% GLADTEX(1) % Sebastian Humenda % 5th of June 2021
GladTeX - generate HTML with LaTeX formulas embedded as images
gladtex [OPTIONS]
GladTeX is a formula preprocessor for HTML files. It recognizes a special tag
(<eq>...</eq>) marking formulas for conversion. The converted vector images
are integrated into the output HTML document.
This eases the process of creating HTML
documents (or web sites) containing formulas.
The generated images are saved in a cache to not render the same image over
and over again. This speeds up the process when formulas occur multiple times or
when a document is extended gradually.
The LaTeX formulas are preserved in the alt attribute of the embedded images, hence screen reader users benefit from an accessible HTML version of the document.
Furthermore it can be used with Pandoc to convert Markdown documents and other
formats with LaTeX formulas to HTML, EPUB and in fact to any HTML-based format,
see the option -P.
See FILE FORMAT for an explanation of the file format and EXAMPLES for examples on how to use GladTeX on its own or with Pandoc.
INPUT FILE NAME : Input .htex file with LaTeX formulas (if omitted or -, stdin will be read).
-h --help : Show this help message and exit.
-a : Save text alternatives for images which are too long for the alt attribute into a single separate file and link images to it.
-b BACKGROUND_COLOR
: Set background color for resulting images (default transparent). GladTeX
understands colors as provided by the dvips option of the xcolor LaTeX
package. Alternatively, a 6-digit hexadecimal value can be provided (as used
e.g. in HTML/CSS).
-c FOREGROUND_COLOR
: Set foreground color for resulting images. See the option above for a more
in-depth explanation.
-d DIRECTORY
: Directory in which to store the generated images in (relative path).
The given path is interpreted relatively to the input file. For instance,:
gladtex -d img dir/file.htex
will create a `dir/img` directory and link accordingly in `x/file.htex`.
-e LATEX_MATHS_ENV
: Set custom maths environment to surround the formula (e.g. flalign).
-E ENCODING : Overwrite encoding to use (default UTF-8).
--epub : Make embedded formula image more EPUB-compliant, i.e. round pixel sizes to integers.
-f FONTSIZE : Overwrite the default font size of 12pt. 12pt is the default in most browsers and hence changing this might lead to less-portable documents.
-i CLASS : CSS class to assign to inline math (default: 'inlinemath').
-K : keep LaTeX file(s) when converting formulas
By default, the generated LaTeX document, containing the formula to be
converted, are removed after the conversion (no matter whether it was
successful or not). If it wasn't successful, it is sometimes helpful to look
at the complete document. This option will keep the file.
-l CLASS : CSS class to assign to block-level math (default: 'displaymath').
-n : Purge unreadable caches along with all eqn*.png files.
Caches can be unreadable if the used GladTeX version is incompatible. If
this option is unset, GladTeX will simply fail when the cache is unreadable.
-m : Print error output in machine-readable format (less concise, better parseable).
Each line will start with a key, followed by a colon, followed by the value,
i.e. `line: 5`.
-o FILENAME
: Set output file name. '-' will print text to stdout. Bydefault, input file
name is used and the .htex extension is replaced by .html.
-p LATEX_STATEMENT
: Add given LaTeX code to the preamble of the LaTeX document that is used to
generate the embedded images. In order to add the contents of a file to the
preamble, use -p "\input{FILE}".
-P
: Act as a pandoc filter. In this mode, input is expected to be a Pandoc JSON
AST and the output will be a modified AST, with all formulas replaced
through HTML image tags. It makes sense to use - as the input file for
this option.
This option implies -E UTF-8. Also see GLADTEX_ARGS on
how to invoke GladTeX as a pandoc filter and how to pass arguments in this
mode.
--png : Switch from SVG to PNG as image output. This image has several known issues, one of them being that images won't resize when zooming into the document. It is also harder to work with for visually impaired users.
-r DPI
: Set resolution (size of images) to 'dpi' (115 by default). This is only
available with the --png option. Also see the -f option.
-R : Replace non-ascii (unicode) characters by LaTeX commands.
GladTeX can automatically detect non-ascii characters in formulas and
replace them through their appropriate LaTeX commands. In the alt attribute
of the resulting image, alphabetical characters won't be replaced. That
means that the alt text from the image is not exactly the same than the
code used for generating the image, but it is far more readable.
For instance, the formula \$\\text{für alle} a\$, would be compiled as
\$\\text{f\\ddot{u}r alle} a\$ and displayed as "\\text{für alle} a" in the alt
attribute.
-u URL : Base URL to image files (relative links are default).
A .htex file is essentially a HTML file containing LaTeX formulas. The formulas
have to be surrounded by <eq> and </eq>.
By default, formulas are rendered as inline maths, so they are squeezed to the
height of the line. It is possible to render a formula as display maths by
setting the env attribute to displaymath, i.e. <eq env="displaymath">...</eq>.
GladTeX can be customised by environment variables:
DEBUG
: If this is set to 1, a full Python traceback, instead of a human-readable
error message, will be displayed.
[GLADTEX_ARGS:]{#gladtex_args}
: When this environment variable is set, GladTeX switches into
the pandoc filter mode: input is read from standard input, output
written to standard output and the -P and -E UTF-8 options are assumed.
The contents of this variable are parsed as command-line switches. Qutoing
can be done in POSIX-shell compatible syntax:
```
export GLADTEX_ARGS='-d "image directory"'
```
It may be empty as well, which will just imply `-P`.
See an example in [Output As EPUB]#output-asepub).
A sample HTEX document could look like this:
<html><head><!-- meta information like charset --></head>
<body>
<h1>Some text</h1>
<p>Circumference of a circle: <eq>u = \pi\cdot d</eq><p>
<p>A useful matrix: <eq env="displaymath">\begin{pmatrix}
1 &2 &3 &4\\
5 &6 &7 &8\\
9 &10&11&12
\end{pmatrix}</eq></p>
</body></html>
This can be converted using
gladtex file.htex
and the result will be a HTML document called file.html along with two files
eqn0000.png and eqn0001.png in the same directory.
GladTeX can be used together with Pandoc. That can be handy to create an online version of a scientific paper written in Markdown. The MarkDown document would look like this:
Some text
=========
Circumference of a circle: $u = \pi\cdot d$
A useful matrix: $$\begin{pmatrix}
1 &2 &3 &4\\
5 &6 &7 &8\\
9 &10&11&12 \end{pmatrix}$$
The conversion is as easy as typing on the command-line:
pandoc -s -t html --gladtex file.md | gladtex -o file.html -
GladTeX can be used together with Pandoc, the swiss knife of format conversion. In short, any format that Pandoc understands can be converted to EPUB using GladTeX:
pandoc -t json myexample.md | gladtex -d "img dir" -P --epub - |
pandoc -f json -o book.epub
GladTeX can be also directly called by Pandoc, by setting the environment
variable GLADTEX_ARGS that automatically implies -P:
export GLADTEX_ARGS='-d "img dir" --epub'
pandoc -o book.EPUB --filter gladtex myexample.md
LaTeX2E is not unicode aware. if you have any unicode (more precisely, non-ascii characters) signs in your documents, you have the choice to do one of the following:
- Look up the symbol in one of the many LaTeX formula listings and replace the symbol with the appropriate command.
- Use the
-rswitch to let GladTeX replace the umlauts for you.
PLEASE NOTE: It is impossible to use GladTeX with LuaLaTeX. At the time of writing, dvipng does not support the extended font features of the lualatex engine.
The project home is at http://humenda.github.io/GladTeX. The source can be found at https://github.com/humenda/gladtex.