July 2025 - ntg-context - Mailing Lists

ALT-text for images in HTML/EPUB export
by Matthias Weber 14 Jul '25

14 Jul '25

Hello again, When providing an alt-text for images like so (which works for PDFs): \setupexternalfigures[location=default] \setupbackend[export=yes,xhtml=yes] \setupinteraction [state=start] \starttext \startchapter[title=Example] \startsection[title={Section}] \placefigure {} {\externalfigure[hacker.jpg][ label={Look, a $e^{\pi i}+1=0$ hacker!}] } \stopchapter \stoptext the figure becomes in the HTML export <div class="float figure method-here" id="aut-3"> <div class="floatcontent"><div class="image label-Look, a $e^{\\\\pi i}+1=0$ hacker!" id="export-example-image-1" image="export-example-image-1"></div></div> <div class="floatcaption"><div class="floatlabel figure">Figure </div><div class="floatnumber figure">1.1</div></div> </div> How do I turn this into an ALT text in the HTML? Or how do I have to provide the Alt text correctly? And what do I do about Alt texts that contain math? The \\\\pi looks a little strange… Thanks once again, Matthias

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interfaces.implement for key-value list
by Henning Hraban Ramm 14 Jul '25

14 Jul '25

Hi, I’m trying to get a simple function with a variable number of parameters working: """ \startluacode interfaces.implement { name = "Autoren", public = true, arguments = { "hash" }, actions = function(t) logs.report('Autoren', 'interface got table of length ' .. #t) end } \stopluacode \starttext Info: \Autoren[text=Hans,melody=Hraban] \stoptext """ The table t has always length 0. Where’s my error? And is there documentation on interfaces.implement anywhere? Hraban

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Line breaks within TABLE cells
by Kip Warner 14 Jul '25

14 Jul '25

Hello list, I am trying to insert a manual line break inside of a TABLE cell, but can't seem to get it to work. I'm typesetting some mathematical formulae. See below minimal: \starttext \placetable[here,split,none][table:appendix_notation]{} { \bTABLE[split=repeat,option=stretch] \setupTABLE[row][each][align=center] \setupTABLE[column][3][align=right] \bTABLEhead \bTR \bTH Symbol \eTH \bTH Constraints \eTH \bTH Description \eTH \eTR \eTABLEhead \bTABLEbody \bTR \bTC \math{\phi_i} \eTC % I want a line break right where the first comma is in the next line, but inserting a \\ doesn't seem to work \bTC \math{\phi_i \in \mathbb{R},\\ i \in \mathbb{N} \cap [0,\Phi)} \eTC \bTC Some random textual description here. \eTC \eTR \bTR \bTC \math{\underline{\phi}_i} \eTC \bTC \math{\underline{\phi}_i \in \mathbb{R} \cap [0,1], i \in \mathbb{N} \cap [0,\Phi)} \eTC \bTC Some additional random textual description here. \eTC \eTR \eTABLEbody \eTABLE } \stoptext Any help appreciated. -- Kip Warner OpenPGP signed/encrypted mail preferred https://www.thevertigo.com

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HTML/EPUB export: Lost Inheritance in enumerations.
by Matthias Weber 13 Jul '25

13 Jul '25

Dear All, Here is another issue: When defining enumerations, it is useful to use inheritance as in the minimal example inci.tex below. This compiles fine, and both PDF and HTML look good. However, when I style the elements in the exported style sheets, only “theorem" gets styled, not “lemma". In the HTML the Theorem style is invoked using <div class="description Theorem”>, while Lemma gets the generic <div class="description”>. To reproduce this, one needs to add <link type="text/css" rel="stylesheet" href="styles/inci3-templates.css" /> to inci3-div.html (to make the styles available to the html), and in styles/inci3-templates.css one needs to change two styles to description[detail=Theorem], div.description.Theorem { display: block ; border-style: solid; } description[detail=Lemma], div.description.Lemma { display: block ; border-style: solid; } The latter style is never used in inci3-div.html. Thanks once again! Matthias

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Minimal example for broken links in epub/html conversion
by Matthias Weber 13 Jul '25

