- dev-luatex - NTG Mailing Lists

Unicode math: italic correction at the end of the math list
by Petr Olsak 28 Apr '25

28 Apr '25

Hello I suppose that the luatex binary is fixed for TeXlive 2025, so I can open an additional problem and I won't disturb you while finalizing the binaries:). Use this test file: ------------------- \input luaotfload.sty \font\f=[latinmodern-math]:mode=base;script=math; \textfont0=\f \Umathcode `f= 0 0 "1D453 % italic f from Unicode math font $f!$, $f$!, $f\/$! \showboxbreadth=100 \batchmode \showlists \bye --------------------- When luatex processes it, we get italic correction only in the first case: \mathon .\f 𝑓 .\kern0.9 (italic) .\f ! .\mathoff .\tenrm , .\glue(\spaceskip) 3.33333 plus 2.08331 minus 0.88889 .\mathon .\f 𝑓 .\mathoff .\tenrm ! .\tenrm , .\glue(\spaceskip) 3.33333 plus 2.08331 minus 0.88889 .\mathon .\f 𝑓 .\kern0.0 (font) .\mathoff .\tenrm ! Yes, fontforge shows that latinmodern-math italic f has italic correction 90, i.e. 0.9pt for the font at 10pt. And the italic correction is inserted in the first case according to rule 17 of appendix G of TeXbook, where we only need to add: "if the symbol is not a text symbol or if \fontdimen2 is zero **or if script=math fontfeature is used** then insert italic correction". It sounds OK, it is natural extension of the original Knuth's idea: his math scripts were in fonts cmmi10 and cmsy10 where \fontdimen2=0pt. But: A) why the italic correction isn't inserted in case 2? The rule 17 in appendix G of TeXbook says that "if the single-char atom isn't a text symbol (i.e. it isn't followed by a next specific atom) then the italic correction is inserted". The condition is obviously true for the last single-char atom of the math list. But luatex with Unicode math font doesn't respect this rule. Why? B) why there is \kern0.0 in the third case where we want to insert explicit italic correction (which is 0.9pt as fontforge says)? When we comment out the third line in our example (\textfont0=...), i.e. the classical plain TeX setting with 7bit tfm fonts is used, then luatex inserts italic correction in all three cases. It means that explicit \/ works and rule 17 from appendix G is respected. OK, maybe it is a decision of somebody who implemented Unicode math because missing italic corrections at the end of math list looks better, for example at the end of a sentence (ef-dot): $f$. I.e. the rule 17 from TeXbook will be not respected. But if our sentence ends by $f$! or by $f$? then the result looks very bad and user is unable to do local corrections by explicit \/. The problem is not due to simplification of the example here. If you try lualatex with unicode-math macros or OpTeX, you get the same results. Note that xetex puts correctly italic corrections in all three cases even though a Unicode math font is loaded. Can someone explain me this confusing behavior? Thanks Petr Olsak

6 11

Document the table variant of character.tounicode
by Max Chernoff 17 Apr '25

17 Apr '25

Hi Luigi, The "tounicode" key in the font character tables also supports passing an array of Unicode codepoints, which is _much_ nicer than trying to reencode characters into UTF-16BE (especially for non-BMP characters). The attached patch adds this to the manual. Thanks, -- Max

2 2

restrict pdfglyphtounicode to a tfm
by Ulrike Fischer 13 Apr '25

13 Apr '25

With pdftex it is possible to restrict a \pdfglyphtounicode declaration to a specific tfm. So in the following example the A from cmr10 is mapped to B, but the A from cmss10 is untouched: \pdfgentounicode=1 \pdfglyphtounicode{tfm:cmr10/A}{0042} A \font\test=cmss10 \test A \bye This is useful, e.g., to setup unicode mappings for older symbol fonts which often (mis)use standard glyph names. With luatex this doesn't work. Only the "general" mapping is honored here: \pdfvariable gentounicode =1 \pdfextension glyphtounicode {C}{0044} \pdfextension glyphtounicode {tfm:cmr10/A}{0042} C A \font\test=cmss10 \test C A \bye Would it be possible to extend luatex to support the tfm: syntax too? Or is there an alternative to change tounicode mappings? -- Ulrike Fischer http://www.troubleshooting-tex.de/

3 4

Use-after-free error with \localleftbox?
by davidweichiang＠gmail.com 12 Apr '25

12 Apr '25

Hello, the following MWE produces an error, which looks like it might be a bug: ``` \localrightbox{xyz}% \hfill\break \localleftbox{abc}% \bye ``` Output: ``` This is LuaTeX, Version 1.21.0 (TeX Live 2025/Homebrew) restricted system commands enabled. (./free.tex warning (nodes): attempt to copy free hlist node 399, ignored warning (nodes): attempt to copy free hlist node 369, ignored Underfull \hbox (badness 10000) in paragraph at lines 2--4 [1{/opt/homebrew/Cellar/texlive/20250308_1/share/texmf-dist/fonts/map/pdftex/up dmap/pdftex.map}]) (see the transcript file for additional information)</opt/homebrew/Cellar/texli ve/20250308_1/share/texmf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb> Output written on free.pdf (1 page, 8930 bytes). Transcript written on free.log. ``` Additionally, the \localleftbox contents do not appear. Additional information from luatex --credits: ``` Compiled with libpng 1.6.47; using 1.6.47 Compiled with lua version 5.3.6 Compiled with mplib version 2.11 Compiled with zlib 1.2.12; using 1.2.12 Development id: 7667 ```

