\hypertarget{introduction}{%
\section{Introduction}\label{introduction}}

\texttt{make4ht} is a simple build system for \texttt{tex4ht}, \TeX~to
XML converter. It provides a command line tool that drive the conversion
process. It also provides a library which can be used to create
customized conversion tools. An example of such conversion tool is
\href{https://github.com/michal-h21/tex4ebook}{tex4ebook} for conversion
of \TeX~to ePub and other e-book formats.

\hypertarget{how-it-works}{%
\subsection{How it works}\label{how-it-works}}

\hypertarget{the-issues-with-default-tex4ht-conversion-commands}{%
\subsubsection{\texorpdfstring{The issues with default \texttt{tex4ht}
conversion
commands}{The issues with default tex4ht conversion commands}}\label{the-issues-with-default-tex4ht-conversion-commands}}

\texttt{tex4ht} system supports several output formats, most notably
\texttt{XHTML}, \texttt{HTML\ 5} and \texttt{ODT}. The conversion can be
invoked using several commands. These commands invoke LaTeX~or Plain TeX
with special instructions to load \texttt{tex4ht.sty} package. The
\TeX~run produces special \texttt{DVI} file which contains the code for
desired output format. The \texttt{DVI} file is then processed and
desired output files are created.

The basic command provided by \texttt{tex4ht} is named \texttt{htlatex}.
It compiles \LaTeX~ files to \texttt{HTML} with this command sequence:

\begin{verbatim}
latex $latex_options 'code for loading tex4ht.sty \input{filename}'
latex $latex_options 'code for loading tex4ht.sty \input{filename}'
latex $latex_options 'code for loading tex4ht.sty \input{filename}'
tex4ht $tex4ht_options filename
t4ht $t4ht_options filename
\end{verbatim}

The options for various parts of the system can be passed on the command
line:

\begin{verbatim}
htlatex filename "tex4ht.sty options" "tex4ht_options" "t4ht_options" "latex_options"
\end{verbatim}

For basic \texttt{HTML} conversion it is possible to use the most basic
invocation:

\begin{verbatim}
htlatex filename.tex
\end{verbatim}

It can be much more involved for \texttt{HTML\ 5} output in
\texttt{UTF-8} encoding:

\begin{verbatim}
htlatex filename.tex "xhtml,html5,charset=utf-8" "-cmozhtf -utf8"
\end{verbatim}

\texttt{make4ht} can simplify it:

\begin{verbatim}
make4ht -uf html5 filename.tex
\end{verbatim}

Another issue is the fixed compilation order and hard-coded number of
LaTeX invocations.

When you need to run a program which interact with LaTeX, such as
\texttt{Makeindex} or \texttt{Bibtex}, you need to create a new script
based on \texttt{htlatex}, or run \texttt{htlatex} twice, which means
that LaTeX will be invoked six times. This can lead to significantly
long compilation times. \texttt{make4ht} provides build files and
extensions, which can be used for interaction with external tools.

It is also possible to have several compilation modes. When you just add
new text to a document, which doesn't contain cross-references, don't
add new stuff to the table of contents, etc., it is possible to use the
\texttt{draft} mode which will invoke LaTeX only once. It can save quite
a lot of the compilation time:

\begin{verbatim}
make4ht -um draft -f html5 filename.tex
\end{verbatim}

There are also issues with a behaviour of the \texttt{t4ht} application.
It reads file \texttt{filename.lg}, generated by \texttt{tex4ht}, where
are instructions about generated files, \texttt{CSS} instructions, calls
to external applications, instructions for image conversions etc. It can
be instructed to copy generated files to some output directory, but it
doesn't preserve directory structure, so when you have images in a
subdirectory, they will be copied to the output directory. Links will be
pointing to a non-existing subdirectory. The following command should
copy all output files to the correct destinations.

\begin{verbatim}
make4ht -d outputdir filename.tex
\end{verbatim}

The image conversion is configured in the
\href{http://www.tug.org/applications/tex4ht/mn35.html\#index35-73001}{env
file}, which has really strange syntax based and the rules are
\href{http://www.tug.org/applications/tex4ht/mn-unix.html\#index27-69005}{os
dependent}. \texttt{make4ht} provides simpler means for the image
conversion in the build files.

