The make4ht build system

Michal Hoftich <[email protected]>

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Contents

1 Introduction
2 Command line options
3 Why make4ht? – htlatex issues
 3.1 Passing command line arguments
 3.2 Compilation sequence
 3.3 Handling of the generated files
 3.4 Image conversion and postprocessing of the generated files
4 Output file formats and extensions
 4.1 Extensions
5 Build files
 5.1 User commands
 5.2 Provided commands
 5.3 File matches
 5.4 Image conversion
 5.5 The mode variable
 5.6 The settings table
6 Configuration file
 6.1 Location
 6.2 Additional commands
 6.3 Example
7 List of available settings for filters and extensions.
 7.1 Indexing commands
 7.2 The tidy extension
 7.3 The collapsetoc dom filter
 7.4 The fixinlines dom filter
 7.5 The joincharacters dom filter
 7.6 The mathjaxnode filter
 7.7 The staticsite filter and extension
 7.8 The dvisvgm_hashes extension
 7.9 The odttemplate filter and extension
 7.10 The aeneas filter
 7.11 The make4ht-aeneas-config package
8 Troubleshooting
 8.1 Incorrect handling of command line arguments for tex4ht, t4ht or latex
 8.2 Filenames containing spaces
 8.3 Filenames containing non-ASCII characters
9 License
10 Changelog

1 Introduction

make4ht is a build system for TeX4ht, TeX to XML converter. It provides a command line tool that drives the conversion process. It also provides a library that can be used to create customized conversion tools. An example of such a tool is tex4ebook, a tool for conversion from TeX to ePub and other e-book formats.

The basic conversion from LaTeX to HTML using make4ht can be executed using the following command:

$ make4ht filename.tex

It will produce a file named filename.html if the compilation goes without fatal errors.

2 Command line options

make4ht - build system for TeX4ht
Usage:
make4ht [options] filename ["tex4ht.sty op." "tex4ht op."
     "t4ht op" "latex op"]
-a,--loglevel (default status) Set log level.
            possible values: debug, info, status, warning, error, fatal
-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 the build filename is different
     than ‘filename‘.mk4
-f,--format  (default nil)  Output file format
-j,--jobname (default nil)  Set the jobname
-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
-x,--xetex Use xelatex for document compilation
-v,--version  Print version number
<filename> (string) Input filename

It is still possible to invoke make4ht in the same way as htlatex:

$ make4ht filename "customcfg, charset=utf-8" "-cunihtf -utf8" "-dfoo"

Note that this will not use make4ht routines for the output directory handling. See section 3.3 for more information about this issue. To use these routines, change the previous listing to:

$ make4ht -d foo filename "customcfg, charset=utf-8" "-cunihtf -utf8"

This call has the same effect as the following:

$ make4ht -u -c customcfg -d foo filename

Output directory does not have to exist, it make4ht creates it automatically. Specified path can be relative to the current directory, or absolute:

$ make4ht -d use/current/dir/ filename
$ make4ht -d ../gotoparrentdir filename
$ make4ht -d ~/gotohomedir filename
$ make4ht -d c:\documents\windowspathsareworkingtoo filename

The short options that do not take parameters can be collapsed:

$ make4ht -ulc customcfg -d foo filename

To pass the output from other commands to make4ht, use the - character as a filename. It is best to use this feature together with the --jobname or -j option.

$ cat hello.tex | make4ht -j world -

By default, make4ht tries to be quiet, so it hides most of the command line messages and output from the executed commands. It displays status messages, warnings, and errors. The logging level can be selected using the --loglevel or -a options. If the compilation fails, it may be useful to display more information using the info or debug levels.

$ make4ht -a debug faulty.tex

3 Why make4ht? – htlatex issues

TeX4ht system supports several output formats, most notably XHTML, HTML 5 and ODT, but it also supports TEI or Docbook.

The conversion can be invoked using several scripts, which are distributed with TeX4ht. They differ in parameters passed to the underlying commands.

These scripts invoke LaTeX or Plain TeX with special instructions to load the tex4ht.sty package. The TeX run produces a special DVI file that contains the code for the desired output format. The produced DVI file is then processed using the tex4ht command, which in conjunction with the t4ht command produces the desired output files.