2 1

Font embedding and variable width fonts
by Patrick Gundlach 09 Apr '25

09 Apr '25

Hello all, a somewhat generic question. I am playing with variable fonts, and I can see that I can create font metrics with font:set_variation(...) so the shaper takes the new widths into account. But writing this font into PDF has no visible effect. I assume the subsetter in LuaTeX does not take the variations into account. If this is correct so far: Are there any plans to change this, for example to use the harfbuzz subsetter? Thanks, Patrick

3 6

Unicode data
by Martin Ruckert 23 Mar '25

23 Mar '25

Hi all! I am currently working on moving the hitex engine to utf8, and I discovered that there are some small differences between luatex and xetex (see below). Are these differences on purpose or is there a bug somewhere? Best regards Martin There are differences between xetex and luatex for these five codepoints: codepoint 1: xetex \lccode=13 luatex \lccode=0 codepoint 26, 32, and 39: xetex math family/class/slot = 0/0/2097151 luatex math family/class/slot = 1/0/0 codepoint 65279: xetex \catcode=12 luatex \catcode=9 -- Martin Ruckert Hochschule München Fakultät für Informatik und Mathematik

2 2

Imprecise language in the OpenType Math specification leading to implementation differences amongst math engines
by Apoorv Potnis 19 Mar '25

19 Mar '25

Dear Developers of LuaTeX, I am writing this mail to report a bug in the OpenType Math specification regarding imprecise language, found by Khaled Hosny: [MATH] The algorithm for applying MathKernInfo is incorrect · Issue #1147 · MicrosoftDocs/typography-issues <https://github.com/MicrosoftDocs/typography-issues/issues/1147>. LuaTeX follows the letter of the specification, while XeTeX follows the intent of the specification. This has created compatibility issues for font developers. Thank you. -- Apoorv Potnis

4 4

Re: CMap unrecoverably broken
by Picone, Rico 18 Mar '25

18 Mar '25

Update: Fixed this by updating Ghostscript from 10.04.0 to 10.05.0. —Rico > On Mar 16, 2025, at 12:30 PM, Rico Picone <rico(a)stmartin.edu> wrote: > > I am getting this error now, too. I have the same situation, using LuaTeX to generate a PDF, trying to process that PDF with GS via the command: > > gs -o $@ -dNoOutputFonts -dColorConversionStrategy=/LeaveColorUnchanged -dEncodeColorImages=false -dEncodeGrayImages=false -dEncodeMonoImages=false -sDEVICE=pdfwrite $< > > Denis, did you find a fix? > > —Rico

2 1

italic kern in math missing
by Ulrike Fischer 16 Mar '25

16 Mar '25

With the newest binaries from today (Development id: 7671) I no longer get an italic kern after a f in math with legacy fonts: \tracingoutput1 \showboxbreadth\maxdimen \showboxdepth\maxdimen $f(x)$ \bye ...\hbox(0.0+0.0)x20.0, direction TLT ...\mathon ...\teni f ...\tenrm ( ...\teni x ...\tenrm ) ...\mathoff with pdftex or luatex from texlive 2024 ...\teni f ...\kern1.0764 (italic) ...\tenrm ( ...\teni x ...\tenrm ) With open type fonts / unicode-math there is no problem. Ulrike

2 2

Change in log indentation for luatex 1.21 (texlive 2025 pretest)
by David Carlisle 12 Feb '25

12 Feb '25

The new luatex shows differences in the way it indents and abbreviates log error lines. This is "only" logging but breaks several tests in the latex test suite which is essentially a regression test based around diff-ing normalised logs. If the change is intentional we can update the reference results (and maintainers of other packages using l3build tests will have to do similar) but if this change might be reverted we will hold off updating the test suite. Attached is a small test file and the tl2024 and tl2025 log. The diff is $ diff 24.log 25.log 1c1 < This is LuaTeX, Version 1.18.0 (TeX Live 2024) (format=luatex 2025.1.30) 12 FEB 2025 19:16 --- > This is LuaTeX, Version 1.21.0 (TeX Live 2025) (format=luatex 2025.2.12) 12 FEB 2025 19:16 7c7 < x} --- > x} 10c10 < l.5 ...elax\relax\relax\relax\relax\relax\show\relax --- > l.5 ...ax\relax\relax\relax\relax\relax\show\relax

2 2