With \texttt{make4ht} build files, we have simple mean to fix these
issues. We can change image conversion parameters without the need to
modify the \texttt{env\ file}, or execute actions on the output files.
These actions can be either external programs such as \texttt{xslt}
processors or \texttt{HTML\ tidy} or \texttt{Lua} functions.

The idea is to make system controlled by a build file. Because
\texttt{Lua} interpreter is included in modern TeX distributions and
\texttt{Lua} is ideal language for such task, it was chosen as language
in which the build scripts are written.

\hypertarget{output-file-formats-and-extensions}{%
\section{Output file formats and
extensions}\label{output-file-formats-and-extensions}}

The default output format used by \texttt{make4ht} is \texttt{html5}.
Different format can be requested using the \texttt{-\/-format} option.
Supported formats are:

\begin{itemize}
\tightlist
\item
  \texttt{xhtml}
\item
  \texttt{html5}
\item
  \texttt{odt}
\end{itemize}

The \texttt{-\/-format} option can be also used for extension loading.

\hypertarget{extensions}{%
\subsection{Extensions}\label{extensions}}

Extensions can be used to modify the build process without the need to
use a build file. They may post-process the output files or request
additional commands for the compilation.

The extensions can be enabled or disabled by appending
\texttt{+EXTENSION} or \texttt{-EXTENSION} after the output format name:

\begin{verbatim}
 make4ht -uf html5+tidy filename.tex
\end{verbatim}

Available extensions:

\begin{description}
\item[latexmk\_build]
use \texttt{Latexmk} for \LaTeX~compilation.
\item[tidy]
clean the \texttt{HTML} files using the \texttt{tidy} command.
\item[dvisvgm\_hashes]
efficient generation of SVG pictures using Dvisvgm. It can utilize
multiple processor cores and generates only changed images.
\item[common\_filters]
clean the output HTML files using filters.
\item[common\_domfilters]
Clean the HTML file using DOM filters. It is more powerful than
\texttt{common\_filters}. Used DOM filters are \texttt{fixinlines},
\texttt{idcolons} and \texttt{joincharacters}.
\item[mathjaxnode]
use \href{https://github.com/pkra/mathjax-node-page/}{mathjax-node-page}
to convert from MathML code to HTML + CSS or SVG. See
\protect\hyperlink{mathjaxsettings}{the available settings}.
\item[staticsite]
build the document in form suitable for static site generators like
\href{https://jekyllrb.com/}{Jekyll}.
\end{description}

\hypertarget{build-files}{%
\section{Build files}\label{build-files}}

\texttt{make4ht} supports build files. These are \texttt{Lua} scripts
which can adjust the build process. You can request external
applications like \texttt{bibtex} or \texttt{makeindex}, pass options to
the commands, modify the image conversion process, or post-process the
generated files.

\texttt{make4ht} tries to load default build file named as
\texttt{filename\ +\ .mk4\ extension}. You can choose different build
file with \texttt{-e} or \texttt{-\/-build-file} command line option.

Sample build file:

\begin{verbatim}
Make:htlatex()
Make:match("html$", "tidy -m -xml -utf8 -q -i ${filename}")
\end{verbatim}

\texttt{Make:htlatex()} is preconfigured command for calling LaTeX with
\texttt{tex4ht} loaded on the input file. In this case, it will be
called one time. After compilation, the \texttt{tidy} command is
executed on the output \texttt{HTML} file.

Note that you don't have to call \texttt{tex4ht} and \texttt{t4ht}
commands explicitly in the build file, they are called automatically.

\hypertarget{user-commands}{%
\subsection{User commands}\label{user-commands}}

You can add more commands like \texttt{Make:htlatex} using
\texttt{Make:add} command:

\begin{verbatim}
Make:add("name", "command", {parameters}, repetition)
\end{verbatim}

The \texttt{name} and \texttt{command} parameters are required, rest of
the parameters are optional.

This defines \texttt{name} command, which can be then executed as
\texttt{Make:name()} command.

