How to set background or default font for a widget in V8.2

How-to
1

Hello,
I have just recently started to work with LVGL and I use the Visual Studio 2019 simulator on windows to see results faster then porgramming the actual device. This problem I have does not cause the simulator to fail but the results are not what expected. On the actual devide I cannot compile it without error.

I am using a roller and I need a rather large font size so I am using the montserrat_48 for the selected font in the roller. I cannot find a way to increase the size of the fonts below and above the selected numbers. I understad that the background font size determines what that size of those fonts are. I could not find a way to overrwrite the background font just for the widget. The only way I could do it is by setting the #define LV_FONT_DEFAULT &lv_font_montserrat_30 in the lv_config.h file. Of course this messes up everything else so it is not a viable option.

I found a post for the V7.x as a solution which was like this but with a different font
lv_style_set_text_font(&style_sel, LV_STATE_DEFAULT, &lv_font_montserrat_30);
but this crashes the compiler so it does not work, it seems to be too many arguments.

I tried this with compile error:
static lv_style_t style_sel;
lv_style_init(&style_sel);
lv_style_set_text_font(&style_sel, LV_STATE_DEFAULT, &lv_font_montserrat_30);
lv_style_set_text_font(&style_sel, &lv_font_montserrat_48);

This works in both the simulator and the hardware but not the results I want with all the styling seem to follow the default character which means the selected numbers are sitting in a smaller selection box starting to clip the top of the selected numbers:
static lv_style_t style_sel;
lv_style_init(&style_sel);
lv_style_set_text_font(&style_sel, &lv_font_montserrat_48);

Thank you for your help in advance
Andrew

2

If someone find this also a problem I actually managed to work it out myself.
I created another style and I found that I can set it with the LV_PART_MAIN like this

 static lv_style_t style_sel;
 lv_style_init(&style_sel);
 lv_style_set_text_font(&style_sel, &lv_font_montserrat_48);

 static lv_style_t style_def;
 lv_style_init(&style_def);
 lv_style_set_text_font(&style_def, &lv_font_montserrat_30);

 lv_obj_t *roller;
 roller = lv_roller_create(lv_scr_act());
 lv_roller_set_options(roller, optsTens, LV_ROLLER_MODE_INFINITE);
 lv_roller_set_visible_row_count(roller, 2); 
 lv_obj_set_width(roller, 60);
 lv_obj_add_style(roller, &style_sel, LV_PART_SELECTED);
 lv_obj_add_style(roller, &style_def, LV_PART_MAIN);

Andrew