October 2025 - dev-luatex

Math "norule" keyword documentation unclear
by Max Chernoff 26 Oct '25

26 Oct '25

Hi Luigi, §7.6.6 of the LuaTeX manual contains the following sentence: The keyword norule will hide the rule with the above variants while keeping the rule related spacing. I would have expected for "the above variants" to mean "the commands listed in the paragraph above", rather than "the commands with the string 'above' in their name", even though the latter is correct. The patch below rewords this to make it clearer that you can only use "norule" with "\above...". This was reported by Yiannis Lazarides in the TeX.SE chat. Thanks, -- Max diff --git a/manual/luatex-math.tex b/manual/luatex-math.tex index 8671519ef..d31c82713 100644 --- a/manual/luatex-math.tex +++ b/manual/luatex-math.tex @@ -1317,10 +1317,10 @@ works. \topicindex {math+fractions} -The \prm {abovewithdelims} command accepts a keyword \type {exact}. When issued -the extra space relative to the rule thickness is not added. One can of course -use the \type {\Umathfraction..gap} commands to influence the spacing. Also the -rule is still positioned around the math axis. +The \prm {abovewithdelims} command accepts keywords \type {exact} and \type +{norule}. When issued the extra space relative to the rule thickness is not +added. One can of course use the \type {\Umathfraction..gap} commands to +influence the spacing. Also the rule is still positioned around the math axis. \starttyping $$ { {a} \abovewithdelims() exact 4pt {b} }$$ @@ -1377,9 +1377,6 @@ For Latin Modern the result looks as follows: \stoptabulate \stop -The keyword \type {norule} will hide the rule with the above variants while -keeping the rule related spacing. - \subsection {Delimiters: \type{\Uleft}, \prm {Umiddle} and \prm {Uright}} \topicindex {math+delimiters}

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[luatex] Possibility of using Lua to fix float/footnote issues with cuted (column switching)?
by Kumaresh Paramasivan (TNQ Software) 22 Oct '25

22 Oct '25

Hello LuaTeX developers, I am facing a classic and difficult layout problem when using the *cuted* package to switch from *twocolumn* to *onecolumn* (using *\switchonecolumn* ). When I do this, two things break: 1. *Footnote Misplacement:* Footnotes that are declared just before the *\switchonecolumn *command are pushed to the previous page, often creating an unwanted blank page. 2. *Float Drifting:* A *figure** float with the *[b] *(bottom) option (using *stfloats*) is not placed at the bottom of the page. It drifts to the very end of the document. I have an MWE (below) that demonstrates both issues. My question for this list is:* Could LuaTeX's capabilities offer a more robust solution to this problem?* I understand this is a complex issue related to TeX's output routine, column balancing, and float/footnote queues, which the* cuted* package tries to manage with TeX macros (like *\onecolumngrid*). Is it conceivable that a Lua-based approach (perhaps using callbacks like *pre_output_filter* or managing the vertical lists directly) could handle the transition? For example, could Lua be used to: - Force-process the pending floats and footnotes before the column switch is executed? - "Snapshot" the state of the footnote/float lists and re-insert them correctly after the switch? I am raising this here specifically to ask if a Lua-based solution is a viable path to explore for this kind of complex page-layout challenge, where traditional package macros seem to struggle. Thank you for any insights. Any help would be greatly appreciated. *MWE:* \documentclass[twocolumn]{article} \usepackage{lipsum}\usepackage{stfloats}\usepackage{cuted} \begin{document} \section{Introduction} Para 1: \lipsum[1-5] \begin{figure}[t]\fbox{\vbox to 10pc{\hbox to .98\columnwidth{}}}\caption{This is single col figure 1.}\end{figure} Para 2: \lipsum[6-8] \begin{figure*}[b]\fbox{\vbox to 10pc{\hbox to \textwidth{}}}\caption{single col figure 2.}\end{figure*} Para 3: \lipsum[8]\footnote{fn1}\footnote{fn2} Para 4: \lipsum[8] \switchonecolumn \section*{Appendix} Para A1: \lipsum[1-4] \switchtwocolumn \end{document} *Current output:* [image: current output] <https://i.sstatic.net/gYezEZ3I.png> *Link: **https://i.sstatic.net/gYezEZ3I.png <https://i.sstatic.net/gYezEZ3I.png>* *Expected output:* [image: expected output] <https://i.sstatic.net/51hMKteH.png> *Link: https://i.sstatic.net/51hMKteH.png <https://i.sstatic.net/51hMKteH.png>* Kumaresh P Engineering Lead P: +91 44 4596 4800 <https://tnqtech.com/> <https://www.linkedin.com/company/tnqtech/> > -- Disclaimer: The entire content of this email message, including any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you are not the named addressee or part of the entity, you should not disseminate, distribute, or copy this email. Please notify the sender immediately by e-mail if you have received this email by mistake and delete this e-mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing, or taking any action in reliance on the contents of this information is strictly prohibited.

