Not sure, if the library is still actively developed.
Anyhow, I was trying to use the lib on an Arduino Due with Hardware SPI.
It fails with many errors saying, that registers are not found in the Pixelshw.h file.
It seems, that the low level registers are directly used.
Therefore from my point of view, it could be possible, that the lib is not compatible with Arduino Due (Atmet SAM).
Can you please clarify if it's possible to run on Arduino Due?