Crowbook User Guide

Élisabeth Henry

1. Crowbook

Render a book written in markdown to HTML, EPUB and/or PDF.

Crowbook’s purpose is to allow you to automatically generate multiple output formats from a book written in Markdown. Its focus is novels, and the default settings should (hopefully) generate readable books with correct typography without requiring you to worry about it.

1.1. Example

To see what Crowbook’s output looks like, you can read the Crowbook guide rendered in HTML, PDF or EPUB.

You can also play with the online demo version.

1.2. Installing

There are two ways to install Crowbook: either using precompiled binaries, or compiling it using cargo.

Binaries

See the releases page to download a precompiled binary for your architecture (currently: Linux, Windows and MacOSX). Just extract the archive and run crowbook (or crowbook.exe on Windows). You might also want to copy the binary somewhere in your PATH for later usage.

If you are on Debian GNU/Linux or Ubuntu (on a PC architecture), you can also download .deb packages on the releases page.

Using Cargo

Cargo is the Rust’s package manager. You can install it here. Once it is done:

$ cargo install crowbook

will automatically download the latest crowbook release on crates.io, compile it, and install it on your system.

Some dependencies also require building C libraries; you might thus also need to install a C compiler and make/cmake build tools.

1.3. Dependencies

While there should be, strictly speaking, no real dependencies to be able to run Crowbook (it is published as a statically compiled binary), some features require additional commands to work correctly:

EPUB rendering requires the zip command to be present on your system;

PDF rendering requires a working installation of LaTeX (preferably xelatex).

1.4. Quick tour

The simplest command is:

$ crowbook <BOOK>

where BOOK is a configuration file. Crowbook will parse this file and generate a book in HTML, EPUB, and/or PDF, according to the settings in the configuration file.

To create a new book, assuming you have a list of Markdown files, you can generate a template configuration file with the --create argument:

$ crowbook my.book --create chapter_*.md

This will generate a default my.book file, which you’ll need to complete. This configuration file contains some metadata, options, and lists the Markdown files.

For short books containing only a single Markdown file, it is possible to embed some metadata at the beginning of the file and use the --single or -s option to run crowbook directly on this Markdown file and avoid creating a separate book configuration file:

$ crowbook -s text.md

For more information see the chapters on the arguments supported by crowbook and on the configuration file.

1.5. Current features

Output formats

Crowbook supports HTML, PDF and EPUB (either version 2 or 3) as output formats. See the Crowbook User Guide rendered in HTML, EPUB and PDF.

Input format

Crowbook uses pulldown-cmark and thus should support most of CommonMark Markdown. Inline HTML, however, is not implemented, and probably won’t be, as the goal is to have books that can also be generated in PDF (and maybe ODT).

Typographic “cleaning”

Maybe the most specific “feature” of Crowbook is that (by default, it can be deactivated) it tries to “clean” the input files. By default, it removes superfluous spaces and tries to use curly quotes. If the book’s language is set to french, it also tries its best to respect french typography by replacing spaces with non-breaking ones when it is appropriate (e.g. before ‘?’, ‘!’, ‘;’ or ‘:’).

Please open an issue describing typographic rules if you want it to be implemented for other languages.

Links handling

Crowbook tries to correctly translate local links in the input Markdown files: e.g. if you have a link to a Markdown file that is part of your book, it will be transformed into a link inside the document.

Inline YAML blocks

Crowbook supports inline YAML blocks:

---
author: Me
title: My title
---

This is mostly useful when Crowbook is run with the --single argument (receiving a single Markdown file instead of a book configuration file), for short texts that only contain one “chapter”.

Proofreading

Crowbook can also generate “proofreading” copies in HTML or PDF, highlighting grammar errors and repetitions. For more information, see the proofreading chapter of the guide.

Bugs

See the github’s issue tracker.

1.6. Contributors

Stéphane Mourey <s+crowbook AT stephanemourey DOT fr>

1.7. Acknowledgements

Besides the Rust compiler and standard library, Crowbook uses the following libraries:

pulldown-cmark

yaml-rust

mustache

clap

chrono

uuid

mime_guess

crossbeam

walkdir

rustc-serialize

caribon

hyper

url

lazy_static

regex

term

numerals

syntect

It also embeds Highlight.js in HTML output to enable syntax highlighting for code blocks.

It also uses configuration files from rust-everywhere to use Travis and Appveyor to generate binaries for various platforms on each release.

While Crowbook directly doesn’t use them, there was also inspiration from Pandoc and mdBook.

Also, the W3C HTML validator and the IDPF EPUB validator proved very useful during development.

1.8. ChangeLog

See ChangeLog.

1.9. Contributing

See how you can contribute to Crowbook.

1.10. Library

While the main purpose of Crowbook is to be run as a standalone program, the code is written as a library, so if you want to build on it you can use it as such. You can look at the generated documentation on docs.rs.

Note that, in order to facilitate code reuse, some features have been split to separate libraries:

epub-builder makes it easier to generate EPUB files.

crowbook-text-processing contains all the “typographic” functions (smart quotes, handling of non-breaking spaces in french, ...).

crowbook-intl is used for the internationalization (translation) process.

1.11. License

Crowbook is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (LGPL), version 2.1 or (at your option) any ulterior version. See LICENSE for more information.

Crowbook’s logo is licensed under the Creative Commons Attribution 4.0 International license, based on the Rust logo by Mozilla Corporation.

Crowbook includes binary (minified) CSS and Javascript files from Highlight.js, written by Ivan Sagalaev, licensed under the following terms:

Copyright (c) 2006, Ivan Sagalaev

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

Neither the name of highlight.js nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS’’ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

2. Arguments

Crowbook can take a number of arguments:

Render a Markdown book in EPUB, PDF or HTML.

USAGE:
    crowbook [OPTIONS] [--] [BOOK]

FLAGS:
    -h, --help            Print help information
    -l, --list-options    List all possible options
    -p, --proofread       Enable proofreading
    -q, --quiet           Don't print info/error messages
    -s, --single          Use a single Markdown file instead of a book configuration file
    -v, --verbose         Print warnings in parsing/rendering
    -V, --version         Print version information

OPTIONS:
    -c, --create <FILES>...            Create a new book with existing Markdown files
    -o, --output <FILE>                Specify output file
        --print-template <TEMPLATE>    Prints the default content of a template
        --set <KEY_VALUES>             Set a list of book options
    -t, --to <FORMAT>                  Generate specific format

ARGS:
    <BOOK>    File containing the book configuration file, or a Markdown file when called with --single

The most important option is obviously <BOOK>, i.e. the book configuration file. It is mandatory in most cases: if you don’t pass it, Crowbook will simply display this help message. In a normal use case this is the only argument you’ll need to pass, and Crowbook will generate the book in all formats specified in the configuration file.

It is, however, possible to pass more arguments to crowbook:

2.1. --create

Usage: crowbook [BOOK] --create file_1.md file_2.md ...

Creates a new book from a list of Markdown files. It will generate a book configuration file with all file names specified as chapters. It either prints the result to stdout (if BOOK is not specified) or generate the file BOOK (or abort if it already exists).

Examples

crowbook foo.book --create  README.md ChangeLog.md LICENSE.md

will generate a file foo.book containing:

author: Your name
title: Your title
lang: en

# Uncomment and fill to generate files
# output.html: some_file.html
# output.epub: some_file.epub
# output.pdf: some_file.pdf

# Uncomment and fill to set cover image (for Epub)
# cover: some_cover.png

# List of chapters
+ README.md
+ ChangeLog.md
+ LICENSE.md

while

crowbook --create README.md ChangeLog.md LICENSE.md

will print the same result, but to stdout (without creating a file).

When crowbook is run with --create, it can also use the keys/values set by --set (see below):

$ crowbook foo.book --create file1.md file2.md --set author "Pierre Dupont" title "Mon œuvre" lang fr

will generate a foo.book file containing:

author: Pierre Dupont
title: Mon œuvre
lang: fr

# List of chapters
+ file1.md
+ file2.md

2.2. --single

usage: crowbook --single <FILE>

(or crowbook -s <FILE>)

This argument allows to give crowbook a single Markdown file. This file can contain an inline YAML block to set some book options. Inline YAML blocks must start and end with a line containing only --- (three dashes). E.g:

---
author: Joan Doe
title: A short story
output.html: short.html
---

If this YAML block is not at the beginning of a file, it must also be preceded by a blank line.

This allows to not have to write a .book configuration file for a short story or an article. crowbook -s foo.md is rougly equivalent to having a book configuration file containing:

! foo.md

That is, the chapter heading (if any) won’t be displayed in the output documents (though they still appear in the TOC).

Note that by default, using --single or -s sets the default LaTeX class of the book to article instead of book.

2.3. --set

usage: crowbook <BOOK> --set [KEY] [VALUE]...

This argument takes a list of KEY VALUE pairs and allows setting or overriding a book configuration option. All valid options in the configuration files are valid as keys. For more information, see the configuration file.

Examples

$ crowbook foo.book --set html.css style.css

will override the CSS for HTML generation (the html.css key) to the file style.css.

$ crowbook foo.book --set author Foo title Bar

will override the book title to Bar and its author to Foo.

2.4. --proofread

usage: crowbook --proofread <BOOK>

(or crowbook -p <BOOK>)

Equivalent to --set proofread true. Enable proofreading. See Proofreading.

2.5. --list-options

usage: crowbook --list-options

(or crowbook -l)

Displays all the valid options to use, whether in a book configuration file, with --set, or in an inline YAML block.

2.6. --print-template

usage: crowbook --print-template template

Prints the built-in template to stdout. Useful if you want to customize the appearance of your document. E.g., if you want to modify the CSS used for HTML rendering:

$ crowbook --print-template html.css > my_style.css
# edit my_style.css in your favourite editor
$ crowbook my.book --set html.css my_style.css
# or add "html.css: my_style.css" in my.book

2.7. --verbose

usage: crowbook <BOOK> --verbose

If this flag is set, Crowbook will print the warnings it detects while parsing and rendering. These warnings are typically related to the inclusion of non-local images, linking to Markdown files that are not part of the book, and so on.

2.8. --to

usage: crowbook <BOOK>--to [FORMAT]

(or crowbook <BOOK> -t [FORMAT])

Generate only the specified format. FORMAT must be either epub, pdf, html, html.dir, odt or tex.

