Working with Scalable Vector Graphics in WordPress


What this talk will cover

What SVGs are and how they work

Why SVGs are important

Icon fonts and why they are bad

How we can use SVGs


About Me

Russell Heimlich
(like the maneuver)

Senior Developer at nclud

Professional Toddler Chaser

What are SVGs?

SVGs are…

  • XML based
  • Vector
  • An open standard

SVGs define points and shapes in relation to one another in space.

SVGs are good for…

  • Icons
  • Logos
  • Charts
  • Any type of flat, low-color graphic

What is a bitmap?

  • A grid of pixel values
  • Binary file format
  • "A fixed set of dots"

JPG, GIF, TIFF, BMP are all bitmap image formats.

Color bitmaps are a grid of color values

Bitmaps are good for…

  • Photos
  • Continuous tones, blends of color
SVG Bitmap

Why is SVG Important?

The websites we build need to work everywhere the web does!

Constraints on Graphics

  • Different screen sizes
  • Different resolutions (HiDPI/Retina)
  • Bandwidth considerations

Graphics need to be as crisp and as performant as possible.

What about icon fonts?

Icon fonts are font files that contain symbols instead of letters or numbers.

(See Font Awesome)

Icon fonts are an ugly hack!

Accessibility Issues

Font icons use characters that get read aloud by screenreaders

Clash with Emoji

Icon fonts use unicode characters to display their icon which can conflict with emoji.

See Etsy's Four Stars and a Horse bug

When icon fonts fail…

SVGs can be just as flexible as icon fonts without the downsides.

Further Reading

Seriously, Don’t Use Icon Fonts by Tyler Sticka

Ten reasons we switched from an icon font to SVG by Ian Feather

Can we use SVGs?


(Unless you need to support IE8 or Android 2.3)

How can we use SVG files?

As an <img>

A gnarly tiger

As a background image

.image {
  background-image: url(/path/to/my.svg);
  background-repeat: no-repeat;
  height: 800px;
  width: 800px;
A mighty tiger!

Defining an SVG Sprite






Using an SVG Sprite



Inlining an SVG Where We Want It



Using <img> or CSS background-image offers no control of what is inside <svg> element

SVG sprites need to load all of the SVG elements on the page whether you use them or not

Inlining SVG requires lots of copy and pasting

Loading SVG Inline is AWESOME!

See the Pen Playing with SVGs by Russell Heimlich (@kingkool68) on CodePen.

Just need a pinch of CSS

svg.icon {
  display: inline-block;
  width: 1em;
  height: 1em;
  fill: currentColor;

Pros of Inlining SVG

Only use an SVG when you need it

No extra HTTP requests

Control of <svg> elements

Takes on size and color of parent element

But what about all of that copy and pasting?

How can we use SVG in WordPress?

Enable SVGs in the Media Library with the SVG Support plugin.

Or add this snippet to functions.php

function enable_svg_mime_types( $mimes = array() ) {

	$mimes['svg']  = 'image/svg+xml';
	$mimes['svgz'] = 'image/svg+xml';

	return $mimes;
add_filter( 'upload_mimes', 'enable_svg_mime_types', 10, 1 );

Function for inlining SVGs

function wp_get_svg( $path = '', $args = array() ) {
  if ( ! $path ) {
  $defaults = array(
    'role' => 'image',
    'css_class' => '',
  $args = wp_parse_args( $args, $defaults );
  $role_attr = $args['role'];
  $css_class = $args['css_class'];
  if ( is_array( $css_class ) ) {
    $css_class = implode( ' ', $css_class );
  if ( file_exists( $path ) ) {
    $svg = file_get_contents( $path );
    $svg = preg_replace( '/(width|height)="[\d\.]+"/i', '', $svg );
    $svg = str_replace( '<svg ',
      '<svg class="' . esc_attr( $css_class ) . '" role="' . esc_attr( $role_attr ) . '" ',
      $svg );

    return $svg;

Helper function we can use in markup

function wp_svg_icon( $icon = '' ) {
  if ( ! $icon ) {
  $path = get_template_directory() . '/icons/' . $icon . '.svg';
  $args = array(
    'css_class' => 'icon icon-' . $icon,
  return wp_get_svg( $path, $args );

Code in our theme

<h1><?php the_title(); ?></h1>

<p><?php echo wp_svg_icon( 'icon-1' ); ?></p>

The rendered markup

<h1>My Awesome Post Title</h1>


Folder structure of icons

We can make as many helper functions as we want for different directories of SVGs.

(See complete code snippet)

Wrapping Up

Where can I get SVG icons?







Optimizing SVGs

SVGO https://github.com/svg/svgo

SVGO UI https://github.com/svg/svgo-gui

SVGO in Action

More Resources

Using SVG - CSS-Tricks.com

Mega List of SVG Information - CSS-Tricks.com

SVG Pocket Guide - Joni Trythall

Amelia Bellamy-Royds CodePen Collections - Amelia Bellamy-Royds

In Conclusion

Why aren't you using SVGs?

Now you can't say you didn't know

Thank You!

Tweet me! @kingkool68