Lvgl buffer variable

I am integrating LVGL library for my college project and i need a little more understanding for how the draw_buff gets populated…
So once i call the lv_demo_widgets()
I see that its setting active screen and all other functions.
But i am not able to find at exactly which function call the object gets filled in the draw buffer.
I tried to search for the draw_buffer in an example code but i wasnt able to find it called or mentioned in the code…

Can someone please help.
Thanks in advance!

The drawing operation of LVGL is located in the _lv_disp_refr_timer function of lv_refr.c. Here LVGL will count the required redrawing area on the screen and send drawing events LV_EVENT_DRAW_XXX to the component located in the redrawing area. When the component receives the drawing event, it will Call the lv_draw_xxx method to draw. Specifically, you can try single-step debugging for tracking analysis.