Webpack plugin that converts set of images into a spritesheet and SASS/LESS/Stylus mixins, using spritesmith and spritesheet-templates

All ideas are shamelessly taken from gulp.spritesmith.

Example

Let's say you have following folder structure

/
|-src
| |-ico
| | |-new.png
| | |-open.png
| | |-save.png
| | ...
| |-style.styl
| ...
|-webpack.config.js

Then you need to instantiate plugin in webpack config like this:

//webpack.config.js
var path = require('path');

var SpritesmithPlugin = require('webpack-spritesmith-handlebars-helpers');

module.exports = {
    // ...
    module: {
        loaders: [
            {test: /\.styl$/, loaders: [
                'style-loader',
                'css-loader',
                'stylus-loader'
            ]},
            {test: /\.png$/, loaders: [
                'file-loader?name=i/[hash].[ext]'
            ]}
        ]
    },
    resolve: {
        //webpack 1:
        modulesDirectories: ["node_modules", "spritesmith-generated"],
        //webpack 2:
        modules: ["node_modules", "spritesmith-generated"]
    },
    plugins: [
        new SpritesmithPlugin({
            src: {
                cwd: path.resolve(__dirname, 'src/ico'),
                glob: '*.png'
            },
            target: {
                image: path.resolve(__dirname, 'src/spritesmith-generated/sprite.png'),
                css: path.resolve(__dirname, 'src/spritesmith-generated/sprite.styl')
            },
            apiOptions: {
                cssImageRef: "~sprite.png"
            }
        })
    ]
    // ...
};

And then just use it

//style.styl
@import '~sprite.styl'

.close-button
    sprite($close)
.open-button
    sprite($open)

There are few things to notice in config

• file-loader used for generated image
• resolve contains location of where generated image is
• cssImageRef is specified as '~sprite.png'

So the way generated image is accessed from generated API at the moment has to be specified manually.

Config

• src - used to build list of source images

  • cwd should be the closest common directory for all source images;
  • glob well... it is a glob

  cwd and glob both will be passed directly to glob (and gaze in watch mode), then resulting list of files will be used as list of source images

• target - generated files

  • image - target image filename. Can be interpolated with loader-utils. Though I would recommend to use file-loader for interpolation.
  • css - can be one of the following

    • "full/path/to/spritesheet/api" - for example path.resolve(__dirname, 'src/spritesmith-generated/sprite.styl')

    • ["full/path/to/spritesheet/api1", "full/path/to/spritesheet/api2"],

    • ["full/path/to/spritesheet/api1", ["full/path/to/spritesheet/api2", spritesmithTemplatesOptions]] spritesmithTemplatesOptions - is the second argument here

      for example

          ...
          css: [
              path.resolve(__dirname, 'src/spritesmith-generated/sprite.styl'),
              [path.resolve(__dirname, 'src/spritesmith-generated/sprite.json'), {
                  format: 'json_texture'
              }]
          ]

• apiOptions - optional

  • generateSpriteName - function. Takes full path to source image file and expected to return name by which it will be referenced in API. Return value will be used as sprite.name for spritesheet-templates. Default behaviour is to use filename (without dirname and extension)
  • cssImageRef - path by which generated image will be referenced in API. If target.image is interpolated, cssImageRef should be interpolated the same way too.

• spritesmithOptions - optional. Options for spritesmith

• retina - optional, when specified, uses retina capabilities of spritesheet-templates. Can be either suffix string (like '@2x') or object consisting of three fields:

  • classifier - Function that allows to say which source is for retina spritesheet and which is not. Will be called with full path to source file, and should return an object of this format -

          
        {
            type: String, // determines which kind of source is this. Can contain one of two values: 'retina' and 'normal'
            normalName: String, //full path to corresponding normal source image
            retinaName: String, //full path to corresponding retina source image
        }

  • targetImage - full path to generated retina image
  • cssImageRef - path by which generated image will be referenced in API

  When used as suffix string it applies to source files, filename for retina spritesheet image and cssImageRef

  apiOptions.generateSpriteName will be applied to normalName returned by retina.classifier

• customTemplates - optional. Object with keys and values corresponding to format names and template descriptions respectively. Template description can be either a path/to/handlebars/template/file or template function

• cssHandlebarsHelpers - optional. Container for helpers to register to handlebars for our template Each

  • key-value pair is the name of a handlebars helper corresponding to its function
  • For example, {half: function (num) { return num/2; } will add a handlebars helper that halves numbers

  You can use templates registered here as format in "target.css"

  For example you can write something like this

  
  //webpack.config.js
  var templateFunction = function (data) {
      var shared = '.ico { background-image: url(I) }'
          .replace('I', data.sprites[0].image);
  
      var perSprite = data.sprites.map(function (sprite) {
          return '.ico-N { width: Wpx; height: Hpx; background-position: Xpx Ypx; }'
              .replace('N', sprite.name)
              .replace('W', sprite.width)
              .replace('H', sprite.height)
              .replace('X', sprite.offset_x)
              .replace('Y', sprite.offset_y);
      }).join('\n');
  
      return shared + '\n' + perSprite;
  });
  
  module.exports = {
      ...
      plugins: [
          new SpritesmithPlugin({
              target: {
                  ...
                  css: [
                      [path.resolve(__dirname, 'src/spritesmith-generated/sprite-1.css'), {
                          format: 'function_based_template'
                      }],
                      [path.resolve(__dirname, 'src/spritesmith-generated/sprite-2.css'), {
                          format: 'handlebars_based_template'
                      }]
                  ]
              },
              customTemplates: {
                  'function_based_template': templateFunction,
                  'handlebars_based_template': path.resolve(__dirname, '../my_handlebars_template.handlebars')
              },
              cssHandlebarsHelpers: {
              		"px2Rem": function(px) {
  						...
              		}
              }
              ...
          })
      ]
  }