On 2024-11-04 01:35, Mikael Sundqvist wrote:
> \startluacode
>
> local classes = fonts.protrusions.classes
> local vectors = fonts.protrusions.vectors
>
> classes.rik = {
>      vector = 'rik',
>      factor = 1,
> }
>
> vectors.rik = table.merged (
>      vectors.quality,
>      {
>        [0x0054] = { 0.35, 0 }, -- T
>      })
>
> \stopluacode

That, of course, works (I would use 0.175 for Libertinus) but as you 
point out does not distinguish roman and italic.

Perhaps instead of protrusion there is something that can be done with 
the bounding box of specific characters.

-- 
Rik