Prawn Lookahead Height

lookahead.rb

require "prawn"

@pdf = Prawn::Document.new(margin: 0)
@text = "Oh hai text rect. " * 10
@options = { :document => @pdf }
text_box = Prawn::Text::Box.new(@text, @options)

p "cursor before dry run: #{@pdf.cursor}"
p "whats the height before dry run?"
p "....who knows????" if text_box.height == 0
text_box.render(:dry_run => true)
p "whats the height after the dry run?"
p "#{text_box.height}" if text_box.height
p "cursor after dry run: #{@pdf.cursor}"