With the templates and CSS in place, let’s round off our theme building by adding a way for visitors to add a personal touch with their own Custom Backgrounds and Custom Headers.

I recommend adding support for these features after you’ve completed the CSS for your theme. It’s faster this way, because you can make the preview of the Custom Header and match your theme’s design. Plus, it’s easier to test the implementation of both backgrounds and headers when your design is complete. Think of them as the final flourish for your theme!

The examples in this lesson are based on the design of the Shape Sample Stylesheet from the CSS lesson.

Custom Background

The WordPress Custom Background feature lets users set their own background color or image. To enable it, we’ll draw on our old friend, add_theme_support(). Open functions.php, and add the following code at the bottom.

/**
 * Setup the WordPress core custom background feature.
 *
 * Use add_theme_support to register support for WordPress 3.4+
 * as well as provide backward compatibility for previous versions.
 * Use feature detection of wp_get_theme() which was introduced
 * in WordPress 3.4.
 *
 * Hooks into the after_setup_theme action.
 *
 */
function shape_register_custom_background() {
	$args = array(
		'default-color' => 'e9e0d1',
	);

	$args = apply_filters( 'shape_custom_background_args', $args );

	if ( function_exists( 'wp_get_theme' ) ) {
		add_theme_support( 'custom-background', $args );
	} else {
		define( 'BACKGROUND_COLOR', $args['default-color'] );
		define( 'BACKGROUND_IMAGE', $args['default-image'] );
		add_custom_background();
	}
}
add_action( 'after_setup_theme', 'shape_register_custom_background' );

/**

We’ve defined a function, shape_register_custom_background(), that:

1. Creates an array, $args, which stores the default background color for our theme (line 13). This color is #e9e0d1 in the Shape Sample Style (feel free to define your own color to match your design). If you wanted to, you could pass other values in this array.
2. Adds the $args array to a filter (line 17)
3. If the wp_get_theme() function exists (WordPress version 3.4 or later), we use add_theme_support() to enable Custom Backgrounds, passing $args as the parameter with all of our Custom Background options (line 20).
4. If the wp_get_theme() function does not exist (in other words, if we’re using a version of WordPress prior to 3.4), enable Custom Backgrounds with the method used in WordPress 3.3 and earlier (lines 22-24).
5. Close the function, and hook it to the after_setup_theme() action (lines 25-27).

That’s all you have to do to get Custom Backgrounds working! WordPress takes care of the rest. Visit Appearance → Background to see it in action.

Custom Headers

Custom Headers have been around for a long time (since version 2.1 to be exact). When you add Custom Header support to your theme, you give your users the ability to upload a “title” image for their site. In addition, users can also choose to change the header text color or hide the header text altogether.

As of WordPress 3.4, you can add Custom Header support using the add_theme_support() function. There are quite a few options you can configure for Custom Headers, so you can implement it in a manner that works best for your theme.

In this tutorial, our implementation of Custom Headers will:

1. Be based on the visual design of the Shape Sample Style
2. Allow users to upload a header image. The header image’s width will be limited to the width of the site’s main container div, but it can have an unlimited height.
3. Allow users to change the color of the header text.
4. Allow users to hide the header text.

custom-header.php

Traditionally, code related to Custom Headers has lived inside functions.php. In order to keep our functions.php clean, we’re going to place all of our Custom Header code inside a custom-header.php file, and call it from within functions.php.

If you don’t already have one, navigate to your inc folder and create custom-header.php.

Go ahead and add this code to custom-header.php. This is most of the code you’ll need to make the Custom Header work. We’ll walk through it in a bit.

<?php
/**
 * Sample implementation of the Custom Header feature
 * http://codex.wordpress.org/Custom_Headers
 *
 * You can add an optional custom header image to header.php like so ...

	<?php $header_image = get_header_image();
	if ( ! empty( $header_image ) ) { ?>
		<a href="<?php echo esc_url( home_url( '/' ) ); ?>" title="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>" rel="home">
			<img src="<?php header_image(); ?>" width="<?php echo get_custom_header()->width; ?>" height="<?php echo get_custom_header()->height; ?>" alt="" />
		</a>
	<?php } // if ( ! empty( $header_image ) ) ?>

