Ubuntu Twitter Wallpaper Updater (v3)

#--------------------#
# REQUIREMENTS
# * Ubuntu (or any GNOME 3 desktop environment?)
# * ImageMagick
# * Ruby
# * Gems
#   * rmagick
#   * twitter
#
# Best run in screen
#--------------------#

#--------------------#
# wallpaper.rb
#--------------------#
require "open-uri"
require 'rmagick' # https://github.com/rmagick/rmagick
include Magick

class Wallpaper
  # Set the wallpaper directory
  @directory = "#{Dir.home}/Pictures/wallpaper"

  # This sets the specified image as the wallpaper and, by default, tiles it. Use
  #   $ gsettings range org.gnome.desktop.background picture-options
  # to see other options for centring/stretching the image. You can also specify a different source directory
  def self.update(filename,display="centered")
    color = average_color(filename)
    `gsettings set org.gnome.desktop.background picture-uri file://#{filename} && gsettings set org.gnome.desktop.background picture-options '#{display}' && gsettings set org.gnome.desktop.background primary-color '#{color}'`
  end

  # Download an image and annotate it with the Twitter handle, if provided
  def self.download(url,username=nil)
    # Get the file extension
    ext = url.to_s.split(".").last
    # Always call the file the same thing, so we overwrite it rather than having thousands of images saved
    target_location = "#{@directory}/mattpaper.#{ext}"

    begin
      # Download the source image to the specified destination
      open(url){|image|
        File.open(target_location,"wb") do |file|
          IO.copy_stream(image,file)
        end
      }

      # Put the user's name on the image as a watermark
      unless username.nil?
        img = ImageList.new(target_location)
        txt = Draw.new
        txt.annotate(img, 0,0,0,0, username){
          self.gravity = Magick::SouthEastGravity
          self.pointsize = 12
          self.fill = "#FFFFFF"
          self.fill_opacity(0.75)
        }
        img = img.write(target_location)
      end

      return target_location
    rescue Exception => e
      puts e.message
    end
    return false
  end

  # Calculate the average color of an image
  # http://blog.dcxn.com/2011/07/05/averaging-image-color-using-rmagick/
  def self.average_color(img)
    begin
      image = ImageList.new(img)
      total = 0
      avg = { :r => 0.0, :g => 0.0, :b => 0.0 }

      image.quantize.color_histogram.each do |c,n|
        avg[:r] += n * c.red
        avg[:g] += n * c.green
        avg[:b] += n * c.blue
        total += n
      end

      avg.each_key do |c|
        avg[c] /= total
        avg[c] = (avg[c] / QuantumRange * 255).to_i
      end

      return "##{avg[:r].to_s(16)}#{avg[:g].to_s(16)}#{avg[:b].to_s(16)}"
    rescue Exception => e
      puts e.message
      return "#000000"
    end
  end
end


#--------------------#
# run.rb
#--------------------#
require "rubygems"
require "twitter" # https://github.com/sferik/twitter
load "./wallpaper.rb"

# Visit http://apps.twitter.com to set up your API keys
client = Twitter::Streaming::Client.new do |config|
  config.consumer_key        = "YOUR_CONSUMER_KEY"
  config.consumer_secret     = "YOUR_CONSUMER_SECRET"
  config.access_token        = "YOUR_ACCESS_TOKEN"
  config.access_token_secret = "YOUR_ACCESS_TOKEN_SECRET"
end

attempts = 0

begin
  attempts += 1
  # Get the live stream
  client.user do |object|
    # We only care about Tweets
    if object.is_a?(Twitter::Tweet)
      # Does this tweet contain an image?
      if object.media.any?
        # Get the image URL
        image = object.media[0].media_url
        # Download the image
        paper = Wallpaper.download(image,object.user.screen_name)
        # Update the wallpaper, if it saved correctly
        if paper
          puts "#{Time.now.strftime("%Y-%m-%d %H:%M:%S")} -- #{image} from #{object.user.screen_name}"
          Wallpaper.update(paper)
        end
      end
    end
  end
rescue Twitter::Error::TooManyRequests => error
  # This bit should only happen if the Access Tokens above are already in use
  puts "#{Time.now.strftime("%H:%M:%S")} -- Attempt #{attempts} failed"
  if attempts % 3 == 0
    puts "#{Time.now.strftime("%H:%M:%S")} -- Waiting 15 minutes..."
    sleep(15*60)
  end
  retry
end