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[LuaTeX] Using Lua callbacks to synchronize twocolumn float placement?
by Kumaresh Paramasivan (TNQ Software) 22 Oct '25

22 Oct '25

Hello LuaTeX experts, I am facing a classic LaTeX float placement problem in a *twocolumn* document, and I am wondering if LuaTeX offers a potential solution where traditional methods seem to fail. The goal is to have a single-column *figure[t]* and a double-column *figure*[b]* (using the *stfloats *package) appear together on the same page, immediately following their definition. The issue is that LaTeX's behavior is inconsistent. When the floats are defined early in the document (e.g., on Page 1), they are split: the *figure[t] *lands on Page 2, but the *figure*[b]* is delayed until Page 3. However, an identical pair defined later (e.g., on Page 3) correctly land together on Page 4. My requirement is for a completely automated solution. I cannot rely on manually re-ordering the floats in the source to make the output routine happy. My question for this group is: *Could this synchronization problem be solved using LuaTeX?* For example, is it feasible to use a Lua callback (perhaps *build_page_insert_filter*, or something influencing the output routine) to: 1. Inspect both the single-column and double-column pending float lists? 2. Detect when a *[t]* float is being placed at the top of a page *and* a *[b]* double-column float is pending? 3. If this condition is met, can Lua somehow *force* or *encourage* the output routine to reserve space for and place *both* floats on the *same* page, synchronizing them before the page is shipped out? I understand this is a complex part of the TeX engine, but this seems like a timing and look-ahead problem that Lua might be uniquely suited to solve. Below is the MWE that demonstrates the problem. *MWE:* \documentclass[twocolumn]{article}\usepackage{lipsum}\usepackage{stfloats}\usepackage{graphicx,color}\setlength\marginparwidth{4pc}\setlength\marginparsep{1pc}\begin{document} Para One: ... Para Two: ... Para Three: ... Para Four: ... Para Five: ... \marginpar{{\color{red}\textbf{Fig 1\&2 placed here}}} \begin{figure}[t]\fbox{\vbox to 10pc{\hbox to .98\columnwidth{}}}\caption{single col figure}\end{figure}\begin{figure*}[b]\fbox{\vbox to 10pc{\hbox to \textwidth{}}}\caption{single col figure}\end{figure*} Para Six: ... Para Seven: ... Para Eight: ... Para Nine: ... Para Ten: ... Para 1-One: ... Para 1-Two: ... Para 1-Three: ... Para 1-Four: ... \marginpar{{\color{red}\textbf{Fig 3\&4 placed here}}} \begin{figure}[t]\fbox{\vbox to 10pc{\hbox to .98\columnwidth{}}}\caption{single col figure}\end{figure}\begin{figure*}[b]\fbox{\vbox to 10pc{\hbox to \textwidth{}}}\caption{single col figure}\end{figure*} Para 1-Five: ... Para 1-Six: ... Para 1-Seven: ... Para 1-Eight: ... Para 1-Nine: ... Para 1-Ten: ... \end{document} *Present Output:* Figures 1 & 2 are separated. Figure 1 is on Page 2, while Figure 2 is pushed to Page 3. [image: Figures 1 & 2] <https://i.sstatic.net/3Kq084Zl.png> [image: Figures 3 & 4] <https://i.sstatic.net/xFbrkgdi.png> *Link: https://i.sstatic.net/xFbrkgdi.png <https://i.sstatic.net/xFbrkgdi.png>* *Required Output:* Figures 1 & 2 should both appear on Page 2, just like Figures 3 & 4 do on Page 4. [image: Required Output] <https://i.sstatic.net/jKr8RYFd.png> *Link: https://i.sstatic.net/jKr8RYFd.png <https://i.sstatic.net/jKr8RYFd.png>* Thanks & Regards Kumaresh P Kumaresh P Engineering Lead P: +91 44 4596 4800 <https://tnqtech.com/> <https://www.linkedin.com/company/tnqtech/> > -- Disclaimer: The entire content of this email message, including any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you are not the named addressee or part of the entity, you should not disseminate, distribute, or copy this email. Please notify the sender immediately by e-mail if you have received this email by mistake and delete this e-mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing, or taking any action in reliance on the contents of this information is strictly prohibited.

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Catch error image loading
by Patrick Gundlach 02 Oct '25

02 Oct '25

Hello all, I have this in my code: print("try to scan image") local image_info = img.scan{filename = filename} print("scanned image") When I have a bad jpeg file (for example a file containing just a few ascii characters), I get this output: try to scan image ! error: (readjpg): no header found ! ==> Fatal error occurred, no output PDF file produced!exit status 1 Is there a way to catch this error without stopping the PDF generation? Thank you Patrick

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