Rémy 🤖

Posted on May 4, 2019

The secret that the fonts industry doesn't want you to know

#css #discuss

One of my favorite tricks recently has become to use currentColor as a flavor to almost anything. Quite unknown for a long time, I'm pretty sure that Lea Verou was the first person to ever use and expose it to the world.

While CSS variables are fucking awesome, it's 1. not always possible to use them yet (oh sweet IE 11) and 2. not always necessary.

Let's go for an example. Remember how everybody loves icon fonts because they automatically get the color of the font? Turns out you can do the same thing with SVG with a greater control.

Well suppose your code looks like this:

<nav class="menu">
    <a class="item">
        <svg><path d="..."/></svg>
        JavaScript
    </a>
    <a class="item">
        <svg><path d="..."/></svg>
        Python
    </a>
    <a class="item">
        <svg><path d="..."/></svg>
        Sass
    </a>
</nav>

You want the SVG icon in front of the text to change with the text's color. What do you do?

<svg><path d="..."/></svg>

Becomes

<svg><path fill="currentColor" d="..."/></svg>

And that's it, your SVG has the color of the text no matter what. Here's a live example, don't forget to hover the buttons!

Have you noticed how the Python logo doesn't change color completely on hover? You don't have to put the currentColor to every path in the SVG. Much more freedom than with fonts!

It's a simple trick but I really used it a lot recently. What about you, what patterns can you think of with currentColor?

Top comments (17)

Ryan Palo • May 4 '19

That half-color-change Python logo is dope, and I'm going to use this technique on my site like right now! Thank you!

Mikhail Panichev • May 6 '19 • Edited

I hate icon fonts and use this technique either with SVG sprites (symbols) and icon components.

You could also use sizing in em to reach similar experience as with icon fonts, or just for better flexibility. It's also great that you can override color and size just using CSS.

Rémy 🤖 • May 6 '19

Interesting, how do you manage your SVG sprites?

And yes indeed, in that case the em sizing would have been more appropriate, thanks for spotting.

Mikhail Panichev • May 7 '19

Usually, I use SVG icon components when working with Vue or React, but sometimes when I build classic websites (eg. using PHP for rendering) I place all icons in <symbol> tags in hidden <svg> with viewBox property and use currentColor where necessary.

In the end, I have something like this:

<svg style="display: none" xmlns="..." otherReqiuredAttrs="...">
  <symbol id="icon-user" veiwBox="0 0 20 20" fill="currentColor" storke="none">
    <!-- content of SVG from graphic editor -->
    <path d="..." fill="none" stroke="currentColor" />
  </symbol>
</svg>

<!-- Use an icon -->
<button class="button">
  <svg class="icon">
    <use xlink:href="#icon-user" />
  </svg>
  Login
</button>

For .icon you can use something like this

.icon {
  display: inline-block;
  fill: currentColor;
  height: 1em;
  width: 1em;
  pointer-events: none;
  stroke-width: 0;
  stroke: currentColor;
  vertical-align: middle;

  &[height],
  &[width] {
    height: auto;
    width: auto;
  }
}

Ben Sinclair • May 5 '19

This is neat. Upvoted despite the title.

Erick Navarro • May 6 '19

Yep, title is clickbait. I fell for it. Was about to share it on Twitter but meh

Rémy 🤖 • May 5 '19

Hahaha sorry :)

Paul Beffa • Jan 23 '20

It's more of a joke than clickbait to me.

Alex Lohr • May 6 '19

More than that, you can also use SVG color filters to derive other colors (for example a complementary color) from currentColor. Unfortunately SVG filters are not supported in some older browsers, so be sure to either not to actually require the additional color or not to support those older browsers.

Rémy 🤖 • May 6 '19

Yes or well hack your way with opacity, different layers, etc. I wanted to keep the use case simple but you're completely right it's quite awesome all the things you could do!

Alex Lohr • May 6 '19

While with opacity, you can only ever mix the color, with color filters, you can get it inverted.

cvanpoelje • Jul 19 '19

When u use scss there is also the $var option which u can use. Now that css has this option on its own, isn't it still better to use the scss variables since they are working across all browsers. When they get cross-browser I would consider using them. What do u think?

Josh Pullen • May 5 '19

I was running into this exact problem the other day and, although I knew about currentColor, it never occurred to me to use it in an SVG! Thanks for the excellent post. 😀