require 'rubygems'
require 'pdf/writer'
require 'RMagick'
 
module Canvas
  class Canvas
    attr_accessor :name
 
    def initialize(name)
      @name, @doc = name, Pdf.new(name)
      @maxWidth, @maxHeight = @doc.pdf.page_width, @doc.pdf.page_height
      @x, @y = 0, @doc.pdf.y - 75 # offset the y-pointer
    end
 
    def save() @doc.save; end
  end
 
  private
 
  class Pdf
    attr_reader :name, :pdf
 
    def initialize(name)
      @name = name
      @pdf = PDF::Writer.new(:orientation => :landscape)
 
      # Set document meta-data
      @pdf.info.title = @name
      @pdf.info.author = "Ilya Grigorik"
      @pdf.info.subject = "Calendar"
      @pdf.margins_pt(0, 0, 0, 0)	 # top, left, bottom, right 
    end
 
    def save() @pdf.save_as(@name); end
    def addImage(*attrs) @pdf.add_image_from_file(*attrs); end
  end
end
 

module Canvas
  class CalendarView < Canvas
    def initialize(name, date)
      super(name)
 
      @topRow = 50
      @rowH = (@doc.pdf.page_height.to_i - @topRow) / 6
      @columnW = (@doc.pdf.page_width.to_i) / 7
      @doc.pdf.stroke_color! Color::RGB.new(140,140,140)
 
      # Draw calendar grid
      1.upto(6) do |n|
        @doc.pdf.line(@doc.pdf.absolute_left_margin, n*@rowH, @doc.pdf.absolute_right_margin, n*@rowH).stroke
      end
 
      1.upto(6) do |n|
        @doc.pdf.line(n*@columnW, @doc.pdf.absolute_bottom_margin+6*@rowH, n*@columnW, @doc.pdf.absolute_bottom_margin).stroke
      end
 
      # Set first day of the week to Monday & figure out the start-position for current month
      @order = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
      @startSquare = @order.index(date.strftime("%A"))-1
    end
 
    def addImage(file, date)
      squareNum = @startSquare + Time.parse(date).day.to_i
      row = squareNum / 7
      col = squareNum % 7
 
      # Calculate the x, y offsets
      x = @doc.pdf.absolute_left_margin + col * @columnW
      y = (@doc.pdf.absolute_top_margin.to_i - @topRow - @rowH * (row+1)) - 3
 
      # Read the source image file and it's corresponding dimensions
      imageMagick = Magick::Image.read(file).first
      imgWidth, imgHeight = imageMagick.columns, imageMagick.rows
      imgRatio = imgWidth.to_f / imgHeight.to_f
 
      # scale to fit in calendar, preserve aspect ratio
      imgWidth, imgHeight = @columnW, (@columnW / imgRatio).to_i if ((imgWidth > imgHeight) and (imgWidth > @columnW))
      imgHeight, imgWidth = @rowH, (@rowH * imgRatio).to_i if ((imgHeight > imgWidth) and (imgHeight > @rowH))
      imgHeight, imgWidth = @rowH, @columnW if (imgHeight == imgWidth)
 
      # center the photo in the calendar square
      x = x + (@columnW-imgWidth)/2 if imgWidth < @columnW
      y = y + (@rowH-imgHeight)/2 if imgHeight < @rowH
 
      @doc.addImage(file, x, y, imgWidth, imgHeight)
    end
  end
end
 

require 'canvas.rb'
require 'calendar.rb'
 
# First parameter: output filename, Second parameter: Date object for the month/year of the calendar view
pdfDoc = Canvas::CalendarView.new("my-calendar.pdf", '2007-02-01')
 
# Load an array of images, provide full path, and the date (read exif from photo?)
images =  [['image1.jpg',  '2007-02-25'],
           ['image2.jpg', '2007-03-26']]
 
# Insert the images into our calendar!
images.each { |image| pdfDoc.addImage(image[0], image[1]) }
pdfDoc.save