If an output file for the format is not specified in the book configuration file, crowbook will fail to render PDF, ODT and EPUB, whereas it will print HTML and TeX files on stdout. It is, however, possible to specify a file with the --output option.

Examples

crowbook --to html foo.book

will generate some HTML, and prints it either to the file specified by output.html in foo.book, or to stdout if it is not specified.

crowbook --to pdf --output foo.pdf foo.book

will generate a foo.pdf file.

2.9. --output

usage: crowbook <BOOK> --to <FORMAT> --output <FILE>

(or crowbook -t <FORMAT> -o <FILE> <BOOK>)

Specifies an output file. Only valid when --to is used.

2.10. --lang

usage: crowbook --lang <LANG>

(or crowbook -L <LANG>)

Set the runtime language used by Crowbook. Currently, only a french translation is available. By default, Crowbook uses the LANG environment variable to determine which language to use, but this option allows to override it (e.g. for operating systems that don’t use such an option, such as Windows).

Example

$ crowbook --lang fr --help

will display Crowbook’s help messages in french.

Note that this argument has nothing to do with the lang option that you can set in the book configuration file, which specifies the language of the book. This argument specifies the language of the text messages that Crowbook will display while running.

3. The configuration file

If you want to use Crowbook for your book, this configuration file is all you’ll have to add (assuming you already have the book in Markdown files; if you don’t, you’ll also have to write a book first, but that’s besides the scope of this document).

The format is not very complicated. This is an example of it:

# metadata
author: Joan Doe
title: Some book
lang: en

output.html: some_book.html

# list of chapters
- preface.md
+ chapter_1.md
+ chapter_2.md
+ chapter_3.md
+ chapter_4.md
- epilogue.md

Basically, it is divided in two parts:

a list of options, under the form key: value, following YAML syntax.

a list of Markdown files.

Lines starting with the # characters are comments and are discarded.

3.1. Configuration in an inline YAML block

Sometimes, you only have one Markdown file and might not want to have a separate configuration file. In this case, you can specify options at the beginning of your Markdown file, using an inline YAML block, separated by two lines containing only ---:

---
author: Joan Doe
title: Some (short) book
lang: en

output.html: some_book.html
---

# Some (short) book

The book content, formatted in Markdown.

This method only allows to set up options: you can’t include a list of chapters in this way, since the only “chapter” that will be included is this Markdown file itself.

You can then use

crowbook -s some_book.md

to generate output formats from this Markdown file.

By default (unless input.yaml_blocks is set to true), Crowboook will only read those inline blocks when it is runned with crowbook --single (or crowbook -s).

3.2. The list of files

There are various options to include a Markdown file.

+ file_name.md includes a numbered chapter.

- file_name.md includes an unnumbered chapter.

! file_name.md includes a chapter whose title won’t be displayed (except in the table of contents); this is useful for e.g. including a copyright at the beginning or the book, or for short stories where there is only one chapter.

42. file_name.md specifies the number for a chapter.

@ includes a part instead of a chapter.

So a typical usage might look like this:

! copyright.md
- preface.md
0. chapter_0.md # We want to start at chapter 0 instead of 1
# Next chapters can be numbered automatically
+ chapter_1.md
+ chapter_2.md
...

There are two important things to note:

you must not use quotes around the file names.

the path of these files are relative to the directory where your configuration file is. This means you can run crowbook books/my_trilogy/first_book/config.book without being in the book’s directory.

Also note that you don’t have to specify a title. This is because the title of the chapter is inferred from the Markdown document. To go back to our previous example:

+ chapter_1.md

does not specify a chapter title, because it will read it directly in chapter_1.md, e.g.:

# The day I was born #
...

You should have one and only one level-one header (i.e. chapter title) in each Markdown file.

If you have more than one, Crowbook will print a warning and treat it as another chapter (numbered according to the scheme specified for including the file). It might however mess the table of contents in some cases (e.g. for EPUB).

If you do not have a level-1 header in a markdown file:

if it is a numbered chapter, Crowbook will infer a chapter name from the numbering scheme;

if it is not numbered, chapter’s title will default to the empty string.

Parts

Parts are included using the @ character, followed by the same characters than for chapters:

@+ numbered_part.md
+ chapter_01.md
+ chapter_02.md
@- unnumbered_part.md
+ chapter_03.md
+ chapter_04.md
@42. part_with_number_42.md
+ chapter_05.md

However, you usually don’t really want to have a content directly below the part, only chapters (though it can be useful to add an introduction before the first chapter of this part), so there is also a more straighforward way to use parts, using only the @ character followed by the (markdown-formatted) title of this part:

@ Beginning
+ chapter_01.md
+ chapter_02.md
@ Middle
+ chapter_03.md
+ chapter_04.md
@ Appendix
- notes.md

With this shortcut, parts are always numbered. So

@ Beginning

is equivalent to

@+ some_file.md

with some_file.md containing only a title:

# Beginning

3.3. Crowbook options

The first part of the configuration file is dedicated to pass options to Crowbook. This is YAML syntax, so each line should be of the form key: value. Note that in most cases you don’t have to put string in quotes, e.g.:

title: My title

It is however possible (and sometimes necessary) to escape some characters to use quotes around strings:

title: "My: title!"

It is possible to use multiline strings with >- and then indenting the lines that are part of the string:

title: >-
 A
 long
 title
author: Joan Doe

will set title to “A long title”. See block literals in YAML for more information on the various way to insert multiline strings (which mostly change the way newlines will or won’t be inserted).

A final note on the syntax: all options must be set before the first chapter inclusion (that is, a line beginning with ‘+’, ‘-’, ‘x.’ (where x is a number) or ‘!’).

Metadata

Metadata are data about the book. Except for cover, which points to an image file, all its fields are strings. The main metadata are:

author: the author(s) of the book.

title: the title of the book.

lang: the language of the book. The unicode language code should be used, e.g. en_GB or en, fr_FR, ...

cover: path to an image file for the cover of the book (not displayed in all output formats).

There are also additional metadata:

subject

description

license

version

date

You can define your own metadata by starting an option name with metadata.foo.

All metadata are accessible from templates, see Templates.

The import special option

The special import option allows you to include the options of another book configuration file. E.g., assuming that you want some common options to be applied to both foo.book and bar.book, you can create a common.book file:

author: Joan Doe
lang: en
license: "Copyright (C) Joan Doe. All rights reserved."

html.header: "[Joan Doe's website](http://joan-doe.com)"
tex.template: my_template.tex

You can then include this file in foo.book:

import: common.book
title: Foo

+ foo_01.md
+ foo_02.md

Or include it in bar.book, but override some of its features:

import: common.book
title: Bar
license: CC-BY-SA  # Override the license from common.book

+ bar_01.md

Output options

These options specify which files to generate.

Note that all file paths are relative to the directory where the config file is, not to the one where you run crowbook. So if you set

output.epub: foo.epub

and runs

$ crowbook some/dir/config.book

foo.epub will be generated in some/dir, not in your current directory.

Crowbook will try to generate each of the output.xxx files that are specified. That means that you’ll have to set at least one of those if you want a call to

$ crowbook my.book

to generate anything. (It’s still possible to generate a specific format, and only this one, by using the --to and --output argument on the command line).

Note that some formats depend on some commands being installed on your system. Most notably, Crowbook depends on LaTeX (xelatex by default, though you can specify the command to use with tex.command) to generate a PDF file, so PDF rendering won’t work if it is not installed on your system. Crowbook also uses the zip command to generate the EPUB and ODT files.

Current output options are:

output.html: renders a standalone HTML file.

output.html.dir: render a HTML directory with one page by chapter.

output.epub: renders an EPUB file.

output.tex: renders a LaTeX file.

output.pdf: renders a PDF file (using tex.command).

(There are other output options for generating proofreading files, see Proofreading.)

output.base_path

Additionally, the output.base_path option allows you to set where the output files will be written (relatively to the book configuration file). E.g.,

output.base_path: docs/book
output.epub: book.epub

will render the EPUB file in docs/book/book.epub.

Input options

Crowbook does its best to improve the typography of your text. Default settings should be good enough for most usages, but you can enable/disable specific options:

input.clean: if set to false, will disable all typographic “cleaning” (default: true). The clean algorithm is dependent on the language, though currently there is only a variant implemented for fr (french), dealing with the specific non-breaking spaces rules for this language.

input.clean.smart_quotes: if set to false, disable the “smart quote” feature, that (tries to) replace straight quotes with curly ones. As it is an heuristics and can’t be perfect, you might want to disable it in some circumstances (default: true).

input.clean.ligature_dashes: if set to true, will convert -- to en dash (–) and --- to em dash (—). This can be useful if you want to use these characters but can’t access them easily on your keymap; however, as it can also cause problems if you do want to have two successive dashes, it is disabled by default.

input.clean.ligature_guillemets is a similar feature for french ‘guilemets’, replacing << and >> to « and ». For the same reason, it is also disabled by default.

Generic options for rendering

These options allow to configure the rendering; they are used (or at least should be) for all formats.

rendering.highlight: specify if and how to perform syntax highlighting for code blocks. Default value is highlight.js; this will use highlight.js for HTML rendering, and will not perform any syntax highlighting for other output formats. Other valid values are:

syntect: uses the syntect library to perform syntax highlighting. This has the advantage of also enabling syntax highlighting for LaTeX/PDF and EPUB formats; however syntect support is still experimental in Crowbook.

none: disable syntax highlighting.

rendering.highlight.theme: only used if rendering.highlight is set to syntect, selects the theme to use for syntax highlighting. Default is “InspiredGitHub”. Valid theme names are “InspiredGitHub”, “Solarized (dark)”, “Solarized (light)”, “base16-eighties.dark”, “base16-mocha.dark”, “base16-ocean.dark” and “base16-ocean.light”.

rendering.num_depth: an integer that represents the maximum level of numbering for your book. E.g., 1 will only number chapters, while 2 will number chapters, sections, but not anything below that. 6 is the maximum level and turns numbering on for all headers. (Default is 1.)

rendering.chapter.template and rendering.part.template: the strings that will be used for chapter and part titles. It is possible to include Markdown formatting in this template, but it isn’t advised, because it might cause problems for some formats (e.g. your EPUB file might not be correct anymore).

rendering.part.roman_numerals and rendering.chapter.roman_numerals: these two booleans allow you to specify if you want roman numerals for part or chapter numbers (default is true for part numbers, and false for chapter numbers).

rendering.inline_toc: if set to true, Crowbook will include a table of contents at the beginning of the document.

rendering.inline_toc.name: the name of this table of contents as it should be displayed in the document.

rendering.initials: if set to true, Crowbook will use initials, or “lettrines”, displaying the first letter of each chapter bigger than the others.

rendering.part.reset_counter: set it to false if you don’t want your chapter numbers to start again at 1 at each part.

