David J. Perry wrote: >If I were to make a complete OT Greek font, with all the above as well >as the combinations already in Unicode, which would provide better >performance: substitutions or positioning via OT features? > There is a similar thread on the [EMAIL PROTECTED] mailing list. My argument is that you cannot expect positioning to be "more complete" because it will form some combinations with apparently less work. Regardless of whether you use substitution or positioning, it's the testing of the actual combinations, alone and in context, that is the bottleneck. The difference between the two methods (which can be characterized as "combination at the factory" and "combination at the installation site") are second order factors. In the case of CFF outlines, which have a notion of subroutine, the size difference is not that big. What is going to drive your choice is the ease of creating combination glyph vs. the ease of creating GPOS lookups in your font development environment, and how much you are willing to depend on Unicode/OpenType support in the target environment (I know some software that is more likely to handle substitutions than mark positioning).
Eric.
