@Kovid, arh, I try to add my idea to append the second line height inside "get_spine_width().linear()", but is such a intricated things, I want to clarifed my idea so that you try on your side (and if I succeed before, sweet).
Code:
def linear(f: float):
return lc.min_spine_width + int(max(0, min(f, 1)) * (lc.max_spine_width - lc.min_spine_width - second_line_height))