HTML Options

These options allow you to customize the HTML rendering (used both by the default HTML standalone renderer and the HTML multifile renderer):

html.icon: allows to set a favicon for the page.

html.header and html.footer allow to set a custom (Markdown) string at the top and at the bottom of the HTML page. This is actually a template, so you can access metadata, such as {{{author}}}, {{{title}}}, or {{{version}}} in it. See the template chapter for more information on the fields you can use.

html.css allow to set up a custom CSS file. You can also redefine the colours in a file and set it using html.css.colours.

html.highlight.theme: similar to rendering.highlight.theme but only sets the theme for HTML output.

Options for standalone HTML

There are a few options specific to the standalone HTML renderer (default, set with output.html):

html.standalone.one_chapter, if set to true, will only display one chapter at a time (using Javascript), making it look similarly to the multifile HTML.

html.standalone.template allows you to change or modify the HTML template for standalone HTML.

Options for LaTeX/PDF rendering

These options allow you to customize the LaTeX renderer (and, thus, the generated PDF documents):

tex.template specifies a different LaTeX template.

tex.class changes the LaTeX class used.

tex.paper_size and tex.font.size (default a5paper and 10pt) allows to modify the page and font size .

tex.links_as_footnotes can be set to false if you don’t want links to also appear as footnotes (which means losing them if it is actually printed).

tex.highlight.theme: similar to rendering.highlight.theme, but only sets the theme for LaTeX/PDF rendering.

Options for EPUB rendering

There are also options specific to the EPUB format:

epub.version can be set to 2 or 3 (default 2).

epub.css can be useful if you want to specify a customized stylesheet.

epub.highlight.theme: similar to rendering.highlight.theme but only sets a theme for EPUB output.

Resources options

These options allow to embed additional files for some formats (currently, only EPUB). This can be useful for embedding fonts.

resources.files

A list of files or directories that should be added. It’s a whitespace-separated list, so it can be, e.g.:

resources.files: font1.otf font2.otf

It is also possible to specify a directory (or multiple directories). So if you have a fonts directories containing font1.otf and font2.otf,

resources.files: fonts

will be equivalent to:

resources.files: fonts/font1.otf fonts/font2.otf

default: not set

resources.out_path

This option determine where (in which directory), in the resulting document, those files will be copied. The default is data, so by default the resources.files in the first example above will search font1.otf and font2.otf in the same directory than the .book file, and will copy them to data/font1.otf and data/font2.otf in the EPUB file. This is therefore this last path that you should use if you want to access those files e.g. in a custom CSS stylesheet.

Note that if you pass directories to resources.files, the whole directory would be copied. So assuming fonts/ contains font1.otf and font2.otf

resources.files: fonts
resources.path: data

will copy these two files to data/fonts/font1.otf and data/fonts/font2.otf (and not data/font1.otf and data/font2.otf).

Similarly, the whole path of resources.files is copied, so

resources.files: fonts/font1.otf fonts/font2.otf

will yield the same result.

default: data

3.4. Full list of options

Here is the complete list of options. You can always look at it by running crowbook --list-options or crowbook -l.

Metadata

author

type: metadata

default value: “”

Author of the book

title

type: metadata

default value: “”

Title of the book

lang

type: metadata

default value: en

Language of the book

subject

type: metadata

default value: not set

Subject of the book (used for EPUB metadata)

description

type: metadata

default value: not set

Description of the book (used for EPUB metadata)

cover

type: path

default value: not set

Path to the cover of the book

Additional metadata

license

type: metadata

default value: not set

License of the book

version

type: metadata

default value: not set

Version of the book

date

type: metadata

default value: not set

Date the book was revised

Output options

output.epub

type: path

default value: not set

Output file name for EPUB rendering

output.html

type: path

default value: not set

Output file name for HTML rendering

output.html.dir

type: path

default value: not set

Output directory name for HTML rendering

output.tex

type: path

default value: not set

Output file name for LaTeX rendering

output.pdf

type: path

default value: not set

Output file name for PDF rendering

output.odt

type: path

default value: not set

Output file name for ODT rendering

output.base_path

type: path

default value: “”

Directory where those output files will we written

Rendering options

rendering.highlight

type: string

default value: syntect

If/how highligh code blocks. Possible values: “syntect” (default, performed at runtime), “highlight.js” (HTML-only, uses Javascript), “none”

rendering.highlight.theme

type: string

default value: InspiredGitHub

Theme for syntax highlighting (if rendering.highlight is set to ‘syntect’)

rendering.initials

type: boolean

default value: false

Use initials (‘lettrines’) for first letter of a chapter (experimental)

rendering.inline_toc

type: boolean

default value: false

Display a table of content in the document

rendering.inline_toc.name

type: string

default value: “{{{loc_toc}}}”

Name of the table of contents if it is displayed in document

rendering.num_depth

type: integer

default value: 1

The maximum heading levels that should be numbered (0: no numbering, 1: only chapters, ..., 6: all)

rendering.chapter.template

type: string

default value: “{{{number}}}\\. {{{chapter_title}}}”

Naming scheme of chapters

rendering.chapter.roman_numerals

type: boolean

default value: false

If set to true, display chapter number with roman numerals

rendering.part.template

type: string

default value: “{{{loc_part}}} {{{number}}}”

Naming scheme of parts

rendering.part.roman_numerals

type: boolean

default value: true

If set to true, display part number with roman numerals

rendering.part.reset_counter

type: boolean

default value: true

If set to true, reset chapter number at each part

Special option

import

type: path

default value: not set

Import another book configuration file

HTML options

html.icon

type: path

default value: not set

Path to an icon to be used for the HTML files(s)

html.highlight.theme

type: string

default value: not set

If set, set theme for syntax highlighting for HTML output (syntect only)

html.header

type: string

default value: not set

Custom header to display at the beginning of html file(s)

html.footer

type: string

default value: not set

Custom footer to display at the end of HTML file(s)

html.css

type: template path

default value: not set

Path of a stylesheet for HTML rendering

html.css.add

type: string

default value: not set

Some inline CSS added to the stylesheet template

html.css.colours

type: template path

default value: not set

Path of a stylesheet for the colours for HTML

html.js

type: template path

default value: not set

Path of a javascript file

html.css.print

type: template path

default value: not set

Path of a media print stylesheet for HTML rendering

html.highlight.js

type: template path

default value: not set

Set another highlight.js version than the bundled one

html.highlight.css

type: template path

default value: not set

Set another highlight.js CSS theme than the default one

html.side_notes

type: boolean

default value: false

Display footnotes as side notes in HTML/Epub (experimental)

html.escape_nb_spaces

type: boolean

default value: true

Replace unicode non breaking spaces with HTML entities and CSS

Standalone HTML options

html.standalone.template

type: template path

default value: not set

Path of an HTML template for standalone HTML

html.standalone.one_chapter

type: boolean

default value: false

Display only one chapter at a time (with a button to display all)

html.standalone.js

type: template path

default value: not set

Path of a javascript file

Multifile HTML options

html.dir.template

type: template path

default value: not set

Path of a HTML template for multifile HTML

EPUB options

epub.version

type: integer

default value: 2

EPUB version to generate (2 or 3)

epub.highlight.theme

type: string

default value: not set

If set, set theme for syntax highlighting for EPUB output (syntect only)

epub.css

type: template path

default value: not set

Path of a stylesheet for EPUB

epub.css.add

type: string

default value: not set

Inline CSS added to the EPUB stylesheet template

epub.chapter.xhtml

type: template path

default value: not set

Path of an xhtml template for each chapter

epub.toc.extras

type: boolean

default value: true

Add ‘Title’ and (if set) ‘Cover’ in the EPUB table of contents

epub.escape_nb_spaces

type: boolean

default value: true

Replace unicode non breaking spaces with HTML entities and CSS

LaTeX options

tex.highlight.theme

type: string

default value: not set

If set, set theme for syntax highlighting for LaTeX/PDF output (syntect only)

tex.links_as_footnotes

type: boolean

default value: true

Add foontotes to URL of links so they are readable when printed

tex.command

type: string

default value: xelatex

LaTeX command to use for generating PDF

tex.template

type: template path

default value: not set

Path of a LaTeX template file

tex.template.add

type: string

default value: not set

Inline code added in the LaTeX template

tex.class

type: string

default value: book

LaTeX class to use

tex.paper_size

type: string

default value: a5paper

Specifies the size of the page.

tex.title

type: boolean

default value: true

If true, generate a title with \maketitle

tex.font.size

type: integer

default value: not set

Specify latex font size (in pt, 10 (default), 11, or 12 are accepted)

tex.stdpage

type: boolean

default value: false

If set to true, use ‘stdpage’ package to format a manuscript according to standards

Resources option

resources.files

type: string

default value: not set

Whitespace-separated list of files to embed in e.g. EPUB file; useful for including e.g. fonts

resources.out_path

type: path

default value: data

Paths where additional resources should be copied in the EPUB file or HTML directory

resources.base_path

type: path

default value: not set

Path where to find resources (in the source tree). By default, links and images are relative to the Markdown file. If this is set, it will be to this path.

resources.base_path.links

type: path

default value: not set

Set base path but only for links. Useless if resources.base_path is set

resources.base_path.images

type: path

default value: .

Set base path but only for images. Useless if resources.base_path is set

resources.base_path.files

type: path

default value: .

Set base path but only for additional files. Useless if resources.base_path is set.

resources.base_path.templates

type: path

default value: .