13 Jul '25

Dear All (and thanks once more for the incredible help!) The attached example uses three link mechanisms inside a document: Linking to a section, to a reference, and a tagged enumeration. All of them work in the generated PDF, but the latter two fail in the generated HTML file. I have tried various bibliography implementations, none of which work; the one below was the shortest I could find. Thanks! Matthias \setupinteraction [ color=red, menu=on, state=start, page=yes ] \tolerant\def\startbibitem[#1]#*[#2]% LMTX! {\doifsomethingelse{#2}% {\startBibItem[reference={#1},title={#2}]}% {\startBibItem[reference={#1},title={#1}]}% } \def\stopbibitem{\stopBibItem} \setupexternalfigures[location=default] \setupbackend[export=yes,xhtml=yes] \setupexport [svgstyle=mathtest-style, hyphen=yes, width=60em] \definedescription[BibItem][ width=broad, margin=4em, indenting={no}, indentnext=no, alternative=hanging, hang=1, headcommand=\gobbleoneargument, align=flushleft ] \def\bibitemrule{\noindentation\vrule height0.5pt width4em depth0pt\thinspace} \definereferenceformat [cite] [type=title,left={},right={}] \definereferenceformat [bibpage] [type=page] \setupenumerations [alternative=hanging, width=fit, right={~}, way=bysection, prefix=chapter, distance=0.5em, prefixsegments={chapter:section}] \defineenumeration[Theorem] [alternative=serried, width=fit, distance=.5\emwidth, text=Theorem, style=italic, title=yes, titlestyle=normal, prefix=yes, headcommand=\groupedcommand{}{.} ] \defineenumeration [Proof] [alternative=serried, width=fit, distance=\emwidth, text=Proof, number=no, headstyle=italic, headcommand=\groupedcommand{}{.}, title=yes, titlestyle=normal, closesymbol=\mathqed] \starttext \startsection[title=Introduction] \startparagraph The Bibliography is \in{here}[sec:biblio]. \stopparagraph \startTheorem[thm:euler] \startformula e^{\pi i}+1=0 \ . \stopformula \stopTheorem \startProof See \cite[Euler1777]. \stopProof % make some fluff so that links have to do some work \dorecurse{5} {\startparagraph \input knuth \stopparagraph } \startparagraph From \in{Theorem}[thm:euler] it follows that \startformula e^{\pi i/2}=i \ . \stopformula \stopparagraph \stopsection \startsection[title=References, reference={sec:biblio}] \startbibitem[Euler1777] Euler: \emph{Collected Works.} \stopbibitem \stopsection \stoptext

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More HTML/EPUB conversion issues: Repeated texts/enumerations
by Matthias Weber 13 Jul '25

13 Jul '25

Thanks to Hans for helping with the images. I ran into various other issues. When using enumerations, sometimes part of the text from a previous enumeration is repeated (usually math). I've attached a minimal example at the end. I am also struggling to get links within the HTML document to work, both for linking to enumerations and bibliography items—links to sections work. I will create a minimal example later. Then, is there a reason that -templates.css is not included in -div.html? This file contains, among other useful things, style tags for enumerations like description[detail=Theorem], div.description.Theorem { display: block ; } that can be used to style enumerations differently. Thanks (always), Matthias \usemodule[mathml] \setupbackend[export=yes,xhtml=yes] \setupenumerations [alternative=hanging, width=fit, right={~}, way=bysection, prefix=chapter, distance=0.5em, prefixsegments={chapter:section}] \defineenumeration[Theorem] [alternative=serried, width=fit, distance=.5\emwidth, text=Theorem, style=italic, title=yes, titlestyle=normal, prefix=yes, headcommand=\groupedcommand{}{.} ] \defineenumeration [Proof] [alternative=serried, width=fit, distance=\emwidth, text=Proof, number=no, headstyle=italic, headcommand=\groupedcommand{}{.}, title=yes, titlestyle=normal, closesymbol=\mathqed] \starttext \startsection[title=Introduction] \startTheorem[thm:euler] \startformula e^{\pi i}+1=0 \ . \stopformula \stopTheorem \startProof See (Euler1777). \stopProof \stopsection \stoptext

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Docker images
by Henning Hraban Ramm 13 Jul '25

13 Jul '25

Hi, esp. Max: the ConTeXt dockerfiles from “Island of TeX” (https://github.com/islandoftex/context) … – still distinguish MkIV beta/current – install modules via rsync also for LMTX which pulls in some outdated ones – use Debian instead of Alpine because Linux/MUSL binary wasn’t working at the time (but should now, otherwise compiling it on the fly is an option) Would it make sense to change this? Hraban

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Minimal example for image bug in xhtml export
by Matthias Weber 12 Jul '25

