Hidden sticker function Huawei Mate 20 Pro?

Pe
- in Mate series
2

I often happen something that I have not heard anything about. I solve, without knowing how, a "Stickermaker function" off. In that state I can stroke my finger over the screen and in the end it makes me a sticker.
Can someone explain how I trigger this?

Ju

It does not become a sticker, but a screenshot in the "painted" form.

You do that with the knuckle. Draw it on your screen. Look at this on the Internet, have a lot of features that you can trigger with the knuckle.

Pe

Thank you for your prompt reply!