Set base path but only for templates files. Useless if resources.base_path is set

Input options

input.clean

type: boolean

default value: true

Toggle typographic cleaning of input markdown according to lang

input.clean.smart_quotes

type: boolean

default value: true

If enabled, tries to replace vertical quotations marks to curly ones

input.clean.ligature.dashes

type: boolean

default value: false

If enabled, replaces ‘--’ to en dash ('–') and ‘---’ to em dash ('—')

input.clean.ligature.guillemets

type: boolean

default value: false

If enabled, replaces ‘<<’ and ‘>>’ to french “guillemets” ('«’ and ‘»’)

input.yaml_blocks

type: boolean

default value: false

Enable inline YAML blocks to override options set in config file

Crowbook options

crowbook.temp_dir

type: path

default value: ``

Path where to create a temporary directory (default: uses result from Rust’s std::env::temp_dir())

crowbook.zip.command

type: string

default value: zip

Command to use to zip files (for EPUB/ODT)

crowbook.verbose

type: boolean

default value: false

Make Crowbook display more messages

Output options (for proofreading)

output.proofread.html

type: path

default value: not set

Output file name for HTML rendering with proofread features

output.proofread.html.dir

type: path

default value: not set

Output directory name for HTML rendering with proofread features

output.proofread.pdf

type: path

default value: not set

Output file name for PDF rendering with proofread features

Proofreading options (only for output.proofread.* targets)

proofread

type: boolean

default value: false

If set to false, will disactivate proofreading even if one of output.proofread.x is present

proofread.languagetool

type: boolean

default value: false

If true, try to use language tool server to grammar check the book

proofread.languagetool.port

type: integer

default value: 8081

Port to connect to languagetool-server

proofread.repetitions

type: boolean

default value: false

If set to true, use Caribon to detect repetitions

proofread.repetitions.max_distance

type: integer

default value: 25

Max distance between two occurences so it is considered a repetition

proofread.repetitions.fuzzy

type: boolean

default value: true

Enable fuzzy string matching

proofread.repetitions.fuzzy.threshold

type: float

default value: 0.2

Max threshold of differences to consider two strings a repetition

proofread.repetitions.ignore_proper

type: boolean

default value: true

Ignore proper nouns for repetitions

proofread.repetitions.threshold

type: float

default value: 2.0

Threshold to detect a repetition

Note that these options have a type, which in most case should be pretty straightforward (a boolean can be true or false, an integer must be composed by a number, a string is, well, any string). The path type might puzzle you a bit, but it’s equivalent to a string, except Crowbook will consider it relatively to the book file. The template path type is just the path of a template. Metadata are just strings.

4. Templates

Crowbook allows the user to specify a number of templates.[1]

Each of this template can be overriden by a custom one, by setting e.g.:

html.css: my_template.css

in the book configuration file. The templates that you are most susceptible to modify are the following:

html.css: stylesheet for HTML output;

epub.css: stylesheet for EPUB output;

tex.template: template of a LaTeX file.

4.1. Create and edit template

Except for inline templates, which are set directly in the book configuration file:

rendering.chapter.template: "{{{loc_chapter}}} {{{number}}}: {{{chapter_title}}}"

most templates must be in a separate file:

tex.template: my_template.tex

--print-template

The easiest way to create a new template is to start with the default one. In order to do so, you can use the --print-template argument:

$ crowbook --print-template tex.template > my_template.tex

In order to get the chapter.xhtml template for EPUB3, you’ll also have to use --set epub.version 3:

$ crowbook --print-template epub.chapter.xhtml --set epub.version 3 > my_epub3_template.xhtml

Mustache syntax

Crowbook uses rust-mustache as its templating engine, which allows to use Mustache syntax in the templates.

It mainly boils down to using {{{foo}}}[2] to insert the value of variable foo in the document:

<h1 class = "title" >{{{title}}}<h1>
<h2 class = "author">{{{author}}}</h2>

Mustache also provides the possibility of checking whether a variable is set:

{{#foo}}
Foo exists
{{/foo}}
{{^foo}}
Foo does not exist
{{^foo}}

Crowbook uses this and sets some variables to true to allow templates to conditionally include some portions. E.g., in html.css:

{{#lang_fr}}
/* Make list displays '–' instead of bullets */
ul li {
    list-style-type: '–';
    padding-left: .5em;
}
{{/lang_fr}}

In this case, Crowbook sets a variable whose name is equal to lang_foo to true, allowing to have different styles for some elements according to the language.

For more information about Mustache syntax, see Mustache manual.

Syntax in LaTeX

Since LaTeX already uses a lot of curly brackets, the default template sets an altenative syntax to access variables, with <<&foo>>[3]:

\title{<<&title>>}
\author{<<&author>>}
<<#has_date>>\date{<<&date>>}<</has_date>

4.2. List of templates

html.js

The javascript file used by both the standalone HTML renderer and the multiple files HTML renderer.

This is not currently an actual template, just a plain javascript file which cannot contain mustache tags.

html.css

The main CSS file used by both the standalone HTML renderer and the multiple files HTML renderer.

html.css.colours

A CSS file containing only colour settings. Used by html.css.

This is not currently an actual template, just a plain CSS file which cannot contain mustache tags.

html.css.print

An additional CSS file used by both the standalone HTML renderer and the multiple files HTML renderer. Its purpose is to provide CSS instructions for printing (i.e., when the user clicks the print button in her browser).

This is not currently an actual template, just a plain CSS file which cannot contain mustache tags.

html.highlight.js

A javascript file used by both HTML renderers to highlight codes in code blocks. It should be a variant of highlight.js.

This is not an actual template, just a plain javascript file.

html.highlight.css

A CSS file used by both HTML renderers to set the theme of highlight.js. It should, though, be an highlight.js theme.

This is not an actual template, just a plain CSS file.

html.standalone.js

A javascript file used only by the standalone HTML renderer. Its main purpose is to handle the displaying of a single chapter at a time when one_chapter is set to true.

html.standalone.template

The main HTML template for standalone HTML renderer.

html.dir.template

The main HTML template for multiple files HTML renderer.

tex.template

The main (and currently only) template used by the LaTeX renderer.

epub.chapter.xhtml

This template is the main template used by the Epub renderer. It contains the XHTML template that will be used for each chapter.

epub.css

This template is used by the Epub renderer and contains the style sheet.

Inline templates

Crowbook also has some inline templates, that are set in the book configuration file:

tex.template.add, html.css.add and epub.css.add allow to specify some LaTeX or CSS code directly in the book configuration file. This code will be added respectively to tex.template, html.css or epub.css template. For CSS templates, this code is inserted at the end of the template (allowing to redefine rules that are set by the template); for the LaTeX template, the code is inserted at the end of the preambule, just before the \begin{document} tag.

rendering.inline_toc.name sets the name of the inline table of content, if it is displayed. By default, is is set to {{{loc_toc}}}, that is, a localised version of “Table of Contents”.

rendering.chapter.template sets the naming scheme for chapters, while rendering.part.template does the same for part.

4.3. List of accessible variables

Metadata

For every template, Crowbook exports all of the metadata:

author;

title;

lang;

subject;

description;

license;

version;

date;

any option metadata.foo defined in the book configuration file will also be exported as metadata_foo.

These metadata can contain Markdown, which will be rendered. E.g., setting date: “20th of **september**” will render september in bold, using <b> tag for HTML or \textbf for LaTeX. (It might be a bad idea to insert Markdown into author or title fields, and it certainly is for lang, but it can be useful for custom metadata or for fields like description).

For each metadata foo that is set, Crowbook also inserts a has_foo bool set to true. This allows to use Mustache’s section for some logic, e.g.:

{{{title}}}
{{#has_version}}, version {{{version}}}{{/has_version}}

will avoid rendering “, version” when version is not set.

Localisation strings

For all templates, Crowbook also exports some localisation strings loc_foo. They currently include:

Localisation key | Value in english
loc_toc | Table of contents
loc_chapter | Chapter
loc_display_all | Display all chapters
loc_display_one | Display one chapter

Template-dependent values

Crowbook also exports some additional fields for some templates, see below.

Mustache tag | Value | Available in...
content | A rendered version of the book or chapter’s content | html.standalone.template, html.dir.template, tex.template, epub.chapter.xhtml
toc | A rendered version of the table of contents | html.standalone.template, html.dir.template
has_toc | Set to true if the table of contents is not empty | html.standalone.template
colours | The content of html.css.colours | html.css
footer | The content of html.footer | html.standalone.template, html.dir.template
header | The content of html.header | html.standalone.template, html.dirtemplate
script | The javascript file for this HTML document | html.standalone.template, html.dir.template
style | The CSS file for this HTML document, that is, a rendered version of html.css | html.standalone.template
A variable whose name corresponds to lang in book options (e.g. lang_en if lang is set to “en”, lang_fr if it is set to “fr”, ...) | true | html.css, epub.css
chapter_title | The title of current chapter | html.dir.template, epub.chapter.xhtml, rendering.chapter.template
highlight_code | True if html.highlight_code is true | html.standalone.template, html.dir.template
highlight_css | The content of html.highlight.css | html.standalone.template
highlight_js | The base64-encoded content of html.highlight.js | html.standalone.tempate
common_script | The content of html.js | html.single.js
one_chapter | True if html.standalone.one_chapter is true, else not present | html.standalone.template, html.standalone.js
book.svg | The base64-encoded image of the button to display all chapters | html.standalone.js, html.standalone.template
pages.svg | The base64-encoded image of the button to display one chapter at a time | html.standalone.js, html.standalone.template
favicon | The <link rel = “icon” ...> tag if html.icon is set | html.standalone.template, html.dir.template
menu_svg | The base64-encoded image of the hamburger menu image | html.standalone.template
prev_chapter | Title and a link of previous chapter | html.dir.template
next_chapter | Title and a link of nexts chapter | html.dir.template
class | The content of tex.class | tex.template
book | True if tex.class is book, not set else | tex.template
tex_lang | The babel equivalent of lang | tex.template
tex_title | Set to true to run \maketitle | tex.template
tex_size | The font size to pass to the LaTeX class | tex.template
has_tex_size | Set to true if tex_size is set | tex.template
initials | True if rendering.initials is true, not set else | tex.template
additional_code | Set to the content of tex.template.add, html.css.add or epub.css.add | tex.template, html.css, epub.css

Notes

[1]

Some of them, though, are not “real” templates, they are just files that are inserted, but can’t contain mustache tags. This will probably evolve in future versions.

[2]

Mustache also provides the {{foo}} variant, which HTML-escapes the content of the variable. You should not use this, as Crowbook already renders and correctly escapes the variables it sets for use in templates.

