module Prawn::View

This mixin allows you to create modular Prawn code without the need to create subclasses of {Prawn::Document}.

“‘ruby class Greeter

include Prawn::View

# Optional override: allows you to set document options or even use
# a custom document class
def document
  @document ||= Prawn::Document.new(page_size: 'A4')
end

def initialize(name)
  @name = name
end

def say_hello
  text "Hello, #{@name}!"
end

def say_goodbye
  font("Courier") do
    text "Goodbye, #{@name}!"
  end
end

end

greeter = Greeter.new(“Gregory”)

greeter.say_hello greeter.say_goodbye

greeter.save_as(“greetings.pdf”) “‘

The short story about why you should use this mixin rather than creating subclasses of ‘Prawn::Document` is that it helps prevent accidental conflicts between your code and Prawn’s code.

Here’s the slightly longer story…

By using composition rather than inheritance under the hood, this mixin allows you to keep your state separate from ‘Prawn::Document`’s state, and also will prevent unexpected method name collisions due to late binding effects.

This mixin is mostly meant for extending Prawn’s functionality with your own additions, but you can also use it to replace or wrap existing Prawn methods. Calling ‘super` will still work as expected, and alternatively you can explicitly call `document.some_method` to delegate to Prawn where needed.

Public Instance Methods

document ()

Source

# File lib/prawn/view.rb, line 65
def document
  @document ||= Prawn::Document.new
end

Lazily instantiates a ‘Prawn::Document` object.

You can also redefine this method in your own classes to use a custom document class.

@return [Prawn::Dcoument]

method_missing (method_name, *args, **kwargs, &block)

Source

# File lib/prawn/view.rb, line 75
def method_missing(method_name, *args, **kwargs, &block)
  return super unless document.respond_to?(method_name)

  document.public_send(method_name, *args, **kwargs, &block)
end

Delegates all unhandled calls to object returned by {document} method.

@param method_name [Symbol] @param args [Array] Positional arguments. @param kwargs [Hash] Keyword arguments. @param block [Proc]

Calls superclass method

respond_to_missing? (method_name, _include_all = false)

Source

# File lib/prawn/view.rb, line 86
def respond_to_missing?(method_name, _include_all = false)
  document.respond_to?(method_name) || super
end

Does this object respond to the specified message?

@param method_name [Symbol] @param _include_all [Boolean] @return [Boolean]

Calls superclass method

save_as (filename)

Source

# File lib/prawn/view.rb, line 112
def save_as(filename)
  document.render_file(filename)
end

Syntatic sugar that calls ‘document.render_file` under the hood.

@example

greeter.save_as("greetings.pdf")

@param filename [String] @return [void]

update (&block)

Source

# File lib/prawn/view.rb, line 101
def update(&block)
  instance_eval(&block)
end

Syntactic sugar that uses ‘instance_eval` under the hood to provide a block-based DSL.

@example

greeter.update do
  say_hello
  say_goodbye
end

@yield @return [void]