for your report! I can't replicate this issue (and the other two duplicates below) on any of my devices (OnePlus 6, Pixel 3a, Pixel 4a), so I suspect it has something to do with either slower devices and/or lower Android versions. I don't know why the first launch would be slower than subsequent ones, but I'll look into it.

I have one question for you in particular though - the other two commenters who reported this issue (M Be and Kind Beaver) reported that it only stayed black for a short while, then the app continued working normally. Can you confirm whether this is the case for you too? Again, thank you for testing my app.

Yeah, I noticed this recently too. This is because the emoji is a so-called ZWJ sequence (https://emojipedia.org/emoji-zwj-sequence/), which means that it's actually made up of multiple emojis joined together using a Zero Width Joiner, hence the name. In my case I'm checking the unicode codepoint range of each entered character to check whether the entered text only contains emojis, so to fix this I'll simply have to add the ZWJ character to the list of allowed code points, which I'll do in case I decide to publish the app.

Thanks for testing my app though! Maybe the information here can help you fix the bug in your case too.

This issue seems to be in the image_cropper library I use, so I can't fix it that easily myself without re-implementing the library's functionality. I'll look into filing an issue there or submitting a Pull Request, thanks for the report.

The operation applied here isn't really "cropping", rather "rotating", so the recommended way is to use the "rotating" mode in that screen (middle button) instead of trying to rotate the image while still in "cropping" mode (as in the video), that way it should work.