WordPress/wp-includes/class-wp-customize.php

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<?php
/**
* Customize
*
* @package WordPress
* @subpackage Customize
* @since 3.4.0
*/
final class WP_Customize {
protected $template;
protected $stylesheet;
protected $previewing = false;
protected $settings = array();
protected $sections = array();
protected $controls = array();
/**
* Constructor.
*
* @since 3.4.0
*/
public function __construct() {
require( ABSPATH . WPINC . '/class-wp-customize-setting.php' );
require( ABSPATH . WPINC . '/class-wp-customize-section.php' );
require( ABSPATH . WPINC . '/class-wp-customize-control.php' );
add_action( 'setup_theme', array( $this, 'setup_theme' ) );
add_action( 'admin_init', array( $this, 'admin_init' ) );
add_action( 'wp_loaded', array( $this, 'wp_loaded' ) );
add_action( 'admin_footer', array( $this, 'admin_footer' ) );
add_action( 'customize_previewing', array( $this, 'customize_previewing' ) );
add_action( 'customize_register', array( $this, 'register_controls' ) );
add_action( 'customize_controls_init', array( $this, 'prepare_controls' ) );
add_action( 'customize_controls_enqueue_scripts', array( $this, 'enqueue_control_scripts' ) );
}
/**
* Update theme modifications for the current theme.
* Note: Candidate core function.
* http://core.trac.wordpress.org/ticket/20091
*
* @since 3.4.0
*
* @param array $mods Theme modifications.
*/
public function set_theme_mods( $mods ) {
$current = get_theme_mods();
$mods = wp_parse_args( $mods, $current );
$theme = get_stylesheet();
update_option( "theme_mods_$theme", $mods );
}
/**
* Start preview and customize theme.
* Check if customize query variable exist.
*
* @since 3.4.0
*/
public function setup_theme() {
if ( ! isset( $_REQUEST['customize'] ) || 'on' != $_REQUEST['customize'] )
return;
if ( ! $this->set_stylesheet() || isset( $_REQUEST['save_customize_controls'] ) )
return;
$this->previewing = true;
do_action( 'customize_previewing' );
}
/**
* Init filters to filter theme options.
*
* @since 3.4.0
*/
public function customize_previewing() {
global $wp_theme_directories;
show_admin_bar( false );
add_filter( 'template', array( $this, 'get_template' ) );
add_filter( 'stylesheet', array( $this, 'get_stylesheet' ) );
add_filter( 'pre_option_current_theme', array( $this, 'current_theme' ) );
// @link: http://core.trac.wordpress.org/ticket/20027
add_filter( 'pre_option_stylesheet', array( $this, 'get_stylesheet' ) );
add_filter( 'pre_option_template', array( $this, 'get_template' ) );
// Handle custom theme roots.
if ( count( $wp_theme_directories ) > 1 ) {
add_filter( 'pre_option_stylesheet_root', array( $this, 'get_stylesheet_root' ) );
add_filter( 'pre_option_template_root', array( $this, 'get_template_root' ) );
}
}
/**
* Register styles/scripts and initialize the preview of each setting
*
* @since 3.4.0
*/
public function wp_loaded() {
do_action( 'customize_register' );
if ( $this->is_preview() && ! is_admin() )
$this->customize_preview_init();
}
/**
* Print javascript settings.
*
* @since 3.4.0
*/
public function customize_preview_init() {
$this->prepare_controls();
wp_enqueue_script( 'customize-preview' );
add_action( 'wp_footer', array( $this, 'customize_preview_settings' ), 20 );
foreach ( $this->settings as $setting ) {
$setting->preview();
}
do_action( 'customize_preview_init' );
}
/**
* Print javascript settings.
*
* @since 3.4.0
*/
public function customize_preview_settings() {
$settings = array(
// @todo: Perhaps grab the URL via $_POST?
'parent' => esc_url( admin_url( 'themes.php' ) ),
'values' => array(),
);
foreach ( $this->settings as $id => $setting ) {
$settings['values'][ $id ] = $setting->value();
}
?>
<script type="text/javascript">
(function() {
if ( typeof wp === 'undefined' || ! wp.customize )
return;
wp.customize.settings = <?php echo json_encode( $settings ); ?>;
})();
</script>
<?php
}
/**
* Is it a theme preview?