 *
 * @package Shape
 * @since Shape 1.0
 */

/**
 * Setup the WordPress core custom header feature.
 *
 * Use add_theme_support to register support for WordPress 3.4+
 * as well as provide backward compatibility for previous versions.
 * Use feature detection of wp_get_theme() which was introduced
 * in WordPress 3.4.
 *
 * @uses shape_header_style()
 * @uses shape_admin_header_style()
 * @uses shape_admin_header_image()
 *
 * @package Shape
 */
function shape_custom_header_setup() {
	$args = array(
		'default-image'          => '',
		'default-text-color'     => 'e9e0e1',
		'width'                  => 1050,
		'height'                 => 250,
		'flex-height'            => true,
		'wp-head-callback'       => 'shape_header_style',
		'admin-head-callback'    => 'shape_admin_header_style',
		'admin-preview-callback' => 'shape_admin_header_image',
	);

	$args = apply_filters( 'shape_custom_header_args', $args );

	if ( function_exists( 'wp_get_theme' ) ) {
		add_theme_support( 'custom-header', $args );
	} else {
		// Compat: Versions of WordPress prior to 3.4.
		define( 'HEADER_TEXTCOLOR',    $args['default-text-color'] );
		define( 'HEADER_IMAGE',        $args['default-image'] );
		define( 'HEADER_IMAGE_WIDTH',  $args['width'] );
		define( 'HEADER_IMAGE_HEIGHT', $args['height'] );
		add_custom_image_header( $args['wp-head-callback'], $args['admin-head-callback'], $args['admin-preview-callback'] );
	}
}
add_action( 'after_setup_theme', 'shape_custom_header_setup' );

/**
 * Shiv for get_custom_header().
 *
 * get_custom_header() was introduced to WordPress
 * in version 3.4. To provide backward compatibility
 * with previous versions, we will define our own version
 * of this function.
 *
 * @todo Remove this function when WordPress 3.6 is released.
 * @return stdClass All properties represent attributes of the curent header image.
 *
 * @package Shape
 * @since Shape 1.1
 */

if ( ! function_exists( 'get_custom_header' ) ) {
	function get_custom_header() {
		return (object) array(
			'url'           => get_header_image(),
			'thumbnail_url' => get_header_image(),
			'width'         => HEADER_IMAGE_WIDTH,
			'height'        => HEADER_IMAGE_HEIGHT,
		);
	}
}

if ( ! function_exists( 'shape_header_style' ) ) :
/**
 * Styles the header image and text displayed on the blog
 *
 * @see shape_custom_header_setup().
 *
 * @since Shape 1.0
 */
function shape_header_style() {

	// If no custom options for text are set, let's bail
	// get_header_textcolor() options: HEADER_TEXTCOLOR is default, hide text (returns 'blank') or any hex value
	if ( HEADER_TEXTCOLOR == get_header_textcolor() && '' == get_header_image() )
		return;
	// If we get this far, we have custom styles. Let's do this.
	?>
	<style type="text/css">
	<?php
		// Do we have a custom header image?
		if ( '' != get_header_image() ) :
	?>
		.site-header img {
			display: block;
			margin: 1.5em auto 0;
		}
	<?php endif;

		// Has the text been hidden?
		if ( 'blank' == get_header_textcolor() ) :
	?>
		.site-title,
		.site-description {
			position: absolute !important;
			clip: rect(1px 1px 1px 1px); /* IE6, IE7 */
			clip: rect(1px, 1px, 1px, 1px);
		}
		.site-header hgroup {
			background: none;
			padding: 0;
		}
	<?php
		// If the user has set a custom color for the text use that
		else :
	?>
		.site-title a,
		.site-description {
			color: #<?php echo get_header_textcolor(); ?> !important;
		}
	<?php endif; ?>
	</style>
	<?php
}
endif; // shape_header_style

if ( ! function_exists( 'shape_admin_header_style' ) ) :
/**
 * Styles the header image displayed on the Appearance > Header admin panel.
 *
 * @see shape_custom_header_setup().
 *
 * @since Shape 1.0
 */
function shape_admin_header_style() {
?>
	<style type="text/css">
	.appearance_page_custom-header #headimg { /* This is the container for the Custom Header preview. */
		background: #33605a;
		border: none;
		min-height: 0 !important
	}
	#headimg h1 { /* This is the site title displayed in the preview */
		font-size: 45px;
		font-family: Georgia, 'Times New Roman', serif;
		font-style: italic;
		font-weight: normal;
		padding: 0.8em 0.5em 0;
	}
	#desc { /* This is the site description (tagline) displayed in the preview */
		padding: 0 2em 2em;
	}
	#headimg h1 a,
	#desc { 
		color: #e9e0d1;
		text-decoration: none;
	}
	</style>
<?php
}
endif; // shape_admin_header_style