3.1 Passing command line arguments

The basic conversion script provided by TeX4ht system is named htlatex. It compiles LaTeX  files to HTML with this command sequence:

$ 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

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

$ htlatex filename "tex4ht.sty options" "tex4ht_options" "t4ht_options" "latex_options"

For basic HTML conversion it is possible to use the most basic invocation:

$ htlatex filename.tex

It can be much more involved for the HTML 5 output in UTF-8 encoding:

$ htlatex filename.tex "xhtml,html5,charset=utf-8" " -cmozhtf -utf8"

make4ht can simplify it:

$ make4ht -u filename.tex

The -u option requires the UTF-8 encoding. HTML 5 is used as the default output format by make4ht.

More information about the command line arguments can be found in section 2.

3.2 Compilation sequence

htlatex has a fixed compilation order and a hard-coded number of LaTeX invocations.

It is not possible to execute additional commands during the compilation. When we want to run a program that interacts with LaTeX, such as Makeindex or Bibtex, we have two options. The first option is to create a new script based on htlatex and add the wanted commands to the modified script. The second option is to execute htlatex, then the additional and then htlatex again. The second option means that LaTeX will be invoked six times, as each call to htlatex executes three calls to LaTeX. This can lead to significantly long compilation times.

make4ht provides a solution for this issue using a build file, or extensions. These can be used for interaction with external tools.

make4ht also provides compilation modes, which enables to select commands that should be executed using a command line option.

There is a built-in draft mode, which invokes LaTeX only once, instead of the default three invocations. It is useful for the compilations of the document before its final stage, when it is not important that all cross-references work. It can save quite a lot of the compilation time:

$ make4ht -um draft filename.tex

More information about the build files can be found in section 5.

3.3 Handling of the generated files

There are also issues with the behavior of the t4ht application. It reads the .lg file generated by the tex4ht command. This file contains information about the generated files, CSS instructions, calls to the external applications, instructions for image conversions, etc.

t4ht can be instructed to copy the generated files to an output directory, but it doesn’t preserve the directory structure. When the images are placed in a
subdirectory, they will be copied to the output directory, losing the directory structure. Links will be pointing to a non-existing subdirectory. The following command should copy all output files to the correct destinations.

$ make4ht -d outputdir filename.tex

3.4 Image conversion and postprocessing of the generated files

TeX4ht can convert parts of the document to images. This is useful for diagrams or complicated math, for example.

By default, the image conversion is configured in a .env file. It has a bit of strange syntax, with operating system dependent rules. make4ht provides simpler means for the image conversion in the build files. It is possible to change the image conversion parameters without a need to modify the .env file. The process is described in section 5.4.

It is also possible to post-process the generated output files. The post-processing can be done either using external programs such as XSLT processors and HTML Tidy or using Lua functions. More information can be found in section 5.3.

4 Output file formats and extensions

The default output format used by make4ht is html5. A different format can be requested using the --format option. Supported formats are:

The --format option can be also used for extension loading.

4.1 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 +EXTENSION or -EXTENSION after the output format name:

 $ make4ht -uf html5+tidy filename.tex

Available extensions:

common_filters
clean the output HTML files using filters.
common_domfilters
clean the HTML file using DOM filters. It is more powerful than common_filters. Used DOM filters are fixinlines, idcolons, joincharacters, and tablerows.
detect_engine
detect engine and format necessary for the document compilation from the magic comments supported by LaTeX editors such as TeXShop or TeXWorks. Add something like the following line at the beginning of the main TeX file:

%!TEX TS-program = xelatex

It supports also Plain TeX, use for example tex or luatex as the program name.

dvisvgm_hashes
efficient generation of SVG pictures using Dvisvgm. It can utilize multiple processor cores and generates only changed images.
join_colors
load the joincolors domfilter for all HTML files.
latexmk_build
use Latexmk for the LaTeX compilation.
mathjaxnode
use mathjax-node-page to convert from MathML code to HTML + CSS or SVG. See the available settings.
odttemplate
it automatically loads the odttemplate filter (page 34).
preprocess_input
compilation of the formats supported by Knitr (.Rnw, .Rtex, .Rmd, .Rrst) and also Markdown and reStructuredText formats. It requires R + Knitr installation, it requires also Pandoc for formats based on Markdown or reStructuredText.
staticsite
build the document in a form suitable for static site generators like Jekyll.
tidy
clean the HTML files using the tidy command.