*
* @since 3.4.0
*
* @return bool True if it's a preview, false if not.
*/
public function is_preview() {
return (bool) $this->previewing;
}
/**
* Set the template name of the previewed theme.
*
* @since 3.4.0
*
* @return bool|string Template name.
*/
public function set_template() {
if ( ! empty( $this->template ) )
return $this->template;
$template = preg_replace('|[^a-z0-9_./-]|i', '', $_REQUEST['template'] );
if ( validate_file( $template ) )
return false;
return $this->template = $template;
}
/**
* Set the stylesheet name of the previewed theme.
*
* @since 3.4.0
*
* @return bool|string Stylesheet name.
*/
public function set_stylesheet() {
if ( ! empty( $this->stylesheet ) )
return $this->stylesheet;
$this->set_template();
if ( empty( $this->template ) )
return false;
if ( empty( $_REQUEST['stylesheet'] ) ) {
$stylesheet = $this->template;
} else {
$stylesheet = preg_replace( '|[^a-z0-9_./-]|i', '', $_REQUEST['stylesheet'] );
if ( $stylesheet != $this->template && validate_file( $stylesheet ) )
return false;
}
return $this->stylesheet = $stylesheet;
}
/**
* Retrieve the template name of the previewed theme.
*
* @since 3.4.0
*
* @return string Template name.
*/
public function get_template() {
return $this->template;
}
/**
* Retrieve the stylesheet name of the previewed theme.
*
* @since 3.4.0
*
* @return string Stylesheet name.
*/
public function get_stylesheet() {
return $this->stylesheet;
}
/**
* Retrieve the template root of the previewed theme.
*
* @since 3.4.0
*
* @return string Theme root.
*/
public function get_template_root() {
return get_raw_theme_root( $this->template, true );
}
/**
* Retrieve the stylesheet root of the previewed theme.
*
* @since 3.4.0
*
* @return string Theme root.
*/
public function get_stylesheet_root() {
return get_raw_theme_root( $this->stylesheet, true );
}
/**
* Filter the current theme and return the name of the previewed theme.
*
* @since 3.4.0
*
* @return string Theme name.
*/
public function current_theme( $current_theme ) {
Introduce WP_Theme, wp_get_themes(), and wp_get_theme() to replace get_themes(), get_theme(), get_theme_data(), current_theme_info(), and others. * Getters and Helpers: Introduces a series of methods to allow for easy generation of headers for display, and other theme metadata, including page templates. * Screenshots: Handles support for multiple screenshots. (see # Additional screenshots must be PNG and start with screenshot-2.png, and be sequential to be counted. see #19816. * Error Handling: Broken themes have a WP_Error object attached to them. * Caching: Introduces a wp_cache_themes_persistently filter (also in [20020]) to enable persistent caching of all filesystem and sanitization operations normally handled by WP_Theme (and formerly get_file_data() and get_themes()). Themes are cached individually and across five different cache keys for different data pieces. * Compatibility: A WP_Theme object is backwards compatible with a theme's array formerly returned by get_themes() and get_theme(), and an stdClass object formerly returned by current_theme_info(). * i18n/L10n: Theme headers are now localizable with proper Text Domain and Domain Path headers, like plugins. (Language packs may remove the requirement for headers.) For page templates, see #6007 (not fixed yet, but will be easy now). For headers, fixes #15858. * PHP and CSS files: New methods that fetch a list of theme files (for the theme editor) only on demand, rather than only loading them into memory. fixes #11214. Functions deprecated: * get_themes(), get_allowed_themes() and get_broken_themes() -- use wp_get_themes() * get_theme() and current_theme_info() -- use wp_get_theme() * get_site_allowed_themes() -- use WP_Theme::get_allowed_on_network() * wpmu_get_blog_allowedthemes() -- use WP_theme::get_allowed_on_site() see also [20016], [20018], [20019], [20020], [20021], [20022], [20025], [20026], [20027]. also fixes #19244. see #20103. git-svn-id: http://svn.automattic.com/wordpress/trunk@20029 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2012-02-28 16:24:44 -05:00
return wp_get_theme( $this->stylesheet )->get('Name');
}
/**
* Trigger save action and load customize controls.