[3]

<<foo>> might also work, but the ampersand is required to prevent mustache HTML-escaping the value. This is not good because:

escaping is already done by Crowbook before setting variable content;

escaping HTML in a LaTeX document won’t probably look good.

5. Proofreading with Crowbook

Since version 0.9.1, Crowbook includes some proofreading features, that can be enabled if you set one of the

output.proofread.html

output.proofread.html_dir

output.proofread.pdf

output files. This allows you to generate different files for publishing and proofreading (you probably don’t want to publish a version that highlights your grammar errors or your repetitions).

Current proofreading features are:

repetition detection;

grammar check;

highlighting non-breaking spaces.

5.1. Enabling proofreading

Since proofreading can take quite a lot of time, particularly for a long book, it is disabled by default. You’ll have to run

$ crowbook --proofread my.book

or

$ crowbook -p my.book

to generate proofreading copies. Alternatively, if you want it to be activated each time you run crowbook on this book (which is not recommanded for long books, particularly if you want to perform a grammar check), you can set

proofread: true

in the book configuration file.

5.2. Repetition detection

Repetition detection is enabled with:

proofread.repetitions: true

It uses Caribon library to detect the repetition in your text. Since the notion of a repetition is relatively arbitrary, it is possible to adapt the settings. Default are:

# The maximum distance between two identical words to
# consider them a repetition
proofread.repetitions.max_distance: 25
# The minimal number of occurences to consider it a repetition
proofread.repetitions.threshold: 2.0
# Ignore proper nouns (words starting by a capital,
# not at a beginning of a sentence)
proofread.repetitions.ignore_proper: true

# Activate fuzzy string matching
proofread.repetitions.fuzzy: true
# The maximal ratio of difference to consider
# that two words are identical
# (E.g., with 0.2, "Rust" and "Lust" won't be
# considered as the same word, but they will be with 0.5)
proofread.repetitions.fuzzy.threshold: 0.2

For more information, see Caribon’s documentation.

Currently, repetitions are not displayed in PDF proofreading output.

5.3. Grammar checking

Crowbook can also use LanguageTool to detect grammar errors in your text. It is, however, a bit more complex to activate.

First, you’ll have to activate this feature in your book configuration file:

# Activate language tool support
proofread.languagetool: true
# (Optional) Sets the port number to connect to (default below)
proofread.languagetool.port: 8081

You’ll then have to download the stand-alone version of LanguageTool. It includes a server mode, which you’ll have to launch:

$ java -cp languagetool-server.jar org.languagetool.server.HTTPServer --port 8081

You can also use the LanguageTool GUI (languagetool.jar) and start the server from the menu “Text Checking -> Options”. This also allows you to configure LanguageTool more precisely by activating or deactivating rules.

You can then run Crowbook, and it will highlight grammar errors in HTML or PDF proofreading output files.

Note: running a grammar check on a long book (like a novel) can take up to a few minutes.

5.4. Highlighting non-breaking spaces

The last proofreading feature is a bit less important, but it can be useful in some cases. It is is dis/activated by setting proofread.nb_spaces to “true” or “false”, and it will highlight different sort of non-breaking spaces in HTML proofreading output files. This can be useful in some cases, but it is mostly a debugging feature to check that the french cleaner of Crowbook correctly replaces spaces with correct non-breaking spaces in the relevant places.

6. Tips and tricks

6.1. Using Crowbook with Emacs’ markdown mode

If you use Emacs as a text editor, there is a nice Markdown mode to edit Markdown files.

It is possible to use Crowbook for HTML previewing in this mode, which requires only minimal configuration and tweaking:

(custom-set-variables
 '(markdown-command "crowbook - -qs  --to html --output -"))

You can then use markdown-preview (or C-c C-c p) to run Crowbook on this file and preview it in your browser, or run markdown-live-preview-mode to see a live preview (updated each time you save you file) in Emacs’ integrated browser.

Some explanations if it looks a bit cryptic to you

We set markdown-command to crowbook, the reason for this is a bit obvious. The arguments we give to crowbook might be a bit less obvious:

the fist argument, -, is actually the book file: it tells crowbook to read it from standard input.

-qs or --quiet --single tells Crowbook that is a a standalone markdown file, and not a book configuration file, and to be a bit quiet on error/info messages;

--to html specifies that HTML must be generated;

--output - tells Crowbook to display the result on the stdout, even if you set output.html to some_file.html.

Limitations

While it renders correctly, this only works really nicely on standalone Markdown files where you have specified, e.g.:

---
author: Your name
title: Some title
---

Else, it will sets author and title to the default values.

6.2. Embedding fonts in an EPUB file

In order to embed fonts in an EPUB file, you’ll first have to edit the stylesheet, which you can first obtain with:

$ crowbook --print-template epub.css > my_epub_stylesheet.css

You’ll need to use the @font-face attribute:

@font-face {
  font-family: MyFont;
  src: url(data/my_font.ttf);
}

Then you can add my_font.ttf to the files that need to be added to the EPUB zip file:

title: My Book
author: Me

cover: cover.png
output.epub: book.epub

resources.files: my_font.ttf

(Note that you’ll have to repeat the process the different font-weight and font-style variants of your font if you want it to display correctly when there is some text in bold, italics, or both.)

7. Contributing

Crowbook is a free software, and you can contribute to it. There are some things that can be accessible even if you don’t know anything about programming.

7.1. Internationalization

Crowbook aims to support multiple languages. However, unfortunately, currently only english, french, and (in a more limited way) spanish are currently supported. If you want to have better support for the language you write in, there are easy things you can do:

Provide a translation for the few strings that Crowbook insert into the rendered documents. This is really easy, as there are currently less than a dozen of them, and you just need to create a new variant of the lang/en.yaml file.

Open an issue about the typographic rules in your language, if Crowbook doesn’t cover them.

Provide a translation for the Crowbook program. It requires creating a variant of the .po file, which is a bit more work because (at this time) it’s around 1,500 lines (and less a priority than the first item of this list, as this translation only affects the the command-line interface and not the rendered documents).

ChangeLog

unreleased

When there is an error setting an option from the book configuration file (e.g. because it is an invalid key), print an error but do not abort, only ignore this specific option.

Proofreading:

Repetition detection is now a bit less of an hack, and should cause less problems when used in conjunction with grammar checking. It now also works on PDF output (so the way it is highlighted could be improved).

New options:

tex.stdpage: if set to true, will use the stdpage package to render the book according to standards for submitting manuscripts.

rendering.highlight.theme allows to specifies a theme for syntax highlighting (only used if rendering.highlight is set to “syntect”).

html.highlight.theme, epub.highlight.theme and tex.highlight.theme allow to specify a theme for HTML/EPUB/LaTeX renderers (only used with syntect).

Deprecated option:

proofread.nb_spaces.

Rendering:

[syntect](https://crates.io/crates/syntect) is now the default for rendering.highlight. Concretely, this means that by default syntax highlighting is now done when crowbook is run instead of using [highlight.js](https://highlightjs.org/). (EDIT: bad idea since syntect seems to have trouble building on windows, at least on appveyor? Revert it before release?)

EPUB:

Now sets the “cover-image” property and meta so readers should display cover correctly.

Narrow non-breaking spaces should display more correctly on KOBO ereaders (hoping this won’t break the way they are displayed everywhere else).

Bugfixes:

Fix mimetype of EPUB files (make sure it is always “stored” and not “deflated” by the zip command).

Avoid initializing syntect (at the cost of performances) if it is not used.

Avoid creating an empty file if some book renderer fails (e.g. EPUB or ODT because zip command is not present).

0.11.1 (2017-01-05)

Rendering:

Avoid page break before or after a separating rule.

Add support for syntect for syntax highlighting. This is activated by setting rendering.highlight to syntect (see below).

EPUB:

Set back HTML escape of narrow non-breaking spaces to true by default (it caused problems on some readers, but cause much more serious one if false).

Add more information to guide/nav landmarks.

LaTeX/PDF:

Improve the way code blocks are displayed, using the mdframed package.

Try to reduce the issues of too long lines when using code and code blocks, by inserting \allowbreak{} directive after some characters (., /, _, ...).

Block quotes are now displayed in italics.

Tables now use tabularx, which allows to break too long lines (it still doesn’t break pages, though).

New options:

rendering.highlight can be set to none, highlight.js (by default, enables syntax highlighting via Javascript, but only on HTML document) or syntect (doesn’t necessitate javascript, and can work in EPUB or LaTeX, but more experimental at this point).

Deprecated options:

html.highlight_code (use rendering.highlight instead).

Bugfixes:

HTML (standalone): fix the template that contained invalid HTML code.

0.11.0 (2016-12-31)

Substantial changes in this release, the more important one being support for parts!

Breaking changes: the API has undergone some breaking changes, hoping they will be the last ones for a while. API should now be more simple and consistent (?). This version contains also substantial options renaming (see below).

Crowbook now supports parts (above the “chapter” level), using the ‘@’ character in the book configuration file.

Command-line interface:

Behaviour of --to should now be consistent for all output formats.

If --output is set to -, prints to stdout.

Conversely, if <BOOK> is set to -, reads from stdin.

Path specified by --output is now interpreted relatively to current directory (and not depending on where <BOOK> is or its options).

Rendering:

Chapters with no titles now have an empty title added (so it can at least display e.g. “Chapter X”).

EPUB:

The toc.ncx file now displays links to “title” and (if set) “cover” (can be deactivated, see below).

The toc.ncx file now displays toc levels below chapter.

The table of contents is now displayed inline if rendering.inline_toc is set to true.

New options:

epub.toc.extras, set to true by default, will add links to the title and the cover (if it is set) in the table of contents.

epub.escape_nb_spaces, similar to html.escape_nb_spaces and set to false by default since at least Kobo reader don’t seem to be able to understand the CSS to escape those nb spaces...

rendering.chapter.roman_numerals, if set to true, will display chapter numbers using roman numerals.

rendering.part.roman_numerals, if set to true (it is by default) will display part numbers using roman numerals.

rendering.part.template specifies the numbering scheme of parts.

rendering.part.reset_counter, if set to true (it is by default), resets chapter number to zero after a part.

Renamed options:

import_config renamed to import.

rendering.chapter_template renamed to rendering.chapter.template.

html_single.html renamed to html.standalone.template.

html_single.js renamed to html.standalone.js.

html_single.one_chapter renamed to html.standalone.one_chapter.

output.html_dir renamed to output.html.dir.

output.proofread.html_dir renamed to output.proofread.html.dir.

html_dir.index.html and html.dir.chapter.html have been merged and both renamed to html.dir.template.

tex.font_size renamed to tex.font.size.

