Two pass conversion

app/models/riiif/transformation.rb

@@ -0,0 +1,35 @@
+module Riiif
+  # Represents a IIIF request
+  class Transformation
+    attr_reader :crop, :size, :quality, :rotation, :format
+    def initialize(crop, size, quality, rotation, format)
+      @crop = crop
+      @size = size
+      @quality = quality
+      @rotation = rotation
+      @format = format
+    end
+
+    # Create a clone of this Transformation, scaled by the factor
+    # @param [Integer] factor the scale for the new transformation
+    # @return [Transformation] a new transformation, scaled by factor
+    def reduce(factor)
+      Transformation.new(crop.dup,
+                         size.reduce(factor),
+                         quality,
+                         rotation,
+                         format)
+    end
+
+    # Create a clone of this Transformation, without the crop
+    # @return [Transformation] a new transformation
+    # TODO: it would be nice if we didn't need image_info
+    def without_crop(image_info)
+      Transformation.new(Region::Full.new(image_info),
+                         size.dup,
+                         quality,
+                         rotation,
+                         format)
+    end
+  end
+end

app/services/riiif/command_runner.rb

@@ -6,7 +6,8 @@ class CommandRunner
     include ActiveSupport::Benchmarkable
     delegate :logger, to: :Rails
 
-    # @return [Sting] all the image data
+    # TODO: this is being loaded into memory.  We could make this a stream.
+    # @return [String] all the image data
     def execute(command)
       out = nil
       benchmark("Riiif executed #{command}") do

app/services/riiif/kakadu_command_factory.rb

@@ -18,11 +18,10 @@ def initialize(path, info, transformation)
 
     attr_reader :path, :info, :transformation
 
+    # @param tmp_file [String] the path to the temporary file
     # @return [String] a command for running kdu_expand to produce the requested output
-    def command
-      # TODO: we must delete this link
-      ::File.symlink('/dev/stdout', link_path)
-      [external_command, quiet, input, threads, region, reduce, output(link_path)].join
+    def command(tmp_file)
+      [external_command, quiet, input, threads, region, reduce, output(tmp_file)].join
     end
 
     def reduction_factor
@@ -34,16 +33,12 @@ def reduction_factor
 
     private
 
-      def link_path
-        @link_path ||= LinkNameService.create
-      end
-
       def input
         " -i #{path}"
       end
 
-      def output(link_path)
-        " -o #{link_path}"
+      def output(output_filename)
+        " -o #{output_filename}"
       end
 
       def threads
@@ -56,7 +51,7 @@ def quiet
 
       def region
         region_arg = transformation.crop.to_kakadu
-        " -region #{region_arg}" if region_arg
+        " -region \"#{region_arg}\"" if region_arg
       end
 
       # kdu_expand is not capable of arbitrary scaling, but it does

app/services/riiif/size/percent.rb

@@ -4,14 +4,16 @@ module Size
     # of the extracted region. The aspect ratio of the returned image is the same as that
     # of the extracted region.
     class Percent < Resize
-      def initialize(info, n)
+      def initialize(info, percentage)
         @image_info = info
-        @n = n
+        @percentage = percentage
       end
 
+      attr_reader :percentage
+
       # @return [String] a resize directive for imagemagick to use
       def to_imagemagick
-        "#{@n}%"
+        "#{percentage}%"
       end
 
       # @return [Integer] the height in pixels
@@ -29,12 +31,18 @@ def reduce?
         true
       end
 
+      # @param [Integer] factor number of times to reduce by 1/2
+      def reduce(factor)
+        pct = percentage.to_f * 2**factor
+        Percent.new(image_info, pct)
+      end
+
       private
 
         # @param [Integer] value a value to convert to the percentage
         # @return [Float]
         def percent_of(value)
-          value * Integer(@n).to_f / 100
+          value * Integer(percentage).to_f / 100
         end
     end
   end

app/transformers/riiif/abstract_transformer.rb

@@ -2,28 +2,26 @@ module Riiif
   # Transforms an image using a backend
   class AbstractTransformer
     # @param path [String] The path of the source image file
-    # @param info [ImageInformation] information about the source
+    # @param image_info [ImageInformation] information about the source
     # @param [Transformation] transformation
-    def self.transform(path, info, transformation)
-      new(path, info, transformation).transform
+    def self.transform(path, image_info, transformation)
+      new(path, image_info, transformation).transform
     end
 