*
* @since 3.4.0
*/
public function admin_init() {
if ( isset( $_REQUEST['save_customize_controls'] ) )
$this->save();
wp_enqueue_script( 'customize-loader' );
if ( ( defined( 'DOING_AJAX' ) && DOING_AJAX ) )
return;
if ( ! isset( $_GET['customize'] ) || 'on' != $_GET['customize'] )
return;
if ( ! $this->is_preview() )
return;
if ( ! current_user_can( 'edit_theme_options' ) )
return;
include( ABSPATH . WPINC . '/customize-controls.php' );
die;
}
/**
* Print the customize template.
*
* @since 3.4.0
*/
public function admin_footer() {
?>
<div id="customize-container" class="wp-full-overlay">
<input type="hidden" class="admin-url" value="<?php echo esc_url( admin_url( 'admin.php' ) ); ?>" />
<a href="#" class="close-full-overlay"><?php printf( __( '&larr; Return to %s' ), get_admin_page_title() ); ?></a>
<a href="#" class="collapse-sidebar button-secondary" title="<?php esc_attr_e('Collapse Sidebar'); ?>">
<span class="collapse-sidebar-label"><?php _e('Collapse'); ?></span>
<span class="collapse-sidebar-arrow"></span>
</a>
</div>
<?php
}
/**
* Switch the theme and trigger the save action of each setting.
*
* @since 3.4.0
*/
public function save() {
if ( $this->is_preview() )
return;
check_admin_referer( 'customize_controls' );
if ( ! $this->set_stylesheet() )
return;
$active_template = get_template();
$active_stylesheet = get_stylesheet();
// Do we have to switch themes?
if ( $this->get_template() != $active_template || $this->get_stylesheet() != $active_stylesheet ) {
if ( ! current_user_can( 'switch_themes' ) )
return;
switch_theme( $this->get_template(), $this->get_stylesheet() );
}
do_action( 'customize_save' );
foreach ( $this->settings as $setting ) {
$setting->save();
}
add_action( 'admin_notices', array( $this, '_save_feedback' ) );
}
/**
* Show an admin notice after settings are saved.
*
* @since 3.4.0
*/
public function _save_feedback() {
?>
<div class="updated"><p><?php printf( __( 'Settings saved and theme activated. <a href="%s">Visit site</a>.' ), home_url( '/' ) ); ?></p></div>
<?php
}
/**
* Add a customize setting.
*
* @since 3.4.0
*
* @param string $id A specific ID of the setting. Can be a
* theme mod or option name.
* @param array $args Setting arguments.
*/
public function add_setting( $id, $args = array() ) {
if ( is_a( $id, 'WP_Customize_Setting' ) )
$setting = $id;
else
$setting = new WP_Customize_Setting( $this, $id, $args );
$this->settings[ $setting->id ] = $setting;
}
/**
* Retrieve a customize setting.
*
* @since 3.4.0
*
* @param string $id A specific ID of the setting.
* @return object The settings object.
*/
public function get_setting( $id ) {
if ( isset( $this->settings[ $id ] ) )
return $this->settings[ $id ];
}
/**
* Remove a customize setting.
*
* @since 3.4.0
*
* @param string $id A specific ID of the setting.
*/
public function remove_setting( $id ) {
unset( $this->settings[ $id ] );
}
/**
* Add a customize section.
*
* @since 3.4.0
*
* @param string $id A specific ID of the section.
* @param array $args Section arguments.
*/
public function add_section( $id, $args = array() ) {
if ( is_a( $id, 'WP_Customize_Section' ) )
$section = $id;
else
$section = new WP_Customize_Section( $this, $id, $args );
$this->sections[ $section->id ] = $section;
}
/**
* Retrieve a customize section.
*
* @since 3.4.0
*
* @param string $id A specific ID of the section.
* @return object The section object.
*/
public function get_section( $id ) {
if ( isset( $this->sections[ $id ] ) )
return $this->sections[ $id ];
}
/**
* Remove a customize section.
*
* @since 3.4.0
*
* @param string $id A specific ID of the section.
*/
public function remove_section( $id ) {
unset( $this->sections[ $id ] );
}
/**
* Add a customize control.