\hypertarget{provided-commands}{%
\subsubsection{Provided commands}\label{provided-commands}}

\begin{description}
\item[\texttt{Make:htlatex}]
One call to TeX engine with special configuration for \texttt{tex4ht}
loading.
\item[\texttt{Make:latexmk}]
Use \texttt{Latexmk} for the document compilation. \texttt{tex4ht} will
be loaded automatically.
\item[\texttt{Make:tex4ht}]
Process the \texttt{DVI} file and creates the output files.
\item[\texttt{Make:t4ht}]
Creates the CSS file.
\end{description}

\hypertarget{command-function}{%
\subsubsection{Command function}\label{command-function}}

The \texttt{command} parameter can be either string template or
function:

\begin{verbatim}
Make:add("text", "echo hello, input file: ${input}")
Make:add("function", function(params) 
  for k, v in pairs(params) do 
    print(k..": "..v) 
  end, {custom="Hello world"}
)
\end{verbatim}

The template can get variable value from the parameters table using a
\texttt{\$\{var\_name\}} placeholder. Templates are executed using
operating system, so they should invoke existing OS commands. Function
commands may execute system commands using \texttt{os.execute} function.

\hypertarget{parameters-table}{%
\subsubsection{Parameters table}\label{parameters-table}}

\texttt{parameters} parameter is optional, it can be table or
\texttt{nil} value, which should be used if you want to use the
\texttt{repetition} parameter, but don't want to modify the parameters
table.

The table with default parameters is passed to all commands, they can be
accessed from command functions or templates. When you specify your own
parameters in the command definition, these additional parameters are
added to the default parameters table for this particular command. You
can override the default parameters in the parameters table.

The default parameters are following:

\begin{description}
\item[\texttt{htlatex}]
used compiler
\item[\texttt{input}]
it is output file name in fact
\item[\texttt{tex\_file}]
input TeX file
\item[\texttt{latex\_par}]
parameters to \texttt{latex}
\item[\texttt{packages}]
insert additional LaTeX code which is inserted before
\texttt{\textbackslash{}documentclass}. Useful for passing options to
packages or additional packages loading
\item[\texttt{tex4ht\_sty\_par}]
parameters to \texttt{tex4ht.sty}
\item[\texttt{tex4ht\_par}]
parameters to the \texttt{tex4ht} application
\item[\texttt{t4ht\_par}]
parameters to the \texttt{t4ht} application
\item[\texttt{outdir}]
the output directory
\item[\texttt{repetition}]
limit number of command execution.
\item[\texttt{correct\_exit}]
expected \texttt{exit\ code} from the command. The compilation will be
terminated if the command \texttt{exit\ code} is different.
\end{description}

\hypertarget{repetition}{%
\subsubsection{Repetition}\label{repetition}}

Repetition is number which specifies a maximal number of executions of
the particular command. This is used for instance for \texttt{tex4ht}
and \texttt{t4ht} commands, as they should be executed only once in the
compilation. They would be executed multiple times if you include them
in the build file because they are called by \texttt{make4ht} by
default. Because these commands allow only one \texttt{repetition}, the
second execution will be blocked.

\hypertarget{expected-exit-code}{%
\subsubsection{Expected exit code}\label{expected-exit-code}}

You can set the expected exit code from a command with a
\texttt{correct\_exit} key in the parameters table. The compilation will
be stopped when the command returns a different exit code.

This mechanism isn't used for LaTeX (for all TeX engines and formats, in
fact), because it doesn't differentiate between fatal and non-fatal
errors, and it returns the same exit code in all cases. Log parsing is
used because of that, error code \texttt{1} is returned in the case of
fatal error, \texttt{0} is used otherwise. The \texttt{Make.testlogfile}
function can be used in the build file to detect compilation errors in
the TeX log file.

\hypertarget{file-matches}{%
\subsection{File matches}\label{file-matches}}

Another type of action which can be specified in the build file is
\texttt{match}. It can be called on the generated files:

\begin{verbatim}
Make:match("html$", "tidy -m -xml -utf8 -q -i ${filename}")
\end{verbatim}

It tests output file names with \texttt{Lua} pattern matching and on
matched items will execute a command or a function, specified in the
second argument. Commands may be specified as strings, the templates
will be expanded, \texttt{\$\{var\_name\}} placeholders will be replaced
with corresponding variables from the \texttt{parameters} table,
described in the previous subsection. One additional variable is
available: \texttt{filename}. It contains the name of the current output
file.

The above example will clean all output \texttt{HTML} files using the
\texttt{tidy} command.

If function is used instead, it will get two parameters. The first one
is a current filename, the second one table with parameters.

\hypertarget{filters}{%
\subsubsection{Filters}\label{filters}}

Some default \texttt{match} actions which can be used are available from
the \texttt{make4ht-filter} module. It contains some functions which are
useful for fixing some \texttt{tex4ht} bugs or shortcomings.

