@ohbendy May be try doing it in a simpler lookup. E.g. without context and no mark filtering to see if deletion works or not. @simoncozens

"#HarfBuzz Study: Introducing #HarfRust"

https://docs.google.com/document/d/1aH_waagdEM5UhslQxCeFEb82ECBhPlZjy5_MwLNLBYo/preview

@TiroTypeworks I can’t really tell if it is a TeX code issue or a font issue without seeing both.

@TiroTypeworks Depends on how the symbol is used. If the integral is used as a big operator then it would be the advance width of the integral. If it is used as a regular symbol then it would be like any another symbol (advance width + italic correction + math cut ins). This is determined by the macro (TeX command) that the symbol.

@iorsh MicroTeX seems to hard-code Computer Modern fonts and does not support OpenType MATH or even changing the font at all.

There are several math renderers that support OpenType MATH and can be more suitable for such project, but I have not tested most of them myself:

https://github.com/cdelker/ziamath
https://github.com/math-blocks/math-blocks
https://github.com/mgriebling/SwiftMath

@elih @TiroTypeworks

@rajeesh Yes, I don’t think any work have been done to support COLRv1. But better ask on luaotfload tracker as I’m not currently closely involved with the project.

@iorsh FontForge has complete support for editing MATH table. The UI is clumsy at places, but no more clumsier than FontForge UI in general. I used it to build several math fonts, and I think a few open source font projects still use it. @TiroTypeworks

@TiroTypeworks It might depend on how the symbol is used (it might be explicitly asking to not stretch the anchor), but the engine has no restrictions in this area AFAIK @iorsh

@iorsh TeX engines in general don’t provide APIs, they are monolithic command line tools. People come up with ways to run TeX as some long running process and feed it code snippets and get DVI in return. I’m not very familiar with this and whether it can be done with XeTeX or not. @TiroTypeworks @rajeesh

@TiroTypeworks No worries. The original cut-ins implementation was indeed buggy (partly my fault, and partly the spec’s). David M. Jones did a great job fixing it, including inferring the actual intent of the spec. @iorsh

@TiroTypeworks I wrote some of the MATH support in XeTeX when I was the maintainer, but most of the MATH support (like the rest of XeTeX) was written by Jonathan Kew. Some of the recent fixes are by David M. Jones. @iorsh

@TiroTypeworks as for the subscript j moving down, it might be caused by subscriptTopMax or subscriptBaselineDropMin constants (https://github.com/notofonts/math/blob/main/documentation/building-math-fonts/index.md#subscriptshiftdown-subscripttopmax-subscriptbaselinedropmin), you can confirm by observing if other glyphs with ascenders move down too @iorsh

@TiroTypeworks I’m afraid neither LuaTeX, XeTeX, or Word apply math cut-ins for large operators. @iorsh

@moyogo @anselmschueler HarfBuzz will enable also frac on the number-fraction slash-number string, so a font with only frac feature will also work.

Any one else seeing weird glyph placement (as in glyphs being displaced up and down left and right) when using Arabic color (OT-SVG) fonts in InDesign?

I tried reporting it but it didn't get any response, and now I wonder if it is a general issue or something in my fonts is triggering it: https://indesign.uservoice.com/forums/601180-adobe-indesign-bugs/suggestions/49040762-in-arabic-opentype-svg-fonts-glyphs-shift-seeming

@jenskutilek https://www-cs-faculty.stanford.edu/~knuth/programs.html#:~:text=HALFTONE

@jenskutilek Not sure if that is what you are looking for, but Knuth wrote an article on generating halftone images using METAFONT fonts: Fonts for Digital Halftones (https://tug.org/TUGboat/tb08-2/tb18knut.pdf)

(His Digital Typography book has an updated version of the article, in case you have access to the book)

@TiroTypeworks see my findings in https://github.com/googlefonts/ufo2ft/issues/808

"#HarfBuzz Study: Subsetter"

https://docs.google.com/document/d/1_vZrt97OorJ0jA1YzJ29LRcGr3YGrNJANdOABjVZGEs/preview

#HarfBuzz 11.0.0 is out with lots of goodies. Among them is integration with the Fontations / Skrifa Rust font library, lots of optimizations, and new APIs:

https://github.com/harfbuzz/harfbuzz/releases/tag/11.0.0