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SvelteKit Next‑Gen Background Image # SvelteKit Next-Gen Background Image #

SvelteKit Next‑Gen Background Image #

Updated 6 months ago

3 minute read

Gunning Fog Index: 5.6

Content by Rodney

🔥 SvelteKit WebP Background Image with Fallback #

A SvelteKit Next-Gen background image is not too difficult to generate. In this video, we clarify what we are talking about by Next-Gen background images. Then we see how you can use the vite-imagetools plugin automatically to generate WebP background images for you. These have the advantage of being smaller than less cutting-edge formats such as JPEG and PNG. The upshot is the page loads faster, users get a better experience, and Google becomes more comfortable ranking your site higher.

We are talking about an image that you set as the background of a DOM element using CSS. The trickiest part here is not creating the modern format image, but making sure a fallback JPEG is shown in browsers which don't yet support Next-Gen formats.

If you are looking for how to add responsive, Next-Gen images as img or picture elements, then you should certainly check out the recent article which covers exactly that.

📹 SvelteKit Next‑Gen Background Image: Video #

Please enable JavaScript to watch the video 📼

SvelteKit Next-Gen Background Image

🖥 Code #

Configure `vite‑imagetools` #

vite.config.js — click to expand code.

vite.config.js

javascript

    1 import { sveltekit } from '@sveltejs/kit/vite';
2 import { imagetools } from 'vite-imagetools';
3 import { defineConfig } from 'vite';
4 
5 /** @type {import('vite').UserConfig} */
6 export default defineConfig({
7 	css: {
8 		preprocessorOptions: {
9 			scss: {
10 				additionalData: "@use 'variables.scss';",
11 				loadPaths: ['src/lib/styles'],
12 			},
13 		},
14 	},
15 	plugins: [sveltekit(), imagetools()],
16 });

Configuring vite-imagetools

SvelteKit Next‑Gen Background Image Svelte Code #

src/routes/+page.svelte — click to expand code.

src/routes/+page.svelte

svelte

    1 <script>
2   import { browser } from '$app/environment';
3   import backgroundImage from '$lib/assets/sunflower.jpg';
4   import backgroundImageWebp from '$lib/assets/sunflower.jpg?format=webp';
5  
6   function serveWebp() {
7     return browser && document.documentElement.classList.contains('webp');
8   }
9  
10   let backgroundImageUsed = $derived(serveWebp() ? backgroundImageWebp : backgroundImage);
11 </script>
12  
13 <svelte:head>
14   <title>Sunflower Poem</title>
15   <meta name="description" content="A poem about sunflowers" />
16   <meta name="theme-color" content="#ffdf00" />
17   <link rel="apple-touch-icon" href="/icons/icon-192x192.png" />
18 	<script
19 		async
20 		integrity="sha384-xms8Nhw0czGEIWf0BZpCsaCY9PPeFf6bJ6cG0CNYoVvDK3M0146DNIywperKRSNI"
21 		src="/modernizr-webp.js"
22 	></script>
23 </svelte:head>
24  
25 <div class="container" style:background-image={`url(${backgroundImageUsed})`}>
26   <div class="panel">
27     <div class="content">
28       <h1>The Soul of the Sunflower</h1>
29       <h2>by Sara Jewett</h2>
30       <blockquote>
31         <p>The warm sun kissed the earth</p>
32         <p>To consecrate thy birth,</p>
33         <p>And from his close embrace</p>
34         <p>Thy radiant face</p>
35         <p>Sprang into sight,</p>
36         <p>A blossoming delight.</p>
37       </blockquote>
38     </div>
39   </div>
40 </div>
41  
42 <style lang="scss">
43 	.container {
44 		display: flex;
45 		background-color: variables.$color-theme-2;
46 		background-position: center center;
47 		background-size: cover;
48 		width: 100%;
49 		min-height: 100vh;
50 		padding: variables.$spacing-12;
51 	}
52 
53 	.panel {
54 		background: rgba(variables.$color-theme-3, variables.$alpha: 0.81);
55 		box-shadow: variables.$spacing-0 variables.$spacing-0 variables.$spacing-1 variables.$spacing-0
56 			variables.$color-theme-4;
57 		border-radius: variables.$spacing-4;
58 		color: #502419;
59 		margin: auto;
60 		padding: variables.$spacing-6 variables.$spacing-24;
61 		height: 100%;
62 	}
63 
64 	.content {
65 		padding: variables.$spacing-4;
66 	}
67 
68 	h1,
69 	h2,
70 	p {
71 		font-family:
72 			Playfair Display,
73 			Times New Roman,
74 			Times,
75 			serif;
76 	}
77 	p {
78 		font-weight: variables.$font-weight-bold;
79 		font-family:
80 			Lato,
81 			Playfair Display,
82 			Times New Roman,
83 			Times,
84             serif;
85         font-size: variables.$font-size-2;
86   }
87 </style>

SvelteKit Next-Gen Background Image: Svelte code.

You can see the full code for creating a SvelteKit Next-Gen background image on the Rodney Lab Git Hub repo .

🗳 Poll #

I try to keep these videos short and to the point, though this one ended up a little longer. Do you mind longer videos?

🔗 SvelteKit Next‑Gen Background Image: Links #

🙏🏽 SvelteKit Next‑Gen Background Image: Feedback #

If you have found this video useful, see links below for further related content on this site. I do hope you learned one new thing from the video. Let me know if there are any ways I can improve on it. I hope you will use the code or starter in your own projects. Be sure to share your work on Twitter, giving me a mention, so I can see what you did. Finally, be sure to let me know ideas for other short videos you would like to see. Read on to find ways to get in touch, further below. If you have found this post useful, even though you can only afford even a tiny contribution, please consider supporting me through Buy me a Coffee.

Finally, feel free to share the post on your social media accounts for all your followers who will find it useful. As well as leaving a comment below, you can get in touch via @askRodney on Twitter and also askRodney on Telegram . Also, see further ways to get in touch with Rodney Lab. I post regularly on SvelteKit as well as Search Engine Optimization among other topics. Also, subscribe to the newsletter to keep up-to-date with our latest projects.