How to add minor division lines to a chart?

How-to
21

If I got it correctly, it uses two levels of enums, a primary (a class pointer) which indicates the implementing class and a secondary which indicates the case within that implementing class.

This looks reasonable to me and will allow you to clearly document the call back by cases.

Adding #define constants may also improve (?)

#define LV_OBJ_CLASS &lv_obj_class
#define OV_CHART_CLASS &lv_chart_class

22

I just added it. See this example: Examples — LVGL documentation

And this commit.