--benchmark, fixes #217

CHANGELOG.markdown

@@ -3,6 +3,7 @@
 ## unreleased
 
 * Correct environment variable to specify `jpeg-recompress` location [@toy](https://github.com/toy)
+* Added --benchmark, to compare performance of each tool [#218]
 
 ## v0.31.4 (2024-11-19)
 

README.markdown

@@ -301,6 +301,27 @@ optipng:
 
 `image_optim` uses standard ruby library for creating temporary files. Temporary directory can be changed using one of `TMPDIR`, `TMP` or `TEMP` environment variables.
 
+### Benchmark
+
+Run with `--benchmark` to compare the performance of each individual tool on your images:
+
+```
+$ image_optim --benchmark -r /tmp/corpus/
+
+benchmarking: 100.0% (elapsed: 3.9m)
+
+BENCHMARK RESULTS
+
+name      files  elapsed  kb saved     kb/s
+--------  -----  -------  --------  -------
+oxipng       50    8.906  1867.253  209.664
+pngquant     50    1.980   214.597  108.386
+pngcrush     50   22.529  1753.704   77.841
+optipng      50  142.940  1641.101   11.481
+advpng       50  137.753   962.549    6.987
+pngout       50  426.706   444.679    1.042
+```
+
 ## Options
 
 * `:nice` — Nice level, priority of all used tools with higher value meaning lower priority, in range `-20..19`, negative values can be set only if run by root user *(defaults to `10`)*

lib/image_optim.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'image_optim/benchmark'
 require 'image_optim/bin_resolver'
 require 'image_optim/cache'
 require 'image_optim/config'
@@ -8,6 +9,7 @@
 require 'image_optim/image_meta'
 require 'image_optim/optimized_path'
 require 'image_optim/path'
+require 'image_optim/table'
 require 'image_optim/timer'
 require 'image_optim/worker'
 require 'in_threads'
@@ -162,6 +164,22 @@ def optimize_image_data(original_data)
     end
   end
 
+  def benchmark_image(original)
+    src = Path.convert(original)
+    return unless (workers = workers_for_image(src))
+
+    workers.map do |worker|
+      start = ElapsedTime.now
+      dst = src.temp_path
+      begin
+        worker.optimize(src, dst)
+        BenchmarkResult.new(src, dst, ElapsedTime.now - start, worker)
+      ensure
+        dst.unlink
+      end
+    end
+  end
+
   # Optimize multiple images
   # if block given yields path and result for each image and returns array of
   # yield results
@@ -186,6 +204,10 @@ def optimize_images_data(datas, &block)
     run_method_for(datas, :optimize_image_data, &block)
   end
 
+  def benchmark_images(paths, &block)
+    run_method_for(paths, :benchmark_image, &block)
+  end
+
   class << self
     # Optimization methods with default options
     def method_missing(method, *args, &block)

lib/image_optim/benchmark.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class ImageOptim
+  # Benchmark result for one worker+src
+  class BenchmarkResult
+    attr_reader :bytes, :elapsed, :worker
+
+    def initialize(src, dst, elapsed, worker)
+      @bytes = bytes_saved(src, dst)
+      @elapsed = elapsed
+      @worker = worker.class.bin_sym.to_s
+    end
+
+  private
+
+    def bytes_saved(src, dst)
+      src, dst = src.size, dst.size
+      return 0 if dst == 0 # failure
+      return 0 if dst > src # the file got bigger
+
+      src - dst
+    end
+  end
+end

lib/image_optim/config.rb

@@ -117,6 +117,9 @@ def threads
 
       case threads
       when true, nil
+        # --benchmark defaults to one thread
+        return 1 if get!(:benchmark)
+
         processor_count
       when false
         1

