Piet

Description

Piet is a gem that optimizes an image stored in a file, and it has integration with CarrierWave uploaders.

This gem is named after the minimalist Dutch painter Piet Mondrian.

Installation

This gem uses the following image optimization utilties:

optipng
pngout
advpng
jpegoptim
jpegrescan (a script that uses jpegtran)

All the tools are available in various platforms such as Unix or Windows. You can install them by following the instructions on each authors' page:

Installation for optipng
Installation for [pngout] (http://advsys.net/ken/utils.htm)
Installation for [advpng] (http://advancemame.sourceforge.net/comp-readme.html)
Installation for jpegoptim
Information on [jpegtran] (http://jpegclub.org/jpegtran/) and [manual for unix] (http://www.gsp.com/cgi-bin/man.cgi?topic=jpegtran)

If you are missing some of the tools (or the crash when executing), Piet will issue a warning and proceed with the rest of the tools, so you don't really need all of the tools if you just want to run a few of them. Also, you can specify which tools you want to run when using Piet.

After installing the utils, simply install the gem:

gem install piet

Usage

You simply require the gem

require 'piet'

and then call the optimize method:

Piet.optimize(path, opts)

There are 2 kind of options, global and per-tool.

Global options are those that apply to all the tools or to Piet itself. Currently, Piet supports the following options:

verbose: Whether you want to get the output of the commands or not. It is interpreted as a Boolean value. Default: false.
tools: Array of symbols with the names of the tools you want to run. Array value. Default: All available tools.

Per-tool options are specified as a hash and will be used only when executing the given tool:

pngout: Options for the pngout command. Hash value
- strategy: strategy used (-s option)
advpng: Options for the advpng command. Hash value
- compression: Factor of compression. Values can go from 0 to 4, where 0 is "don't compress" and 4 is "compress extreme".
- iterations: Number of iterations performed by the tools (-i option)
jpegoptim: Options for the jpegoptm command. Hash value
- quality: If you wanna add a compression, adjust the quality parameter. Valid values are any integer between 0 and 100 (100 means no compression and highest quality). Default: 100

CarrierWave integration

As stated before, Piet can be integrated into CarrierWave uploaders. This way, you can optimize the original image or a version.

In order to do that, firstly add piet to your Gemfile:

gem 'piet'

Then go to your CarrierWave uploader and include Piet's extension:

class ImageUploader < CarrierWave::Uploader::Base
  ...
  include Piet::CarrierWaveExtension
  ...
end

And finally use Piet! For all the images:

class ImageUploader < CarrierWave::Uploader::Base
  ...
  process :optimize
  ...
end

Or only for a version:

class ImageUploader < CarrierWave::Uploader::Base
  ...
  version :normal do
    ...
    process :optimize
  end
  ...
end

Examples

Simply Optimizing

Piet.optimize('/my/wonderful/pics/piggy.png')

Piet.optimize('/my/wonderful/pics/pony.jpg')

would optimize those PNG, GIF and JPEG files but ouput nothing.

Optimizing PNG/GIF and getting feedback

Piet.optimize('/my/wonderful/pics/piggy.png', :verbose => true)

would optimize that PNG/GIF file and ouput something similar to this one:

** Processing: piggy.png
340x340 pixels, 4x8 bits/pixel, RGB+alpha
Input IDAT size = 157369 bytes
Input file size = 157426 bytes

Trying:
  zc = 9  zm = 9  zs = 0  f = 1   IDAT size = 156966
  zc = 9  zm = 8  zs = 0  f = 1   IDAT size = 156932

Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 1   IDAT size = 156932

Output IDAT size = 156932 bytes (437 bytes decrease)
Output file size = 156989 bytes (437 bytes = 0.28% decrease)

Optimizing JPEG and getting feedback

Piet.optimize('/my/wonderful/pics/pony.jpg', :verbose => true)

would optimize that JPEG file and ouput similar to this one:

/my/wonderful/pics/pony.jpg 235x314 24bit JFIF  [OK] 15305 --> 13012 bytes (14.98%), optimized.

Pngquant

You can use Piet to convert 24/32-bit PNG images to paletted (8-bit) PNGs. The conversion reduces file sizes significantly and preserves full alpha transparency.

Simply use Piet like this:

Piet.pngquant('/a/path/where/you/store/the/file/to/convert')

Please note you have to install the binary in order to use the tool. Simply follow the instructions (and read more info about it) in the official site.

Thanks to @rogercampos for providing the awesome png_quantizator gem, which you can find here.

TODO

Binary tool for optimizing a file
Add some testing!

Changelog

v.0.1.0 Optimization of PNGs and JPEGs, including an integration with Carrierwave
v.0.1.1 Added support for GIFs. Added an extra option to use pngquant (thanks @rogercampos). Solved problems with Carrierwave >= 0.6 (thanks @mllocs and @huacnlee).
v.0.1.2 Fixed some problems with missing processing, thanks to @lentg.
v.0.1.3 Use png_quantizator gem instead of the own implementation.
v.0.2 Added more tools and refactored structure. NOTE: This version is not backwards compatible with the previous, since now it encapsulates the 'quality' option for jpegoptim in a hash corresponding to the options passed to this tool

oriolbcn / piet