We have a problem we struggled with for many years without success and face now one more time, I am hoping that someone on the list may have a solution.
For fonts that have both Arabic and Latin scripts we need the space character to be narrower in Arabic, especially in bolder styles. When we use an existing Latin as a companion, the space character becomes wider than required for Arabic. In the past, we added a narrower “space.arab" glyph and a substitution lookup to replace the Latin space with the Arabic space. This substitution works in Word but not in InDesign. We have tried placing the substitution lookup in <calt>, <rclt>, <ccmp>, as well as combinations of these features; ALL of these substitute correctly in Word, and NONE of them work in InDesign.
We tried a slightly different approach now by making the narrow space as the default and changing that to the wider space in Latin script via a substitution lookup in the <ccmp> feature. We think this is a better approach since Arabic is the primary script in these fonts. This did not work and the narrow space is applied in both scripts in Word and in InDesign.
Does anyone have information to shed light on this issue and solve our problem? Did anyone succeed in applying two different space characters to two scripts in the same font?
Thanks in advance.