Error: Running make on Python binding

[AWSb24]

I tried to run make according to the readme on the python binding. It results in several warnings and one error. I am running python3.9 on an RPI4.

rgbmatrix/graphics.cpp:3442:41: error: ‘PyTypeObject’ {aka ‘struct _typeobject’} has no member named ‘tp_print’ 3442 | __pyx_type_9rgbmatrix_8graphics_Color.tp_print = 0; | ^~~~~~~~ rgbmatrix/graphics.cpp:3450:40: error: ‘PyTypeObject’ {aka ‘struct _typeobject’} has no member named ‘tp_print’ 3450 | __pyx_type_9rgbmatrix_8graphics_Font.tp_print = 0; |

How can I solve this?

[rhtenhove]

This is because tp_print was removed in python3.9 (and only deprecated in 3.8). You can ignore the warnings.

You can solve this on a raspberry pi using pyenv to install python3.8. The following is based on my shell history on a raspberry pi 3 running ubuntu 21.04 64-bit. If something isn't working, let me know.

We're adding things to root, since root needs to run the library to work properly.

curl https://pyenv.run | sudo bash

Add the following to /root/.bashrc

export PYENV_ROOT="$HOME/.pyenv"
export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init --path)"

Finally run the following in a root shell sudo su. cd to the root of the rgb matrix git repo for the make commands.

apt install -y libbz2-dev libreadline-dev libssl-dev
pyenv install 3.8.10
pyenv global 3.8.10

pip install Pillow

make build-python PYTHON=$(which python3.8)
make install-python PYTHON=$(which python3.8)

Then you can run things like

/home/ubuntu/rpi-rgb-led-matrix/bindings/python/samples/runtext.py --led-gpio-mapping=adafruit-hat --text="Hello, world!"

[nvski]

These .cpp files were compiled by old cython. If you don't want to downgrade to python 3.8, you can recompile them with newer cython:

python3 -m pip install cython
cd path_to_repo/bindings/python/rgbmatrix/
python3 -m cython -3 --cplus *.pyx

[mikewebkist]

It took a slight variation on @nvski's comment for me to succeed with Python 3.9.5. I needed to use language_level=2 instead of 3:

python3 -m cython -2 --cplus *.pyx

But with that, I was able to get it working properly in pyenv local 3.9.5.

[sityware]

Seems like it can be fixed in code.

rename tp_print to tp_vectorcall_offset in /bindings/python/rgbmatrix/core.cpp /bindings/python/rgbmatrix/graphics.cpp

[josh1hart]

@sityware You saying renaming every mention of tp_print in each line to tp vectorcall_offset? for both core and grahpics? nothing else on top of this?

[stefffe]

That seems to fix the issue. I just did a search and replace for tp_print to tp_vectorcall_offset in core.cpp and graphics.cpp, and after that I can build and successfully run the python samples with Python 3.9.2.

[hzeller]

I've updated now updated the pre-generated cpp files with the latest cython; can you test if this is now working for you ?