Generate a graph using Gruff (See related posts)

This Ruby code produced a graph using gruff. The output shows a line graph [twitxr.com] for the different fruits. Source code origin: Gruff Update With Bar Graphs | Ruby on Rails for Newbies [rubyonrails.com]

require 'gruff'

g = Gruff::Line.new
g.title = "My Graph" 

g.data("Apples", [1, 2, 3, 4, 4, 3])
g.data("Oranges", [4, 8, 7, 9, 8, 9])
g.data("Watermelon", [2, 3, 1, 5, 6, 8])
g.data("Peaches", [9, 9, 10, 8, 7, 9])

g.labels = {0 => '2003', 2 => '2004', 4 => '2005'}

g.write('my_fruity_graph.png')

Note: I executed the code within an irb session on my Gentoo box. With Gentoo, Gruff was installed [gentoo-portage.com] using the command emerge -va gruff. I tried installing it on Ubuntu but ran into some difficulty, even with help from the article install rmagick ubuntu [dzone.com].

*udpate 21:48 24-Feb*

The following code does exactly as the same code above, however it uses XML to separate the data from the process, making it easier and more efficient to build graphs.

#!/usr/bin/ruby
# file: xml2gruff.rb

require 'rexml/document'
require 'gruff'
include REXML

class Xml2Gruff
  
  def initialize(filename)
    file = File.new(filename, 'r')
    doc = Document.new(file)
    # get the title
    @title = doc.root.elements['summary/title'].text
    
    @record = Hash.new
    # get each record
    doc.root.elements.each('records/item') {|item|
      avalues = Array.new
      item.elements.each('values/value') { |value| avalues << value.text.to_i }
      @record[item.elements['label'].text] = avalues
    }
    
    # get the summary labels
    @labels = Hash.new  
    doc.root.elements.each('summary/scale/label') {|l| @labels[l.elements['value'].text.to_i] = l.elements['title'].text} 
    
  end
  
  def save_line_graph(filename)

    g = Gruff::Line.new
    g.title = @title 
    @record.each {|label, data| g.data(label, data) }
    g.labels = @labels
    g.write(filename)

  end
end

if __FILE__ == $0
 x2g = Xml2Gruff.new('my_fruit.xml')
 x2g.save_line_graph('my_fruit2.png')
end

file: my_fruit.xml

<graph>
  <summary>
    <title>My Graph</title>
    <scale>
      <label><title>2003</title><value>0</value></label>
      <label><title>2004</title><value>2</value></label>
      <label><title>2005</title><value>4</value></label>
    </scale>
  </summary>
  <records>
    <item>
      <label>Apples</label>
      <values><value>1</value><value>2</value><value>3</value><value>4</value><value>4</value><value>3</value></values>
    </item>
    <item>
      <label>Oranges</label>
      <values><value>4</value><value>8</value><value>7</value><value>9</value><value>8</value><value>9</value></values>
    </item>
    <item>
      <label>Watermelon</label>
      <values><value>2</value><value>3</value><value>1</value><value>5</value><value>6</value><value>8</value></values>
    </item>
    <item>
      <label>Peaches</label>
      <values><value>9</value><value>9</value><value>10</value><value>8</value><value>7</value><value>9</value></values>
    </item>
  </records>
</graph>

Reference: gruff's gruff-0.2.9 Documentation [rubyforge.org]
to ruby rmagick image ubuntu gentoo magick graph chart gruff by jrobertson on Sun Feb 24 13:52:14 -0500 2008