LVGL can't render normally with my monochrome UI

How-to
1

What do you want to achieve?

Although the code can run successfully in simulator, it can’t run normally on my board.

What have you tried so far?

I try to modify the UI code snippet, but it still can’t work normally. It seems that it is a problem about the rendering, because of the wrong data point by px_map in disp_flush() at lv_port_disp.c.

Code to reproduce

    lv_theme_t * mono_theme;
    mono_theme = lv_theme_mono_init(lv_display_get_default(), true, &lv_font_montserrat_14);
    lv_display_set_theme(lv_display_get_default(), mono_theme);
    
    static lv_style_t style;
    lv_style_init(&style);
    lv_style_set_text_color(&style, lv_color_white());
    lv_style_set_bg_color(&style, lv_color_black());

    lv_obj_add_style(lv_screen_active(), &style, LV_PART_MAIN);
       
    lv_obj_t * btn1 = lv_button_create(lv_screen_active());
    lv_obj_set_pos(btn1, 10, 10);                         
    lv_obj_set_size(btn1, 60, 30); 
    
    lv_obj_t * label2 = lv_label_create(btn1);
    lv_label_set_text(label2, "btn1");

Screenshot and/or video

IMG_20250717_094305
IMG_20250717_0943051920×1440 110 KB

Environment

  • MCU/MPU/Board: AT32F403AVGT7(just like STM32F4xxx)
  • Diaplay panel: 0.96’ monochrome OLED(128x64) drivered by SSD1306
  • LVGL version: 9.3
2

It seems that some precautions need to be considered when write a monochrome UI. Below is another UI code, it work normally:

    lv_theme_t * theme = lv_theme_mono_init(lv_display_get_default(), true, NULL);
    lv_display_set_theme(lv_display_get_default(), theme);
    
    /*Create a list*/
    lv_obj_t * list1 = lv_list_create(lv_screen_active());
    lv_obj_set_size(list1, 100, 60);
    lv_obj_set_style_bg_color(list1, lv_color_hex(0x000000), LV_PART_MAIN);
    lv_obj_center(list1);
    
    lv_obj_t * label1 = lv_list_add_text(list1, "File");
    lv_obj_set_style_text_color(label1, lv_color_hex(0xffffff), LV_PART_MAIN);
    lv_obj_t * label2 = lv_list_add_text(list1, "Setting");
    lv_obj_set_style_text_color(label2, lv_color_hex(0xffffff), LV_PART_MAIN);

IMG_20250717_134711
IMG_20250717_1347111920×1440 87.2 KB

3

Everything seems to be ok.

    lv_theme_t * theme = lv_theme_mono_init(lv_display_get_default(), true, NULL);
    lv_display_set_theme(lv_display_get_default(), theme);
    
    /*Create a list*/
    lv_obj_t * list1 = lv_list_create(lv_screen_active());
    lv_obj_set_size(list1, 100, 60);
    lv_obj_set_style_bg_color(list1, lv_color_hex(0x000000), LV_PART_MAIN);
    lv_obj_center(list1);
    
    lv_obj_t * label1 = lv_list_add_text(list1, "File");
    lv_obj_set_style_text_color(label1, lv_color_hex(0xffffff), LV_PART_MAIN);
    lv_obj_t * label2 = lv_list_add_text(list1, "Setting");
    lv_obj_set_style_text_color(label2, lv_color_hex(0xffffff), LV_PART_MAIN);
    lv_obj_t * label3 = lv_list_add_text(list1, "Music");
    lv_obj_set_style_text_color(label3, lv_color_hex(0xffffff), LV_PART_MAIN);
    lv_obj_t * label4 = lv_list_add_text(list1, "Video");
    lv_obj_set_style_text_color(label4, lv_color_hex(0xffffff), LV_PART_MAIN);

1752731682732
17527316827321920×864 117 KB