Example:

\begin{verbatim}
local filter = require "make4ht-filter"
local process = filter{"cleanspan", "fixligatures", "hruletohr"}
Make:htlatex()
Make:htlatex()
Make:match("html$",process)
\end{verbatim}

The \texttt{make4ht-filter} module return a function which can be used
for the filter chain building. Multiple filters can be chained, each of
them can modify the string which was modified by the previous filters.
The changes are then saved to the processed file.

Built-in filters are:

\begin{description}
\item[cleanspan]
clean spurious span elements when accented characters are used
\item[cleanspan-nat]
alternative clean span filter, provided by Nat Kuhn
\item[fixligatures]
decompose ligatures to base characters
\item[hruletohr]
\texttt{\textbackslash{}hrule} commands are translated to series of
underscore characters by \texttt{tex4ht}, this filter translate these
underscores to \texttt{\textless{}hr\textgreater{}} elements
\item[entites]
convert prohibited named entities to numeric entities (currently, only
\texttt{\&nbsp;}, as it causes validation errors, and \texttt{tex4ht} is
producing it sometimes)
\item[fix-links]
replace colons in local links and \texttt{id} attributes with
underscores. Some cross-reference commands may produce colons in
internal links, which results in validation error.
\item[mathjaxnode]
use \href{https://github.com/pkra/mathjax-node-page/}{mathjax-node-page}
to convert from MathML code to HTML + CSS or SVG. See
\protect\hyperlink{mathjaxsettings}{the available settings}.
\item[staticsite]
create HTML file in format suitable for static site generators such as
\href{https://jekyllrb.com/}{Jekyll}
\item[svg-height]
some SVG images produced by \texttt{dvisvgm} seem to have wrong
dimensions. This filter tries to set the correct image size.
\end{description}

Function \texttt{filter} accepts also function arguments, in this case
this function takes file contents as a parameter and modified contents
are returned.

Example:

\begin{verbatim}
local filter  = require "make4ht-filter"
local changea = function(s) return s:gsub("a","z") end
local process = filter{"cleanspan", "fixligatures", changea}
Make:htlatex()
Make:htlatex()
Make:match("html$",process)
\end{verbatim}

In this example, spurious span elements are joined, ligatures are
decomposed, and then all letters `a' are replaced with `z' letters.

\hypertarget{dom-filters}{%
\subsubsection{DOM filters}\label{dom-filters}}

DOM filters use the \href{https://ctan.org/pkg/luaxml}{\texttt{LuaXML}}
library to modify directly the XML object. This enables more powerful
operations than the regex based filters from the previous section.

Example:

\begin{verbatim}
local domfilter = require "make4ht-domfilter"
local process = domfilter {"joincharacters"}
Make:match("html$", process)
\end{verbatim}

Available DOM filters:

\begin{description}
\item[aeneas]
\href{https://www.readbeyond.it/aeneas/}{Aeneas} is a tool for
automagical synchronization of text and audio. This filter modifies the
HTML code to support the synchronization.
\item[fixinlines]
put all inline elements which are direct children of the
\texttt{\textless{}body\textgreater{}} elements to a paragraph.
\item[idcolons]
replace the colon (\texttt{:}) character in internal links and
\texttt{id} attributes. They cause validation issues.
\item[joincharacters]
join consecutive \texttt{\textless{}span\textgreater{}} or
\texttt{\textless{}mn\textgreater{}} elements.
\end{description}

\hypertarget{make4ht-aeneas-config-package}{%
\subsubsection{make4ht-aeneas-config
package}\label{make4ht-aeneas-config-package}}

Companion for the \texttt{aeneas} DOM filter is the
\texttt{make4ht-aeneas-config} plugin. It can be used to write Aeneas
configuration file or execute Aeneas on the generated HTML files.

Available functions:

\begin{description}
\item[write\_job(parameters)]
write Aenas job configuration to \texttt{config.xml} file. See the
\href{https://www.readbeyond.it/aeneas/docs/clitutorial.html\#processing-jobs}{Aeneas
documentation} for more information about jobs.
\item[execute(parameters)]
execute Aeneas.
\item[process\_files(parameters)]
process the audio and generated subtitle files.
\end{description}

By default, the \texttt{smil} file is created. It is assumed that there
is audio file in \texttt{mp3} format named as the TeX file. It is
possible to use different formats and file names using mapping.

