Impressed with Prawn for PDF Generation

05 Apr 2009

I’ve been aware of Prawn, the Ruby PDF generation library for some time. Today was the first occasion I had an opportunity to utilise it and I was delighted with how easy it was to use.

My Ruby application needed to generate some tabular PDF reports so I installed the prawn gem and, with a little help from the examples on the Prawn home page and the core and layout documentation, I was off and running.

An example of using prawn via a rake task follows:

require 'rubygems'  
require 'prawn'  
require 'prawn/layout'  
namespace :report do  
  desc "Generate top 10 points getters report"  
  task :top10 =\> :environment do  
    Prawn::Document.generate("reports/top10.pdf") do  
      font "#{Prawn::BASEDIR}/data/fonts/DejaVuSans.ttf"  
      font_size 14  
      text "Top 10 Points Getters"  
      text " "  
      # fetch two-dimensional array of data for the table  
      data = Player.top10_data  
      table data,  
        :font_size => 9,  
        :position => :center,  
        :headers => ["#", "Player", "Points"],  
        :row_colors => ["ffffff", "eeeeee"]  
    end  
  end  
end  

Generating the report was then as simple as running:

rake report:top10  

I’m looking forward to using other features of Prawn such as image embedding and content positioning. At the time of writing prawn itself is version 0.4.1 and prawn-layout is 0.1.0. Hopefully James Healy, an Australian noted as “instrumental to the forward development of the library”, is coming to Railscamp 5 next month. Then I can pick his brains about what other features are in the pipeline.

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