Hello -
The Adobe Type Team has been working to extend the OpenType Feature File Specification to add direct support for Variable fonts. We are introducing the specification changes in two stages:
- Stage 1 adds support for variable values
- Stage 2 will add support for feature variations (such as swapping one glyph for another based on axis range conditions)
The stage 1 changes are now in a public review period that will end January 15th 2025. The review repository is:
We expect these changes will be of most interest to tool developers and designers of fonts with extensive or unusual GSUB or GPOS features. The top-level README of the review repository has more information on the review process and guidance on whether and how you may want to participate. Everyone is of course free to discuss this topic here in this forum as they like, but we are more likely to respond to issues and discussions in the repository.
Note that while Adobe has no control over how other toolsets, including Glyphs, adapt the feature file format, we have tried to take the wider needs of the font development community into account in developing these extensions. We are also aware that there has already been fragmentation in this space, and the Glyphs application includes some extensions in this area that use a different syntax. (Other tools have also implemented their own syntax.) However, it is still our hope that these different approaches might still be unified and that feature files can continue to be more or less portable between different font development toolchains.
Thank you,
Skef Iterum
Adobe, Inc.
