Hello,
currently, the Build Environments for Raspberry Pi (3B and 4B) are prepared to work with the official Raspberry Pi 7" touch display with a screen resolution of 800x480 pixel.
Of course, you can adapt your own display (as you already have done) and your own touch device. If you want to adapt the touch coordinates, please have a look into the file ew_bsp_touch.c: There you will find the function EwBspTouchGetEvents() which is called from the main loop - there you can implement the mapping from touch coordinates to GUI coordinates.
The touch coordinates have to match always the GUI coordinates - there is no adaptation required within the Touch Handlers.
Does this help?
Best regards,
Manfred.