Raible Designs

RE: Customizing an Asciidoctor PDF so it looks like an InfoQ Mini-Book

Last week, I wrote about customizing an Asciidoctor PDF so it looks like an InfoQ Mini-Book. Shortly after writing that blog post, Dan Allen responded to my questions and showed me how to customize Asciidoctor's PDF generation. I ended up using both techniques he described: creating a custom theme and using Ruby to override methods. To recap, here are the changes I was hoping to make:

1. The colophon is not aligned to the bottom of the page.
2. The title page (first one after the cover) and colophon pages should be merged.
3. The dedication and acknowledgement headers are not center-aligned and underlined like InfoQ's format.
4. The main sections don't have whole-page delimiters.
5. The table of contents comes right after the title page, rather than after the dedication and acknowledgement.

I'm happy to report that I was able to fix most these issues, except for the second one and last one. There is a pull request to allow changing the location of the table of contents, but I was unable to make it work. I spent a good hour building the asciidoctor-pdf gem and trying to modify AsciidoctorJ to use it. In the end, I decided to mark this as a bug in the JHipster book and we'll fix it when Asciidoctor supports moving the table of contents.

To customize the output, I created an src/main/ruby/asciidoctor-pdf-extensions.rb file and added the following code to it:

require 'asciidoctor-pdf' unless defined? ::Asciidoctor::Pdf

module AsciidoctorPdfExtensions

  def layout_title_page doc
      # no title page
  end

  def layout_chapter_title node, title
    if node.id == "dedication" || node.id == "acknowledgements"
      layout_heading_custom title, align: :center
    elsif node.id.include? "mini-book" # colophon
      move_down 470
      layout_heading title, size: @theme.base_font_size
    elsif node.id.include? "jhipster" #chapters
      puts 'Processing ' + node.id + '...'
      move_down 120
      # set Akkurat font for all custom headings
      font 'Akkurat'
      layout_heading 'PART', align: :right, size: 120, color: [91, 54, 8, 13], style: :normal
      move_up 40

      part_number = "ONE"
      if node.id.include? "ui-components"
        part_number = "TWO"
      elsif node.id.include? "api"
        part_number = "THREE"
      end

      layout_heading part_number, align: :right, size: 120, color: [42, 1, 83, 1], style: :bold
      layout_heading title, align: :right, color: [42, 1, 83, 1], style: :normal, size: 30
      move_up 30
      start_new_page
    else
       # delegate to default implementation
       super
    end
  end

  def layout_heading_custom string, opts = {}
      move_down 100
      typeset_text string, calc_line_metrics((opts.delete :line_height) || @theme.heading_line_height), {
          inline_format: true
      }.merge(opts)
      move_up 5
      $i = 0
      underline = ''
      while $i < string.length do
          if string == 'Dedication'
            underline += '/////'
          else
            underline += '//////'
          end
          $i += 1
      end
      if string == 'Dedication'
          underline += '////'
      end
      typeset_text underline, calc_line_metrics((opts.delete :line_height) || @theme.heading_line_height), {
            inline_format: true, color: 'B0B0B0', size: 8, style: :italic
      }.merge(opts)
      move_down 20
  end

end

Asciidoctor::Pdf::Converter.prepend AsciidoctorPdfExtensions

Then I modified build.gradle to use this file.

asciidoctor {
    backends 'html5', 'pdf', 'epub3'
    attributes 'sourcedir': '../../../main/webapp',
            'source-highlighter': 'coderay',
            'imagesdir': './images',
             toc: 'left',
             icons: 'font',
             linkattrs: true,
             encoding: 'utf-8',
            'setanchors': true,
            'idprefix': '',
            'idseparator': '-',
            'docinfo1': 'true'
    requires file('src/main/ruby/asciidoctor-pdf-extensions.rb')
}

After getting this to work, we're very close to publishing the JHipster Mini-Book! Thanks to Dan for creating Asciidoctor and supporting this great open source project. It's been a pleasure to write with it and the editing process with Git and pull requests has been wonderful.

Update: The JHipster Mini-Book has been released!