Could not convert TeX math \frac

[nopria]

I try to convert from markdown to rtf using

pandoc test.md -s --self-contained --webtex -o test.rtf

a very simple markdown file containing just

Equation $\frac{1}{2}$

and I get the warning message

[WARNING] Could not convert TeX math \frac{1}{2}, rendering as TeX

and of course in the RTF file the equation is not rendered.

Pandoc version

pandoc 2.16.2 Compiled with pandoc-types 1.22.1, texmath 0.12.3.2, skylighting 0.12.1, citeproc 0.6, ipynb 0.1.0.2

Under Ubuntu running inside Windows Subsystem for Linux.

[jgm]

This isn't a bug, just a warning. Pandoc will try to convert TeX math to an equation that works in the target format, e.g. OMML equation in docx. If it can't do this, it issues this warning and includes the plain TeX code. RTF doesn't have a native equation syntax, and fractions can't be "faked" with plain text since they involve putting things in a vertical stack, hence this warning.

You might look at the --webtex option which would allow you to include images for the equations.

[nopria]

The warning remains also if you try to obtain an RTF with equations rendered as images (which is what I'm trying to achieve), using the option --webtex=https://latex.codecogs.com/png.latex?.

[jgm]

I'm sorry, I forgot that --webtex only works with HTML output.

[jgm]

There's actually no reason we couldn't make --webtex work with RTF, and indeed with every format. I'll open a separate issue about this.

[nopria]

Ok, thanks.

I also tried conversion to RTF from HTML containing equation rendered as PNG, but I get the message

[WARNING] Could not fetch resource data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAcAAAAXBAMAAAA1qkh7AAAAMFBMVEX///8AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAv3aB7AAAAD3RSTlMAEFS7zSLdRInvZpl2qzIdro3DAAAACXBIWXMAAA7EAAAOxAGVKw4bAAAATElEQVQIHWNgVGZgYGBSARIMIbiIMKAEe+dSkDQM/P///wOMDaSZVmxgYIhhuMHA8IRhMUi8A4gZE4EE7wMgcY4VaEABDwND/P8fDADhqhD/i+mPyQAAAABJRU5ErkJggg==: image is not a jpeg or png

I checked the HTML and the image of the equation is a PNG.

Vector rendering

The PNG rendering obtained with the --webtex option is very bad quality, I don't know if here is a way to improve it. Another option would be to render equation as SVG using as final format ODT, which can contain vector graphics (whereas RTF can't, as I just discovered doing some tests).

[jgm]

If you use ODT, you don't need to mess with images; ODT supports mathml and pandoc will do the conversion for you.

[nopria]

Even if ODT supports math rendering, the quality of math rendered by LaTeX is much higher, so I would prefer anyway to have LaTeX rendered images in ODT.

[jgm]

I just pushed a fix to the problem with data URIs you noted above.