For my own use, I further modified my fork to allow being used as a library.
See this super short example on how to display an animated GIF in your own code:
This library also supports:
seamless switching between SmartMatrix and NeoMatrix backends
gamma correction on the fly on NeoMatrix backend (via serial)
changing files by index number or previous/next (via serial)
ESP8266 support for NeoMatrix
SPIFFS support on ESP8266/ESP32 (no sdcard needed)