-    def initialize(path, info, transformation)
+    def initialize(path, image_info, transformation)
       @path = path
-      @info = info
+      @image_info = image_info
       @transformation = transformation
     end
 
-    attr_reader :path, :info, :transformation
+    attr_reader :path, :image_info, :transformation
 
     def transform
-      builder = command_factory.new(path, info, transformation)
-      post_process(execute(builder.command), builder.reduction_factor)
+      execute(command_builder.command)
     end
 
-    # override this method in subclasses if we need to transform the output data
-    def post_process(image, _reduction_factor)
-      image
+    def command_builder
+      @command_builder ||= command_factory.new(path, image_info, transformation)
     end
 
     delegate :execute, to: Riiif::CommandRunner

app/transformers/riiif/kakadu_transformer.rb

@@ -5,22 +5,35 @@ def command_factory
       KakaduCommandFactory
     end
 
+    def transform
+      with_tempfile do |file_name|
+        execute(command_builder.command(file_name))
+        post_process(file_name, command_builder.reduction_factor)
+      end
+    end
+
+    def with_tempfile
+      Tempfile.open(['riiif-intermediate', '.bmp']) do |f|
+        yield f.path
+      end
+    end
+
     # The data we get back from kdu_expand is a bmp and we need to change it
     # to the requested format by calling Imagemagick.
-    # TODO: Calculate a new set of transforms with respect to reduction_factor
-    def post_process(data, reduction_factor)
-      puts "Reduction factor is #{reduction_factor}"
-      data_io = StringIO.new(data)
-      data_io.binmode
-      out = ''
-      command = "/usr/local/bin/convert - #{transformation.format}:-"
-      IO.popen(command, 'r+b') do |io|
-        io.write(data_io.read(4096)) until data_io.eof?
-        io.close_write
-        # Read from convert into our buffer
-        out << io.read(4096) until io.eof?
-      end
-      out
+    def post_process(intermediate_file, reduction_factor)
+      # Calculate a new set of transforms with respect to reduction_factor
+      transformation = if reduction_factor
+                         self.transformation.without_crop(image_info).reduce(reduction_factor)
+                       else
+                         self.transformation.without_crop(image_info)
+                       end
+      Riiif::File.new(intermediate_file).extract(transformation, image_info)
     end
+
+    private
+
+      def tmp_path
+        @link_path ||= LinkNameService.create
+      end
   end
 end

lib/riiif.rb

@@ -17,7 +17,6 @@ class ImageNotFoundError < Error; end
   # This error is raised when Riiif can't convert an image
   class ConversionError < Error; end
 
-  Transformation = Struct.new(:crop, :size, :quality, :rotation, :format)
   mattr_accessor :not_found_image # the image to use when a lookup fails
   mattr_accessor :unauthorized_image # the image to use when a user doesn't have access
 

spec/models/riiif/transformation_spec.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Riiif::Transformation do
+  subject(:transformation) do
+    Riiif::Transformation.new(region,
+                              size,
+                              quality,
+                              rotation,
+                              fmt)
+  end
+
+  let(:region) { Riiif::Region::Full.new(image_info) }
+  let(:size) { Riiif::Size::Percent.new(image_info, 20) }
+  let(:quality) { nil }
+  let(:rotation) { nil }
+  let(:fmt) { nil }
+  let(:image_info) { double('Image info', height: 4381, width: 6501) }
+
+  describe 'reduce' do
+    subject { transformation.reduce(factor) }
+    context 'when reduced by 2' do
+      let(:factor) { 2 }
+      let(:size) { Riiif::Size::Percent.new(image_info, 20) }
+
+      it 'downsamples the size' do
+        expect(subject.size).to be_kind_of Riiif::Size::Percent
+        expect(subject.size.percentage).to eq 80.0
+      end
+    end
+  end
+
+  describe 'without_crop' do
+    let(:region) { Riiif::Region::Absolute.new(image_info, 5, 6, 7, 8) }
+
+    subject { transformation.without_crop(image_info) }
+    it 'nullifies the crop' do
+      expect(subject.crop).to be_kind_of Riiif::Region::Full
+    end
+  end
+end