The configuration options can be passed directly to the functions or set
using \texttt{filter\_settings\ "aeneas-config"\ \{parameters\}}
function.

Available parameters:

\begin{description}
\item[lang]
document language. It is interfered from the HTML file, so it is not
necessary to set it.
\item[map]
mapping between HTML, audio and subtitle files. More info bellow.
\item[text\_type]
type of the input. The \texttt{aeneas} DOM filter produces
\texttt{unparsed} text type.
\item[id\_sort]
sorting of id attributes. Default value is \texttt{numeric}.
\item[id\_regex]
regular expression to parse the id attributes.
\item[sub\_format]
generated subtitle format. Default \texttt{smil}.
\end{description}

Additional parameters for the job configuration file:

\begin{itemize}
\tightlist
\item
  description
\item
  prefix
\item
  config\_name
\item
  keep\_config
\end{itemize}

It is possible to generate multiple HTML files from the LaTeX source.
For example, \texttt{tex4ebook} generates separate file for each chapter
or section. It is possible to set options for each HTML file, in
particular names of the corresponding audio files. This mapping is done
using \texttt{map} parameter.

Example:

\begin{verbatim}
filter_settings "aeneas-config" {
  map = {
    ["sampleli1.html"] = {audio_file="sample.mp3"}, 
    ["sample.html"] = false
  }
}
\end{verbatim}

Table keys are the configured file names. It is necessary to insert them
as \texttt{{[}"filename.html"{]}}, because of Lua syntax rules.

This example maps audio file \texttt{sample.mp3} to a section subpage.
The main HTML file, which may contain title and table of contents
doesn't have an corresponding audio file.

The filenames of sub files corresponds to chapter numbers, so they are
not stable when a new chapter is added. It is possible to request file
names interfered from the chapter titles using the \texttt{sec-filename}
option or \texttt{tex4ht}.

Available \texttt{map} options:

\begin{description}
\item[audio\_file]
the corresponding audio file
\item[sub\_file]
name of the generated subtitle file
\end{description}

The following options are same as their counter-parts from the main
parameters table and generally don't need to be set:

\begin{itemize}
\tightlist
\item
  prefix
\item
  file\_desc
\item
  file\_id
\item
  text\_type
\item
  id\_sort
\item
  id\_prefix
\item
  sub\_format
\end{itemize}

Full example:

\begin{verbatim}
local domfilter = require "make4ht-domfilter"
local aeneas_config = require "make4ht-aeneas-config"

filter_settings "aeneas-config" {
  map = {
    ["krecekli1.xhtml"] = {audio_file="krecek.mp3"}, 
    ["krecek.xhtml"] = false
  }
}

local process = domfilter {"aeneas"}
Make:match("html$", process)

if mode == "draft" then
  aeneas_config.process_files {}
else
  aeneas_config.execute {}
end
\end{verbatim}

\hypertarget{image-conversion}{%
\subsection{Image conversion}\label{image-conversion}}

It is possible to convert parts of LaTeX input to pictures, it is used
for example for math or diagrams in \texttt{tex4ht}.

These pictures are stored in a special \texttt{dvi} file, which can be
processed by the \texttt{dvi\ to\ image} commands.

This conversion is normally configured in the \texttt{env\ file}, which
is system dependent and which has a bit unintuitive syntax. This
configuration is processed by the \texttt{t4ht} application and
conversion commands are called for all pictures.

It is possible to disable \texttt{t4ht} image processing and configure
image conversion in the build file:

\begin{verbatim}
Make:image("png$",
"dvipng -bg Transparent -T tight -o ${output}  -pp ${page} ${source}")
\end{verbatim}

\texttt{Make:image} takes two parameters, pattern to match image name
and action. Action can be either string template with conversion
command, or function which takes a table with parameters as an argument.

