How to switch the built-in themes?

How to
1

What do you want to achieve?

I just want to switch the built-in themes.

Others

  • SquareLine Studio version:
    1.5.1
  • Operating system:
    Linux
  • Target hardware:
    ESP32-S3

What have you tried so far?

I have carefully studied the example from the documentation

but didn’t find anything similar on how to switch the built-in themes.
I tried to apply the method from the example and came to the conclusion that it greatly complicates the code.
In an existing project, I need to change the properties of all the elements.
This is especially true for checkboxes, drop-down lists and etc.
How to apply the properties of embedded themes when switching via

ui_theme_set(0); for light theme or
ui_theme_set(1); for dark theme

in a simple way?
The macro #define LV_THEME_DEFAULT_DARK 0 in the settings file lv_conf.h in the LVGL library is used only once in the lv_display_create() function.

#if LV_USE_THEME_DEFAULT
    if(lv_theme_default_is_inited() == false) {
        disp->theme = lv_theme_default_init(disp, lv_palette_main(LV_PALETTE_BLUE), lv_palette_main(LV_PALETTE_RED),
                                            LV_THEME_DEFAULT_DARK, LV_FONT_DEFAULT);
    }
    else {
        disp->theme = lv_theme_default_get();
    }
#elif LV_USE_THEME_SIMPLE
    if(lv_theme_simple_is_inited() == false) {
        disp->theme = lv_theme_simple_init(disp);
    }
    else {
        disp->theme = lv_theme_simple_get();
    }
#endif

Why not let the user change the theme, colors and font at runtime at the initialization stage, eg this?

lv_display_t * lv_display_create(int32_t hor_res, int32_t ver_res, bool dark_theme, lv_palette_t primary, lv_palette_t secondary, const lv_font_t *font_default)
{
   ...
#if LV_USE_THEME_DEFAULT
    if(lv_theme_default_is_inited() == false) {
        disp->theme = lv_theme_default_init(disp, lv_palette_main(primary), lv_palette_main(secondary),
                                            dark_theme, font_default);
    }
    else {
        disp->theme = lv_theme_default_get();
    }
#elif LV_USE_THEME_SIMPLE
    if(lv_theme_simple_is_inited() == false) {
        disp->theme = lv_theme_simple_init(disp);
    }
    else {
        disp->theme = lv_theme_simple_get();
    }
#endif
   ....
}

// User Code
    lv_font_t *my_font = lv_binfont_create("L:/fonts/main14.bin");
    static lv_disp_t *disp;
    disp = lv_display_create(TFT_WIDTH, TFT_HEIGHT, true, LV_PALETTE_BLUE, LV_PALETTE_RED, my_font);
    lv_display_set_buffers(disp, buf1, buf2, _BUF_SIZE * sizeof(lv_color_t), LV_DISPLAY_RENDER_MODE_PARTIAL);
    lv_display_set_flush_cb(disp, my_disp_flush);

Or, in order not to complicate the code and make edits in the entire documentation, just cut this code fragment

#if LV_USE_THEME_DEFAULT
    if(lv_theme_default_is_inited() == false) {
        disp->theme = lv_theme_default_init(disp, lv_palette_main(primary), lv_palette_main(secondary),
                                            dark_theme, font_default);
    }
    else {
        disp->theme = lv_theme_default_get();
    }
#elif LV_USE_THEME_SIMPLE
    if(lv_theme_simple_is_inited() == false) {
        disp->theme = lv_theme_simple_init(disp);
    }
    else {
        disp->theme = lv_theme_simple_get();
    }
#endif

from the functionv_display_create() and insert the display driver initialization examples in the code user

// User Code
    lv_font_t *my_font = lv_binfont_create("L:/fonts/main14.bin");
    static lv_disp_t *disp;
    disp = lv_display_create(TFT_WIDTH, TFT_HEIGHT);

#if LV_USE_THEME_DEFAULT
    if(lv_theme_default_is_inited() == false) {
        disp->theme = lv_theme_default_init(disp, llv_palette_main(LV_PALETTE_BLUE), lv_palette_main(LV_PALETTE_RED),
                                            true, my_font); // or false for light thene
    }
    else {
        disp->theme = lv_theme_default_get();
    }
#elif LV_USE_THEME_SIMPLE
    if(lv_theme_simple_is_inited() == false) {
        disp->theme = lv_theme_simple_init(disp);
    }
    else {
        disp->theme = lv_theme_simple_get();
    }
#endif

    lv_display_set_buffers(disp, buf1, buf2, _BUF_SIZE * sizeof(lv_color_t), LV_DISPLAY_RENDER_MODE_PARTIAL);
    lv_display_set_flush_cb(disp, my_disp_flush);

then in project the theme will not have to be initialized again

void ui_init(void)
{
    lv_disp_t * dispp = lv_display_get_default();
    lv_theme_t * theme = lv_theme_default_get();
    lv_disp_set_theme(dispp, theme);
    ui_main_screen_init();
    ui____initial_actions0 = lv_obj_create(NULL);
    lv_obj_add_event_cb(ui____initial_actions0, ui_event____initial_actions0, LV_EVENT_ALL, NULL);

    lv_disp_load_scr(ui____initial_actions0);
    lv_disp_load_scr(ui_main);
}

and the default font may be custom rather than built-in from the start.

And why is it still necessary to edit the project file manually in order to change the default theme and change the primary and secondary colors?

    "theme_dark": true,
    "theme_color1": 15,
    "theme_color2": 0,