That library is so buggy that is not even funny.
Also, there is some random codding being commented where it shouldn't...
I've fixed that, but nothing seems to change on the "clearPixel" error.
I get to the point to comment out and delete part of the code related to "clearPixel", and the error stays there randomly on different parts of the code with the same "clearPixel" error, where there is no more "clearPixel" in the code!
That library is buggy pal. Try to find another one. vvvvvvvvvvvvvvvvvvvvvvvv
Edit: I've found the one working. Delete the previous library first! Download this library.
After installing T6963_Lib to Arduino's "libraries" folder, download this file
and replace it for the same file on T6963_Lib's library.
Both examples should work after that with the new library.