README.md

ember-lazy-image

ember-lazy-image is a component that allows you to gracefully handle image loading.

Component will load images lazily, only if they appeared in the view port. This optimization brings page load time down.

Default loading placeholder is stolen from aurer and his awesome codepen.

Installation

From inside your ember-cli project, run the following:

ember install ember-lazy-image

Installation for ember-cli 0.1.5 - 0.2.2

ember install:addon ember-lazy-image

Installation without ember-cli

npm install ember-lazy-image --save

lazy-image

{{lazy-image url='http://my-valid-url.com/foo.jpg'}}

Component will wait until the image is loaded and while waiting it will show default loading placeholder (see above).

You can customize loading placeholder by passing it as an parameter:

{{#lazy-image url='http://my-valid-url.com/foo.jpg'}}
  <!-- custom template goes here, spinner, svg, etc. -->
{{/lazy-image}}

You can also define the fallback if the image failed to load. By default, component will render Image failed to load text.

You can customize error text by passing it as an parameter:

{{lazy-image url='http://my-not-valid-url.com/foo.jpg' errorText='Something went wrong.'}}

width, height and data-* attributes

Lazy Image supports width, height and data-* attribute bindings.

{{lazy-image url='http://my-valid-url.com/foo.jpg' width=400 height=400 data-foo-bar="my-foo-bar"}}
{{lazy-image url='http://my-valid-url.com/foo.jpg' width=400 height=400 data-foo-bar=foo.bar.path}}

class attribute

You can also pass class names for the image element.

{{lazy-image url='http://my-valid-url.com/foo.jpg' class='foo-bar baz-bar'}}

alt attribute

You can pass the alt attribute to the component and it will be rendered on the image element

{{lazy-image url='http://my-valid-url.com/foo.jpg' alt='foo description'}}

ember-in-viewport options

Lazy Image uses ember-in-viewport for viewport detection. Due to the way listeners and requestAnimationFrame is setup, you'll have to override the ember-in-viewport options by creating app/components/lazy-image.js:

// app/components/lazy-image.js

import Ember from 'ember';
import LazyImage from 'ember-lazy-image/components/lazy-image';

export default LazyImage.extend({
  viewportOptionsOverride: Ember.on('didInsertElement', function() {
    Ember.setProperties(this, {
      viewportUseRAF      : true,
      viewportSpy         : false,
      viewportRefreshRate : 150,
      viewportTolerance: {
        top    : 50,
        bottom : 50,
        left   : 20,
        right  : 20
      }
    });
  })
});

See Advanced usage (options) for more in detail ember-in-viewport options.

The use of threshold is deprecated in favor of viewportTolerance.

Experimental lazy-background-image

This is an experimental component that will add background-image style attribute to a component's div. It also sets min-height attribute to 270px so the image is visible. You should be able to overwrite it by using lazy-background-image class.

Installation

• git clone this repository
• npm install
• bower install

Running

• ember server
• Visit your app at http://localhost:4200.

Running Tests

• ember test
• ember test --server

Building

• ember build

For more information on using ember-cli, visit http://www.ember-cli.com/.