spec/services/riiif/kakadu_command_factory_spec.rb

@@ -22,11 +22,7 @@
   end
 
   describe '#command' do
-    subject { instance.command }
-    before do
-      allow(::File).to receive(:symlink)
-      allow(Riiif::LinkNameService).to receive(:create).and_return('/tmp/bar.bmp')
-    end
+    subject { instance.command '/tmp/bar.bmp' }
 
     context 'with a full size image' do
       it { is_expected.to eq 'kdu_expand -quiet -i foo.jp2 -num_threads 4 -o /tmp/bar.bmp' }
@@ -43,17 +39,17 @@
 
     context 'with absolute' do
       let(:region) { Riiif::Region::Absolute.new(info, 25, 75, 150, 100) }
-      it { is_expected.to eq ' -region {0.25,0.08333333333333333},{0.3333333333333333,0.5}' }
+      it { is_expected.to eq ' -region "{0.25,0.08333333333333333},{0.3333333333333333,0.5}"' }
     end
 
     context 'with a square' do
       let(:region) { Riiif::Region::Square.new(info) }
-      it { is_expected.to eq ' -region {0.0,0},{1.0,1.0}' }
+      it { is_expected.to eq ' -region "{0.0,0},{1.0,1.0}"' }
     end
 
     context 'with a percentage' do
       let(:region) { Riiif::Region::Percentage.new(info, 20, 30, 40, 50) }
-      it { is_expected.to eq ' -region {0.3,0.2},{0.5,0.4}' }
+      it { is_expected.to eq ' -region "{0.3,0.2},{0.5,0.4}"' }
     end
   end
 

spec/transformers/riiif/kakadu_transformer_spec.rb

@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Riiif::KakaduTransformer do
+  subject(:instance) { described_class.new(path, image_info, transformation) }
+
+  let(:image_info) { double('Image info', height: 4381, width: 6501) }
+  let(:path) { 'baseball.jp2' }
+  let(:region) { Riiif::Region::Full.new(image_info) }
+  let(:size) { Riiif::Size::Full.new }
+  let(:quality) { nil }
+  let(:rotation) { nil }
+  let(:fmt) { 'jpg' }
+
+  let(:transformation) do
+    Riiif::Transformation.new(region,
+                              size,
+                              quality,
+                              rotation,
+                              fmt)
+  end
+
+  describe '#transform' do
+    let(:image_data) { double }
+
+    subject(:transform) { instance.transform }
+
+    before do
+      allow(instance).to receive(:with_tempfile).and_yield('/tmp/foo.bmp')
+    end
+
+    context 'when reduction_factor is 0' do
+      let(:reduction_factor) { 0 }
+      it 'calls the Imagemagick transform' do
+        expect(Riiif::CommandRunner).to receive(:execute)
+          .with('kdu_expand -quiet -i baseball.jp2 -num_threads 4 -o /tmp/foo.bmp')
+        expect(Riiif::CommandRunner).to receive(:execute)
+          .with('convert -quality 85 -sampling-factor 4:2:0 -strip /tmp/foo.bmp jpg:-')
+        transform
+      end
+    end
+
+    context 'when reduction_factor is 1' do
+      let(:size) { Riiif::Size::Percent.new(image_info, 30) }
+      let(:reduction_factor) { 1 }
+
+      it 'calls the Imagemagick transform' do
+        expect(Riiif::CommandRunner).to receive(:execute)
+          .with('kdu_expand -quiet -i baseball.jp2 -num_threads 4 -reduce 1 -o /tmp/foo.bmp')
+        expect(Riiif::CommandRunner).to receive(:execute)
+          .with('convert -resize 60.0% -quality 85 -sampling-factor 4:2:0 -strip /tmp/foo.bmp jpg:-')
+        transform
+      end
+    end
+
+    context 'when reduction_factor is 2' do
+      let(:size) { Riiif::Size::Percent.new(image_info, 20) }
+      let(:reduction_factor) { 2 }
+      it 'calls the Imagemagick transform' do
+        expect(Riiif::CommandRunner).to receive(:execute)
+          .with('kdu_expand -quiet -i baseball.jp2 -num_threads 4 -reduce 2 -o /tmp/foo.bmp')
+        expect(Riiif::CommandRunner).to receive(:execute)
+          .with('convert -resize 80.0% -quality 85 -sampling-factor 4:2:0 -strip /tmp/foo.bmp jpg:-')
+        transform
+      end
+    end
+  end
+end