/* Join two areas into a third which involves the other two  */
void _lv_area_join(lv_area_t *a_res_p, const lv_area_t *a1_p, const lv_area_t *a2_p)
/* Join two areas into a third which involves the other two  */
void _lv_area_join(lv_area_t *a_res_p, const lv_area_t *a1_p, const lv_area_t *a2_p)
{
    a_res_p->x1 = LV_MIN(a1_p->x1, a2_p->x1);
    a_res_p->y1 = LV_MIN(a1_p->y1, a2_p->y1);
    a_res_p->x2 = LV_MAX(a1_p->x2, a2_p->x2);
    a_res_p->y2 = LV_MAX(a1_p->y2, a2_p->y2);
}