5 Build files

make4ht supports build files. These are Lua scripts that can adjust the build process. They can request external applications like BibTeX or Makeindex, pass options to the commands, modify the image conversion process, or post-process the generated files.

make4ht tries to load default build file named as filename + .mk4 extension. It is possible to select a different build file with -e or --build-file command line option.

Sample build file:

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

Make:htlatex() is preconfigured command for calling LaTeX with the tex4ht.sty package loaded. In this example, it will be executed only once. After the compilation, the tidy command is executed on the output HTML files.

Note that it is not necessary to call tex4ht and t4ht commands explicitly in the build file, they are called automatically.

5.1 User commands

It is possible to add more commands like Make:htlatex using the Make:add command:

Make:add("name", "command", {settings table}, repetition)

This defines the name command, which can be then executed using Make:name() command in the build file.

The name and command parameters are required, the rest of the parameters are optional.

The defined command receives a table with settings as a parameter at the call time. The default settings are provided by make4ht. Additional settings can be declared in the Make:add commands, user can also override the default settings when the command is executed in the build file:

Make:name({hello="world"})

More information about settings, including the default settings provided by make4ht, can be found in section 5.6 on page 40.

5.1.1 The command function

The command parameter can be either a string template or function:

Make:add("text", "echo hello, input file: ${input}")

The template can get a variable value from the parameters table using a ${var_name} placeholder. Templates are executed using the operating system, so they should invoke existing OS commands.

5.1.2 The settings table table

The settings table parameter is optional. If it is present, it should be a table with new settings available in the command. It can also override the default make4ht settings for the defined command.

Make:add("sample_function", function(params)
  for k, v in pairs(params) do
    print(k..": "..v)
  end, {custom="Hello world"}
)

5.1.3 Repetition

The repetition parameter specifies the maximum number of executions of the particular command. This is used for instance for tex4ht and t4ht commands, as they should be executed only once in the compilation. They would be executed multiple times when they are included in the build file, as they are called by make4ht by default. Because these commands allow only one repetition, the second execution is blocked.

5.1.4 Expected exit code

You can set the expected exit code from a command with a correct_exit key in the settings table. The compilation will be terminated when the command returns a different exit code.

Make:add("biber", "biber ${input}", {correct_exit=0})

Commands that execute lua functions can return the numerical values using the return statement.

This mechanism isn’t used for TeX, because it doesn’t differentiate between fatal and non-fatal errors. It returns the same exit code in all cases. Because of this, log parsing is used for a fatal error detection instead. Error code value 1 is returned in the case of a fatal error, 0 is used otherwise. The Make.testlogfile function can be used in the build file to detect compilation errors in the TeX log file.

5.2 Provided commands

Make:htlatex
One call to the TeX engine with special configuration for loading of the tex4ht.sty package.
Make:httex
Variant of Make:htlatex suitable for Plain TeX.
Make:latexmk
Use Latexmk for the document compilation. tex4ht.sty will be loaded automatically.
Make:tex4ht
Process the DVI file and create output files.
Make:t4ht
Create the CSS file and generate images.
Make:biber
Process bibliography using the biber command.
Make:pythontex
Process the input file using pythontex.
Make:bibtex
Process bibliography using the bibtex command.
Make:xindy
Generate index using Xindy index processor.
Make:makeindex
Generate index using the Makeindex command.
Make:xindex
Generate index using the Xindex command.

5.3 File matches

Another type of action that can be specified in the build file is Make:match. It can be used to post-process the generated files:

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

The above example will clean all output HTML files using the tidy command.

The Make:match action tests output filenames using a Lua pattern matching function.
It executes a command or a function, specified in the second argument, on files whose filenames match the pattern.

The commands to be executed can be specified as strings. They can contain ${var_name} placeholders, which are replaced with corresponding variables from the settings table. The templating system was described in subsection 5.1.1. There is an additional variable available in this table, called filename. It contains the name of the current output file.

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

Make:match("html$", function(filename, settings)
  print("Post-processing file: ".. filename)
  print("Available settings")
  for k,v in pairs(settings)
    print(k,v)
  end
  return true

end)

Multiple post-processing actions can be executed on each filename. The Lua action functions can return an exit code. If the exit code is false, the execution of the post-processing chain for the current file will be terminated.

