I don't know if I'm in the right branch, but I want to help, which believes this and it worked for my Note 9 that uses 18: 5: 90 aspect.
I created an Options Menu which added the "Aspect 18: 5: 90" option and so I use the Switch to activate or deactivate.
Here the configuration, the Aspect that is in the image I have it deactivated because first my game will be on PC and in the end I activate Android n.n
And here is the configuration:
Here add a simple example
*If you realize I had to reposition the objects to make it look good.
Well to reach the conclusion of how to enlarge the sides when you play a 16: 9 game you realize that the black edges are visible and you only have to measure 1 edge example 1cm measures, and that will convert it and it will come out when it measures:
Here I leave the page you fill it with 1cm both sides if it were like that on your cell phone = approx 38cm and with this you should grow the screen in the middle of game operation.
* That if you enlarge the sides not TOP-Left as the images, well if it serves them Great !! because it served me, so you don't modify the C2 APP itself.
***Use Google Translator*** Im speak Spanish
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