django-lazy-image
v0.5.2
Published
An image utility that renders images lazily as well as intrinsically sizes them.
Downloads
1
Readme
Django Lazy Image
django-lazy-image
is a small Django utility that allows you to render images lazily on the frontend to minimise initial page load.
Installation
To install django-lazy-image
just run:
pip install django-lazy-image
Requirements
- Jinja2
- Django >= 1.11 (It's only been tested on 1.11 but i'm pretty sure it will work on 1.8+)
- Django Jinja
Configuration
Add django_lazy_image
to your INSTALLED_APPS
INSTALLED_APPS = [
...
'django_lazy_image',
...
]
Add url(r'^assets/', include('django_lazy_image.urls', namespace='assets')),
to your base urls.py
urlpatterns = [
...
url(r'^assets/', include('django_lazy_image.urls', namespace='assets')),
...
Then there are 2 ways to use the static files with Django:
NPM (The preferred way)
You can simply do
npm install django-lazy-image
or
yarn add django-lazy-image
Then include the Javascript / CSS as a module
file.js
import LazyImage from 'django-lazy-image';
// Only run the below code if the page has a lazy image instance
const lazyImage = document.querySelector('.js-LazyImage')
if (lazyImage) {
// Collect all the lazy images on the page
const lazyImages = document.querySelectorAll('.js-LazyImage')
// Set up our IntersectionObserver callback
const callback = (entries, observer) => {
Array.from(entries).forEach((entry, index) => {
// If any of the images have come in to view, activate them sequentially
if (entry.isIntersecting && !entry.target.dataset.activating) {
entry.target.dataset.activating = true
window.setTimeout(() => {
new LazyImage({ el: entry.target })
observer.unobserve(entry.target)
}, 150 * index)
}
})
}
const observer = new IntersectionObserver(callback, {
threshold: 0.4
})
Array.from(lazyImages).forEach(image => observer.observe(image))
}
file.css
@import 'django-lazy-image/dist/css/lazy-image.css';
Django Static
Somewhere in your base.html
add:
{{ static('django_lazy_image/css/lazy-image.css') }}
{{ static('django_lazy_image/js/lazy-image.js') }}
You can then use the lazyImage
function that is on the global object
var images = [].slice.call(document.querySelectorAll('.js-LazyImage'))
images.forEach(function (el) {
var image = window.lazyImage(el)
...
})