Class: BbEPUB::Transform::Rendition

Inherits:
Bookbinder::Transform
  • Object
show all
Defined in:
lib/bb-epub/transform/rendition.rb

Overview

For the original Apple extension to EPUB 2, see any version of the iBooks Asset Guide prior to version 5. Here’s a link to version 4.7:

http://www.mobileread.com/forums/attachment.php?attachmentid=74234

In particular, see the section titled “Configuring Display Options”

For the EPUB 3 Fixed Layout specification (actually a Mixed Layout specification), see:

http://www.idpf.org/epub/301/spec/epub-publications.html#sec-package-metadata-fxl

NOTE: a potential gotcha. The EPUB3 properties are ‘rendition:…’, with a colon, whereas the Openbook form follows the dash convention for property names, ie ‘rendition-…’.

Constant Summary collapse

RENDITION_DEFAULT_PROPERTIES = 
{
  'rendition:flow' => 'paginated',
  'rendition:layout' => 'reflowable',
  'rendition:spread' => 'auto',
  'rendition:orientation' => 'auto',
  'rendition:viewport' => nil
}
APPLE_FXL_PATH = 
'META-INF/com.apple.ibooks.display-options.xml'

Instance Method Summary collapse

Instance Method Details

#dependencies ⇒ Object 



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# File 'lib/bb-epub/transform/rendition.rb', line 29

def dependencies
  [BbEPUB::Transform::Spine, BbEPUB::Transform::Metadata]
end

#from_map(package) ⇒ Object 



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# File 'lib/bb-epub/transform/rendition.rb', line 42

def from_map(package)
  first_cmpt = package.map['spine'][0]
  book_properties = {
    'rendition:flow' => first_cmpt['rendition-flow'],
    'rendition:layout' => first_cmpt['rendition-layout'],
    'rendition:spread' => first_cmpt['rendition-spread'],
    'rendition:orientation' => first_cmpt['rendition-orientation'],
    'rendition:viewport' => first_cmpt['rendition-viewport']
  }
  opf_doc = package.file(:opf).document
  opf_doc.add_prefix('rendition')
  book_properties.each_pair { |prop, content|
    if content && RENDITION_DEFAULT_PROPERTIES[prop] != content
      book_meta_tag(opf_doc, prop, content)
    end
  }
  opf_doc.each('opf|spine > opf|itemref') { |itemref|
    # Update the itemref properties attribute.
    cmpt = component_for_itemref(package, itemref)
    props = (itemref['properties'] || '').split
    book_properties.each_pair { |prop, book_content|
      key = prop.gsub(':', '-')
      if cmpt[key] != book_content
        cmpt_content = cmpt[key] || RENDITION_DEFAULT_PROPERTIES[prop]
        props.push("#{prop}-#{cmpt_content}")
      end
    }
    if ['left', 'right'].include?(cmpt['rendition-position'])
      props.push('page-spread-'+cmpt['rendition-position'])
    elsif cmpt['rendition-position'] == 'center'
      props.push('rendition:page-spread-center')
    end
    if cmpt['rendition-align-x-center']
      props.push('rendition:align-x-center')
    end
    itemref['properties'] = props.join(' ')  if props.any?

    # Update the viewport/viewBox attribute in the component file.
    add_icb_to_component(
      package.file(cmpt['path']),
      cmpt['rendition-viewport']
    ) if cmpt['rendition-viewport']
  }
end

#to_map(package) ⇒ Object 



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# File 'lib/bb-epub/transform/rendition.rb', line 34

def to_map(package)
  package.map['rendition-format'] = 'ebook'
  book_properties = book_properties_from_apple_display_options(package)
  book_properties.update(book_properties_from_opf(package))
  component_rendition_properties_from_opf(package, book_properties)
end