pngquant worker (kudos to adammathys for #32 and smasry for #40)

bin/image_optim

@@ -3,11 +3,13 @@
 
 require 'image_optim/runner'
 require 'image_optim/true_false_nil'
+require 'image_optim/non_negative_integer_range'
 
 options = {}
 
 option_parser = OptionParser.new do |op|
   ImageOptim::TrueFalseNil.add_to_option_parser(op)
+  ImageOptim::NonNegativeIntegerRange.add_to_option_parser(op)
 
   op.banner = <<-TEXT.gsub(/^\s*\|/, '')
     |#{ImageOptim.full_version}
@@ -66,6 +68,8 @@ option_parser = OptionParser.new do |op|
         [Integer, 'N']
       when Array >= type
         [Array, 'a,b,c']
+      when ImageOptim::NonNegativeIntegerRange == type
+        [type, 'M-N']
       else
         fail "Unknown type #{type}"
       end

lib/image_optim.rb

@@ -201,7 +201,7 @@ def apply_threading(enum)
 end
 
 %w[
-  pngcrush pngout optipng advpng
+  pngcrush pngout optipng advpng pngquant
   jhead jpegoptim jpegtran
   gifsicle
   svgo

lib/image_optim/non_negative_integer_range.rb

@@ -0,0 +1,11 @@
+class ImageOptim
+  # Denote range of non negative integers for worker option
+  class NonNegativeIntegerRange
+    # Add handling of range of non negative integers in OptionParser instance
+    def self.add_to_option_parser(option_parser)
+      option_parser.accept(self, /(\d+)(?:-|\.\.)(\d+)/) do |_, m, n|
+        m.to_i..n.to_i
+      end
+    end
+  end
+end

lib/image_optim/worker/pngquant.rb

@@ -0,0 +1,43 @@
+require 'image_optim/worker'
+require 'image_optim/option_helpers'
+require 'image_optim/non_negative_integer_range'
+
+class ImageOptim
+  class Worker
+    # http://pngquant.org/
+    class Pngquant < Worker
+      QUALITY_OPTION =
+      option(:quality, 100..100, NonNegativeIntegerRange, 'min..max - don\'t '\
+          'save below min, use less colors below max (both in range `0..100`; '\
+          'in yaml - `!ruby/range 0..100`)') do |v|
+        min = OptionHelpers.limit_with_range(v.begin, 0..100)
+        min..OptionHelpers.limit_with_range(v.end, min..100)
+      end
+
+      SPEED_OPTION =
+      option(:speed, 3, 'speed/quality trade-off: '\
+          '`1` - slow, '\
+          '`3` - default, '\
+          '`11` - fast & rough') do |v|
+        OptionHelpers.limit_with_range(v.to_i, 1..11)
+      end
+
+      # Always run first
+      def run_order
+        -5
+      end
+
+      def optimize(src, dst)
+        args = %W[
+          --quality=#{quality.begin}-#{quality.end}
+          --speed=#{speed}
+          --output=#{dst}
+          --force
+          --
+          #{src}
+        ]
+        execute(:pngquant, *args) && optimized?(src, dst)
+      end
+    end
+  end
+end