if ( ! function_exists( 'shape_admin_header_image' ) ) :
/**
 * Custom header image markup displayed on the Appearance > Header admin panel.
 *
 * @see shape_custom_header_setup().
 *
 * @since Shape 1.0
 */
function shape_admin_header_image() { ?>
	<div id="headimg">
		<?php
		if ( 'blank' == get_header_textcolor() || '' == get_header_textcolor() )
			$style = ' style="display:none;"';
		else
			$style = ' style="color:#' . get_header_textcolor() . ';"';
		?>
		<h1><a id="name"<?php echo $style; ?> onclick="return false;" href="<?php echo esc_url( home_url( '/' ) ); ?>"><?php bloginfo( 'name' ); ?></a></h1>
		<div id="desc"<?php echo $style; ?>><?php bloginfo( 'description' ); ?></div>
		<?php $header_image = get_header_image();
		if ( ! empty( $header_image ) ) : ?>
			<img src="<?php echo esc_url( $header_image ); ?>" alt="" />
		<?php endif; ?>
	</div>
<?php }
endif; // shape_admin_header_image

With our Custom Header code in place, we now need to tell WordPress to load our Custom Header file. At the bottom of functions.php, add the following.

/**
 * Implement the Custom Header feature
 */
require( get_template_directory() . '/inc/custom-header.php' );

Visit the Dashboard and check out the Appearance menu. You should now have a “Header” option. If you’re using the Shape Sample Style, you should see the following:

Let’s walk through the code in inc/custom-header.php, function by function.

<?php
/**
 * Sample implementation of the Custom Header feature
 * http://codex.wordpress.org/Custom_Headers
 *
 * You can add an optional custom header image to header.php like so ...

	<?php $header_image = get_header_image();
	if ( ! empty( $header_image ) ) { ?>
		<a href="<?php echo esc_url( home_url( '/' ) ); ?>" title="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>" rel="home">
			<img src="<?php header_image(); ?>" width="<?php echo get_custom_header()->width; ?>" height="<?php echo get_custom_header()->height; ?>" alt="" />
		</a>
	<?php } // if ( ! empty( $header_image ) ) ?>

 *
 * @package Shape
 * @since Shape 1.0
 */

Here’s the usual documentation information. It also tells you how you can add Custom Header images to your header.php file, to make the header image show up. Technically, you could add this code anywhere you want to show the image, but header.php is the logical spot for it. Let’s add it right now. Open header.php and paste the following, just before the opening <nav> tag.

<?php $header_image = get_header_image();
		if ( ! empty( $header_image ) ) { ?>
			<a href="<?php echo esc_url( home_url( '/' ) ); ?>" title="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>" rel="home">
				<img src="<?php header_image(); ?>" width="<?php echo get_custom_header()->width; ?>" height="<?php echo get_custom_header()->height; ?>" alt="" />
			</a>
<?php } // if ( ! empty( $header_image ) ) 
?>

Save header.php, and return to custom-header.php. Let’s continue walking through the code.

/**
 * Setup the WordPress core custom header feature.
 *
 * Use add_theme_support to register support for WordPress 3.4+
 * as well as provide backward compatibility for previous versions.
 * Use feature detection of wp_get_theme() which was introduced
 * in WordPress 3.4.
 *
 * @uses shape_header_style()
 * @uses shape_admin_header_style()
 * @uses shape_admin_header_image()
 *
 * @package Shape
 */
function shape_custom_header_setup() {
	$args = array(
		'default-image'          => '',
		'default-text-color'     => 'e9e0e1',
		'width'                  => 1050,
		'height'                 => 250,
		'flex-height'            => true,
		'wp-head-callback'       => 'shape_header_style',
		'admin-head-callback'    => 'shape_admin_header_style',
		'admin-preview-callback' => 'shape_admin_header_image',
	);

	$args = apply_filters( 'shape_custom_header_args', $args );

	if ( function_exists( 'wp_get_theme' ) ) {
		add_theme_support( 'custom-header', $args );
	} else {
		// Compat: Versions of WordPress prior to 3.4.
		define( 'HEADER_TEXTCOLOR',    $args['default-text-color'] );
		define( 'HEADER_IMAGE',        $args['default-image'] );
		define( 'HEADER_IMAGE_WIDTH',  $args['width'] );
		define( 'HEADER_IMAGE_HEIGHT', $args['height'] );
		add_custom_image_header( $args['wp-head-callback'], $args['admin-head-callback'], $args['admin-preview-callback'] );
	}
}
add_action( 'after_setup_theme', 'shape_custom_header_setup' );

