PostCSS Webp Processing

PostCSS plugin to process all png and jpg files to webp files from a css file. This has been designed to work with webpacker and webpack

.my-background {
  background: url("~image/foo.jpg") no-repeat;
}

.my-border-image {
  border-image: url("~image/borders/bar.png");
}

.my-background-image {
  background-image: url("~image/foobar.jpeg");
}

.my-background {
  background: url("~image/foo.jpg") no-repeat;
}

.my-border-image {
  border-image: url("~image/borders/bar.png");
}

.my-background-image {
  background-image: url("~image/foobar.jpeg");
}

.webp .my-background {
  background: url("~webp/foo.webp") no-repeat;
}

.webp .webp.my-border-image {
  border-image: url("~webp/borders/bar.webp");
}

.webp .my-background-image {
  background-image: url("~webp/foobar.webp");
}

Usage

postcss([
  require("postcss-webp-processing")({
    /* ...your config */
  })
]);

or in postcss.config.js

const WebpProcessing = require("postcss-webp-processing");
module.exports = {
  plugins: [
    WebpProcessing({
      /* ...your config */
    })
  ]
};

Option	Description	default
environments	sets the enviroments that it will be triggered, can be string 'production' or array ['staging', 'production']	'all',
imageFolder	The expected image folder	/~images/
quality	Quality of webp images	60
replaceFrom	Files to replace	/.(jpe?g|png)/
replaceTo	optional either function replaceTo({ file, folder, url }) or regex	N/A
resolvePath	Actual path to images	'app/javascript/images'
webpClass:	css class to be set for webp	'.webp'
webpFolder	Where webp images will be generated	'tmp/webp'
webpPath:	Image path to be set in css	'~webp'

Additional webpacker config:

const { resolve } = require("path");
const { environment } = require("@rails/webpacker");
const config = require("@rails/webpacker/package/config");

environment.config.set("resolve.alias", {
  images: resolve(config.source_path, "images"),
  webp: resolve("tmp", "webp")
});

Additional or your webpack.config.js:

const { resolve } = require('path');

module.exports = {
  mode: 'development',
  entry: './foo.js',
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'foo.bundle.js'
  }
  resolve.: {
    alias: {
      images: resolve('path/to/images', 'images'),
      webp: resolve('tmp', 'webp'),
    }
  }
};

To set for webp, either use modernzr or use this:

function checkWebP(callback) {
  var webP = new Image();

  const event = () => {
    callback(webP.height === 2);
  };

  webp.addEventListener("load", event);

  webp.addEventListener("error", event);

  webP.src =
    "data:image/webp;base64,UklGRjoAAABXRUJQVlA4IC4AAACyAgCdASoCAAIALmk0mk0iIiIiIgBoSygABc6WWgAA/veff/0PP8bA//LwYAAA";
}

checkWebP(function(support) {
  if (support) {
    document.body.classList.add("webp");
  } else {
    document.body.classList.add("no-webp");
  }
});

Bug reports

If you discover any bugs, feel free to create an issue on GitHub. Please add as much information as possible to help us fixing the possible bug. We also encourage you to help even more by forking and sending us a pull request.

https://github.com/djforth/postcss-webp-processing/issues

Contribute

If you'd like to contribute, postcss-webp-processing is written using babel and rollup in ES6.

Please make sure any additional code should be covered in tests (Jest).

If you need to run the test please use:

yarn test

or to rebuild the JS run:

yarn build

Maintainers

Adrian Stainforth (https://github.com/djforth)

License

postcss-webp-processing is an open source project falling under the MIT License. By using, distributing, or contributing to this project, you accept and agree that all code within the @morsedigital/select-filter project are licensed under MIT license.