[NTG-context] More problems with html/epub export

12 Jul 2025

      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!

[NTG-context] More problems with html/epub export

Matthias Weber