lib/image_optim/runner.rb

@@ -45,6 +45,46 @@ def size_percent(size_a, size_b)
       end
     end
 
+    # files, elapsed, kb saved, kb/s
+    class BenchmarkResults
+      def initialize
+        @all = []
+      end
+
+      def add(rows)
+        @all.concat(rows)
+      end
+
+      def print
+        if @all.empty?
+          puts 'nothing to report'
+          return
+        end
+
+        # group by worker
+        report = @all.group_by(&:worker).map do |name, results|
+          kb = (results.sum(&:bytes) / 1024.0)
+          elapsed = results.sum(&:elapsed)
+          {
+            'name' => name,
+            'files' => results.length,
+            'elapsed' => elapsed,
+            'kb saved' => kb,
+            'kb/s' => (kb / elapsed),
+          }
+        end
+
+        # sort
+        report = report.sort_by do |row|
+          [-row['kb/s'], row['name']]
+        end
+
+        # output
+        puts "\nBENCHMARK RESULTS\n\n"
+        Table.new(report).write($stdout)
+      end
+    end
+
     def initialize(options)
       options = HashHelpers.deep_symbolise_keys(options)
       @recursive = options.delete(:recursive)
@@ -53,26 +93,49 @@ def initialize(options)
         glob = options.delete(:"exclude_#{type}_glob") || '.*'
         GlobHelpers.expand_braces(glob)
       end
+
+      # --benchmark
+      @benchmark = options.delete(:benchmark)
+      if @benchmark
+        options[:threads] = 1 # for consistency
+        if options[:timeout]
+          warning '--benchmark ignores --timeout'
+        end
+      end
+
       @image_optim = ImageOptim.new(options)
     end
 
     def run!(args) # rubocop:disable Naming/PredicateMethod
       to_optimize = find_to_optimize(args)
       unless to_optimize.empty?
-        results = Results.new
+        if @benchmark
+          benchmark_results = BenchmarkResults.new
+          benchmark_images(to_optimize).each do |_original, rows| # rubocop:disable Style/HashEachMethods
+            benchmark_results.add(rows)
+          end
+          benchmark_results.print
+        else
+          results = Results.new
 
-        optimize_images!(to_optimize).each do |original, optimized|
-          results.add(original, optimized)
-        end
+          optimize_images!(to_optimize).each do |original, optimized|
+            results.add(original, optimized)
+          end
 
-        results.print
+          results.print
+        end
       end
 
       !@warnings
     end
 
   private
 
+    def benchmark_images(to_optimize, &block)
+      to_optimize = to_optimize.with_progress('benchmarking') if @progress
+      @image_optim.benchmark_images(to_optimize, &block)
+    end
+
     def optimize_images!(to_optimize, &block)
       to_optimize = to_optimize.with_progress('optimizing') if @progress
       @image_optim.optimize_images!(to_optimize, &block)

lib/image_optim/runner/option_parser.rb

@@ -153,6 +153,11 @@ def wrap_regex(width)
     options[:pack] = pack
   end
 
+  op.separator nil
+  op.on('--benchmark', 'Run in benchmark mode, to compare tools without modifying images') do
+    options[:benchmark] = true
+  end
+
   op.separator nil
   op.separator '  Caching:'
 

lib/image_optim/table.rb

@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+class ImageOptim
+  # Handy class for pretty printing a table in the terminal. This is very simple, switch to Terminal
+  # Table, Table Tennis or similar if we need more.
+  class Table
+    attr_reader :rows
+
+    def initialize(rows)
+      @rows = rows
+    end
+
+    def write(io)
+      io.puts render_row(columns)
+      io.puts render_sep
+      rows.each do |row|
+        io.puts render_row(row.values)
+      end
+    end
+
+  protected
+
+    # array of column names
+    def columns
+      @columns ||= rows.first.keys
+    end
+
+    # should columns be justified left or right?
+    def justs
+      @justs ||= columns.map do |col|
+        rows.first[col].is_a?(Numeric) ? :rjust : :ljust
+      end
+    end
+
+    # max width of each column
+    def widths
+      @widths ||= columns.map do |col|
+        values = rows.map{ |row| fmt(row[col]) }
+        ([col] + values).map(&:length).max
+      end
+    end
+
+    # render an array of row values
+    def render_row(values)
+      values.zip(justs, widths).map do |value, just, width|
+        fmt(value).send(just, width)
+      end.join('  ')
+    end
+
+    # render a separator line
+    def render_sep
+      render_row(widths.map{ |width| '-' * width })
+    end
+
+    # format one cell value
+    def fmt(value)
+      if value.is_a?(Float)
+        format('%0.3f', value)
+      else
+        value.to_s
+      end
+    end
+  end
+end

spec/image_optim_spec.rb

@@ -269,6 +269,20 @@ def temp_copy(image)
     end
   end
 
+  describe 'benchmark_images' do
+    it 'does it' do
+      image_optim = ImageOptim.new
+      pairs = image_optim.benchmark_images(test_images)
+      test_images.zip(pairs).each do |original, (src, bm)|
+        expect(original).to equal(src)
+        expect(bm[0]).to be_a(ImageOptim::BenchmarkResult)
+        expect(bm[0].bytes).to be_a(Numeric)
+        expect(bm[0].elapsed).to be_a(Numeric)
+        expect(bm[0].worker).to be_a(String)
+      end
+    end
+  end
+
   %w[
     optimize_image
     optimize_image!