Need control of baseline stretching

[r12a]

It is very common in Arabic script to stretch words or phrases to a particular width (eg. to match a Latin translation or transcription above or below). This is achieved by lengthening the connections between letters, and to some extent by use of wide glyph variants, etc. The rules for which part of the text to stretch and how far are complicated - this is not the even spacing that usually occurs in tracked Latin text. There are currently no mechanisms for managing this process effectively in HTML/CSS.

[r12a]

The first comment in this issue contains text that will automatically appear in the Arabic & Persian gap-analysis document as a subsection with the same title as this issue. Any edits made to that comment will be immediately available in the document. Proposals for changes or discussion of the content can be made in comments below this point.

[xfq]

See also the last paragraph of https://r12a.github.io/scripts/arab/arb.html#justification