first commit

LICENSE.txt

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+   Copyright 2008 Donald A. Ball Jr. <donald.ball@gmail.com>
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

README.txt

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+Zoomifier is a ruby library for creating directories of tiled images
+suitable for viewing with the free Zoomify flash player:
+
+http://www.zoomify.com/

bin/zoomify

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+require 'zoomifier'
+Zoomifier::zoomify(ARGV[0])

lib/zoomifier.rb

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+require 'fileutils'
+require 'open-uri'
+require 'rexml/document'
+require_gem 'rmagick'
+
+# Breaks up images into tiles suitable for viewing with Zoomify.
+# See http://zoomify.com/ for more details.
+#
+# @author Donald A. Ball Jr. <donald.ball@gmail.com>
+# @version 1.1
+# @copyright (C) 2008 Donald A. Ball Jr.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+module Zoomifier
+
+  TILESIZE = 256
+
+  # Zoomifies the image file specified by filename. The zoomified directory
+  # name will be the filename without its extension, e.g. 5.jpg will be
+  # zoomified into a directory named 5. If there is already a directory with
+  # this name, it will be destroyed without mercy.
+  def self.zoomify(filename)
+    raise ArgumentError unless File.exists?(filename) && File.file?(filename)
+    outputdir = File.basename(filename, '.*')
+    raise ArgumentError unless filename != outputdir
+    FileUtils.rm_rf(outputdir) if File.exists?(outputdir)
+    Dir.mkdir(outputdir)
+    tmpdir = "#{outputdir}/tmp"
+    Dir.mkdir(tmpdir)
+    tilesdir = nil
+    image = Magick::Image.read(filename).first.strip!
+    # Each level of zoom is a factor of 2. Here we obtain the number of zooms
+    # allowed by the original file dimensions and the constant tile size.
+    levels = (Math.log([image.rows, image.columns].max.to_f / TILESIZE) / Math.log(2)).ceil
+    tiles = 0
+    (0..levels).each do |level|
+      n = levels - level
+      # Obtain the image to tile for this level. The 0th level should consist
+      # of one tile, while the highest level should be the original image.
+      level_image = image.resize(image.columns >> n, image.rows >> n)
+      tiles(tmpdir, level, level_image) do |filename|
+        # The tile images are chunked into directories named TileGroupN, N
+        # starting at 0 and increasing monotonically. Each directory contains
+        # at most 256 images. The images are sorted by level, tile row, and
+        # tile column.
+        div, mod = tiles.divmod(256)
+        if mod == 0
+          tilesdir = "#{outputdir}/TileGroup#{div}"
+          Dir.mkdir(tilesdir)
+        end
+        FileUtils.mv("#{tmpdir}/#{filename}", "#{tilesdir}/#{filename}")
+        tiles += 1
+      end
+      # Rmagick needs a bit of help freeing image memory.
+      level_image = nil
+      GC.start
+    end
+    File.open("#{outputdir}/ImageProperties.xml", 'w') do |f|
+      f.write("<IMAGE_PROPERTIES WIDTH=\"#{image.columns}\" HEIGHT=\"#{image.rows}\" NUMTILES=\"#{tiles}\" NUMIMAGES=\"1\" VERSION=\"1.8\" TILESIZE=\"#{TILESIZE}\" />")
+    end
+    Dir.rmdir(tmpdir)
+    outputdir
+  end
+
+  # Splits the given image up into images of TILESIZE, writes them to the
+  # given directory, and yields their names
+  def self.tiles(dir, level, image)
+    slice(image.rows).each_with_index do |y_slice, j|
+      slice(image.columns).each_with_index do |x_slice, i|
+        # The images are named "level-column-row.jpg"
+        filename = "#{level}-#{i}-#{j}.jpg"
