Used ESP32 and you miss Images — LVGL documentation
and ofcourse on rendering routine is pixel readed from flash , recalculated with alpha and background and writed into ram buffer only new two bytes.
I mean most important here is on big width images cant cache between flash and core handle read lines without recaching. My plan for monday test is split image into more segments where width pass cache size for one buff. And here i mean 30 lines is perfect.
Too overhead from 16 areas isnt problem .
EDIT: I read more about caching and seems fetch is only 32bytes then size and split images is not relevant. Too prefetch on ESP isnt offloaded then …?