look at the arduino libs for the sn3218 in the Pimoroni github repo as it might help you with the LEDdriver part: https://github.com/pimoroni/pimoroni_arduino_sn3218
the st7036 also has a few arduino libs out there you could peek at. It's not C per se, but it will be some way towards what you want to achieve, I guess... as far as I know porting that kind of stuff to the Pi was one of the goal of WiringPi?