Show screenshot of current game in "Edit touch control layout..."

[bengalih]

What should happen

When editing the touch control layout when a game is loaded, display the controls over an overlay of the current screen of the game.

This makes it much easier to determine optimal position of controls for a particular game rather then trial and error of adjusting and switching back and forth a dozen times to try an tune them.

Who would this benefit

Anyone who uses touch controls and likes to reposition them depending on game.

Platform (if relevant)

Android

Games this would be useful in

ALL

Other emulators or software with a similar feature

No response

Checklist

• Check the latest git build in case it's already implemented.
• Search for other requests of the same feature.

I like this fr to be implemented :)

[hrydgard]

Implementation note for later:

We'd probably reuse our currently existing path for transparent UI on top of the game, where DrawGameBackground simply calls gpu->CopyDisplayToOutput(true);. We could have a way to scale this down to a subregion of the screen, which would have the desired effect.