0.0.4 • Public • Published


Generate responsive images with clown car technique

Getting Started

This plugin requires Grunt ~0.4.1 and GraphicsMagick to be installed.

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

Install GraphicsMagick on OSX:

brew install graphicsmagick
npm install grunt-clowncar --save-dev

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:


The "clowncar" task


In your project's Gruntfile, add a section named clowncar to the data object passed into grunt.initConfig().

  clowncar: {
    options: {
      sizes: [1000, 800, 600, 400]
    , quality: 75
    your_target: {
      files: {
        "dist/images/content/grunt.svg": 'images/content/grunt.jpg'

Note that each produced SVG file are provided with a specific class name in their <svg> tag. The class name consists of a namespace clowncar and the name of the file minus its extension and separated with a -. For instance, if you clown a file named photo001.jpg, the tag is going to be <svg class="clowncar-photo001" ... >. This prevents CSS class to collide with your development or with your imported frameworks.



Type: Array Default value: [600, 400]

Images with width as specified in the array to be generated. Widths can also be specified as percentage: ['75%', '50%', '30%']


Type: Number Default value: 90

Quality of the image to be generated


Preparing the circus

First thing first, we import the necessary tooling.

This cookbook has been created using OSX. But there's no hassle doing it with your operating system of choice.

With your favorite terminal, hop into an empty directory and create a package.json file for your project, if it's not already done.

npm init

We are using the following directory structure::

├── dist
├── package.json
├── src
│   ├── img
│   │   └── photo001.jpg
│   └── index.jade
└── tmp

With :

  • : Our Grunt file in coffee.
  • dist : A directory for our generated web files.
  • tmp : A directory for temporary files (unminified stuff, for instance).
  • src: A directory containing all our source files that need treatment.
  • src/index.jade : The main jade file that generates our index.html file.
  • src/img : A directory containing all the image that we are about to clown.

Note that the folder strucure is easily adapted in the grunt file provided hereafter.

Now, we import our grunt plugins and a some other neat stuff:

npm install --save-dev grunt grunt-clowncar \
  grunt-contrib-jade grunt-svgmin grunt-contrib-clean \
  grunt-contrib-watch grunt-express grunt-contrib-copy \
  grunt-open matchdep

And, if you haven't done it already, install GraphicsMagick system wide. Here's the command on OSX for convenience:

brew install graphicsmagick

OK. Now, we can proceed with the 1st recipe.

Embedded SVG in HTML code

So, we start with our Grunt file which should look something like:

# Grunt tasks 
module.exports = (grunt) ->
  # Load all plugings from our package.json files 
  # Project configuration 
    # Here comes the fun part. Your image are going to be clowned! 
    # Every image stored in 'src/img' produces an SVG file and all 
    #  the resolution required by responsive image depending on the 
    #  screens that you are targeting. 
    # Hereafter, the sizes matches the ones from the default 
    #  Twitter's Bootstrap CSS framework. 
    # Feel free to adapt them to the screens that you are targeting. 
    # All our produced stuff go in the 'tmp' dir as some additional 
    #  and optimizing steps are required for our beloved mobile users. 
        sizes: [1280992768400]
        files: [{
            expand: true
            cwd: 'src/img/'
            src: ['*.jpg']
            dest: 'tmp/'
            ext: '.svg'
    # Minify the produced SVG (our clown cars). 
        datauri: 'base64'
        files: [{
          expand: true
          cwd: 'tmp/'
          src: ['*.svg']
          dest: 'tmp/minified/'
          ext: '.min.svg'
    # Copy our multi-resolution images (the clowns under the car) 
    #  to our production dir 'dist'. 
        expand: true
        cwd: 'tmp/'
        src: ['*-*.jpg']
        dest: 'dist/'
    # Use jade to produce HTML. 
          # Minify our produced HTML file automatically. 
          pretty: false
          'dist/index.html': ['src/index.jade']
    # Remove everything created so far. 
    clean: [ 'dist''tmp' ]
    # Create a custom Express server on the fly. 
          port: 9000
          hostname: ''
          bases: ['dist/']
          livereload: true
    # Open a browser when site is ready. 
        path: 'http://localhost:<%= express.all.options.port %>'
    # Watch every changes in the 'src' dir and fire up the buuild task. 
        # Note: Livereload is not set in this task as it's already provided 
        #  by the express server (the grunt task). 
        livereload: false
        files: 'src/**'
        tasks: ['build']
  # Build tasks. 
  grunt.registerTask 'build'['clowncar''svgmin''copy''jade']
  # Default task. 
  grunt.registerTask 'default'[

Pfeww, that was long. But, we've provided you with a real world example with comments. Comments that should be worth reading.

Note that there's no need in minifying our produced image with grunt-contrib-imagemin. grunt-clowncar does it for you. It uses GraphicsMagick's 'convert & thumbnail' feature that does the job pretty well.

So, the produced SVG (the clown car) are in the tmp/minified dir. On the other hand, the responsive images (the clowns or the reduced JPEGs) are directly provided in dist, the production dir. Let's target these with a neat HTML file written in Jade:

- var pageTitle = 'Check the clowns'
    title= pageTitle
    h1= pageTitle
    include ../tmp/minified/photo001.min.svg

That's it! A oneliner for every included image.

Now, just hit the grunt command and watch your image being clowned:


Check the dev tools to see the image downloaded from the server while redimensioning your browser.


In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.


Release History

  • 2013-11-27 v0.0.4 Namespaced class in SVG's style for avoiding style collision.
  • 2013-11-23 v0.0.3 Fixed broken build on v0.0.2, Sorry! Added fixed for thumbnail generation based on smallest image to the original image, thanks to Pierre-Eric Marchandet
  • 2013-10-29 v0.0.2 Added options to set width as percentages, Thanks Pedro Figueiredo!
  • 2013-08-05 v0.0.1 Inital release




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