export_images_to_pdf.rb

require 'rubygems'
require 'prawn'
require "prawn/measurement_extensions"
require 'ruby-debug'
 

# Put ignored bmml files here, one per line
src = ARGV[0]
output = ARGV[1]


ignored_files = [ 
  "SKIP_ME.jpg"
]

# http://snippets.dzone.com/posts/show/805
class JPEG
  attr_reader :width, :height, :bits

  def initialize(file)
    if file.kind_of? IO
      examine(file)
    else
      File.open(file, 'rb') { |io| examine(io) }
    end
  end

private
  def examine(io)
    raise 'malformed JPEG' unless io.getc == 0xFF && io.getc == 0xD8 # SOI

    class << io
      def readint; (readchar << 8) + readchar; end
      def readframe; read(readint - 2); end
      def readsof; [readint, readchar, readint, readint, readchar]; end
      def next
        c = readchar while c != 0xFF
        c = readchar while c == 0xFF
        c
      end
    end

    while marker = io.next
      case marker
        when 0xC0..0xC3, 0xC5..0xC7, 0xC9..0xCB, 0xCD..0xCF # SOF markers
          length, @bits, @height, @width, components = io.readsof
          raise 'malformed JPEG' unless length == 8 + components * 3
        when 0xD9, 0xDA:  break # EOI, SOS
        when 0xFE:        @comment = io.readframe # COM
        when 0xE1:        io.readframe # APP1, contains EXIF tag
        else              io.readframe # ignore frame
      end
    end
  end
end

class Util  
  def self.dimension_of file
    case file
    when /\.png$/i
      IO.read( file )[0x10..0x18].unpack('LL')
    when /\.gif$/i
      IO.read( file )[6..10].unpack('SS')
    when /\.jpe?g$/i
      jpg = JPEG.new( file )
      return [ jpg.width, jpg.height ]
    end
  end
end

# Queue up the images
images = []
Dir.chdir src do 
  %w( *.png *.gif *.jpg *.jpeg ).each do |ext|
    Dir.glob( ext ) do |file|
      images << "#{src}/#{file}" unless ignored_files.include? file
    end
  end
end

images.sort!




# Baill out if there's no images
return if images.empty?

# Read the first image size to determine the initial layout
dim = Util.dimension_of images.first
Prawn::Document.generate( output, :page_size => "A4", :page_layout => dim[1] > dim [ 0 ] ? :portrait : :landscape  ) do 

  # Append image to the pdf document 
  images.each_with_index do |img, i|
    dim = Util.dimension_of( img )
    start_new_page( :layout => dim[1] > dim [ 0 ] ? :portrait : :landscape ) if i > 0
    image img, :position => :left, :vposition => :top , :fit => bounds.top_right
  end

  # Print the page #
  number_pages "<page>", [bounds.left, 0]
  
  # build the section outline
  define_outline do
    section 'Outline', :page => 1, :closed => true do
      for i in 0...images.length 
        page i + 1, :title => images[i].split('/').last
      end
    end
  end
  
  
end