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Too Many SVGs

Slow down, your blog’s gotta last. You’ve got to make that download fast! Just zipping through the kilobytes. Viewing your site should be so groovy.

I was looking into moving a site from Font Icons to SVGs for a few reasons. The primary is that, with an SVG, images will look crisp on all monitors, including the non-retina displays. They literally look better on my crappy old MacBook, instead of just on my iPad.

Once I had the one site done, I went to look at another. It was a smaller site, running a Hugo as a static site generator, and I thought it would be perfect.

I was wrong.

Using SVGs is Easy

Replacing my font icon with an SVG was as easy as making my Facebook call this:

<object type="image/svg+xml" data="/images/social/facebook.svg"><span class="screen-reader-text">Facebook</span></object>

Done. It’s tiny (2kb) and there are six similarly sized images which makes for 18kb which is incredibly smaller than the 200kb or more that Font Awesome can be. Simply, I realized I was only using five of the icons (on every page) and how stupid was that? I don’t need the whole library!

I will note that ‘styling’ SVGs can be an exercise in patience, since you cannot apply CSS styles when you embed as an object. Thankfully, I wanted to make the icon match my style so I edited the style directly (which is the topic of another post). If you use PHP, I recommend using file_get_contents() to get the contents of the svg, and then use normal CSS to style. I was using plain HTML. There are tradeoffs.

Using too many SVGs sucks

My initial tests, using the footer first, and my page loaded much faster. Elated, I jumped over to all uses of the fonts, and remembered I had a page that listed a series of items with star rankings (none through five). I changed the generator code behind that to be object icons and reloaded.

The page was slow.

It was like dialup modem slow. Absolutely painful.

After some research, I ran into this post about why SVG was so slow, and found a graphic that explained it clearly.

Render times per number of objects on a page

What the graph demonstrates is simply that the more objects you have on a page, the slower it is. That part is obvious. The more anything on a page, the slower it is. So why are SVGs slower than PNGs? Why was I only seeing this on an HTML page with 50 images, and not on a WordPress generated PHP page with the same amount.

The answer was because the SVGs have to be rendered on the HTML page. I was using <object> tags on the HTML and file_get_contents on the PHP. The way the PHP code works, it pulls the file into content and dumps it out, not processing. Since the files are so small, and since the there’s no object rendering involved, the rendered PHP was faster than a static HTML. In this case.

Can It Be Faster?

After I was done face-palming, I asked myself if it was possible to speed this up? Fixing this comes with understanding the cause. Once I determined that the issue was rendering the object and not the SVG itself, the solution unfurled before me.

Instead of using object tags, I could include SVGs like this:

<svg version="1.1" id="facebook" xmlns="" xmlns:xlink="" 
x="0px" y="0px" width="50px" height="50px" viewBox="0 0 438.536 438.536" 
style="enable-background:new 0 0 438.536 438.536;" xml:space="preserve">
<path class="social" d="M414.41,24.123C398.333,8.042,378.963,0,356.315,0H82.228C59.58,0,40.21,8.042,24.126,24.123 C8.045,40.207,0.003,59.576,0.003,82.225v274.084c0,22.647,8.042,42.018,24.123,58.102c16.084,16.084,35.454,24.126,58.102,24.126 
h274.084c22.648,0,42.018-8.042,58.095-24.126c16.084-16.084,24.126-35.454,24.126-58.102V82.225 C438.532,59.576,430.49,40.204,414.41,24.123z 

The downside is that this looks uglier. The upside? This is hella fast and it’s still lighter weight than including a font icon, and I don’t have to upload images.

SVGs or Font Icons?

This is a question for the ages. They can both be made accessibility friendly, they can both be optimized. Arguably, font icons are compatible with more browsers, but it’s also 2016 and if people are still on IE 8 (sorry banks), the Internet looks pretty shitty anyway. I can’t tell you which is better, and I find use for both in different situations. I love font icons a great deal, but just as I love WordPress, there’s a time and a place for them. And a time and a place for something else.

2 replies on “Too Many SVGs”

There is another way – SVG sprites.
You put that SVG code just after and reference it in the content with xlink to the ID.

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