Prawn_rails explanation

demo.rb

require 'prawn'
# NOTE: this file won't actually run


# How the prawn documentation is written:
# provides a block without an argument,
# recognized methods are implicity called
# on the resulting PDF
Prawn::Document.generate("demo.pdf") do
  move_cursor_to 50
  text "Hello World!"
end

# How (roughly) Prawn::Rails calls Prawn
# an argument is provided and all Prawn
# methods must be called on the pdf object
Prawn::Document.generate("demo2") do |pdf|
  pdf.move_cursor_to 50
  pdf.text "Hello World!"
end

# Prawn document requires a block with
# an argument to avoid overriding many
# Rails methods which may be useful
# e.x. translate
prawn_document do |pdf|
  pdf.move_cursor_to 50
  pdf.text "Look! I'm a PDF"
end