lazy-blur.js

A progressive image loader library with SVG blur effect.

• Demo page
• try it on jsbin

Usage

steps:

1. install
2. image setup
3. initialize library

Install

You could download this script directly or install via npm.

npm install lazy-blur.js

<script src="lazy-blur.min.js"></script>

Image setup

• requirement

  • imgRatio, img-width / img-height, unit: %
  • imgS.url
  • imgL.url

• html markup

  <figure class="image">
    <div class="lazy-blur">
      <div style="padding-bottom: ${imgRatio}"><!-- lazy-blur__imgS__placeholder --></div>
      <img src="${imgS.url}" data-src="${imgL.url}" class="lazy-blur__imgS"/>
      <noscript><img src="${imgL.url}"/></noscript>
    </div>
    <figcaption>something~</figcaption>
  </figure>

• css style

  .lazy-blur {
    position: relative;
    overflow: hidden;
  }
  .lazy-blur img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  }
  .lazy-blur__imgL {
    opacity: 0;
    transition: opacity .3s;
  }
  .done > .lazy-blur__imgL {
    opacity: 1;
  }

initialize library

new LazyBlur();

Options

All options are optional.

new LazyBlur({
  imgSQuery: ,
  imgLClass: ,
  filterSelector: ,
  getImgLSrc: ,
  onLoad: ,
  blurSize: ,
  scrollThreshold: ,
  eventType:
});

Options	Type	Default	Description
imgSQuery	String	'.lazy-blur__imgS'	query selector of small images. used in document.querySelectorAll.
imgLClass	String	'lazy-blur__imgL'	class name of large images loaded by lazy-blur.js.
eventType	String	'scroll'	The event to active loading large images. optional: 'scroll', 'click', 'mouseover'
blurSize	Number	20	value of svg gaussian blur filter. larger is more blurred.
scrollThreshold	Number	50	distance of scroll threshold (buffer), unit: px
filterSelector	String	'html.svg *:not(.done) > ' + opt.imgSQuery	css selector for small images with SVG filter.
getImgLSrc	Function	function (imgS) { return imgS.getAttribute('data-src'); }	function for getting large image's source url.
onLoad	Function	function (imgS) { imgS.parentElement.className += ' done '; }	callback for large image loaded.

Browser support

License

MIT. © 2015 Rplus