Add pdf backend to asciidoctor task

.gitignore

@@ -11,5 +11,7 @@ build
 # Java
 *.class
 
+!docs/resources/images/logo.svg
+
 # Miscellaneous
-.DS_Store
+.DS_Store

docs/build.gradle

@@ -4,6 +4,7 @@ buildscript {
     }
     dependencies {
         classpath 'org.asciidoctor:asciidoctor-gradle-plugin:1.6.1'
+        classpath 'org.asciidoctor:asciidoctorj-pdf:1.5.0-beta.2'
     }
 }
 
@@ -19,10 +20,23 @@ asciidoctorj {
 }
 
 asciidoctor {
-    backends 'html5'
+    backends 'html5', 'pdf'
+    setRequires('./src/docs/resources/styles/github_light.rb')
     sources {
         include 'index.adoc'
     }
+    options doctype: 'book'
+    attributes = [
+            'revnumber'         : project.version,
+            'imagesdir'         : '../resources/images',
+            'pdf-stylesdir'     : '../resources/styles',
+            'pdf-fontsdir'      : '../resources/fonts',
+            'pdf-style'         : 'ocp',
+            'icons'             : 'font',
+            'source-highlighter': 'rouge',
+            'rouge-style'       : 'github_light',
+            'sourcedir'         : 'src/docs/asciidoc'
+    ]
 }
 
 gitPublish {

docs/src/docs/resources/styles/github_light.rb

@@ -0,0 +1,74 @@
+# -*- coding: utf-8 -*- #
+# frozen_string_literal: true
+
+require 'rouge' unless defined? ::Rouge.version
+
+module Rouge
+  module Themes
+    class GithubLight < CSSTheme
+      name 'github_light'
+
+      style Comment::Multiline,               :fg => '#6a737d', :italic => false
+      style Comment::Preproc,                 :fg => '#999999', :bold => false
+      style Comment::Single,                  :fg => '#6a737d', :italic => false
+      style Comment::Special,                 :fg => '#999999', :italic => false, :bold => false
+      style Comment,                          :fg => '#999988', :italic => false
+      style Error,                            :fg => '#a61717', :bg => '#e3d2d2'
+      style Generic::Deleted,                 :fg => '#000000', :bg => '#ffdddd'
+      style Generic::Emph,                    :fg => '#000000', :italic => false
+      style Generic::Error,                   :fg => '#aa0000'
+      style Generic::Heading,                 :fg => '#999999'
+      style Generic::Inserted,                :fg => '#000000', :bg => '#ddffdd'
+      style Generic::Output,                  :fg => '#888888'
+      style Generic::Prompt,                  :fg => '#555555'
+      style Generic::Strong,                  :bold => true
+      style Generic::Subheading,              :fg => '#aaaaaa'
+      style Generic::Traceback,               :fg => '#aa0000'
+      style Keyword::Constant,                :fg => '#005cc5', :bold => false
+      style Keyword::Declaration,             :fg => '#d73a49', :bold => false
+      style Keyword::Namespace,               :fg => '#d73a49', :bold => false
+      style Keyword::Pseudo,                  :fg => '#d73a49', :bold => false
+      style Keyword::Reserved,                :fg => '#d73a49', :bold => false
+      style Keyword::Type,                    :fg => '#d73a49', :bold => false
+      style Keyword,                          :fg => '#d73a49', :bold => false
+      style Literal::Number::Float,           :fg => '#005cc5'
+      style Literal::Number::Hex,             :fg => '#005cc5'
+      style Literal::Number::Integer::Long,   :fg => '#005cc5'
+      style Literal::Number::Integer,         :fg => '#005cc5'
+      style Literal::Number::Oct,             :fg => '#005cc5'
+      style Literal::Number,                  :fg => '#005cc5'
+      style Literal::String::Backtick,        :fg => '#032f62'
+      style Literal::String::Char,            :fg => '#032f62'
+      style Literal::String::Doc,             :fg => '#032f62'
+      style Literal::String::Double,          :fg => '#032f62'
+      style Literal::String::Escape,          :fg => '#032f62'
+      style Literal::String::Heredoc,         :fg => '#032f62'
+      style Literal::String::Interpol,        :fg => '#032f62'
+      style Literal::String::Other,           :fg => '#032f62'
+      style Literal::String::Regex,           :fg => '#032f62'
+      style Literal::String::Single,          :fg => '#032f62'
+      style Literal::String::Symbol,          :fg => '#005cc5'
+      style Literal::String,                  :fg => '#032f62'
+      style Name::Attribute,                  :fg => '#000000'
+      style Name::Builtin::Pseudo,            :fg => '#999999'
+      style Name::Builtin,                    :fg => '#d73a49'
+      style Name::Class,                      :fg => '#6f42c1', :bold => false
+      style Name::Constant,                   :fg => '#005cc5'
+      style Name::Decorator,                  :fg => '#d73a49', :bold => false
+      style Name::Entity,                     :fg => '#6f42c1'
+      style Name::Exception,                  :fg => '#990000', :bold => true
+      style Name::Function,                   :fg => '#6f42c1', :bold => false
+      style Name::Label,                      :fg => '#000000'
+      style Name::Namespace,                  :fg => '#000000'
+      style Name::Tag,                        :fg => '#000000'
+      style Name::Variable::Class,            :fg => '#000000'
+      style Name::Variable::Global,           :fg => '#000000'
+      style Name::Variable::Instance,         :fg => '#000000'
+      style Name::Variable,                   :fg => '#000000'
+      style Operator::Word,                   :fg => '#d73a49', :bold => true
+      style Operator,                         :fg => '#000000', :bold => false
+      style Text::Whitespace,                 :fg => '#bbbbbb'
+      style Text,                             :bg => '#ffffff'
+    end
+  end
+end