update _write_char

[mushunrek]

Changing the default encoding to cp437, with the possibility to fall back to ascii.

[tekktrik]

Since this library also supports the microcontrollers, which use UTF-8 encoding and basically ignore this parameter, I think changing the default to something else would confuse users expecting it on those devices - technically, it shouldn't even be ASCII currently.

Additionally, since this is only for the internal _write_char() function, there's no way to modify in a public function like print().

I think a solution could be to provide an encoding argument to print() (and any functions like it) with a default of utf-8 (despite that the printer probably doesn't necessarily support all UTF-8), pass that down to the function you changed, and explain in the public functions that the argument is only supported on Blinka platforms like the Raspberry Pi.

[mushunrek]

I don't understand exactly why the tests failed...

Important notes: I chose to force the keyword encoding in the function _write_char(...). This lead to a necessary change in thermal_printer_legacy.py, but should not change the user experience.

However, following PEP, I also made the options end and encoding in print(...) keyword-only arguments. This makes code a lot clearer, but may break older codes. If you want the code to be backwards compatible, I can remove this feature.

[tekktrik]

Thanks for the changes!

The CI is failing because it wants to reformat the file. You run pre-commit yourself, and then commit the changes it automatically makes.

[tekktrik]

Looks like we're just missing the note that only UTF-8 is available for CircuitPython, but otherwise looks good!

[tekktrik]

Hi! Looks like there's one remaining change needed, as well as a merge from main needed. Let me know if you're still working on this, otherwise I'm happy to finish it :)

[mushunrek]

Sorry, this got lost in the other stuff. Added the note.

[tekktrik]

No worries! I'll take a look at this soon :)

[tekktrik]

Thanks!