5.3.1 Filters

To make it easier to post-process the generated files using the match actions, make4ht provides a filtering mechanism thanks to the make4ht-filter module.

The make4ht-filter module returns a function that can be used for the filter chain building. Multiple filters can be chained into a pipeline. Each filter can modify the string that is passed to it from the previous filters. The changes are then saved to the processed file.

Several built-in filters are available, it is also possible to create new ones.

Example that use only the built-in filters:

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

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

Example with custom filter:

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

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

Built-in filters are the following:

cleanspan
clean spurious span elements when accented characters are used
cleanspan-nat
alternative clean span filter, provided by Nat Kuhn
fixligatures
decompose ligatures to base characters
hruletohr
\hrule commands are translated to series of underscore characters by TeX4ht, this filter translates these underscores to <hr> elements
entites
convert prohibited named entities to numeric entities (only &nbsp; currently).
fix-links
replace colons in local links and id attributes with underscores. Some cross-reference commands may produce colons in internal links, which results in a validation error.
mathjaxnode
use mathjax-node-page to convert from MathML code to HTML + CSS or SVG. See the available settings.
odttemplate
use styles from another ODT file serving as a template in the current document. It works for the styles.xml file in the ODT file. During the compilation, this file is named as \jobname.4oy.
staticsite
create HTML files in a format suitable for static site generators such as Jekyll
svg-height
some SVG images produced by dvisvgm seem to have wrong dimensions. This filter tries to set the correct image size.

5.3.2 DOM filters

DOM filters are variants of filters that use the LuaXML library to modify directly the XML object. This enables more powerful operations than the regex-based filters from the previous section.

Example:

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

Available DOM filters:

aeneas
Aeneas is a tool for automagical synchronization of text and audio. This filter modifies the HTML code to support synchronization.
booktabs
fix lines produced by the \cmidrule command provided by the Booktabs package.
collapsetoc
collapse table of contents to contain only top-level sectioning level and sections on the current page.
fixinlines
put all inline elements which are direct children of the <body> elements to a paragraph.
idcolons
replace the colon (:) character in internal links and id attributes. They cause validation issues.
joincharacters
join consecutive <span> or <mn> elements. This DOM filter supersedes the cleanspan filter.
joincolors
many <span> elements with unique id attributes are created when LaTeX colors are being used in the document. A CSS rule is added for each of these elements, which may result in substantial growth of the CSS file. This filter replaces these rules with a common one for elements with the same color value.
odtimagesize
set correct dimensions for images in the ODT format. It is loaded by default for the ODT output.
odtpartable
resolve tables nested inside paragraphs, which is invalid in the ODT format.
tablerows
remove spurious rows from HTML tables.
mathmlfixes
fix common issues for MathML.
t4htlinks
fix hyperlinks in the ODT format.

5.4 Image conversion

It is possible to convert parts of the LaTeX input as pictures. It can be used for preserving the appearance of math or diagrams, for example.

These pictures are stored in a special DVI file, which can be processed by a DVI to image commands, such as dvipng or dvisvgm.

This conversion is normally configured in the tex4ht.env file. This file is system dependent and it has quite an unintuitive syntax. The configuration is processed by the t4ht application and the conversion command is called for all pictures.

It is possible to disable t4ht image processing and configure image conversion in the build file using the image action:

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

Make:image takes two parameters, a Lua pattern to match the image name, and the action.

Action can be either a string template with the conversion command or a function that takes a table with parameters as an argument.

There are three parameters:

5.5 The mode variable

The mode variable available in the build process contains contents of the --mode command line option. It can be used to run some commands conditionally. For example:

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

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

make4ht -m draft filename

5.6 The settings table

It is possible to access the parameters outside commands, file matches and image conversion functions. For example, to convert the document to the OpenDocument Format (ODT), the following settings can be used. They are based on the oolatex command:

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 "

(Note that it is possible to use the --format odt option which is superior to the previous code. This example is intended just as an illustration)

There are some functions to simplify access to the settings:

set_settings{parameters}
overwrite settings with values from a passed table
settings_add{parameters}
add values to the current settings
filter_settings "filter name" {parameters}
set settings for a filter
get_filter_settings(name)
get settings for a filter

For example, it is possible to simplify the sample from the previous code listings:

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

Settings for filters and extensions can be set using filter_settings:

filter_settings "test" {
  hello = "world"
}

These settings can be retrieved in the extensions and filters using the get_filter_settings function:

function test(input)
   local options = get_filter_settings("test")
   print(options.hello)
   return input
end

5.6.1 Default settings

The default parameters are the following:

htlatex
used TeX engine
input
content of \jobname, see also the tex_file parameter.
interaction
interaction mode for the TeX engine. The default value is batchmode to suppress user input on compilation errors. It also suppresses most of the TeX  compilation log output. Use the errorstopmode for the default behavior.
tex_file
input TeX filename
latex_par
command line parameters to the TeX engine
packages
additional LaTeX code inserted before \documentclass. Useful for passing options to packages used in the document or to load additional packages.
tex4ht_sty_par
options for tex4ht.sty
tex4ht_par
command line options for the tex4ht command
t4ht_par
command line options for the t4ht command
outdir
the output directory
correct_exit
expected exit code from the command. The compilation will be terminated if the exit code of the executed command has a different value.

6 Configuration file

It is possible to globally modify the build settings using the configuration file. It is a special version of a build file where the global settings can be set.

Common tasks for the configuration file can be a declaration of the new commands, loading of the default filters or specification of a default build sequence.

One additional functionality not available in the build files are commands for enabling and disabling of extensions.

6.1 Location

The configuration file can be saved either in the $HOME/.config/make4ht/config.lua file, or in the .make4ht file placed in the current directory or it’s parent directories (up to the $HOME directory).

6.2 Additional commands

There are two additional commands:

Make:enable_extension(name)
require extension
Make:disable_extension(name)
disable extension

6.3 Example

The following example of the configuration file adds support for the biber command, requires common_domfilters extension and requires MathML output for math.

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

7 List of available settings for filters and extensions.

These settings may be set using filter_settings function in a build file or in the make4ht configuration file.

7.1 Indexing commands

The indexing commands (like xindy or makeindex) use some common settings.

idxfile
name of the .idx file. Default value is \jobname.idx.
indfile
name of the .ind file. Default value is the same as idxfile with the file extension changed to .ind.

Each indexing command can have some additional settings.

7.1.1 The xindy command

encoding
text encoding of the .idx file. Default value is utf8.
language
index language. Default language is English.
modules
table with names of additional Xindy modules to be used.

7.1.2 The makeindex command

options
additional command line options for the Makeindex command.

7.1.3 The xindex command

options
additional command line options for the Xindex command.
language
document language

7.2 The tidy extension

options
command line options for the tidy command. Default value is -m -utf8 -w 512 -q.

7.3 The collapsetoc dom filter

toc_query
CSS selector for selecting the table of contents container.
title_query
CSS selector for selecting all elements that contain the section ID attribute.
toc_levels
table containing a hierarchy of classes used in TOC

Default values:

filter_settings "collapsetoc" {
  toc_query = ".tableofcontents",
  title_query = ".partHead a, .chapterHead a, .sectionHead a, .subsectionHead a",
  toc_levels = {"partToc", "chapterToc", "sectionToc", "subsectionToc", "subsubsectionToc"}
}

7.4 The fixinlines dom filter

inline_elements
table of inline elements that shouldn’t be direct descendants of the body element. The element names should be table keys, the values should be true.

Example

filter_settings "fixinlines" {inline_elements = {a = true, b = true}}

7.5 The joincharacters dom filter

charclasses
table of elements that should be concatenated when two or more of such elements with the same value of the class attribute are placed one after another.

Example

filter_settings "joincharacters" { charclasses = { span=true, mn = true}}

7.6 The mathjaxnode filter

options
command line options for the mjpage command. Default value is --output CommonHTML

Example

filter_settings "mathjaxnode" {
  options="--output SVG --font Neo-Euler"
}

cssfilename
the mjpage command puts some CSS code into the HTML pages. mathjaxnode extracts this information and saves it to a standalone CSS file. Default CSS filename is mathjax-chtml.css
fontdir
directory with MathJax font files. This option enables the use of local fonts, which is useful in the conversion to ePub, for example. The font directory should be sub-directory of the current directory. Only TeX font is supported at the moment.