There are three parameters:

\begin{itemize}
\tightlist
\item
  \texttt{output} - output image file name
\item
  \texttt{source} - \texttt{dvi} file with the pictures
\item
  \texttt{page} - page number of the converted image
\end{itemize}

\hypertarget{the-mode-variable}{%
\subsection{\texorpdfstring{The \texttt{mode}
variable}{The mode variable}}\label{the-mode-variable}}

There is global \texttt{mode} variable available in the build file. It
contains contents of the \texttt{-\/-mode} command line option. It can
be used to run some commands conditionally. For example:

\begin{verbatim}
 if mode == "draft" then
   Make:htlatex{} 
 else
   Make:htlatex{}
   Make:htlatex{}
   Make:htlatex{}
 end
\end{verbatim}

In this example (which is the default configuration used by
\texttt{make4ht}), LaTeX is called only once when \texttt{make4ht} is
called with \texttt{draft} mode:

\begin{verbatim}
make4ht -m draft filename
\end{verbatim}

\hypertarget{the-settings-table}{%
\subsection{\texorpdfstring{The \texttt{settings}
table}{The settings table}}\label{the-settings-table}}

You may want to access to the parameters also outside commands, file
matches and image conversion functions. For example, if you want to
convert your file to the \texttt{OpenDocument\ Format\ (ODT)}, you can
use the following settings, based on the \texttt{oolatex} command:

\begin{verbatim}
settings.tex4ht_sty_par = settings.tex4ht_sty_par ..",ooffice"
settings.tex4ht_par = settings.tex4ht_par .. " ooffice/! -cmozhtf"
settings.t4ht_par = settings.t4ht_par .. " -cooxtpipes -coo "
\end{verbatim}

There are some functions to ease access to the settings:

\begin{description}
\item[\texttt{set\_settings\{parameters\}}]
overwrite settings with values from a passed table
\item[\texttt{settings\_add\{parameters\}}]
add values to the current settings
\item[\texttt{filter\_settings\ "filter\ name"\ \{parameters\}}]
set settings for a filter
\item[\texttt{get\_filter\_settings(name)}]
get settings for a filter
\end{description}

Using these functions, it is possible to simplify the settings for the
\texttt{ODT} format:

\begin{verbatim}
settings_add {
  tex4ht_sty_par =",ooffice",
  tex4ht_par = " ooffice/! -cmozhtf",
  t4ht_par = " -cooxtpipes -coo "
}
\end{verbatim}

Settings for filters and extensions can be set using
\texttt{filter\_settings}:

\begin{verbatim}
filter_settings "test" {
  hello = "world"
}
\end{verbatim}

These settings can be read in the extensions and filters using
\texttt{get\_filter\_settings}:

\begin{verbatim}
function test(input)
   local options = get_filter_settings("test")
   print(options.hello)
   return input
end
   
\end{verbatim}

\hypertarget{list-of-available-settings-for-filters-and-extensions.}{%
\subsection{List of available settings for filters and
extensions.}\label{list-of-available-settings-for-filters-and-extensions.}}

These settings may be set using \texttt{filter\_settings} function.

\hypertarget{the-tidy-extension}{%
\subsubsection{\texorpdfstring{The \texttt{tidy}
extension}{The tidy extension}}\label{the-tidy-extension}}

\begin{description}
\item[options]
command line options for the \texttt{tidy} command. Default value is
\texttt{-m\ -utf8\ -w\ 512\ -q}.
\end{description}

\hypertarget{the-fixinlines-dom-filter}{%
\subsubsection{\texorpdfstring{The \texttt{fixinlines} dom
filter}{The fixinlines dom filter}}\label{the-fixinlines-dom-filter}}

\begin{description}
\item[inline\_elements]
table of inline elements which shouldn't be direct descendants of the
\texttt{body} element. The element names should be table keys, the
values should be true.
\end{description}

Example

\begin{verbatim}
filter_settings "fixinlines" {inline_elements = {a = true, b = true}}
\end{verbatim}

\hypertarget{the-joincharacters-dom-filter}{%
\subsubsection{\texorpdfstring{The \texttt{joincharacters} dom
filter}{The joincharacters dom filter}}\label{the-joincharacters-dom-filter}}

\begin{description}
\item[charelements]
table of elements which should be joined if several instances with the
same value of \texttt{class} attribute are side by side.
\end{description}

Example

\begin{verbatim}
filter_settings "joincharacters" { charclases = { span=true, mn = true}}
\end{verbatim}

\hypertarget{mathjaxsettings}{%
\subsubsection{\texorpdfstring{The \texttt{mathjaxnode}
filter}{The mathjaxnode filter}}\label{mathjaxsettings}}

\begin{description}
\item[options]
command line options for the \texttt{mjpage} command. Default value is
\texttt{-\/-output\ CommonHTML}
\end{description}

