Generate Favicons using RMagick. Includes a Middleman-3.0 extension

favicon_generator.rb

###
# Simple Script to generate favicons from a base PNG image
# Relies on RMagick to do the job
# Also includes a Middleman-3.0 extension
###

require 'fileutils'

class MagickFavicon
    include Magick

    attr_accessor :base_image, :source_dir, :target_dir

    Icons = {
            'favicon.ico' => '16x16',
            'apple-touch-icon-144x144-precomposed.png' => '144x144',
            'apple-touch-icon-114x114-precomposed.png' => '114x114',
            'apple-touch-icon-72x72-precomposed.png' => '72x72',
            'apple-touch-icon-57x57-precomposed.png' => '57x57',
            'apple-touch-icon-precomposed.png' => '57x57',
            'apple-touch-icon.png' => '57x57',
    }


    def initialize
        self.base_image = 'favicon_base.png'
        self.source_dir = 'source'
        self.target_dir = 'tmp'
    end

    def make

        # Load the base image
        base_file = File.join(source_dir, base_image)
        base_icon = ImageList.new base_file

        # Generate!
        Icons.each do |filename, size|
            w, h = size.split 'x'

            favicon = base_icon.scale(w.to_i, h.to_i)
            favicon.write File.join(target_dir, filename)

            favicon.destroy!

            yield filename if block_given?
        end
    end
end

### Middleman Extension ###
module FaviconMaker
    class << self
        def registered(app)

            app.after_build do |builder|
                fm = MagickFavicon.new
                fm.source_dir = source
                fm.target_dir = build_dir

                fm.make { |f| builder.say_status :generated, f }
                FileUtils.rm_f File.join(build_dir, fm.base_image)
            end
        end

        alias :included :registered
    end
end

::Middleman::Extensions.register(:favicon_maker, FaviconMaker)