Example

filter_settings "mathjaxnode" {
  fontdir="fonts/TeX/woff/"
}

7.7 The staticsite filter and extension

site_root
directory where generated files should be copied.
map
a hash table where keys contain patterns that match filenames and values contain destination directory for the matched files. The destination directories are relative to the site_root (it is possible to use .. to switch to a parent directory).
file_pattern
a pattern used for filename generation. It is possible to use string templates and format strings for os.date function. The default pattern %Y-%m-%d-${input} creates names in the form of YYYY-MM-DD-file_name.
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.

Example:

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
  }
}

7.8 The dvisvgm_hashes extension

options
command line options for Dvisvgm. The default value is -n --exact -c 1.15,1.15.
cpu_cnt
the number of processor cores used for the conversion. The extension tries to detect the available cores automatically by default.
parallel_size
the number of pages used in each Dvisvgm call. The extension detects changed pages in the DVI file and constructs multiple calls to Dvisvgm with only changed pages.
scale
SVG scaling.

7.9 The odttemplate filter and extension

template
filename of the template ODT file

odttemplate can also get the template filename from the odttemplate option from tex4ht_sty_par parameter. It can be set using the following command line call:

 make4ht -f odt+odttemplate filename.tex "odttemplate=template.odt"

7.10 The aeneas filter

skip_elements
List of CSS selectors that match elements that shouldn’t be processed. Default value: { "math", "svg"}.
id_prefix
prefix used in the ID attribute forming.
sentence_match
Lua pattern used to match a sentence. Default value: "([^%.^%?^!]*)([%.%?!]?)".

7.11 The make4ht-aeneas-config package

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

Available functions:

write_job(parameters)
write Aenas job configuration to config.xml file. See the Aeneas documentation for more information about jobs.
execute(parameters)
execute Aeneas.
process_files(parameters)
process the audio and generated subtitle files.

By default, a SMIL file is created. It is assumed that there is an audio file in the mp3 format, named as the TeX file. It is possible to use different formats and filenames using mapping.

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

7.11.1 Available parameters

lang
document language. It is interfered from the HTML file, so it is not necessary to set it.
map
mapping between HTML, audio and subtitle files. More info below.
text_type
type of input. The aeneas DOM filter produces an unparsed text type.
id_sort
sorting of id attributes. The default value is numeric.
id_regex
regular expression to parse the id attributes.
sub_format
generated subtitle format. The default value is smil.

7.11.2 Additional parameters for the job configuration file

It is possible to generate multiple HTML files from the LaTeX source. For example, tex4ebook generates a 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 the map parameter.

Example:

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

Table keys are the configured filenames. It is necessary to insert them as ["filename.html"], because of Lua syntax rules.

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

Filenames of the subfiles correspond to the chapter numbers, so they are not stable when a new chapter is added. It is possible to request filenames derived from the chapter titles using the sec-filename option for tex4ht.sty.

7.11.3 Available map options

audio_file
the corresponding audio file
sub_file
name of the generated subtitle file

The following options are the same as their counterparts from the main parameters table and generally, don’t need to be set:

7.11.4 Full example
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

8 Troubleshooting

8.1 Incorrect handling of command line arguments for tex4ht, t4ht or latex

Sometimes, you may get a similar error:

make4ht:unrecognized parameter: i

It may be caused by a following make4ht invocation:

$ make4ht hello.tex "customcfg,charset=utf-8" "-cunihtf -utf8" -d foo

The command line option parser is confused by mixing options for make4ht and TeX4ht in this case. It tries to interpret the -cunihtf -utf8, which are options for the tex4ht command, as make4ht options. To fix that, try to move the -d foo directly after the make4ht command:

$ make4ht -d foo hello.tex "customcfg,charset=utf-8" "-cunihtf -utf8"

Another option is to add a space before the tex4ht options:

$ make4ht hello.tex "customcfg,charset=utf-8" " -cunihtf -utf8" -d foo

The former way is preferable, though.

8.2 Filenames containing spaces

tex4ht command cannot handle filenames containing spaces. to fix this issue, make4ht replaces spaces in the input filenames with underscores. The generated XML filenames use underscores instead of spaces as well.

8.3 Filenames containing non-ASCII characters

The odt output doesn’t support accented filenames, it is best to stick to ASCII characters in filenames.

9 License

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

10 Changelog