Lanistor

@hlhr202 Still cannot.

> Cool will try this when I find some time. Leaving this open for a while so I don't forget! I don't know if it's the best way, let me...

> @lanistor Another idea: Afaik LVGL also supports grayscale (8 bit). You could use two buffers, one as a draw buffer for LVGL and another that you transfer into then...

Sorry, i havn't start on it yet, for Busying in mass production of products.

> Lanistor we 've been working into LVGL also for a client needs using a v7 clone. You can follow our efforts here: https://github.com/martinberlin/lv_port_esp32-epaper/ Target is an Eink Kaleido 6"...

> > I found another way for optimizing: rendering screen on cpu that does not contain ui thread, this speed up a lot. > > That sounds very interesting. When...

> Is this an `lv_btn` with the default theme? If so, it has a slight shadow which increases its draw area. See the grey line here:  No, it's just...

> Hm, it shouldn't be the default behavior. > > Which LVGL version do you use? > > What if you call `lv_obj_remove_style_all(obj)` right after creating that widget? Using 8.x...

This problem still exists, how should I solve it?

> If you can use a debugger (or printf-s) could you check what happens in [_lv_inv_area](https://github.com/lvgl/lvgl/blob/master/src/core/lv_refr.c). This is the final functions to mark an area as invalidated. Does the input...