class Prawn::Outline

The Outline class organizes the outline tree items for the document. Note that the prev and parent instance variables are adjusted while navigating through the nested blocks. These variables along with the presence or absense of blocks are the primary means by which the relations for the various OutlineItems and the OutlineRoot are set. Unfortunately, the best way to understand how this works is to follow the method calls through a real example.

Some ideas for the organization of this class were gleaned from name_tree. In particular the way in which the OutlineItems are finally rendered into document objects in PdfObject through a hash.

Attributes

document[RW]
items[RW]
outline_root[RW]
parent[RW]
prev[RW]

Public Class Methods

new(document) click to toggle source
# File lib/prawn/outline.rb, line 54
def initialize(document)
  @document = document
  @outline_root = document.outline_root(OutlineRoot.new)
  @parent = outline_root
  @prev = nil
  @items = {}
end

Public Instance Methods

add_section(&block) click to toggle source

Adds an outine section to the outline tree (see define_outline). Although you will probably choose to exclusively use define_outline so that your outline tree is contained and easy to manage, this method gives you the option to add sections to the outline tree at any point during document generation. Note that the section will be added at the top level at the end of the outline. For more a more flexible API try using outline.insert_section_after.

block uses the same DSL syntax as define_outline, for example:

outline.add_section do
  section 'Added Section', :page => 3 do
    page 3, :title => 'Page 3'
  end
end
# File lib/prawn/outline.rb, line 120
def add_section(&block)
  @parent = outline_root
  @prev = outline_root.data.last
  if block
    block.arity < 1 ? instance_eval(&block) : block[self]
  end      
end
define(&block) click to toggle source

Defines an outline for the document. The outline is an optional nested index that appears on the side of a PDF document usually with direct links to pages. The outline DSL is defined by nested blocks involving two methods: section and page.

section(title, options{}, &block)

title: the outline text that appears for the section.
options: page - optional integer defining the page number for a destination link.
              - currently only :FIT destination supported with link to top of page.
         closed - whether the section should show its nested outline elements.
                - defaults to false.

page(page, options{})

page: integer defining the page number for the destination link.
      currently only :FIT destination supported with link to top of page.
      set to nil if destination link is not desired.
options: title - the outline text that appears for the section.
         closed - whether the section should show its nested outline elements.
                - defaults to false.

The syntax is best illustrated with an example:

Prawn::Document.generate(outlined document) do

text "Page 1. This is the first Chapter. "
start_new_page
text "Page 2. More in the first Chapter. "
start_new_page
define_outline do
  section 'Chapter 1', :page => 1, :closed => true do 
    page 1, :title => 'Page 1'
    page 2, :title => 'Page 2'
  end
end

end

It should be noted that not defining a title for a page element will raise a RequiredOption error

# File lib/prawn/outline.rb, line 99
def define(&block)
  if block
    block.arity < 1 ? instance_eval(&block) : block[self]
  end
end
insert_section_after(title, &block) click to toggle source

Inserts an outline section to the outline tree (see define_outline). Although you will probably choose to exclusively use define_outline so that your outline tree is contained and easy to manage, this method gives you the option to insert sections to the outline tree at any point during document generation. Unlike outline.add_section, this method allows you to enter a section after any other item at any level in the outline tree. Currently the only way to locate the place of entry is with the title for the item. If your titles names are not unique consider using define_outline.

block uses the same DSL syntax as define_outline, for example:

go_to_page 2
start_new_page
text "Inserted Page"
outline.insert_section_after :title => 'Page 2' do 
  page page_number, :title => "Inserted Page"
end
# File lib/prawn/outline.rb, line 146
def insert_section_after(title, &block)
  @prev = items[title]
  if @prev
    @parent = @prev.data.parent
    nxt = @prev.data.next
    if block
      block.arity < 1 ? instance_eval(&block) : block[self]
    end
    adjust_relations(nxt)
  else
    raise Prawn::Errors::UnknownOutlineTitle, 
      "\n No outline item with title: '#{title}' exists in the outline tree"
  end
end

Private Instance Methods

add_outline_item(title, options, &block) click to toggle source
# File lib/prawn/outline.rb, line 178
def add_outline_item(title, options, &block)
  outline_item = create_outline_item(title, options)
  set_relations(outline_item)
  increase_count
  set_variables_for_block(outline_item, block)
  block.call if block
  reset_parent(outline_item)
end
adjust_relations(nxt) click to toggle source
# File lib/prawn/outline.rb, line 229
def adjust_relations(nxt)
  if nxt 
    nxt.data.prev = @prev
    @prev.data.next = nxt
    @parent.data.last = nxt
  else 
    @parent.data.last = @prev
  end
end
create_outline_item(title, options) click to toggle source
# File lib/prawn/outline.rb, line 187
def create_outline_item(title, options)
  outline_item = OutlineItem.new(title, parent, options)

  if options[:page]
    page_index = options[:page] - 1
    outline_item.dest = [document.pages[page_index].dictionary, :Fit] 
  end

  outline_item.prev = prev if @prev
  items[title] = document.ref!(outline_item)
end
increase_count() click to toggle source
# File lib/prawn/outline.rb, line 205
def increase_count
  counting_parent = parent
  while counting_parent
    counting_parent.data.count += 1
    if counting_parent == outline_root
      counting_parent = nil
    else
      counting_parent = counting_parent.data.parent
    end
  end
end
page(page = nil, options = {}) click to toggle source
# File lib/prawn/outline.rb, line 167
def page(page = nil, options = {})
  if options[:title]
    title = options[:title] 
    options[:page] = page
  else
    raise Prawn::Errors::RequiredOption, 
      "\nTitle is a required option for page"
  end
  add_outline_item(title, options)
end
reset_parent(outline_item) click to toggle source
# File lib/prawn/outline.rb, line 222
def reset_parent(outline_item)
  if parent == outline_item
    self.prev = outline_item
    self.parent = outline_item.data.parent
  end
end
section(title, options = {}, &block) click to toggle source
# File lib/prawn/outline.rb, line 163
def section(title, options = {}, &block)
  add_outline_item(title, options, &block)
end
set_relations(outline_item) click to toggle source
# File lib/prawn/outline.rb, line 199
def set_relations(outline_item)
  prev.data.next = outline_item if prev
  parent.data.first = outline_item unless prev
  parent.data.last = outline_item
end
set_variables_for_block(outline_item, block) click to toggle source
# File lib/prawn/outline.rb, line 217
def set_variables_for_block(outline_item, block)
  self.prev = block ? nil : outline_item
  self.parent = outline_item if block
end