A basic sketch for use SSD2119 color LCD on Arduino MEGA and Arduino DUE, connected via SPI bus. This sketch contains also 2 different fonts and some drawing functions.
On April 2020, @mgaman revised this code and converted it in a C++ class: SSD2119-for-Adafruit-GFX
He made also other improvements and make the code compatible to Adafruit GFX library. Reaching this compatibility made possible to delete informations about fonts and some drawing functions, because they are inherited from Adafruit GFX library itself.
If you are using a SSD2119, take in consideration also to its repository.