Change arc widget - knob position issue if width in LV_PART_MAIN and LV_PART_INDICATOR are different

How-to
1

Description

I know you can change the knob size by using style padding

lv_obj_set_style_arc_width(arc, 20, LV_PART_MAIN | LV_STATE_DEFAULT);
lv_obj_set_style_arc_width(arc, 20, LV_PART_INDICATOR | LV_STATE_DEFAULT);
lv_obj_set_style_pad_left(arc, 40, LV_PART_KNOB | LV_STATE_DEFAULT);
lv_obj_set_style_pad_right(arc,40, LV_PART_KNOB | LV_STATE_DEFAULT);
lv_obj_set_style_pad_top(arc, 40, LV_PART_KNOB | LV_STATE_DEFAULT);
lv_obj_set_style_pad_bottom(arc, 40, LV_PART_KNOB | LV_STATE_DEFAULT);

but if you make the arc width PART_MAIN different to LV_PART_INDICATOR then the knob is offset from the indicator and as you move the knob around the arc it changes position relative to the arc. If the padding is set to 0 then as expected.

lv_obj_set_style_arc_width(arc, 40, LV_PART_MAIN | LV_STATE_DEFAULT);
lv_obj_set_style_arc_width(arc, 20, LV_PART_INDICATOR | LV_STATE_DEFAULT);
lv_obj_set_style_pad_left(arc, 40, LV_PART_KNOB | LV_STATE_DEFAULT);
lv_obj_set_style_pad_right(arc,40, LV_PART_KNOB | LV_STATE_DEFAULT);
lv_obj_set_style_pad_top(arc, 40, LV_PART_KNOB | LV_STATE_DEFAULT);
lv_obj_set_style_pad_bottom(arc, 40, LV_PART_KNOB | LV_STATE_DEFAULT);

Changing the KNOB offset does not help. The problem I think is if you change the width of the indicator it is reference from the left side of PART_MAIN not the center of PART_MAIN which results in the above observation.