Function lv_obj_set_style_transform_width 

pub unsafe extern "C" fn lv_obj_set_style_transform_width(
    obj: *mut lv_obj_t,
    value: i32,
    selector: lv_style_selector_t,
)

Make Widget wider on both sides with this value. Pixel and percentage (with lv_pct(x)) values can be used. Percentage values are relative to Widget’s width. Default: 0, inherited: No, layout: No, ext. draw: Yes. @param obj Pointer to Widget @param value Value to submit @param selector A joint type for lv_part_t and lv_state_t. Example values: - 0: means LV_PART_MAIN | LV_STATE_DEFAULT - LV_STATE_PRESSED - LV_PART_KNOB - LV_PART_KNOB | LV_STATE_PRESSED | LV_STATE_CHECKED