UI_Init very slow

[robkettridge]

Hello

We have a project in the works at the moment using EEZ-Studio with LVGL flow on an STM32 processor driving a small 2.5" screen. We have about 20 screens, 6 styles, 2 fonts, 5 small bitmaps. Nothing massively complicated. Just buttons and labels mostly.

The issue we are having is that executing UI_INIT takes about 11 seconds before the interface loads. We would really like to get this down considerably, or at least be able to show something on the screen whilst this is taking place. We're assuming that it's due to LVGL loading everything into RAM from ROM? Does it have to load every screen at start up? Is it possible to load screens on first use?

Are there any settings, or areas we should be looking at to speed this process up? We've done all the optimisations we can think of, and if anything it's getting slower.

Thanks

[mvladic]

It is true that currently EEZ Studio generates ui_init that will create all the screens in advance. I'm surprised it takes 11 seconds to create 20 screens. Fonts and bitmaps should be used from the ROM, so no preloading to RAM is required, I think.

Did you try to measure how much time it takes for each screen to be created? I think it would be interesting to do that. It can be done like this:

In ui.c modify ui_init:

void ui_init() {
    LV_LOG_USER("START");

    eez_flow_init(assets, sizeof(assets), (lv_obj_t **)&objects, sizeof(objects), images, sizeof(images), actions);

    LV_LOG_USER("END");
}

In screens.c modify create_screens:

void create_screens() {
    ui_create_groups();
    
    eez_flow_init_styles(add_style, remove_style);
    
    eez_flow_init_screen_names(screen_names, sizeof(screen_names) / sizeof(const char *));
    eez_flow_init_object_names(object_names, sizeof(object_names) / sizeof(const char *));
    eez_flow_init_group_names(group_names, sizeof(group_names) / sizeof(const char *));
    eez_flow_init_style_names(style_names, sizeof(style_names) / sizeof(const char *));
    
    lv_disp_t *dispp = lv_disp_get_default();
    lv_theme_t *theme = lv_theme_default_init(dispp, lv_palette_main(LV_PALETTE_BLUE), lv_palette_main(LV_PALETTE_RED), false, LV_FONT_DEFAULT);
    lv_disp_set_theme(dispp, theme);

    LV_LOG_USER("init");
    
    create_screen_main();

    LV_LOG_USER("main");

    create_screen_screen_a();
    
    LV_LOG_USER("a");
    
    create_screen_screen_b();

    LV_LOG_USER("b");

    create_screen_screen_c();

    LV_LOG_USER("c");
}

Printout example:

[User]	(0.093, +93)	 ui_init: START ui.c:187
[User]	(0.094, +1)	 create_screens: init screens.c:353
[User]	(0.099, +5)	 create_screens: main screens.c:357
[User]	(0.100, +1)	 create_screens: a screens.c:361
[User]	(0.101, +1)	 create_screens: b screens.c:365
[User]	(0.102, +1)	 create_screens: c screens.c:369
[User]	(0.103, +1)	 ui_init: END ui.c:191

So, in this case ui_init started at 0.093 sec and finished at 0.103 sec. So, 10 ms in total was required to initialize UI.