Bugfixes:

EPUB:

Fix duplicate HTML escaping (resulting in e.g. "&" instead of "&").

HTML directory:

Fix panic when trying to generate html directory in “../xxx” (#23).

Fix “previous chapter” links that were not displayed when “html.header” was set.

HTML:

Fix the way initial letter is displayed if rendering.initials is true.

Internationalization:

Strings in generated Crowbook documents (such as “Table of contents", “Title”, “Cover” and such) are now translated in spanish.

0.10.4 (2016-12-16)

New options:

tex.font_size specifies an optional font size (in pt) passed to the LaTeX class (must be 10, 11 or 12).

tex.title can be set to false to avoid rendering the title with \maketitle.

tex.paper_size specifies the paper size for PDF output.

tex.template.add, html.css.add and epub.css.addallow to specify inline LaTex or CSS code in the book configuration file that will be added respectively to tex.template.add, html.css.add and epub.css.add.

html.icon allows to specify the path of an icon for HTML documents.

Command-line interface:

Paths that are displayed should now be normalized, e.g. “foo/bar.pdf” instead of “baz/../foo/bar.pdf”.

Rendering:

HTML:

The default CSS style has been slightly modified.

0.10.3 (2016-11-19)

Building:

Crowbook now requires rustc >= 1.13.0 to build.

Pre-built binaries now all include the proofreading feature.

Linux binaries are now linked against musl library so they should really work on any Linux platform.

Bugfixes:

Fixed escaping of author and title fields.

Fixed text cleaning in ODT rendering that causes corrupt files to be generated.

CommandLine Interface:

Crowbook displays clearer error messages when unable to launch latex or zip commands.

Crowbook uses term library in order to display colours correctly on e.g. Windows.

The new argument --lang (or -L) allows to set the runtime language used by Crowbook, overriding LANG environment variable.

--list-options no longer uses colours as it caused problems depending on the terminal or when piping to less.

0.10.2 (2016-10-21)

Only minor changes in this version:

Options:

author and title’s default values are both set to the empty string, instead of Anonymous and Untitled.

input.autoclean has been renamed input.clean.

input.smart_quotes has been renamed input.clean.smart_quotes.

new option: input.clean.ligature.dashes will (if set to true) replace -- to en dash (–) and --- to em dash (—).

new option: input.clean.ligature.guillemets will (if set to true) replace << and >> to french guillemets (« and »).

Rendering:

HTML: if html_single.one_chapter and rendering.inline_toc are both set to true, only render the TOC if currently displayed chapter is the first.

0.10.1 (2016-10-18)

Fixed a bug in fr.po translation that prevented building from fresh install.

0.10.0 (2016-10-18)

This release contains some breaking changes (mostly for the API, which has been split in separate libraries). It alse features some internationalization support, and the program should now be tranlated if your LANG environment variable is set to french.

Breaking changes:

Templates:

Conditional inclusion depending on lang must now be done using lang_LANG (e.g. lang_fr, lang_en, and so on). This might impact custom epub.css and html.css templates.

API:

The escape module has been moved to a separate crate, crowbook_text_processing. The cleaner module is no longer public, but the features it provided are also available in crowbook_text_processing.

New options:

html.css.colours allows to provide a CSS file that only redefine the colour scheme. Such a file can be built from crowbook --print-template html.css.colours.

input.smart_quotes: if set to true, tries to replace ' and " by curly quotes.

Command line interface:

Crowbook is now (imperfectly) localized in french, and can be translated to other languages.

Added the --quiet (or -q) argument, that makes crowbook run without displaying any messages (except some error messages at this point).

Rendering:

HTML:

The table of contents menu is no longer displayed in the HTML single renderer if it doesn’t contain at least two elements.

The default colour theme has been modified a little.

Bugfixes:

Fix the escaping of non-breaking spaces in EPUB, as &nbsp; and its friends aren’t valid entities in XHTML, apparently.

0.9.1 (2016-09-29)

This release mainly introduces generation of proofreading copies, allowing, if they are set (and crowbook was compiled with the proofread feature) to generate proofreading copies, using tools to check grammar and detect repetitions. These features are currently experimental.

New options:

html.escape_nb_spaces, if set to true (by default), will replace unicode non breaking spaces with HTML entites and CSS so it can display correctly even if reader’s don’t have a browser/font supporting these unicode symbols.

Output files for proofread documents: output.proofread.html, output.proofread.html_dir and output.proofread.pdf.

Proofread options proofread.repetitions and proofread.nb_spaces have been added.

proofread.nb_spaces, if set to true, highlights non-breaking spaces so it is easier to check the correct typography of a book. Note that it requires that html.escape_nb_spaces be set to true (default) to work.

proofread.reppetitions, if set to true, uses Caribon to highlight repetitions in a document. It also uses the settings proofread.repetitions.fuzzy, proofread.repetitions.max_distance, proofread.repetitions.threshold, proofread.repetitions.fuzzy.threshold, proofread.repetitions.ignore_proper. Note that this feature is not built by default, you’ll have to build crowbook with cargo build --release --features “repetitions”.

New default settings for options:

tex.command is now xelatex by default.

Rendering:

LaTeX:

Add support for xelatex in the default template.

Improved french cleaner (see an article (in french) that talks about what it does).

Crowbook user guide: documentation has been updated to correctly reflect 0.9.x options.

API:

clap dependency is now optional, people who want to use Crowbook as a library should include it with crowbook = { version = “0.9”, default-features = false }. (clap is still required to build a working binary).

0.9.0 (2016-09-23)

The main objective of this release is to clean public interfaces, in order to limit breaking changes in the future. Ideally, all pre-1.0 releases should thus be 0.9.x. Concretely, this meant three things:

reducing the surface of Crowbook’s library API;

cleaning options names

cleaning the names exported in templates and document them, in order not to break user-defined templates in future (non-breaking) releases. More detailed changes for this release:

Breaking change for users: removed tex.short option, replaced by a more generic tex.class (default being book). html.crowbook_link has also been removed.

Renamed options. Using the old name will print a deprecation warning but will still work for a while.

temp_dir -> crowbook.temp_dir

zip.command -> crowbook.zip.command

verbose -> crowbook.verbose

html.print_css -> html.css.print

html.display_chapter -> html_single.one_chapter

html.script -> html_single.js

numbering -> rendering.num_depth

numbering_template -> rendering.chapter_template

display_toc -> rendering.inline_toc

toc_name -> rendering.inline_toc.name

enable_yaml_blocks -> input.yaml_blocks

use_initials -> rendering.initials

autoclean -> input.autoclean

html_dir.css -> html.css (not really renamed, html_dir.css isactually removed as there is no point in having different CSS for standalone and multifile HTML rendering, is it?)

New options:

More metadata: license, version and date. These metadata are not treated by the renderers, but they are exported to the templates: {{{metadata}}} allows to access the content. If they are present, a has_metadata is also set to true, allowing to do something like {{{title}}} {{#has_version}}version {{{version}}} {{/has_version}}.

Yet more metadata: it is possible to add custom metadata by prefixing it with metadata.. They will then be accessible in the templates, with dots ('.') replaced by underscores ('_'). E.g., with metadata.foo: bar you can access it in your templates with {{{metadata_foo}}}.

output.base_path specifies a directory where the output files (set by output.FORMAT will be written.

resources.base_path.templates specifies where templates can be found.

Rendering:

Metadata can now contain Markdown and will be rendered by the renderers. This might not be a good idea for common fields (e.g. “title”), though. Use with caution.

rendering.inline_toc.name can use {{{loc_toc}}} to specify a localized name.

HTML:

html.top and hstml.footer are now considered as templates, so you can use some {{{metadata}}} in it.

Improved the way footnotes are displayed.

In standalone HTML, footnotes are rendered at the end of the document instead of at the end of the chapter, unless html_single.one_chapter is true.

LaTeX:

If tex.class is set to article, chapters will be displayed as \sections since article class doesn’t handle chapters.

Except if tex.class is set to book, margins are now symmetrical.

LaTex template now uses version and date.

Bugfixes:

import_config only import options from another book file that are not equal to the default ones and that haven’t already been set by the caller. E.g., author: foo then import_config: bar.book won’t erase the author previously set.

import_config now correctly translates the imported book’s paths.

Crowbook program:

Still working to improve error messages.

crowbook --list-options uses colours. This might hurt your eyes.

Display an error message when mustache can’t compile a template, instead of panicking.

Internal/API:

Added static methods to Logger to allows displaying messages more easily/prettily.

Reduce pubic API’s surface so less changes will need to be considered breaking in the future.

0.8.0 (2016-09-19)

This release adds support for syntax higlighting in code blocks, customized top and footer blocks for HTML rendering, and the special import_config option that allows to import options from another book file. It also provides (hopefully) better error messages.

New options:

import_configis not really an option, but allows to import another configuration file, useful if you share a same set of options between multiple books.

use_initials (set to false by default) makes Crowbook use initials (“lettrines”) at start of each chapter. Support is still experimental.

html.highlight_code (set to true by default) allows syntax highlighting for code blocks, using highlight.js.

html.higlight.css and html.highlight.js can be used to provide other themes (default is default.css) and an highlight.js build that support other languages.

html.footer allows to specify custom footer. If not set, html.crowbook_link allows to disable “Generated by Crowbook” message.

html.top allows to specify a custom header that will be displayed at the top of HTML file(s).

Deprecated options:

side_notes has been renamed html.side_notes.

Crowbook program:

All output formats are now rendered concurrently.

Better error messages. Crowbook now tries to give more information when displaying an error, with the file name where a problem was found, and, in some cases, the line. It also tries to detect errors (such as files not found) sooner.

Some “warning” messages have also been “moved” to error messages, to make sure they are displayed even when crowbook isn’t runned with --verbose.

Rendering:

Hidden chapter now produce empty \chapter*{} and <h1> in LaTeX and HTML. This allow to delimit a chapter break even if nothing is displayed.

Bugfixes:

Navigation menu of standalone HTML didn’t include a call to javascript when html.display_chapter was set to true, meaning it didn’t display the chapter correctly.

Implementations of Image and StandaloneImage were reversed in LaTeX.

