Simon Cozens

If you're saying that the database is purely factual (which I think I agree with), I'm not sure that you can also say that it you require its users to...

Weirder and weirder. In `PairPosBuilder`, we create a separate builder for each value format: https://github.com/fonttools/fonttools/blob/d5a08b3b96f405b0fdca42e3f1f6baa32c59c687/Lib/fontTools/otlLib/builder.py#L1401-L1405 This is a `ClassPairPosSubtableBuilder`, which does its work by calling `buildPairPosClassesSubtable`. But `buildPairPosClassesSubtable` explicitly handles...

Right, exactly. They would go in the same subtable were it not for the difference in value record formats. However, we can (and should) overcome that difference by promoting the...

> I wonder if we could find a way to do the value format merging only when required such as in this case, but otherwise keep the subtables split by...

Masters are at Thin: Weight=26 Width=100 Black: Weight=170 Width=100 Condensed Extra Thin: Weight=26 Width=68 Condensed Extra Black: Weight=170 Width=68 Regular: Weight=78 Width=100 Desired instance is at: Condensed: Weight=26 Width=100

Sorry, desired should be Weight=78 Width=68. Regular is the default. And I was wrong about my hunch. This isn't just a UFO interpolation issue; a variable font generated from these...

But it does work with mutatormath.

It also works correctly when exporting from Glyphs. Maybe better to say that varLib is the only model where it doesn’t work!

> Probably the instance Weight: 78, Width: 68 will look like Weight 78, Width 100. This is not a good solution, but it questions "it works" I just tried it...

Trying to understand the scope of this. At the very least: - We need to implement Structured PDF in libtexpdf. - We need to implement Tagged PDF in libtexpdf. -...