/**
 * Shiv for get_custom_header().
 *
 * get_custom_header() was introduced to WordPress
 * in version 3.4. To provide backward compatibility
 * with previous versions, we will define our own version
 * of this function.
 *
 * @return stdClass All properties represent attributes of the curent header image.
 *
 * @package Shape
 * @since Shape 1.1
 */

if ( ! function_exists( 'get_custom_header' ) ) {
	function get_custom_header() {
		return (object) array(
			'url'           => get_header_image(),
			'thumbnail_url' => get_header_image(),
			'width'         => HEADER_IMAGE_WIDTH,
			'height'        => HEADER_IMAGE_HEIGHT,
		);
	}
}

Here, we’re using add_theme_support() to add the Custom Header feature to the theme. Just like we did for backgrounds, we’re also adding background compatibility for WordPress versions prior to 3.4.

Let’s look at the $args array, starting on line 16 in the code block above, and running through line 25. Here is where we’re defining the parameters for our Custom Header. These values will change based on your theme.

• default-image' => '', – If your theme has a default header image, you’d specify the path to that image here. It would look something like this: 'default-image' => get_template_directory_uri() . '/images/header.jpg',. The Shape Sample Style doesn’t have a default header image, so we’re leaving it blank.
• 'default-text-color' => 'e9e0e1', – This is the default text color of your site title. In the case of the Shape Sample Style, it’s #e9e0e1.
• 'width' => 1050, and 'height' => 250, – Specify the width and height, in pixels that you want the header image to be. Users will have the option to crop images that are larger than these dimensions. Usually, the width and height that you define here should fit in the area where you plan to place the header image on your theme. We’re using 1050px as the width here because that is the maximum width of the container in the Shape Sample Style.
• 'flex-height' => true, – This allows the height of the header image to be flexible. We’e already specified that the header image height is 250px. Since we’re allowing flexible heights, That 250px becomes a mere “recommended” height. We’re still restricting the width to 1050px, but if you wanted a flexible width, you’d simply add: 'flex-width' => true,
• 'wp-head-callback' => 'shape_header_style',, 'admin-head-callback' => 'shape_admin_header_style',, and 'admin-preview-callback' => 'shape_admin_header_image', – These functions are known as callback functions. We will call on them to: 1) control the appearance of the Custom Header when viewed in the theme; 2) control the preview of the Custom Header that you see when you go to Dashboard → Header; and 3) control the markup of the Custom Header image on the Custom Header preview at Dashboard → Header, respectively.

There are more parameters that you can add to this $args array. For a list, see the WordPress Codex.

The Shiv for get_custom_header() (starting on line 42 in the code block above) is present for background compatibility with earlier versions of WordPress. In a nutshell, it takes the values that you’ve specified in the $args array and assigns them to the “old” method of adding Custom Headers, so that previous versions of WordPress can understand. If you don’t wish to provide this background compatibility, you can remove it. If you pan to distribute your theme, however, it might be a good idea to keep it around.

Moving right along. Next, we have:

if ( ! function_exists( 'shape_header_style' ) ) :
/**
 * Styles the header image and text displayed on the blog
 *
 * @see shape_custom_header_setup().
 *
 * @since Shape 1.0
 */
function shape_header_style() {

	// If no custom options for text are set, let's bail
	// get_header_textcolor() options: HEADER_TEXTCOLOR is default, hide text (returns 'blank') or any hex value
	if ( HEADER_TEXTCOLOR == get_header_textcolor() && '' == get_header_image() )
		return;
	// If we get this far, we have custom styles. Let's do this.
	?>
	<style type="text/css">
	<?php
		// Do we have a custom header image?
		if ( '' != get_header_image() ) :
	?>
		.site-header img {
			display: block;
			margin: 1.5em auto 0;
		}
	<?php endif;

		// Has the text been hidden?
		if ( 'blank' == get_header_textcolor() ) :
	?>
		.site-title,
		.site-description {
			position: absolute !important;
			clip: rect(1px 1px 1px 1px); /* IE6, IE7 */
			clip: rect(1px, 1px, 1px, 1px);
		}
		.site-header hgroup {
			background: none;
			padding: 0;
		}
	<?php
		// If the user has set a custom color for the text use that
		else :
	?>
		.site-title a,
		.site-description {
			color: #<?php echo get_header_textcolor(); ?> !important;
		}
	<?php endif; ?>
	</style>
	<?php
}
endif; // shape_header_style

This is the callback function that controls how the Custom Header will appear on your theme. The comments in the code should help explain what it’s doing, but in summary, if the user has uploaded a header image or set a custom header text color, this function adds a block of CSS inside your <head> tag. This block contains the presentation rules for the header image or text.

