LVGL V8 vs V9 bindings

[mark-hoy]

While I'm attempting to learn more about micropython and LVGL code, I look over the samples at the LVGL docs
V8 Samples with C & Micropython

Unfortunately, I'm not sure what the new mapping are for things that are missing.

I think lv.btn() is now lv.button() but perhaps I'm mistaken...

Another example, text auto formatting sample code looks for a text area on an event.
text auto formatting sample code

The ta is a struct lv_event_t that no longer has a get_text()
attribute.

AttributeError: 'Blob' object has no attribute 'get_text'

def ta_event_cb(e):
    ta = e.get_target()
    txt = ta.get_text()

I seem to recall @kdschlosser mentioning that there is a micropython in the build that describes the C to micropython binding, but for the life of me I can't recall or find the discussion.

Thanks in advance.

[mark-hoy]

A partial answer from discussion 178
to use the lvgl.pyi file for an IDE to understand the bindings.

[kdschlosser]

the stub file that gets generated as part of the build process is not 100% perfect and does have some errors in it. It is correct enough where it removes a lot of frustration from trying to figure out the API. To use it you will want to be running an IDE that supports reading of the stub files. These are the ones that I know support it:

• Visual Studio
• VSCode
• Pycharm
• Eclipse

I do not know if Thonny does but I really do not recommend using Thonny anyhow as it has an issue with the way it restarts the ESP32's which causes issues with the ESP32 having a core panic. I have attempted to work around the problem without any success and there is a whole other problem that gets thrown into the mix and that is if the ESP32 has built in USB CDC support and the way MicroPython is coded and not being able to perform a hard reset like can be done using the UART.

[mark-hoy]

I'm going to try out Visual Studio Code on my M1 Mac. I just have to get used to the key bindings.

I wonder if the V8/V9 LVGL code switch has the maintainers too busy getting the C code working to bother with Python right now.

[kdschlosser]

They don't have the time to invest in learning MicroPython. The person that wrote the official binding no longer works on the project and the code that was written to make it work is not all that easy to understand what is going on. It is a constant headache and it breaks very easily when changes are made to LVGL. I have been working on a hard coded version of it instead of having the binding code generated. there is not going to be a huge API change like what was seen going from 8 to 9 probably ever again so hard coding the binding would be a safer things to do. There is a lot of overhead in the way the current binding is written. I call it VooDoo magic code because not even an IDE is able to follow the data path through the code and with the lack proper debugging with micro controllers that kind of code is very hard to fix when it breaks.