Arc main is visible under the indicator


Im trying to create simple arc and color it. I changed the color of the indicator and now the main arc is partially visible at the edges (see picture).

What MCU/Processor/Board and compiler are you using?

The program runs on a RPI4 and is displayed on a GC9A01 which is connected via SPI. LVGL uses the linux framebuffer.

What LVGL version are you using?

The newest one, I cloned it today.

What do you want to achieve?

A simple arc cause Im new to LVGL and trying to learn the basics.

What have you tried so far?

Increasing the width of the indicator, using a different color…

Code to reproduce

    // Fuel level
    lv_obj_t* fuel = lv_arc_create(lv_screen_active());
    lv_obj_remove_style(fuel, NULL, LV_PART_KNOB);
    lv_obj_remove_flag(fuel, LV_OBJ_FLAG_CLICKABLE);
    lv_obj_set_size(fuel, 230, 230);
    lv_arc_set_rotation(fuel, 90);
    lv_arc_set_bg_angles(fuel, 30, 150);
    lv_arc_set_value(fuel, 50);

    // Fuel level style
    lv_style_t fuelStyle;
    lv_style_set_arc_rounded(&fuelStyle, false);
    lv_obj_add_style(fuel, &fuelStyle, LV_PART_MAIN);

    // Fuel level style 2
    lv_style_t fuelStyle2;
    lv_style_set_arc_rounded(&fuelStyle2, false);
    lv_style_set_arc_width(&fuelStyle2, lv_obj_get_style_arc_width(fuel, LV_PART_MAIN) + 1);
    lv_style_set_arc_color(&fuelStyle2, lv_color_hex(0x873e23));
    lv_obj_add_style(fuel, &fuelStyle2, LV_PART_INDICATOR);

Screenshot and/or video

Here is a screenshot of what I mean. Especially around the pivot point of the arcs you can see the white main arc clearly along the edges. Even if I look at the display from 50cm away its clearly noticeable and annoying.
Unfortunately it looks extremely weak on the picture. IRL it is way stronger and definitely noticeable, the camera simply doesnt capture the truth that well…