Jeremy Keith

Here’s a tiny lesson that I picked up from Trys that I’d like to share with you…

I was working on some upcoming changes to the Clearleft site recently. One particular component needed some SVG background images. I decided I’d inline the SVGs in the CSS to avoid extra network requests. It’s pretty straightforward:

.myComponent {
    background-image: url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

You can basically paste your SVG in there, although you need to a little bit of URL encoding: I found that converting # to %23 to was enough for my needs.

But here’s the thing. My component had some variations. One of the variations had multiple background images. There was a second background image in addition to the first. There’s no way in CSS to add an additional background image without writing a whole background-image declaration:

.myComponent--variant {
    background-image: url('data:image/svg+xml;utf8,<svg> ... </svg>'), url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

So now I’ve got the same SVG source inlined in two places. That negates any performance benefits I was getting from inlining in the first place.

That’s where Trys comes in. He shared a nifty technique he uses in this exact situation: put the SVG source into a custom property!

:root {
    --firstSVG: url('data:image/svg+xml;utf8,<svg> ... </svg>');
    --secondSVG: url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

Then you can reference those in your background-image declarations:

.myComponent {
    background-image: var(--firstSVG);
}
.myComponent--variant {
    background-image: var(--firstSVG), var(--secondSVG);
}

Brilliant! Not only does this remove any duplication of the SVG source, it also makes your CSS nice and readable: no more big blobs of SVG source code in the middle of your style sheet.

You might be wondering what will happen in older browsers that don’t support CSS custom properties (that would be Internet Explorer 11). Those browsers won’t get any background image. Which is fine. It’s a background image. Therefore it’s decoration. If it were an important image, it wouldn’t be in the background.

Progressive enhancement, innit?

There are 73 days to go until Patterns Day. Do you have your ticket yet?

Perhaps you’ve been holding out for some more information on the line-up. Well, I’m more than happy to share the latest news with you—today there are three new speakers on the bill…

Emil Björklund, the technical director at the Malmö outpost of Swedish agency inUse, is a super-smart person I’ve known for many years. Last year, I saw him on stage in his home town at the Confront conference sharing some of his ideas on design systems. He blew my mind! I told him there and then that he had to come to Brighton and expand on those thoughts some more. This is going to be an unmissable big-picture talk in the style of Paul’s superb talk last year.

Speaking of superb talks from last year, Alla Kholmatova is back! Her closing talk from the first Patterns Day was so fantastic that it I just had to have her come back. Oh, and since then, her brilliant book on Design Systems came out. She’s going to have a lot to share!

The one thing that I felt was missing from the first Patterns Day was a focus on inclusive design. I’m remedying that this time. Heydon Pickering, creator of the Inclusive Components website—and the accompanying book—is speaking at Patterns Day. I’m very excited about this. Given that Heydon has a habit of casually dropping knowledge bombs like the lobotomised owl selector and the flexbox holy albatross, I can’t wait to see what he unleashes on stage in Brighton on June 28th.

Be there or be square.

Tickets for Patterns Day are still available, but you probably don’t want to leave it ‘till the last minute to get yours. Just sayin’.

The current—still incomplete—line-up comprises:

• Una Kravets,
• Amy Hupe,
• Inayaili de León Persson,
• Emil Björklund,
• Alla Kholmatova, and
• Heydon Pickering.

That isn’t even the full roster of speakers, and it’s already an unmissable event!

I very much hope you’ll join me in the beautiful Duke of York’s cinema on June 28th for a great day of design system nerdery.