Adding pngquant to the mix

.travis.yml

@@ -14,7 +14,7 @@ rvm:
 script: bundle exec rspec
 before_install:
   - sudo apt-get update -qq
-  - sudo apt-get install -qq advancecomp gifsicle jhead jpegoptim libjpeg-progs optipng pngcrush
+  - sudo apt-get install -qq advancecomp gifsicle jhead jpegoptim libjpeg-progs optipng pngcrush pngquant
   - wget http://static.jonof.id.au/dl/kenutils/pngout-20130221-linux.tar.gz
   - tar -xzf pngout-*-linux.tar.gz
   - mv pngout-*-linux pngout-linux

README.markdown

@@ -11,6 +11,7 @@ Optimize (lossless compress) images (jpeg, png, gif, svg) using external utiliti
 * [pngcrush](http://pmt.sourceforge.net/pngcrush/)
 * [pngout](http://www.advsys.net/ken/util/pngout.htm)
 * [svgo](https://github.com/svg/svgo)
+* [pngquant](http://pngquant.org/)
 
 Based on [ImageOptim.app](http://imageoptim.com/).
 
@@ -107,7 +108,7 @@ make && cp -f pngcrush /usr/local/bin
 ### OS X: Macports
 
 ```bash
-sudo port install advancecomp gifsicle jhead jpegoptim jpeg optipng pngcrush
+sudo port install advancecomp gifsicle jhead jpegoptim jpeg optipng pngcrush pngquant
 ```
 
 ### OS X: Brew

image_optim.gemspec

@@ -3,7 +3,7 @@
 Gem::Specification.new do |s|
   s.name        = 'image_optim'
   s.version     = '0.12.0'
-  s.summary     = %q{Optimize (lossless compress) images (jpeg, png, gif, svg) using external utilities (advpng, gifsicle, jpegoptim, jpegtran, optipng, pngcrush, pngout, svgo)}
+  s.summary     = %q{Optimize (lossless compress) images (jpeg, png, gif, svg) using external utilities (advpng, gifsicle, jpegoptim, jpegtran, optipng, pngcrush, pngout, svgo, pngquant)}
   s.homepage    = "http://github.com/toy/#{s.name}"
   s.authors     = ['Ivan Kuchin']
   s.license     = 'MIT'

lib/image_optim.rb

@@ -184,7 +184,7 @@ def apply_threading(enum)
 end
 
 %w[
-  pngcrush pngout optipng advpng
+  pngcrush pngout optipng advpng pngquant
   jhead jpegoptim jpegtran
   gifsicle
   svgo

lib/image_optim/worker/pngquant.rb

@@ -0,0 +1,29 @@
+require 'image_optim/worker'
+require 'image_optim/option_helpers'
+
+class ImageOptim
+  class Worker
+    class Pngquant < Worker
+      option(:quality, 80 , "don't save below min, use less colors below max (0-100)") do |v|
+        OptionHelpers.limit_with_range(v.to_i, 0..100)
+      end
+
+      option(:speed, 1 , '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
+        -1
+      end
+
+      def optimize(src, dst)
+        args = %W[--quality=#{quality} --speed=#{speed} --ext=-min.png #{src}]
+        mv_args = %W[#{src}-min.png #{dst}]
+        execute(:pngquant, *args) &&
+        execute(:mv, *mv_args) &&
+        optimized?(src, dst)
+      end
+    end
+  end
+end