12 Jul '25

I minimized my example to the following. To have the image displayed in the html file (filename-div.html in the filename-export directory), you need to put hacker.jpg into filename-export/images). The problem appears also without the image present, the formula is covered by an image that shouldn’t be there. Notice too that the overline is present in the pdf, but not in the html. \usemodule[mathml] \setupexternalfigures[location=default] \setupbackend[export=yes,xhtml=yes] \setupexport [svgstyle=mathtest-style, hyphen=yes, width=60em] \starttext \subject{Introduction} \startparagraph \input knuth \stopparagraph \placefigure [force] [figure:configurations] {Some simple Image} {\externalfigure[hacker.jpg] [width=\textwidth]} \startparagraph Let $p$ and $q$ be two different points. The \emph{segment} $\overline{pq}$ connecting $p$ and $q$ is the set \startformula pq = \{(1-t) p + t q: t\in[0,1]\}\ . \stopformula \stopparagraph \stoptext Any help will be appreciated! Thanks, Matthias

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The size keyword in \fenced seems not working
by fv leung 12 Jul '25

12 Jul '25

The following code (copied from the math manual) doesn’t produce the intended results with the most recent version of ConTeXt: \starttext \startformula \fenced[bracket]{\frac{1 + x}{1 - x}} = \fenced[bracket][size=0]{\frac{1 + x}{1 - x}} = \fenced[bracket][size=1]{\frac{1 + x}{1 - x}} = \fenced[bracket][size=2]{\frac{1 + x}{1 - x}} = \fenced[bracket][size=3]{\frac{1 + x}{1 - x}} = \fenced[bracket][size=4]{\frac{1 + x}{1 - x}} \stopformula \stoptext What's the proper way of setting size in \fenced ? Thanks in advance. FV Leung

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More problems with html/epub export
by Matthias Weber 12 Jul '25

12 Jul '25

Hello, I am trying to get a longer set of notes, heavy on math and images, exported to epub. Currently, I am adapting the CSS style sheets, using the exported css sheets In combination with the exported -div.html file. So far, so good. But I ran into a bizarre issue with images randomly occurring in the HTML code, instead of formulas. This happens halfway into the document, so at the moment it isn't easy to provide a minimal example. Maybe the following is enough to resolve the issue: My ConTeXt code The \idx{segment} $pq$ connecting $p$ and $q$ is the set \startformula pq = \{(1-t) p + t q: t\in[0,1]\}\ . \stopformula is exported to the following in …-div.html: (I have highlighted the problematic image) The <div class="highlight idx">segment</div> <math data-lmtx-blob="122" data-lmtx-meaning="𝑝 times 𝑞" display="inline" displaystyle="false" xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><mi>𝑝</mi><mi>𝑞</mi></mrow></math> connecting <math data-lmtx-blob="123" data-lmtx-meaning="𝑝" display="inline" displaystyle="false" xmlns="http://www.w3.org/1998/Math/MathML"><mi>𝑝</mi></math> and <math data-lmtx-blob="124" data-lmtx-meaning="𝑞" display="inline" displaystyle="false" xmlns="http://www.w3.org/1998/Math/MathML"> <mi>𝑞</mi></math> is the set <div class="formula"> <div class="formulacontent n-2" image="incidences-image-2"> <math data-lmtx-blob="125" data-lmtx-meaning="𝑝 times 𝑞 equals group group 1 minus 𝑡 end group times 𝑝 plus 𝑡 times 𝑞 : 𝑡 belongs to group 0 comma 1 end group end group times" display="block" displaystyle="true" xmlns="http://www.w3.org/1998/Math/MathML"> <mrow> <mi>𝑝</mi> <mi>𝑞</mi> <mo>=</mo> <mo stretchy="false">{</mo> <mo stretchy="false">(</mo> <mn>1</mn> <mo>−</mo> <mi>𝑡</mi> <mo stretchy="false">)</mo> <mi>𝑝</mi> <mo>+</mo> <mi>𝑡</mi> <mi>𝑞</mi> <mo>:</mo> <mi>𝑡</mi> <mo>∈</mo> <mo stretchy="false">[</mo> <mn>0</mn> <mo>,</mo> <mn>1</mn> <mo stretchy="false">]</mo> <mo stretchy="false">}</mo> <mi>.</mi> </mrow> </math></div> </div> That image "incidences-image-2” was used correctly many pages earlier. Manually deleting the highlighted text fixes the problem. I have many more senselessly repeated figures in the text like this, without a clue why they appear. They are certainly not in the PDF. Less dramatically, I also noticed that \overline doesn’t seem to appear in the HTML code. I am doing all this to produce accessible versions of my notes. I had hoped that going via HTML and possibly eventually Epub would be less of a nightmare than creating accessible PDFs, but maybe I was wrong…. Thanks for any help!

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