Kent LewMay 19, 2025

*DrawBot bug alert*:

While running out extensive proofing texts, I realized that GSUB and GPOS are not being applied to FormattedString() if it runs to more than three pages.

OTFeatures and, most importantly, *kerning* only get applied to the last few pages, and not the initial pages.

Issue filed and confirmed: https://github.com/typemytype/drawbot/issues/585

@justvanrossum identified the bug as part of CoreText.

FormattedString(openTypeFeatures) not applied consistently · Issue #585 · typemytype/drawbot

If I have a text that lays out on three pages or less, then the OT Features (ex. {liga}) get applied throughout. If the text is longer than three pages, then only the last three pages have features...

GitHub
Show threadIndra Kupferschmid 💙💛May 19, 2025
@kentlew @justvanrossum Das ist ja voll toll!
Show threadKent LewMay 19, 2025

@kupfers @justvanrossum Here I was thinking I was so clever now, leveraging DrawBot instead of my old InDesign CS6 templates.

Imagine me poring over proofs and second-guessing all the kerning I’d done ten years ago on the original fonts, thinking I had to tweak more than I’d been intending. 😬

Until: hey, wait a minute … 🤨

Show threadTiro Typeworks
@kentlew Welcome to my morning. Spent a bunch of time making updates to MATH cut-in kerning data only to find that recompiling TeX documents doesn’t show any difference from previous version.
May 19, 2025 at 9:37pmWeb
Show threadKent LewMay 19, 2025
@TiroTypeworks Crazy-making! 🤪
Show threadTiro TypeworksMay 21, 2025

@kentlew Today, I ended up making a diagnostic font to confirm what the heck I am seeing in the output.

Turns out a couple of the key test documents simply are not recompiling at all, so what I am seeing is always the old PDF with the embedded earlier version of the font. Grrrr.

Show threadKent LewMay 21, 2025

@TiroTypeworks That sounds frustrating. Tools that you can’t be sure you can rely on are less-than-helpful tools. 🤨

(diagnostic font is good trick, but unfortunate to have to need.)

Show threadTiro TypeworksMay 21, 2025
@kentlew Sorted now. A lot of TeX is still pretty opaque to me, so it is difficult for me to debug test docs for math layout. Thankfully, I have access to some people who can figure this out.