Formally define the method of interpreting lookups
be5invis opened this issue · 2 comments
be5invis commented
- GSUB
- How are the substitution performed?
- How are the cluster map maintained?
- GPOS
- How are the positioning method maintained?
mhosken commented
These questions are too big and vague to be answered directly. Could you break down your questions?
be5invis commented
@mhosken
I am referring this question that I twitted: https://twitter.com/belleveinvis/status/1072886672444993537
From @tiroj:
Correct. There's never been an implementation specification for OpenType Layout, only a data format specification. Not only is interpretation of lookups not specified, nor is run segmentation and other dependent or dependency-creating aspects.
From @behdad:
There's an implied algorithm but the fine details are not written down in the standard.