Recursive Font, multiple axes, fontspec, texlive 2022

Question

I've installed texlive 2022 pretest and play around with it.

I've found a font called Recursive, see here: https://fonts.google.com/specimen/Recursive#about and the website here: https://www.recursive.design/ . According to the manual here https://www.recursive.design/assets/arrowtype-recursive-sansmono-specimen.pdf there are multiple axes.

I've found this explanation how to use axes of font features, see https://tex.stackexchange.com/a/591485/4736 .

But I fail to get italic axis working.

The above mentioned font comes with a variable font file, called Recursive-VariableFont_CASL,CRSV,MONO,slnt,wght.ttf, which I renamed to Recursive-VariableFont.ttf.

I fail to find any documentation about +axis=. Where is this documented? I'm using fontspec v2.8a.

What I've tried so far:

\documentclass[a4paper,12pt]{article}
\usepackage{fontspec}
\defaultfontfeatures{%
   RawFeature={+axis={CRSV}}%, slnt, CASL, wght}},
   % RawFeature={+axis={wght=100}},
   % RawFeature={+axis={mono=0}},
   % RawFeature={+axis={slnt=0}},
   % RawFeature={+axis={CASL=0}},
}
\setmainfont[
   ItalicFont=Recursive-VariableFont.ttf,
   BoldFont=Recursive-VariableFont.ttf,
   BoldItalicFont=Recursive-VariableFont.ttf,
    BoldFeatures={RawFeature={+axis={wght=500}}},
    BoldItalicFeatures={RawFeature={+axis={wght=900}}},
    ItalicFeatures = {RawFeature={+axis={CRSV=1}}}
    ]{Recursive-VariableFont.ttf}

    \setmonofont{Recursive-VariableFont.ttf}[%
    RawFeature={+axis={mono=1}}]


    
\begin{document}
\par the quick brown fox jumps over the lazy dog.
\par\textit{the quick brown fox jumps over the lazy dog.}
\par\textbf{the quick brown fox jumps over the lazy dog.}
\par\textbf{\textit{the quick brown fox jumps over the lazy dog.}}

\texttt{Es irrt der Mensch..}

\end{document}
% Local Variables:
% TeX-engine: luatex
% End:

The output:

Running `LaTeX' on `variable-recursive' with ``lualatex --jobname=variable-recursive  -file-line-error   --synctex=1 -interaction=nonstopmode variable-recursive.tex''
This is LuaHBTeX, Version 1.15.0 (TeX Live 2022) 
 restricted system commands enabled.
(./variable-recursive.tex
LaTeX2e <2021-11-15> patch level 1
 L3 programming layer <2022-02-24>
(/local/texlive/2022/texmf-dist/tex/latex/base/article.cls
Document Class: article 2021/10/04 v1.4n Standard LaTeX document class
(/local/texlive/2022/texmf-dist/tex/latex/base/size12.clo))
(/local/texlive/2022/texmf-dist/tex/latex/fontspec/fontspec.sty
(/local/texlive/2022/texmf-dist/tex/latex/l3packages/xparse/xparse.sty
(/local/texlive/2022/texmf-dist/tex/latex/l3kernel/expl3.sty
(/local/texlive/2022/texmf-dist/tex/latex/l3backend/l3backend-luatex.def)))
(/local/texlive/2022/texmf-dist/tex/latex/fontspec/fontspec-luatex.sty
(/local/texlive/2022/texmf-dist/tex/latex/base/fontenc.sty)
(/local/texlive/2022/texmf-dist/tex/latex/fontspec/fontspec.cfg)))
(./variable-recursive.aux)
(/local/texlive/2022/texmf-dist/tex/latex/base/ts1cmr.fd) [1{/local/texlive/2022/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (./variable-recursive.aux))
 406 words of node memory still in use:
   3 hlist, 1 vlist, 1 rule, 2 glue, 3 kern, 1 glyph, 4 attribute, 48 glue_spec, 4 attribute_list, 1 write nodes
   avail lists: 2:49,3:12,4:1,5:96,6:10,7:460,9:34
</home/AW/.fonts/r/Recursive-VariableFont.ttf></home/AW/.fonts/r/Recursive-VariableFont.ttf></home/AW/.fonts/r/Recursive-VariableFont.ttf></home/AW/.fonts/r/R
ecursive-VariableFont.ttf></home/AW/.fonts/r/Recursive-VariableFont.ttf>
Output written on variable-recursive.pdf (1 page, 41296 bytes).
SyncTeX written on variable-recursive.synctex.gz.
Transcript written on variable-recursive.log.

TeX Output finished at Tue Mar  1 18:03:24

But no italic letters in the pdf:

Any ideas?

Answer 1

The axis feature is documented in the luaotfload manual. Mostly this was already present in TeX Live 2021, but there it only worked with the node shaper and not the HarfBuzz based harf shaper. In TeX Live 2022 we extended it to also work with HarfBuzz. As you noticed the node implementation doesn't like uppercase axis names, but you can work around that in TL 2022 by switching to HarfBuzz:

\documentclass[a4paper,12pt]{article}
\usepackage{fontspec}

\setmainfont[
   Renderer=HarfBuzz,
   ItalicFont=Recursive-VariableFont.ttf,
   BoldFont=Recursive-VariableFont.ttf,
   BoldItalicFont=Recursive-VariableFont.ttf,
    BoldFeatures={RawFeature={+axis={wght=500}}},
    BoldItalicFeatures={RawFeature={+axis={wght=900}}},
    ItalicFeatures = {RawFeature={+axis={CRSV=1}}}
    ]{Recursive-VariableFont.ttf}

    \setmonofont{Recursive-VariableFont.ttf}[%
    Renderer=HarfBuzz,
    RawFeature={+axis={MONO=1}}]


    
\begin{document}
\par the quick brown fox jumps over the lazy dog.
\par\textit{the quick brown fox jumps over the lazy dog.}
\par\textbf{the quick brown fox jumps over the lazy dog.}
\par\textbf{\textit{the quick brown fox jumps over the lazy dog.}}

\texttt{Es irrt der Mensch..}

\end{document}