StandaloneImage urls were not adjusted (meanning that running crowbook from another directory failed).

Image paths are now found correctly in HtmlDir rendering even if crowbook is called from another directory (same fix as 0.6’s for Epub and LaTeX, which was forgotten for HtmlDir).

Internal/API:

In order to have better error messages, there was a need to refactor the Error type, and make more methods return Result<X> instead of X. The API is, therefore, quite modified.

Added a Renderer trait used by the various renderers.

Removed some methods from public API.

0.7.0 (2016-09-11)

This releases renders images differently when they are on a standalone paragraph or inside a paragraph.

Internal/API:

Token has a new variant, StandaloneImage. This is used to distinguish an image that is alone in a paragraph of an image that is inlined alongside text.

Parser.parse method now distingues between Image and StandaloneImage. Currently, an image is considered “standalone” if it is the sole element of a paragraph, even if it is among a link.

Token has a new is_image method.

Rendering:

Standalone images are now rendered differently than inline images (80% of width VS original size) in HTML/EPUB and LaTeX.

0.6.0 (2016-09-09)

Deprecated options:

nb_char: since it was only used for french cleaner and for typography reasons it’s better to use different non breaking spaces according to context, this option was not really useful anymore.

Rendering:

Images are now displayed at 80% width of the page.

Bugfixes:

Image paths are now found correctly in LaTeX and EPUB rendering even if crowbook is called from another directory.

Fixed a bug in French cleaner when a string to clean ended by a non-breaking space (space was doubled with a breaking one).

LaTeX/PDF:

“Autocleaning” is now also activated (for french at least) for LaTeX rendering, since it doesn’t correctly insert non-breaking spaces for e.g. ‘«’ or ‘»’.

Fixed escaping of -- to -{}- to avoid tex ligatures.

HTML/EPUB:

html.display_chapter now defaults to false (e.g., by default the HTML displays the entirety of a book).

Fixed rendering of lists when lang is set to fr.

Links are now HTML-escaped, fixing errors in XHTML (for EPUB rendering) when links contained ‘&’ character.

0.5.1 (2016-04-14)

Mostly rendering fixes:

Epub:

Fix a validation problem when book contained hidden chapters.

French cleaner:

Use semi-cadratine space instead of cadratine space for dialogs.

Use non-narrow non-breaking spapce instead of narrow one for ‘:’, ‘«’ and ‘»’ (following https://fr.wikipedia.org/wiki/Espace_ins%C3%A9cable#En_France).

HTML:

Add viewport meta tags.

Standalone HTML:

Don’t display the button to display chapter and the previous/next chapter link if html.display_chapter is set to false.

Fix chapter displaying when some chapters are not numbered.

Multi-files HTML:

Fix previous/next chapter display to make it consistent with standalone HTML.

0.5.0 (2016-04-02)

Crowbook now requires Rustc 1.7.0.

It is now possible to render HTML in multiple files:

output.html_dir will activate this renderer, and specify in which directory to render these files;

html_dir.css allows to override the CSS for this rendering;

html_dir.index.html allows to specify a template for the index.html page;

html_dir.chapter.html allows to specify a template for the chapters pages.

New book options:

tex.short: if set to true, the LaTeX renderer will use article instead of book as document class, and will use the default \maketitle command for article. This option is by default set to false, except when Crowbook is called with --single.

enable_yaml_blocks: parsing YAML blocks is no longer activated by default, except when using --single. This is because you might want to have e.g. multiple short stories using YAML blocks to set their titles and so on, and a separate .book file to render a book as a collection of short stories. In this case, you wouldn’t want the displayed title or the output.pdf/html/epub files be redefined by the short stories .md files.

html.print_css: allows to specify a stylesheet for media print

html.display_chapter: displays one chapter at a time in standalone HTML

html.script: allows to specify a custom javascript file for standalone HTML

html_dir.script: same thing for multipage HTML

resources.base_path: by default, Crowbook resolves local links in markdown files relatively to the markdown file. This option allows to resolve them relatively to a base path. This option comes with two variants, resources.base_path.images and resources.base_path.links, which only activate it for respectively images tags and links tags. These two options are ignored when base_path is set. There is also resources.base_path.files which specify where additional files (see below) should be read, but this is one is set to . (i.e., the directory where the .book file is) by default.

resources.files: indicate a (whitespace-separated) list of files that should be embedded. Currently only used with the EPUB renderer.

resources.out_path: indicate where resources.files should be copied in the final document. Default to data, meaning that files will be placed in a data directory in the EPUB.

Rendering:

Templates can now use localized strings according to the lang option

Standalone HTML now includes locale files using base64.

Standalone HTML displays one chapter at a time, thouht it can be changed via a button in the menu.

HTML/EPUB: default CSS now uses the lang value do determine how to display lists (currently the only difference is it uses “–” when lang is set to “fr” and standard bullets for other languages).

Bugfixes:

Fixed a bug of filename “resolution” when Crowbook was called with --single (e.g., crowbook -s tests/test.md would previously try to load `tests/tests/test.md).

Epub renderer now uses the mime_guess library to guess the mime type based on extension, which should fix the mime type guessed for a wide range of extensions (e.g., svg).

Internal/API:

The Book::new, new_from_file, and new_from_markdown_file take an additional options parameter. To create a book with default options, set it to &[].

0.4.0 (2016-03-01)

Crowbook now internally uses a true YAML parser, yaml_rust, for its options. Since the “old” Crowbooks’s config format was similar, but had some subtle differences, this is somewhat of a breaking change:

strings should now be escaped with “” in some cases (e.g. if it contains special characters). On the other hand, it allows to optionally escape a string with these quotes, which wasn’t possible until then and might be useful in some cases.

multiline strings now follow the YAML format, instead of the previous “YAML-ish” format. This can impact the way newlines are added at the end of a multiline string. See e.g. this link for the various ways to include mulitiline strings in Yaml.

Crowbook now parses YAML blocks (delimited by two lines with “---”) in Markdown files, ignoring keys that it doesn’t recognize. This allows crowbook to be compatible(-ish) with Markdown that contains YAML blocks for Jekyll or Pandoc.

New option --single allows to give Crowbook a single Markdown file (which can contain options within an inline YAML block) instead of a book configuration file. This is useful for e.g. short stories.

Enhanced the way debugging/warning/info messages are handled and displayed:

Added a --debug option to the binary.

Internal: added a Logger struct.

Different levels of information (debug/warning/info/error) get different colours.

Bugfixes:

Crowbook no longer crashes when called with the --to argument if it can’t create a file.

0.3.0 (2016-02-27)

Crowbook now tries to convert local links. That is, if you link to a Markdown file that is used in the book. (e.g. README.md), it should link to an appropriate inner reference inside the book.

Latex renderer now supports (local) images.

Epub renderer now embed (local) images in the EPUB file.

Some changes to the HTML/Epub stylesheets.

Internal (or usage as a library):

Crowbook no longer changes current directory, which worked in the binary but could cause problem if library was used in multithreaded environment (e.g. in cargo test).

More modules and methods are now private.

Improved documentation.

Added more unit tests.

Bugfixes:

Epub renderer now correctly renders unnumbered chapter without a number in its toc.ncx file

0.2.2 (2016-02-25)

Bugfixes:

French cleaner now correctly replaces space after — (in e.g. dialogs) with “em space”.

0.2.1 (2016-02-25)

Bugfixes:

HTML/Epub rendering no longer incorrectly increment chapter count for unnumbered chapters.

Latex: makes what is possible to avoid orverflowing the page.

Minor changes:

Latex: improvement of the default way URLs are displayed.

0.2.0 (2016-02-25)

Command line arguments:

New argument --print-template now allows to print a built-in template to stdout.

New argument --list-options prints out all valid options in a config file (or in set), their type and default value.

New argument --set allows to define or override whatever option set in a book configuration.

--create can now be used without specifying a BOOK, printing its result on stdout.

Configuration file:

Added support for multiline strings in .book files, with either ‘|’ (preserving line returns) or ‘>’ (transforming line returns in spaces)

New option display_toc allows to display the table of contents (whose name, at least for HTML, is specified by toc_name) in HTML and PDF documents.

Option numbering now takes an int instead of a boolean, allowing to specify the maximum level to number (e.g. 1: chapters only, 2: chapters and sectino, ..., 6: everything).

Rendering:

Added support for numbering all headers, not just level-1 (e.g., having a subsection numbered 2.3.1).

Tables and Footnotes are now implemented for HTML/Epub and LaTeX output.

Internal:

Refactored Book to use an HashMap of BookOptions instead of having like 42 fields.

0.1.0 (2016-02-21)

initial release

GNU LESSER GENERAL PUBLIC LICENSE

                   Version 2.1, February 1999

Copyright (C) 1991, 1999 Free Software Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

[This is the first released version of the Lesser GPL. It also counts as the successor of the GNU Library Public License, version 2, hence the version number 2.1.]

                        Preamble

The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public Licenses are intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users.

This license, the Lesser General Public License, applies to some specially designated software packages--typically libraries--of the Free Software Foundation and other authors who decide to use it. You can use it too, but we suggest you first think carefully about whether this license or the ordinary General Public License is the better strategy to use in any particular case, based on the explanations below.

When we speak of free software, we are referring to freedom of use, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish); that you receive source code or can get it if you want it; that you can change the software and use pieces of it in new free programs; and that you are informed that you can do these things.

To protect your rights, we need to make restrictions that forbid distributors to deny you these rights or to ask you to surrender these rights. These restrictions translate to certain responsibilities for you if you distribute copies of the library or if you modify it.

For example, if you distribute copies of the library, whether gratis or for a fee, you must give the recipients all the rights that we gave you. You must make sure that they, too, receive or can get the source code. If you link other code with the library, you must provide complete object files to the recipients, so that they can relink them with the library after making changes to the library and recompiling it. And you must show them these terms so they know their rights.

We protect your rights with a two-step method: (1) we copyright the library, and (2) we offer you this license, which gives you legal permission to copy, distribute and/or modify the library.

To protect each distributor, we want to make it very clear that there is no warranty for the free library. Also, if the library is modified by someone else and passed on, the recipients should know that what they have is not the original version, so that the original author’s reputation will not be affected by problems that might be introduced by others.

