I have a question about vertical metrics metadata info, and variable/static fonts.
I have seen this topic mentioned here from time to time in past posts, but I’m unclear after reading those threads, on what the resolution is at the moment.
I am familiar with the idea of, for instance, setting values like winAscent and winDescent on an individual instance for export, via Custom Parameters.
Let’s say I did so, and exported static fonts, which then reflect those values.
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What happens if I then export a variable font of the same .glyphs file?
I presume the winAscent/descent values I just set are not present in the variable font file, because there was nothing connecting those metadata values to the masters?
Is it possible to set these values at the master level, and have them interpolated across the variable font design space?
And if so, is it possible to have the static fonts inherit those interpolated values, or do the static fonts still require them to be set instance-by-instance?
What is the best approach to handle changing vertical metrics in variable vs static? Does Glyphs support variable metrics at all, as of now? Are they supported by apps/web?
I want to change the x-height and descender for narrow styles, and ideally avoid difference between static and variable. The x-height doesn’t matter, I suppose, but the descender change appears to be quite important.
Those values need to go into the MVAR table. That is not supported in Glyphs, yet. And it would be most likely supported on the master level (not instances).
What is the roadmap for MVAR support in Glyphs outlining? Will this come soon or am I better of writing an export plugin that utilizes fonttools to write the MVAR table if I want that in my VFonts?
Edit:
I made a plugin that adds the MVAR table after export. It does work in my case but might be not perfectly working in all cases. But let me know if you want it as a basis draft for a potential implementation.
It’s currently no available publicly, as it is very specific and does not take care about potential differences in setups (non-generic), but I gave it to Georg in order for him to see if he can implement it directly into Glyphs.