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mirror of https://github.com/locomotivemtl/locomotive-boilerplate.git synced 2026-01-15 00:55:08 +08:00

Merge pull request #97 from locomotivemtl/devenini-add-lazy-loading-utils

Add lazy loading utils & implement in Scroll.js
This commit is contained in:
Deven Caron
2021-10-20 14:46:51 -04:00
committed by GitHub
6 changed files with 169 additions and 32 deletions

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@@ -1,4 +1,5 @@
import { module } from 'modujs';
import { lazyLoadImage } from '../utils/image';
import LocomotiveScroll from 'locomotive-scroll';
export default class extends module {
@@ -22,16 +23,27 @@ export default class extends module {
})
}
toggleLazy(args) {
let src = this.getData('lazy', args.obj.el)
if (src.length) {
if (args.obj.el.tagName === 'IMG') {
args.obj.el.src = src
} else {
args.obj.el.style.backgroundImage = `url('${src}')`
}
this.setData('lazy', '', args.obj.el)
}
/**
* Lazy load the related image.
*
* @see ../utils/image.js
*
* It is recommended to wrap your `<img>` into an element with the
* CSS class name `.c-lazy`. The CSS class name modifier `.-lazy-loaded`
* will be applied on both the image and the parent wrapper.
*
* ```html
* <div class="c-lazy o-ratio u-4:3">
* <img data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=1" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" />
* </div>
* ```
*
* @param {LocomotiveScroll} args - The Locomotive Scroll instance.
*/
lazyLoad(args) {
lazyLoadImage(args.obj.target, null, () => {
//callback
})
}
destroy() {

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@@ -0,0 +1,87 @@
const LAZY_LOADED_IMAGES = []
export function loadImage(url, options = {}) {
return new Promise((resolve, reject) => {
const $img = new Image();
if (options.crossOrigin) {
$img.crossOrigin = options.crossOrigin;
}
const loadCallback = () => {
resolve({
element: $img,
...getImageMetadata($img),
});
}
if($img.decode) {
$img.src = url
$img.decode().then(loadCallback).catch(e => {
reject(e)
})
} else {
$img.onload = loadCallback
$img.onerror = (e) => {
reject(e);
};
$img.src = url
}
});
}
export function getImageMetadata($img) {
return {
url: $img.src,
width: $img.naturalWidth,
height: $img.naturalHeight,
ratio: $img.naturalWidth / $img.naturalHeight,
};
}
/**
* Lazy load the given image.
*
* @param {HTMLImageElement} $el - The image element.
* @param {?string} url - The URI to lazy load into $el.
* If falsey, the value of the `data-src` attribute on $el will be used as the URI.
* @param {?function} callback - A function to call when the image is loaded.
*/
export async function lazyLoadImage($el, url, callback) {
let src = url ? url : $el.dataset.src
let loadedImage = LAZY_LOADED_IMAGES.find(image => image.url === src)
if (!loadedImage) {
loadedImage = await loadImage(src)
if (!loadedImage.url) {
return;
}
LAZY_LOADED_IMAGES.push(loadedImage)
}
if($el.src === src) {
return
}
if ($el.tagName === 'IMG') {
$el.src = loadedImage.url;
} else {
$el.style.backgroundImage = `url(${loadedImage.url})`;
}
requestAnimationFrame(() => {
let lazyParent = $el.closest('.c-lazy');
if(lazyParent) {
lazyParent.classList.add('-lazy-loaded')
lazyParent.style.backgroundImage = ''
}
$el.classList.add('-lazy-loaded')
callback?.()
})
}

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@@ -14,7 +14,7 @@
<link rel="icon" type="image/png" sizes="16x16" href="assets/images/favicons/favicon-16x16.png">
<link rel="mask-icon" href="assets/images/favicons/safari-pinned-tab.svg" color="#000000">
<link id="stylesheet" rel="stylesheet" href="assets/styles/main.css" media="print" onload="this.media='all'; this.onload=null; this.isLoaded=true">
<link id="main-css" rel="stylesheet" href="assets/styles/main.css" media="print" onload="this.media='all'; this.onload=null; this.isLoaded=true">
</head>
<body data-module-load>
<div data-load-container>

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@@ -1,5 +1,5 @@
<!doctype html>
<html class="is-loading" lang="en" data-page="home">
<html class="is-loading" lang="en" data-page="images">
<head>
<meta charset="utf-8">
<title>Images | Locomotive Boilerplate</title>
@@ -14,7 +14,7 @@
<link rel="icon" type="image/png" sizes="16x16" href="assets/images/favicons/favicon-16x16.png">
<link rel="mask-icon" href="assets/images/favicons/safari-pinned-tab.svg" color="#000000">
<link id="stylesheet" rel="stylesheet" href="assets/styles/main.css" media="print" onload="this.media='all'; this.onload=null; this.isLoaded=true">
<link id="main-css" rel="stylesheet" href="assets/styles/main.css" media="print" onload="this.media='all'; this.onload=null; this.isLoaded=true">
</head>
<body data-module-load>
<div data-load-container>
@@ -57,21 +57,59 @@
<h4 class="c-heading -h3">Using o-ratio & img</h3>
<div style="width: 640px; max-width: 100%;">
<div class="o-ratio u-4:3"><img data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=1" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" /></div>
<div class="o-ratio u-4:3"><img data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=2" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" /></div>
<div class="o-ratio u-4:3"><img data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=3" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" /></div>
<div class="o-ratio u-4:3"><img data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=4" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" /></div>
<div class="o-ratio u-4:3"><img data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=5" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" /></div>
<div class="o-ratio u-4:3">
<img data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=1" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" />
</div>
<div class="o-ratio u-4:3">
<img data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=2" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" />
</div>
<div class="o-ratio u-4:3">
<img data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=3" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" />
</div>
<div class="o-ratio u-4:3">
<img data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=4" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" />
</div>
<div class="o-ratio u-4:3">
<img data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=5" alt="" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" />
</div>
</div>
<h4 class="c-heading -h3">Using o-ratio & background-image</h3>
<div style="width: 480px; max-width: 100%;">
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=1"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=2"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=3"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=4"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="toggleLazy, Scroll, main" data-scroll-lazy="http://picsum.photos/640/480?v=5"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=1"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=2"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=3"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=4"></div>
<div style="background-size: cover; background-position: center;" class="o-ratio u-16:9" data-scroll data-scroll-call="lazyLoad, Scroll, main" data-src="http://picsum.photos/640/480?v=5"></div>
</div>
<h4 class="c-heading -h3">Using SVG viewport for ratio</h3>
<div style="width: 480px; max-width: 100%;">
<img
data-scroll
data-scroll-call="lazyLoad, Scroll, main"
data-src="http://picsum.photos/640/480?v=6"
alt=""
src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 640 480'%3E%3C/svg%3E"
/>
<img
data-scroll
data-scroll-call="lazyLoad, Scroll, main"
data-src="http://picsum.photos/640/480?v=7"
alt=""
src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 640 480'%3E%3C/svg%3E"
/>
<img
data-scroll
data-scroll-call="lazyLoad, Scroll, main"
data-src="http://picsum.photos/640/480?v=8"
alt=""
src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 640 480'%3E%3C/svg%3E"
/>
</div>
</section>
</div>