Is there any way to get a callback when screen is competely drawn?

Feature request
1

It will be useful to have a callback when screen is completely ready to be presented for user. For example, when backlight is enabled during boot it is visible (for a couple hundred milliseconds, maybe) that screen is populated with random noise, then lvgl redraws screen in a couple of steps. This effect is a bit undesirable and it can be avoided by disabling backlight during initialization and enabling it a couple of milliseconds after initialization. So my question is: is there any way to reliably know when screen is completely drawn and ready?

2

monitor_cb is called every time the display finishes refreshing, so you should be able to use that and turn on the backlight the first time it’s called.

3

Wow, thanks, that is exactly what I wanted.

In display driver initialization…

disp_drv.monitor_cb = ui_ll_redraw_cb;

And later…

static void ui_ll_redraw_cb(lv_disp_drv_t *disp_drv, uint32_t time, uint32_t px)
{
    board_lcd_bl_on();
    disp_drv->monitor_cb = NULL;
}

Does the trick.