Preloading @font-face fonts?

Is it possible to preload or otherwise cache @font-face fonts, most likely with javascript, before the page loads so you don't get that ugly jump when the page finally does load?

Answers


I'm not aware of any current technique to avoid the flicker as the font loads, however you can minimize it by sending proper cache headers for your font and making sure that that request goes through as quickly as possible.


A simple technique is to put this somewhere in your index:

<div class="font_preload" style="opacity: 0">
    <span style="font-family: 'myfontface#1font-family', Arial, sans-serif;"></span>
    <span style="font-family: 'myfontface#2font-family', Arial, sans-serif;"></span>
    ...
</div>

Tested on Chrome 34, Safari 7 and FF 29 and IE 11


There are a few techniques for "preloading" here: http://paulirish.com/2009/fighting-the-font-face-fout/

Mostly tricking the browser into downloading the file as fast as possible..

You can also deliver it as a data-uri, which helps a lot. and also you could hide the page content and show it when its ready.


2017: You now have preload

MDN: The preload value of the element's rel attribute allows you to write declarative fetch requests in your HTML , specifying resources that your pages will need very soon after loading, which you therefore want to start preloading early in the lifecycle of a page load, before the browser's main rendering machinery kicks in. This ensures that they are made available earlier and are less likely to block the page's first render, leading to performance improvements.

<link rel="preload" href="/fonts/myfont.eot" as="font" crossorigin="anonymous" />

Check browser compatibility.

It is most useful for font preloading (not waiting for the browser to find it in some CSS). You can also preload some logos, icons and scripts.

Other techniques pro/cons are discussed here (not my blog).


Proper font pre-loading is a big hole in the HTML5 spec. I've gone through all of this stuff and the most reliable solution I've found is to use Font.js:

http://pomax.nihongoresources.com/pages/Font.js/

You can use it to load fonts using the same API you use to load images

var anyFont = new Font();
anyFont.src = "fonts/fileName.otf";
anyFont.onload = function () {
  console.log("font loaded");
}

It's much simpler and more lightweight than Google's hulking Webfont Loader

Here's the github repo for Font.js:

https://github.com/Pomax/Font.js


This should solve your problem.

To answer your initial question: yes you can. Only Gecko and WebKit browsers support it currently though. You just need to add link tags in your head:

<link rel="prefetch" href="pathto/font">
<link rel="prerender" href="pathto/page">

i did this by adding some letter in my main document and made it transparent and assigned the font that I wanted to load.

e.g.

<p>normal text from within page here and then followed by:
<span style="font-family:'Arial Rounded Bold'; color:transparent;">t</span>
</p>

Via Google's webfontloader

var fontDownloadCount = 0;
WebFont.load({
    custom: {
        families: ['fontfamily1', 'fontfamily2']
    },
    fontinactive: function() {
        fontDownloadCount++;
        if (fontDownloadCount == 2) {
            // all fonts have been loaded and now you can do what you want
        }
    }
});

Recently I was working on a game compatible with CocoonJS with DOM limited to the canvas element - here is my approach:

Using fillText with a font that has not been loaded yet will execute properly but with no visual feedback - so the canvas plane will stay intact - all you have to do is periodically check the canvas for any changes (for example looping through getImageData searching for any non transparent pixel) that will happen when the font loads properly.

I have explained this technique a little bit more in my recent article http://rezoner.net/preloading-font-face-using-canvas,686


Google has a nice library for this: https://developers.google.com/webfonts/docs/webfont_loader You can use almost any fonts and the lib will add classes to the html tag.

It even gives you javascript events on when certrain fonts are loaded and active!

Don't forget to serve your fontfiles gzipped! it will certainly speed things up!


Use the standard CSS Font Loading API.

Wait for (all) the fonts to load, and then show your content:

document.fonts.ready.then((fontFaceSet) => {
    console.log(fontFaceSet.size, 'FontFaces loaded.');
    document.getElementById('waitScreen').style.display = 'none';
});

Demo CodePen.


As I found the best way is doing is preloading a stylesheet that contains the font face, and then let browser to load it automatically. I used the font-face in other locations (in the html page), but then I could observe the font changing effect briefly.

<link href="fonts.css?family=Open+Sans" rel="preload stylesheet" as="style">

then in the font.css file, specify as following.

@font-face {
  font-family: 'Open Sans';
  font-style: normal;
  font-weight: 400;
  src: local('Open Sans Regular'), local('OpenSans-Regular'),
       url('open-sans-v16-latin-regular.woff2') format('woff2'); /*  Super Modern Browsers */
}

You can't assign a name to fonts when it's preloaded through link tag (correct me if I was wrong I couldn't find a way yet), and thus you have to use font-face to assign the name to the font. Even though it's possible to load a font through link tag, it's not recommended as you can't assign a name to the font with it. Without a name as with font-face, you won't be able to use it anywhere in the web page. According to gtmetrix, style sheet loads at the beginning, then rest of the scripts/style by order, then the font before dom is loaded, and therefore you don't see font changing effect.


Your head should include the preload rel as follows:

<head>
    ...
    <link rel="preload" as="font" href="/somefolder/font-one.woff2">
    <link rel="preload" as="font" href="/somefolder/font-two.woff2">
</head>

This way woff2 will be preloaded by browsers that support preload, and all the fallback formats will load as they normally do. And your css font face should look similar to to this

@font-face {
    font-family: FontOne;
    src: url(../somefolder/font-one.eot);
    src: url(../somefolder/font-one.eot?#iefix) format('embedded-opentype'),
    url(../somefolder/font-one.woff2) format('woff2'), //Will be preloaded
    url(../somefolder/font-one.woff) format('woff'),
    url(../somefolder/font-one.ttf)  format('truetype'),
    url(../somefolder/font-one.svg#svgFontName) format('svg'); 
}
@font-face {
    font-family: FontTwo;
    src: url(../somefolder/font-two.eot);
    src: url(../somefolder/font-two.eot?#iefix) format('embedded-opentype'),
    url(../somefolder/font-two.woff2) format('woff2'), //Will be preloaded
    url(../somefolder/font-two.woff) format('woff'),
    url(../somefolder/font-two.ttf)  format('truetype'),
    url(../somefolder/font-two.svg#svgFontName) format('svg');
}

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