Class: Prawn::Outline

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

Overview

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.

Stable API collapse

Constructor Details

#initialize(document) ⇒ Outline

Returns a new instance of Outline.


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# File 'lib/prawn/outline.rb', line 31

def initialize(document)
  @document = document
  @parent = root
  @prev = nil
  @items = {}
end

Instance Method Details

#add_subsection_to(title, position = :last, &block) ⇒ Object

Inserts an outline section to the outline tree (see outline#define). Although you will probably choose to exclusively use outline#define 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. This method allows you to add a child subsection to 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 title names are not unique consider using define_outline. The method takes the following arguments:

title: a string that must match an outline title to add
  the subsection to
position: either :first or :last (the default) where the subsection will
  be placed relative to other child elements. If you need to position
  your subsection in between other elements then consider using
  #insert_section_after
block: uses the same DSL syntax as outline#define, for example:

Consider using this method inside of outline.update if you want to have the outline object to be scoped as self (see #insert_section_after example).

go_to_page 2
start_new_page
text "Inserted Page"
outline.add_subsection_to :title => 'Page 2', :first do
  outline.page :destination => page_number, :title => "Inserted Page"
end

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# File 'lib/prawn/outline.rb', line 108

def add_subsection_to(title, position = :last, &block)
  @parent = items[title]
  unless @parent
    raise Prawn::Errors::UnknownOutlineTitle,
      "\n No outline item with title: '#{title}' exists in the outline tree"
  end
  @prev = position == :first ? nil : @parent.data.last
  nxt = position == :first ? @parent.data.first : nil
  insert_section(nxt, &block)
end

#define(&block) ⇒ Object Also known as: update

Defines/Updates 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; see the documentation on those methods for their arguments and options. Note that one can also use outline#update to add more sections to the end of the outline tree using the same syntax and scope.

The syntax is best illustrated with an example:

Prawn::Document.generate(outlined_document.pdf) do

text "Page 1. This is the first Chapter. "
start_new_page
text "Page 2. More in the first Chapter. "
start_new_page
outline.define do
  section 'Chapter 1', :destination => 1, :closed => true do
    page :destination => 1, :title => 'Page 1'
    page :destination => 2, :title => 'Page 2'
  end
end
start_new_page do
outline.update do
  section 'Chapter 2', :destination =>  2, do
    page :destination => 3, :title => 'Page 3'
  end
end

end


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# File 'lib/prawn/outline.rb', line 74

def define(&block)
  instance_eval(&block) if block
end

#insert_section_after(title, &block) ⇒ Object

Inserts an outline section to the outline tree (see outline#define). Although you will probably choose to exclusively use outline#define 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 title names are not unique consider using define_outline. The method takes the following arguments:

title: the title of other section or page to insert new section after
block: uses the same DSL syntax as outline#define, for example:

go_to_page 2
start_new_page
text "Inserted Page"
update_outline do
  insert_section_after :title => 'Page 2' do
    page :destination => page_number, :title => "Inserted Page"
  end
end

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# File 'lib/prawn/outline.rb', line 141

def insert_section_after(title, &block)
  @prev = items[title]
  unless @prev
    raise Prawn::Errors::UnknownOutlineTitle,
      "\n No outline item with title: '#{title}' exists in the outline tree"
  end
  @parent = @prev.data.parent
  nxt = @prev.data.next
  insert_section(nxt, &block)
end

#page(options = {}) ⇒ Object

See Outline#define above for more documentation on how it is used in that context

Adds a page to the outline. Although you will probably choose to exclusively use outline#define so that your outline tree is contained and easy to manage, this method also gives you the option to add pages to the root of outline tree at any point during document generation. Note that the page will be added at the top level after the other root outline elements. For more flexible placement try using outline#insert_section_after and/or outline#add_subsection_to.

Takes the following arguments:

options:
  title - REQUIRED. The outline text that appears for the page.
  destination - optional integer defining the page number for
          a destination link to the top of the page (using a :FIT
          destination).
          or an array with a custom destination (see the dest_* methods
          of the PDF::Destination module)
  closed - whether the section should show its nested outline elements.
         - defaults to false.

example usage:

outline.page :title => "Very Last Page"

Note: this method is almost identical to section except that it does not accept a block thereby defining the outline item as a leaf on the outline tree structure.


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# File 'lib/prawn/outline.rb', line 213

def page(options = {})
  if options[:title]
    title = options[:title]
  else
    raise Prawn::Errors::RequiredOption,
      "\nTitle is a required option for page"
  end
  add_outline_item(title, options)
end

#page_numberObject

Returns the current page number of the document


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# File 'lib/prawn/outline.rb', line 41

def page_number
  @document.page_number
end

#section(title, options = {}, &block) ⇒ Object

See outline#define above for documentation on how this is used in that context

Adds an outine section to the outline tree. Although you will probably choose to exclusively use outline#define 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. When not being called from within another #section block the section will be added at the top level after the other root elements of the outline. For more flexible placement try using outline#insert_section_after and/or outline#add_subsection_to

Takes the following arguments:

title: the outline text that appears for the section.
options: destination - optional integer defining the page number for
              a destination link to the top of the page (using a :FIT
              destination).
              - or an array with a custom destination (see the #dest_*
              methods of the PDF::Destination module)
         closed - whether the section should show its nested outline
                  elements.
                - defaults to false.
         block: more nested subsections and/or page blocks

example usage:

outline.section 'Added Section', :destination => 3 do
  outline.page :destionation => 3, :title => 'Page 3'
end

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# File 'lib/prawn/outline.rb', line 181

def section(title, options = {}, &block)
  add_outline_item(title, options, &block)
end