Apply a Theme

After creating a theme, you’ll need to tell Asciidoctor PDF where to find it. This is done using AsciiDoc attributes.

Theme and font directories

There are three AsciiDoc attributes that tell Asciidoctor PDF how to locate and apply your theme.

pdf-theme: The name of the YAML theme file to load. If the name ends with .yml, it’s assumed to be the complete name of a file and is resolved relative to pdf-themesdir, if specified, otherwise the current directory. Otherwise, -theme.yml is appended to the name to make the file name (i.e., <name>-theme.yml) and is resolved relative to pdf-themesdir, if specified, otherwise the built-in themes dir. Can be specified using the --theme CLI option.
pdf-themesdir: The directory where the theme file is located. If the path is relative, the value is resolved starting from the current working directory. You can use the {docdir} token as the first path segment to create an absolute path starting from the directory of the document. Specifying an absolute path is recommended.

If you use images in your theme, image paths are resolved relative to this directory. If pdf-theme ends with .yml, and pdf-themesdir is not specified, then pdf-themesdir defaults to the directory of the path specified by pdf-theme.
pdf-fontsdir: The directory or directories where the fonts used by your theme, if any, are located. Multiple entries must be separated by either a comma or a semicolon. To reference a file inside a JAR file on the classpath, prefix with the path with uri:classloader: (AsciidoctorJ only). If the path is relative, the value is resolved starting from the current working directory. You can use the {docdir} token as the first path segment to create an absolute path starting from the directory of the document. Specifying an absolute path is recommended.

Load a theme

Let’s assume that you’ve put your theme files inside a directory named resources with the following layout:

doc.adoc
resources/
  themes/
    basic-theme.yml
  fonts/
    roboto-normal.ttf
    roboto-italic.ttf
    roboto-bold.ttf
    roboto-bold_italic.ttf

Here’s the formal way of loading your theme when calling Asciidoctor PDF:

$ asciidoctor-pdf -a pdf-theme=basic -a pdf-themesdir=resources/themes -a pdf-fontsdir=resources/fonts doc.adoc

You can shorten -a pdf-theme= to --theme:

$ asciidoctor-pdf --theme basic -a pdf-themesdir=resources/themes -a pdf-fontsdir=resources/fonts doc.adoc

If all goes well, Asciidoctor PDF will convert your document without any errors or warnings.

You only need to specify the pdf-fontsdir if you’re using custom fonts in your theme.

You can skip setting the pdf-themesdir attribute by passing the relative path of your theme file to the theme option:

$ asciidoctor-pdf --theme resources/themes/basic-theme.yml -a pdf-fontsdir=resources/fonts doc.adoc

However, when theme assets are specified using relative paths, image paths in your theme may not resolve properly. Paths in the theme file are resolved relative to the current directory. In the future, this may change so that paths are resolved relative to the base directory (typically the document’s directory). For now, it’s recommended that you specify absolute paths to future-proof your configuration.

$ asciidoctor-pdf --theme /path/to/resources/themes/basic-theme.yml -a pdf-fontsdir=/path/to/resources/fonts doc.adoc

Alternately, you can prefix image paths in the theme using the {docdir} or {docimagesdir} attribute references.

Using Maven and Gradle

As usual, you can also use build tools like Maven and Gradle to build a themed PDF. The only thing you need to add to an existing build is the attributes mentioned above.

Speaking of Java, you can bundle and distribute your theme and fonts in a jar file. To reference the theme file and/or directory of fonts from inside the jar, refer to their location on the classpath using the uri:classloader: prefix. Here’s how you’d load both the theme and fonts from the classpath:

$ asciidoctorj -b pdf -a pdf-theme="uri:classloader:/path/to/themes/my-theme.yml" -a pdf-fontsdir="uri:classloader:/path/to/fonts" document.adoc

This only works when running Asciidoctor PDF on the JVM.