Finally, software patents pose a constant threat to the existence of any free program. We wish to make sure that a company cannot effectively restrict the users of a free program by obtaining a restrictive license from a patent holder. Therefore, we insist that any patent license obtained for a version of the library must be consistent with the full freedom of use specified in this license.

Most GNU software, including some libraries, is covered by the ordinary GNU General Public License. This license, the GNU Lesser General Public License, applies to certain designated libraries, and is quite different from the ordinary General Public License. We use this license for certain libraries in order to permit linking those libraries into non-free programs.

When a program is linked with a library, whether statically or using a shared library, the combination of the two is legally speaking a combined work, a derivative of the original library. The ordinary General Public License therefore permits such linking only if the entire combination fits its criteria of freedom. The Lesser General Public License permits more lax criteria for linking other code with the library.

We call this license the “Lesser” General Public License because it does Less to protect the user’s freedom than the ordinary General Public License. It also provides other free software developers Less of an advantage over competing non-free programs. These disadvantages are the reason we use the ordinary General Public License for many libraries. However, the Lesser license provides advantages in certain special circumstances.

For example, on rare occasions, there may be a special need to encourage the widest possible use of a certain library, so that it becomes a de-facto standard. To achieve this, non-free programs must be allowed to use the library. A more frequent case is that a free library does the same job as widely used non-free libraries. In this case, there is little to gain by limiting the free library to free software only, so we use the Lesser General Public License.

In other cases, permission to use a particular library in non-free programs enables a greater number of people to use a large body of free software. For example, permission to use the GNU C Library in non-free programs enables many more people to use the whole GNU operating system, as well as its variant, the GNU/Linux operating system.

Although the Lesser General Public License is Less protective of the users’ freedom, it does ensure that the user of a program that is linked with the Library has the freedom and the wherewithal to run that program using a modified version of the Library.

The precise terms and conditions for copying, distribution and modification follow. Pay close attention to the difference between a “work based on the library” and a “work that uses the library”. The former contains code derived from the library, whereas the latter must be combined with the library in order to run.

GNU LESSER GENERAL PUBLIC LICENSE TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

This License Agreement applies to any software library or other program which contains a notice placed by the copyright holder or other authorized party saying it may be distributed under the terms of this Lesser General Public License (also called “this License”). Each licensee is addressed as “you”.

A “library” means a collection of software functions and/or data prepared so as to be conveniently linked with application programs (which use some of those functions and data) to form executables.

The “Library”, below, refers to any such software library or work which has been distributed under these terms. A “work based on the Library” means either the Library or any derivative work under copyright law: that is to say, a work containing the Library or a portion of it, either verbatim or with modifications and/or translated straightforwardly into another language. (Hereinafter, translation is included without limitation in the term “modification”.)

“Source code” for a work means the preferred form of the work for making modifications to it. For a library, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the library.

Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running a program using the Library is not restricted, and output from such a program is covered only if its contents constitute a work based on the Library (independent of the use of the Library in a tool for writing it). Whether that is true depends on what the Library does and what the program that uses the Library does.

You may copy and distribute verbatim copies of the Library’s complete source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and distribute a copy of this License along with the Library.

You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.

You may modify your copy or copies of the Library or any portion of it, thus forming a work based on the Library, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:

a) The modified work must itself be a software library.

b) You must cause the files modified to carry prominent notices
stating that you changed the files and the date of any change.

c) You must cause the whole of the work to be licensed at no
charge to all third parties under the terms of this License.

d) If a facility in the modified Library refers to a function or a
table of data to be supplied by an application program that uses
the facility, other than as an argument passed when the facility
is invoked, then you must make a good faith effort to ensure that,
in the event an application does not supply such function or
table, the facility still operates, and performs whatever part of
its purpose remains meaningful.

(For example, a function in a library to compute square roots has
a purpose that is entirely well-defined independent of the
application.  Therefore, Subsection 2d requires that any
application-supplied function or table used by this function must
be optional: if the application does not supply it, the square
root function must still compute square roots.)

These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Library, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Library, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Library.

In addition, mere aggregation of another work not based on the Library with the Library (or with a work based on the Library) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.

You may opt to apply the terms of the ordinary GNU General Public License instead of this License to a given copy of the Library. To do this, you must alter all the notices that refer to this License, so that they refer to the ordinary GNU General Public License, version 2, instead of to this License. (If a newer version than version 2 of the ordinary GNU General Public License has appeared, then you can specify that version instead if you wish.) Do not make any other change in these notices.

Once this change is made in a given copy, it is irreversible for that copy, so the ordinary GNU General Public License applies to all subsequent copies and derivative works made from that copy.

This option is useful when you wish to copy part of the code of the Library into a program that is not a library.

You may copy and distribute the Library (or a portion or derivative of it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange.

If distribution of object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place satisfies the requirement to distribute the source code, even though third parties are not compelled to copy the source along with the object code.

A program that contains no derivative of any portion of the Library, but is designed to work with the Library by being compiled or linked with it, is called a “work that uses the Library”. Such a work, in isolation, is not a derivative work of the Library, and therefore falls outside the scope of this License.

However, linking a “work that uses the Library” with the Library creates an executable that is a derivative of the Library (because it contains portions of the Library), rather than a “work that uses the library”. The executable is therefore covered by this License. Section 6 states terms for distribution of such executables.

When a “work that uses the Library” uses material from a header file that is part of the Library, the object code for the work may be a derivative work of the Library even though the source code is not. Whether this is true is especially significant if the work can be linked without the Library, or if the work is itself a library. The threshold for this to be true is not precisely defined by law.

If such an object file uses only numerical parameters, data structure layouts and accessors, and small macros and small inline functions (ten lines or less in length), then the use of the object file is unrestricted, regardless of whether it is legally a derivative work. (Executables containing this object code plus portions of the Library will still fall under Section 6.)

Otherwise, if the work is a derivative of the Library, you may distribute the object code for the work under the terms of Section 6. Any executables containing that work also fall under Section 6, whether or not they are linked directly with the Library itself.

As an exception to the Sections above, you may also combine or link a “work that uses the Library” with the Library to produce a work containing portions of the Library, and distribute that work under terms of your choice, provided that the terms permit modification of the work for the customer’s own use and reverse engineering for debugging such modifications.

You must give prominent notice with each copy of the work that the Library is used in it and that the Library and its use are covered by this License. You must supply a copy of this License. If the work during execution displays copyright notices, you must include the copyright notice for the Library among them, as well as a reference directing the user to the copy of this License. Also, you must do one of these things:

a) Accompany the work with the complete corresponding
machine-readable source code for the Library including whatever
changes were used in the work (which must be distributed under
Sections 1 and 2 above); and, if the work is an executable linked
with the Library, with the complete machine-readable "work that
uses the Library", as object code and/or source code, so that the
user can modify the Library and then relink to produce a modified
executable containing the modified Library.  (It is understood
that the user who changes the contents of definitions files in the
Library will not necessarily be able to recompile the application
to use the modified definitions.)

b) Use a suitable shared library mechanism for linking with the
Library.  A suitable mechanism is one that (1) uses at run time a
copy of the library already present on the user's computer system,
rather than copying library functions into the executable, and (2)
will operate properly with a modified version of the library, if
the user installs one, as long as the modified version is
interface-compatible with the version that the work was made with.

c) Accompany the work with a written offer, valid for at
least three years, to give the same user the materials
specified in Subsection 6a, above, for a charge no more
than the cost of performing this distribution.

d) If distribution of the work is made by offering access to copy
from a designated place, offer equivalent access to copy the above
specified materials from the same place.

e) Verify that the user has already received a copy of these
materials or that you have already sent this user a copy.

For an executable, the required form of the “work that uses the Library” must include any data and utility programs needed for reproducing the executable from it. However, as a special exception, the materials to be distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.

It may happen that this requirement contradicts the license restrictions of other proprietary libraries that do not normally accompany the operating system. Such a contradiction means you cannot use both them and the Library together in an executable that you distribute.

You may place library facilities that are a work based on the Library side-by-side in a single library together with other library facilities not covered by this License, and distribute such a combined library, provided that the separate distribution of the work based on the Library and of the other library facilities is otherwise permitted, and provided that you do these two things:

a) Accompany the combined library with a copy of the same work
based on the Library, uncombined with any other library
facilities.  This must be distributed under the terms of the
Sections above.

b) Give prominent notice with the combined library of the fact
that part of it is a work based on the Library, and explaining
where to find the accompanying uncombined form of the same work.

You may not copy, modify, sublicense, link with, or distribute the Library except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, link with, or distribute the Library is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Library or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Library (or any work based on the Library), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Library or works based on it.

Each time you redistribute the Library (or any work based on the Library), the recipient automatically receives a license from the original licensor to copy, distribute, link with or modify the Library subject to these terms and conditions. You may not impose any further restrictions on the recipients’ exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties with this License.

If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Library at all. For example, if a patent license would not permit royalty-free redistribution of the Library by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Library.

If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply, and the section as a whole is intended to apply in other circumstances.

It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.

This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.

If the distribution and/or use of the Library is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Library under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License.

The Free Software Foundation may publish revised and/or new versions of the Lesser General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

Each version is given a distinguishing version number. If the Library specifies a version number of this License which applies to it and “any later version”, you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Library does not specify a license version number, you may choose any version ever published by the Free Software Foundation.

If you wish to incorporate parts of the Library into other free programs whose distribution conditions are incompatible with these, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally.

                  NO WARRANTY

BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE LIBRARY “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE LIBRARY IS WITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

           END OF TERMS AND CONDITIONS

How to Apply These Terms to Your New Libraries

If you develop a new library, and you want it to be of the greatest possible use to the public, we recommend making it free software that everyone can redistribute and change. You can do so by permitting redistribution under these terms (or, alternatively, under the terms of the ordinary General Public License).

To apply these terms, attach the following notices to the library. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.

<one line to give the library's name and a brief idea of what it does.>
Copyright (C) <year>  <name of author>

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

Also add information on how to contact you by electronic and paper mail.

You should also get your employer (if you work as a programmer) or your school, if any, to sign a “copyright disclaimer” for the library, if necessary. Here is a sample; alter the names:

Yoyodyne, Inc., hereby disclaims all copyright interest in the library `Frob’ (a library for tweaking knobs) written by James Random Hacker.

<signature of Ty Coon>, 1 April 1990 Ty Coon, President of Vice

That’s all there is to it!