Some devices have a LED as a front flash like Galaxy J7 and some chinese brands. Could you implement an option, so front LED can be used as flash instead of white screen (either turned on from snapchat or with volume buttons)?
There are some apps that uses the front led in this link: https://forum.xda-developers.com/galaxy-j7/themes/j7-flash-notification-torch-t3338126
The author released the source code here: https://app.box.com/s/bacyb9f9z5fvtq19vrw4ah08mh3ubo3h
Thanks!