Hi,
As I could not reply in the following topic: https://forum.arduino.cc/index.php?topic=503416.0 I have a simple solution for people having issues with the rows order and like me have the following one: 5 6 7 8 1 2 3 4 13 14 15 16 9 10 11 12
You just need to change in the drawPixel function
if (y < 4 || (y > 7 && y < 12)) { shift += 8; // top rows start after lower 8 leds }
to
if ((y > 3 && y < 8) || (y > 11 && y < 16)) { shift += 8; // top rows start after lower 8 leds }
Xavier