On-screen touchpad for mouse control on mobile

[pdjstone]

It would be great to be able to use the emulator on mobile devices. For mouse control this could be done using an on-screen touchpad. This would appear below the screen when in portrait mode, or beside it when in landscape.

Some prototyping will need to be done to figure out how best to handle mouse clicks (including middle and right button clicks) and drag-drop.

[pdjstone]

I implemented a very basic touchpad with pointer events but I will definitely need to implement pointer acceleration to make it feel right. See http://who-t.blogspot.com/2014/07/pointer-acceleration-in-libinput.html and https://web.archive.org/web/20130126195342/http://msdn.microsoft.com/en-us/windows/hardware/gg463319.aspx