Class: Pdfrb::Document::Outline

Inherits:
Object
  • Object
show all
Defined in:
lib/pdfrb/document/outline.rb

Overview

Bookmark/outline facade. Two directions:

* build — add/build! construct the /Outlines tree on the
Catalog so PDF viewers show a navigation panel;
* read — each/to_a walk an existing outline depth-first
(parents before children), yielding typed
Model::Type::OutlineItem objects.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(document) ⇒ Outline

Returns a new instance of Outline.



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# File 'lib/pdfrb/document/outline.rb', line 14

def initialize(document)
  @document = document
  @entries = []
end

Instance Attribute Details

#document ⇒ Object (readonly)

Returns the value of attribute document.



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# File 'lib/pdfrb/document/outline.rb', line 12

def document
  @document
end

#entries ⇒ Object (readonly)

Returns the value of attribute entries.



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# File 'lib/pdfrb/document/outline.rb', line 12

def entries
  @entries
end

Instance Method Details

#add(title, dest: nil, parent: nil) ⇒ Object 



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# File 'lib/pdfrb/document/outline.rb', line 19

def add(title, dest: nil, parent: nil)
  entry = OutlineEntry.new(title: title.to_s, dest: dest)
  if parent
    parent.add_child(entry)
  else
    @entries << entry
  end
  entry
end

#build! ⇒ Object 



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# File 'lib/pdfrb/document/outline.rb', line 29

def build!
  return if @entries.empty?

  root = @document.add(
    { Type: :Outlines },
    type: Pdfrb::Model::Cos::Dictionary
  )
  root_ref = root.ref

  prev_dict = nil
  first_ref = nil
  @entries.each do |entry|
    dict = entry.build!(@document)
    ref = dict.ref

    dict.value[:Parent] = root_ref
    dict.value[:Prev] = prev_dict.ref if prev_dict
    dict.value[:Next] = nil
    prev_dict&.value&.[]=(:Next, ref)

    first_ref ||= ref
    prev_dict = dict
  end

  root.value[:First] = first_ref
  root.value[:Last] = prev_dict.ref if prev_dict
  root.value[:Count] = @entries.length

  @document.catalog.value[:Outlines] = root_ref
  root
end

#each ⇒ Object

Enumerate bookmark items depth-first (preorder: a parent yields before its children). Returns an Enumerator when blockless. Malformed chains (loops, dangling refs) are tolerated: each item is visited once.



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# File 'lib/pdfrb/document/outline.rb', line 65

def each(&)
  return enum_for(:each) unless block_given?

  root = outline_root
  walk_outline_chain(root&.value&.[](:First), {}, &)
  self
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/document/outline.rb', line 77

def empty?
  root = outline_root
  root.nil? || root.value[:First].nil?
end

#to_a ⇒ Object 



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# File 'lib/pdfrb/document/outline.rb', line 73

def to_a
  each.to_a
end