Example

\begin{verbatim}
filter_settings "mathjaxnode" {
  options="--output SVG --font Neo-Euler"
}
\end{verbatim}

\begin{description}
\item[cssfilename]
\texttt{mjpage} puts some CSS code into the HTML pages.
\texttt{mathjaxnode} extracts this information and saves it to a
standalone CSS file. Default CSS filename is \texttt{mathjax-chtml.css}
\item[fontdir]
directory with MathJax font files. This option enables use of local
fonts, which is usefull in Epub conversion, for example. The font
directory should be sub-directory of the current directory. Only TeX
font is supported at the moment.
\end{description}

Example

\begin{verbatim}
filter_settings "mathjaxnode" {
  fontdir="fonts/TeX/woff/" 
}
\end{verbatim}

\hypertarget{the-aeneas-filter}{%
\subsubsection{\texorpdfstring{The \texttt{aeneas}
filter}{The aeneas filter}}\label{the-aeneas-filter}}

\begin{description}
\item[skip\_elements]
List of CSS selectors that match elements which shouldn't be processed.
Default value: \texttt{\{\ "math",\ "svg"\}}.
\item[id\_prefix]
prefix used in the ID attribute forming.
\item[sentence\_match]
Lua pattern used to match a sentence. Default value:
\texttt{"({[}\^{}\%.\^{}\%?\^{}!{]}*)({[}\%.\%?!{]}?)"}.
\end{description}

\hypertarget{the-staticsite-filter-and-extension}{%
\subsubsection{\texorpdfstring{The \texttt{staticsite} filter and
extension}{The staticsite filter and extension}}\label{the-staticsite-filter-and-extension}}

\begin{description}
\item[site\_root]
directory where generated files should be copied.
\item[map]
table where keys are patterns that match filenames, value contains
destination directoryfor matched files, relative to the
\texttt{site\_root} (it is possible to use \texttt{..} to swich to
parent directory).
\item[file\_pattern]
pattern used for filename generation. It is possible to use string
templates and format strings for \texttt{os.date} function. Default
value of \texttt{\%Y-\%m-\%d-\$\{input\}} creates names in the form of
\texttt{YYYY-MM-DD-file\_name}.
\item[header]
table with variables to be set in the YAML header in HTML files. If the
table value is a function, it is executed with current parameters and
HTML page DOM object as arguments.
\end{description}

Example:

\begin{verbatim}
local outdir = os.getenv "blog_root" 

filter_settings "staticsite" {
  site_root = outdir, 
  map = {
    [".css$"] = "../css/"
  },
  header = {
     layout="post",
     date = function(parameters, dom)
       return os.date("!%Y-%m-%d %T", parameters.time)
     end
  }
}
\end{verbatim}

\hypertarget{the-dvisvgm_hashes-extension}{%
\subsubsection{\texorpdfstring{The \texttt{dvisvgm\_hashes}
extension}{The dvisvgm\_hashes extension}}\label{the-dvisvgm_hashes-extension}}

\begin{description}
\item[options]
command line options for Dvisvgm. The default value is
\texttt{-n\ -\/-exact\ -c\ 1.15,1.15}.
\item[cpu\_cnt]
number of processor cores used for conversion. The extension tries to
detect the available cores automatically by default.
\item[parallel\_size]
number of pages used in each Dvisvgm call. The extension detects changed
pages in the DVI file and construct multiple calls to Dvisvgm with only
changed pages.
\end{description}

\hypertarget{configfile}{%
\section{Configuration file}\label{configfile}}

It is possible to globally modify the build settings using the
configuration file. New compilation commands can be added, extensions
can be loaded or disabled and settings can be set.

\hypertarget{location}{%
\subsection{Location}\label{location}}

The configuration file can be saved either in
\texttt{\$HOME/.config/make4ht/config.lua} or in \texttt{.make4ht} in
the current directory or it's parents (up to \texttt{\$HOME}).

\hypertarget{additional-commands}{%
\subsection{Additional commands}\label{additional-commands}}

There are two additional commands:

\begin{description}
\item[\texttt{Make:enable\_extension(name)}]
require extension
\item[\texttt{Make:disable\_extension(name)}]
disable extension
\end{description}

\hypertarget{example}{%
\subsection{Example}\label{example}}

The following configuration add support for the \texttt{biber} command,
requires \texttt{common\_domfilters} extension and requires MathML
output for math.

\begin{verbatim}
Make:add("biber", "biber ${input}")
Make:enable_extension "common_domfilters"
settings_add {
  tex4ht_sty_par =",mathml"
}
\end{verbatim}

