Google Art Project fullsize image downloader. Specify the page URL and the tiles are downloaded, stitched and trimmed.

google_art_project.rb

# Google Art Project fullsize image downloader.
# By Henrik Nyh <http://henrik.nyh.se> 2011-02-05 under the MIT license.
# Requires Ruby and ImageMagick.
#
# Usage e.g.:
#   ruby google_art_project.rb http://www.googleartproject.com/museums/tate/portrait-of-william-style-of-langley-174
#
# You can specify multiple URLs on the command line, separated by space.
# Or you can specify no URLs on the command line and instead list them at the end of this file, one on each line,
# with "__END__" before the list.
#
# On OS X, it sets "Downloaded from" metadata and reveals in Finder.
#
# Can reportedly run on Windows as well, with Ruby from http://www.ruby-lang.org/en/downloads/
# and ImageMagick from http://www.imagemagick.org/script/binary-releases.php#windows
# Note that you may need to edit the TEMP_DIRECTORY/OUTPUT_DIRECTORY below.

require "open-uri"
require "fileutils"
require "rbconfig"

module Kernel
  def windows?
    Config::CONFIG['host_os'].match(/mswin|windows|mingw/i)
  end
end

class GAPDownloader

  # Set this to "jpg" or "tif".
  # jpg is a lot smaller but destructively compressed.
  OUTPUT_EXTENSION = "jpg"

  if windows?
    # Case-sensitive. Use forward slashes, or double-escape backslashes.
    TEMP_DIRECTORY = "C:/WINDOWS/Temp"
    OUTPUT_DIRECTORY = TEMP_DIRECTORY
  else
    TEMP_DIRECTORY = "/tmp"
    OUTPUT_DIRECTORY = "#{ENV['HOME']}/Downloads"
    FileUtils.mkdir_p OUTPUT_DIRECTORY
  end

  # You can lower this if you get ridiculously high-res images otherwise.
  MAX_ZOOM_ALLOWED = 10

  class RuntimeError < StandardError; end

  def initialize(url)
    ensure_image_magick!
    @url = url
    verify_url!
  end

  def download
    get_image_id
    determine_zoom
    get_tiles
    stitch_tiles
    trim
    set_metadata
    done
  end

private

  def ensure_image_magick!
    if !windows? && `which montage`.empty?
      error "You must have ImageMagick installed. Could not find 'montage' in your PATH."
    end
  end

  def verify_url!
    unless @url.to_s.match(%r{\Ahttp://www\.googleartproject\.com/})
      error "Please specify a Google Art Project URL."
    end
  end

  def get_image_id
    @html = open(@url).read
    # Reportedly the data-thumbnail can change in the middle of a long download session, but
    # the encodedInfospotId will not. So if we key local files by the InfospotId, we can
    # check for them if download fails and we start over. Also makes for more human names.
    # If I run into it myself, I may adapt the code to auto-resolve a changed data-thumbnail.
    @thumb_id = @html[/data-thumbnail="(.+?)"/, 1]
    @perma_id = @html[/data-encodedInfospotId="(.+?)"/, 1]
    unless @thumb_id && @perma_id
      error "Couldn't find an image at this URL, sorry!"
    end
  end

  def determine_zoom
    0.upto(MAX_ZOOM_ALLOWED) do |zoom|
      open(tile_url(0, 0, zoom))
      @max_zoom = zoom
    end
  rescue OpenURI::HTTPError => e
    raise unless e.message == "404 Not Found"
  end

  def get_tiles
    @max_x = 999
    @max_y = 999

    0.upto(@max_y) do |y|
      0.upto(@max_x) do |x|
        url = tile_url(x, y, @max_zoom)
        path = tile_path(x, y)
        if File.exists?(path)
          puts "Skipping #{url} (already downloaded)..."
          next
        end
        begin
          data = open(url)  # Raises at 404.
          puts "Getting #{url}..."
          File.open(path, "wb") { |f| f.print data.read }
        rescue OpenURI::HTTPError => e
          raise unless e.message == "404 Not Found"
          if y.zero?
            # Found max x. Start on next row.
            @max_x = x - 1
            break
          else
            # Found max y. We have all tiles, so bail.
            @max_y = y - 1
            return
          end
        end
      end
    end
  end

  def stitch_tiles
    # `montage` is ImageMagick.
    # We first stitch together the tiles of each row, then stitch all rows.
    # Stitching the full image all at once can get extremely inefficient for large images.
    tiles_wide = @max_x + 1
    tiles_high = @max_y + 1

    puts "Stitching #{tiles_wide} x #{tiles_high} = #{tiles_wide*tiles_high} tiles..."