We’ve already added the header image markup to header.php. On line 22 above, we can style the image if necessary. Just make sure .site-header img is the correct selector name for your theme!

We want to hide the header text if the user has opted to hide the text (lines 28-40 above).

Finally, we want the site title and description to display the user’s custom header text color (lines 42-48 above). You don’t have to apply the header text color to the site description, that part is up to you.

Moving along, we next have this:

if ( ! function_exists( 'shape_admin_header_style' ) ) :
/**
 * Styles the header image displayed on the Appearance > Header admin panel.
 *
 * @see shape_custom_header_setup().
 *
 * @since Shape 1.0
 */
function shape_admin_header_style() {
?>
	<style type="text/css">
	.appearance_page_custom-header #headimg { /* This is the container for the Custom Header preview. Notice how the min-height value on this element matches the "height" value we specified earlier in the Custom Header $args array. */
		background: #33605a;
		border: none;
	}
	#headimg h1 { /* This is the site title displayed in the preview */
		font-size: 45px;
		font-family: Georgia, 'Times New Roman', serif;
		font-style: italic;
		font-weight: normal;
		padding: 0.8em 0.5em 0;
	}
	#desc { /* This is the site description (tagline) displayed in the preview */
		padding: 0 2em 2em;
	}
	#headimg h1 a,
	#desc { 
		color: #e9e0d1;
		text-decoration: none;
	}
	</style>
<?php
}
endif; // shape_admin_header_style

This callback function controls the styling of the Custom Header in the preview you see at Dashboard → Appearance → Header. The goal is to make this match the front end of your theme as much as possible. This means you should style these elements with the same fonts, colors and backgrounds you used in your theme’s main stylesheet. You might need to make adjustments to these styles, so keep chipping away until you get it just right.

Finally, we have a function that controls the markup for the Custom Header image in the Custom Header preview. Feel free to modify it to fit your theme.

if ( ! function_exists( 'shape_admin_header_image' ) ) :
/**
 * Custom header image markup displayed on the Appearance > Header admin panel.
 *
 * @see shape_custom_header_setup().
 *
 * @since Shape 1.0
 */
function shape_admin_header_image() { ?>
	<div id="headimg">
		<?php
		if ( 'blank' == get_header_textcolor() || '' == get_header_textcolor() )
			$style = ' style="display:none;"';
		else
			$style = ' style="color:#' . get_header_textcolor() . ';"';
		?>
		<h1><a id="name"<?php echo $style; ?> onclick="return false;" href="<?php echo esc_url( home_url( '/' ) ); ?>"><?php bloginfo( 'name' ); ?></a></h1>
		<div id="desc"<?php echo $style; ?>><?php bloginfo( 'description' ); ?></div>
	</div>
	<?php $header_image = get_header_image();
	if ( ! empty( $header_image ) ) : ?>
		<img src="<?php echo esc_url( $header_image ); ?>" alt="" />
	<?php endif; ?>
<?php }
endif; // shape_admin_header_image

And there you have it. A working Custom Header implementation! The best way to learn how these functions work is to make small adjustments to each one, and then reload your Custom Header Dashboard page to see what changes. Trial and error is one of the best ways to learn! The following annotated screenshots will help you to see which functions change which parts of the header.

How To Create a WordPress Theme

This post is part of the The ThemeShaper WordPress Theme Tutorial: 2nd Edition that will show you how to create a powerful WordPress Theme from scratch. Read it from the beginning and code yourself up something awesome.

1. WordPress Theme Tutorial Introduction
2. Developing Theme Sense
3. Theme Development Tools
4. Creating a Theme HTML Structure
5. Template and Directory Structure
6. Setting Up Your Theme Functions
7. Secure Your WordPress Theme
8. The Header Template
9. The Index Template
10. The Single Post, Post Attachment, & 404 Templates
11. The Comments Template
12. The Search Template & The Page Template
13. The Archive Template
14. The Sidebar Template & The Footer Template
15. Reset-Rebuild Theme CSS & Define Your Layouts
16. Custom Background & Custom Header
17. Distributing Your WordPress Theme