\hypertarget{command-line-options}{%
\section{Command line options}\label{command-line-options}}

\begin{verbatim}
make4ht - build system for tex4ht
Usage:
make4ht [options] filename ["tex4ht.sty op." "tex4ht op." 
     "t4ht op" "latex op"]
-b,--backend (default tex4ht) Backend used for xml generation.
     possible values: tex4ht or lua4ht
-c,--config (default xhtml) Custom config file
-d,--output-dir (default "")  Output directory
-e,--build-file (default nil)  If build file name is different 
     than `filename`.mk4
-f,--format  (default nil)  Output file format
-l,--lua  Use lualatex for document compilation
-m,--mode (default default) Switch which can be used in the makefile
-n,--no-tex4ht  Disable dvi file processing with tex4ht command
-s,--shell-escape Enables running external programs from LaTeX
-u,--utf8  For output documents in utf8 encoding
-v,--version  Print version number
-x,--xetex Use xelatex for document compilation
<filename> (string) Input file name
\end{verbatim}

You can still invoke \texttt{make4ht} in the same way as
\texttt{htlatex}:

\begin{verbatim}
make4ht filename "customcfg, charset=utf-8" "-cunihtf -utf8" "-dfoo"
\end{verbatim}

Note that this will not use \texttt{make4ht} routines for output
directory making and copying. If you want to use them, change the line
above to:

\begin{verbatim}
make4ht -d foo filename "customcfg, charset=utf-8" "-cunihtf -utf8"
\end{verbatim}

This call has the same effect as the following:

\begin{verbatim}
make4ht -u -c customcfg -d foo filename
\end{verbatim}

Output directory doesn't have to exist, it will be created
automatically. Specified path can be relative to current directory, or
absolute:

\begin{verbatim}
make4ht -d use/current/dir/ filename
make4ht -d ../gotoparrentdir filename
make4ht -d ~/gotohomedir filename
make4ht -d c:\documents\windowspathsareworkingtoo filename
\end{verbatim}

\hypertarget{troubleshooting}{%
\section{Troubleshooting}\label{troubleshooting}}

\hypertarget{incorrect-handling-of-command-line-arguments-for-tex4ht-t4ht-or-latex}{%
\subsection{\texorpdfstring{Incorrect handling of command line arguments
for \texttt{tex4ht}, \texttt{t4ht} or
\texttt{latex}}{Incorrect handling of command line arguments for tex4ht, t4ht or latex}}\label{incorrect-handling-of-command-line-arguments-for-tex4ht-t4ht-or-latex}}

Sometimes, you may get a similar error:

\begin{verbatim}
make4ht:unrecognized parameter: i
\end{verbatim}

It may be caused by a following \texttt{make4ht} invocation:

\begin{verbatim}
make4ht hello.tex "customcfg,charset=utf-8" "-cunihtf -utf8" -d foo
\end{verbatim}

The command line option parser is confused by mixing options for
\texttt{make4ht} and \texttt{tex4ht} in this case and tries to interpret
the \texttt{-cunihtf\ -utf8}, which are options for \texttt{tex4ht}
command as \texttt{make4ht} options. To fix that, you can either move
the \texttt{-d\ foo} directly after \texttt{make4ht} command:

\begin{verbatim}
make4ht -d foo hello.tex "customcfg,charset=utf-8" "-cunihtf -utf8"
\end{verbatim}

Another option is to add a space before \texttt{tex4ht} options:

\begin{verbatim}
make4ht hello.tex "customcfg,charset=utf-8" " -cunihtf -utf8" -d foo
\end{verbatim}

The former way is preferable, though.

\hypertarget{filenames-containing-spaces}{%
\subsection{Filenames containing
spaces}\label{filenames-containing-spaces}}

\texttt{tex4ht} cannot handle filenames containing spaces.
\texttt{make4ht} thus replaces spaces in input file names with
underscores, so generated XML files use underscores instead of spaces as
well.

\hypertarget{filenames-containing-non-ascii-characters}{%
\subsection{Filenames containing non-ASCII
characters}\label{filenames-containing-non-ascii-characters}}

The \texttt{odt} output doesn't support accented filenames, it is best
to stick to ASCII characters in filenames.

\hypertarget{license}{%
\section{License}\label{license}}

Permission is granted to copy, distribute and/or modify this software
under the terms of the LaTeX Project Public License, version 1.3.