    0.upto(@max_y) do |y|
      tiles = (0..@max_x).map { |x| tile_path(x, y) }.join(' ')
      `montage #{tiles} -geometry +0+0 -tile #{tiles_wide}x1 #{row_path(y)}`
    end

    tiles = (0..@max_y).map { |y| row_path(y) }.join(' ')
    `montage #{tiles} -geometry +0+0 -tile 1x#{tiles_high} #{full_path}`
  end

  def trim
    # Trim the black blocks that may appear on right and bottom.
    # We first add a black border to ensure no other color is trimmed, as described on
    # http://www.imagemagick.org/Usage/crop/#trim
    `convert #{full_path} -bordercolor black -border 1x1 -trim #{full_path}`
  end

  def set_metadata
    # 300 DPI instead of 72 DPI; more sane for printing.
    `convert #{full_path} -density 300 #{full_path}`
    if !windows? && !`which xattr`.empty?
      # Set "Downloaded from" Finder metadata, like Safari does.
      system('xattr', '-w', 'com.apple.metadata:kMDItemWhereFroms', @url, full_path)
    end
  end

  def done
    puts "Done: #{full_path}"
    # Reveal in Finder if on OS X.
    unless windows?
      `which osascript && osascript -e 'tell app "Finder"' -e 'reveal POSIX file "#{full_path}"' -e 'activate' -e 'end'`
    end
  end


  def error(message)
    raise GAPDownloader::RuntimeError, "#{message} (#{@url})"
  end


  def tile_url(x, y, zoom)
    # The subdomain can seemingly be anything from lh3 to lh6.
    "http://lh5.ggpht.com/#{@thumb_id}=x#{x}-y#{y}-z#{zoom}"
  end

  def tile_path(x, y)
    File.join(TEMP_DIRECTORY, "gap-#{@perma_id}-tile-#{x}-#{y}.jpg")
  end

  def row_path(y)
    File.join(TEMP_DIRECTORY, "gap-#{@perma_id}-row-#{@max_zoom}-#{y}.#{OUTPUT_EXTENSION}")
  end

  def full_path
    File.join(OUTPUT_DIRECTORY, "#{@perma_id}.#{OUTPUT_EXTENSION}")
  end

end

if __FILE__ == $0
  urls = ARGV.any? ? ARGV : (defined?(DATA) ? DATA.read.strip.split("\n")  : [])
  puts "Error: No URLs given!" if urls.empty?

  urls.each do |url|
    begin
      GAPDownloader.new(url).download
    rescue GAPDownloader::RuntimeError => e
      puts "Error: #{e.message}"
    end
  end
end

When I try to run this on my Mac I get:
ruby google_art_project.rb google_art_project.rb:24:inwindows?': uninitialized constant Kernel::Config (NameError)
Did you mean? RbConfig
from google_art_project.rb:34:in <class:GAPDownloader>' from google_art_project.rb:28:in

'`

Giga Fine Art doesn't work

It's now at http://gigafineart.herokuapp.com/gcidownload... but it seems like it's no longer working, I just get black images.

Yes, Giga Fine Art is not working for me either (black images). Is there any other alternate site?

Confirmed. Giga Fine Art generates black canvas images. Alternatives or a way to contact the author about the malfunction?

You can contact the author: http://gigafineart.herokuapp.com/contact

Giga Fine Art always shows black image...

I'm working on it, and it seems to work, check the full resolution of https://www.dropbox.com/s/gih93ye4v1y6lsu/the_starry_night.jpg?dl=0 @wendingp @tkalfigo

@infinitesheldon , I too am getting a black image when downloading at all sizes with all images from the new google domain.