+        tile_image = image.crop(x_slice[0], y_slice[0], x_slice[1], y_slice[1])
+        tile_image.write("#{dir}/#{filename}") do
+          # FIXME - the images end up being 4-5x larger than those produced
+          # by Zoomifier EZ and friends... no idea why just yet, except to note
+          # that the density of these tiles ends up being 400x400, while
+          # everybody else produces tiles at 72x72. Can't see why that would
+          # matter though...
+          self.quality = 80 
+        end
+        # Rmagick needs a bit of help freeing image memory.
+        tile_image = nil
+        GC.start
+        yield filename
+      end
+    end
+  end
+
+  # Returns an array of slices ([offset, length]) obtained by slicing the
+  # given number by TILESIZE.
+  # E.g. 256 -> [[0, 256]], 257 -> [[0, 256], [256, 1]],
+  #      513 -> [[0, 256], [256, 256], [512, 1]]
+  def self.slice(n)
+    results = []
+    i = 0
+    while true
+      if i + TILESIZE >= n
+        results << [i, n-i]
+        break
+      else
+        results << [i, TILESIZE]
+        i += TILESIZE
+      end
+    end
+    results
+  end
+
+  def self.unzoomify(url)
+    tmpdir = 'tmp'
+    FileUtils.rm_rf(tmpdir) if File.exists?(tmpdir)
+    Dir.mkdir(tmpdir)
+    doc = nil
+    begin
+      open("#{url}/ImageProperties.xml") do |f|
+        doc = REXML::Document.new(f)
+      end
+    rescue OpenURI::HTTPError
+      return nil
+    end
+    attrs = doc.root.attributes
+    return nil unless attrs['TILESIZE'] == '256' && attrs['VERSION'] == '1.8'
+    width = attrs['WIDTH'].to_i
+    height = attrs['HEIGHT'].to_i
+    tiles = attrs['NUMTILES'].to_i
+    image_paths = (0 .. tiles/256).map {|n| "TileGroup#{n}"}
+    max_level = 0
+    while (get_tile(url, image_paths, tmpdir, "#{max_level}-0-0.jpg"))
+      max_level += 1
+    end
+    max_level -= 1
+    image = Magick::Image.new(width, height)
+    (0 .. width / TILESIZE).each do |column|
+      (0 .. height / TILESIZE).each do |row|
+        filename = "#{max_level}-#{column}-#{row}.jpg"
+        get_tile(url, image_paths, tmpdir, filename)
+        tile_image = Magick::Image.read("#{tmpdir}/#{filename}").first
+        image.composite!(tile_image, column*TILESIZE, row*TILESIZE, Magick::OverCompositeOp)
+        time_image = nil
+        GC.start
+      end
+    end
+    # FIXME - get filename from the url
+    image.write('file.jpg') { self.quality = 90 }
+    image = nil
+    GC.start
+    FileUtils.rm_rf(tmpdir)
+  end
+
+  # TODO - could reduce the miss rate by using heuristics to guess the
+  # proper path from which to download the file
+  def self.get_tile(url, image_paths, tmpdir, filename)
+    image_paths.each do |path|
+      begin
+        open("#{tmpdir}/#{filename}", 'wb') {|f| f.write(open("#{url}/#{path}/#{filename}").read)}
+        return filename
+      rescue OpenURI::HTTPError
+      end
+    end
+    nil
+  end 
+  
+end

zoomifier.gemspec

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+require 'rubygems'
+spec = Gem::Specification.new do |s|
+  s.name = 'Zoomifier'
+  s.version = '1.1'
+  s.author = 'Donald Ball'
+  s.email = 'donald.ball@gmail.com'
+  s.platform = Gem::Platform::RUBY
+  s.summary = 'A library for zoomifying images'
+  s.files = ['lib/zoomifier.rb', 'bin/zoomify']
+  s.require_path = 'lib'
+  s.autorequire = 'zoomifier'
+  s.bindir = 'bin'
+  s.executables = ['zoomify']
+  s.default_executable = 'zoomify'
+  s.has_rdoc = true
+  s.extra_rdoc_files = ['README.txt']
+  s.add_dependency('rmagick')
+end
+
+if $0 == __FILE__
+  Gem::manage_gems
+  Gem::Builder.new(spec).build
+end