*
* @since 3.4.0
*
* @param string $id A specific ID of the control.
* @param array $args Setting arguments.
*/
public function add_control( $id, $args = array() ) {
if ( is_a( $id, 'WP_Customize_Control' ) )
$control = $id;
else
$control = new WP_Customize_Control( $this, $id, $args );
$this->controls[ $control->id ] = $control;
}
/**
* Retrieve a customize control.
*
* @since 3.4.0
*
* @param string $id A specific ID of the control.
* @return object The settings object.
*/
public function get_control( $id ) {
if ( isset( $this->controls[ $id ] ) )
return $this->controls[ $id ];
}
/**
* Remove a customize setting.
*
* @since 3.4.0
*
* @param string $id A specific ID of the control.
*/
public function remove_control( $id ) {
unset( $this->controls[ $id ] );
}
/**
* Helper function to compare two objects by priority.
*
* @since 3.4.0
*
* @param object $a Object A.
* @param object $b Object B.
*/
protected final function _cmp_priority( $a, $b ) {
$ap = $a->priority;
$bp = $b->priority;
if ( $ap == $bp )
return 0;
return ( $ap > $bp ) ? 1 : -1;
}
/**
* Prepare settings and sections.
*
* @since 3.4.0
*/
public function prepare_controls() {
// Prepare controls
// Reversing makes uasort sort by time added when conflicts occur.
$this->controls = array_reverse( $this->controls );
$controls = array();
foreach ( $this->controls as $id => $control ) {
if ( ! isset( $this->sections[ $control->section ] ) || ! $control->check_capabilities() )
continue;
$this->sections[ $control->section ]->controls[] = $control;
$controls[ $id ] = $control;
}
$this->controls = $controls;
// Prepare sections
$this->sections = array_reverse( $this->sections );
uasort( $this->sections, array( $this, '_cmp_priority' ) );
$sections = array();
foreach ( $this->sections as $section ) {
if ( ! $section->check_capabilities() || ! $section->controls )
continue;
usort( $section->controls, array( $this, '_cmp_priority' ) );
$sections[] = $section;
}
$this->sections = $sections;
}
/**
* Enqueue scripts for customize controls.
*
* @since 3.4.0
*/
public function enqueue_control_scripts() {
foreach ( $this->controls as $control ) {
$control->enqueue();
}
}
/**
* Register some default controls.
*
* @since 3.4.0
*/
public function register_controls() {
/* Custom Header */
$this->add_section( 'header', array(
'title' => __( 'Header' ),
'theme_supports' => 'custom-header',
'priority' => 20,
) );
$this->add_setting( 'header_textcolor', array(
// @todo: replace with a new accept() setting method
// 'sanitize_callback' => 'sanitize_hexcolor',
'control' => 'color',
'theme_supports' => array( 'custom-header', 'header-text' ),
'default' => get_theme_support( 'custom-header', 'default-text-color' ),
) );
$this->add_control( 'display_header_text', array(
'settings' => 'header_textcolor',
'label' => __( 'Display Header Text' ),
'section' => 'header',
'type' => 'checkbox',
) );
$this->add_control( 'header_textcolor', array(
'label' => __( 'Text Color' ),
'section' => 'header',
'type' => 'color',
) );
// Input type: checkbox
// With custom value
$this->add_setting( 'header_image', array(
'default' => get_theme_support( 'custom-header', 'default-image' ),
'theme_supports' => 'custom-header',
) );
$this->add_control( new WP_Customize_Image_Control( $this, 'header_image', array(
'label' => 'Header Image',
'section' => 'header',
'context' => 'custom-header',
'removed' => 'remove-header',
'get_url' => 'get_header_image',
'tabs' => array(
array( 'uploaded', __('Uploaded'), 'wp_customize_print_uploaded_headers' ),
array( 'included', __('Included'), 'wp_customize_print_included_headers' ),
),
) ) );
/* Custom Background */
$this->add_section( 'background', array(
'title' => __( 'Background' ),
'theme_supports' => 'custom-background',
'priority' => 30,
) );
// Input type: Color
// With sanitize_callback
$this->add_setting( 'background_color', array(
Introduce new registration methods for custom headers and custom backgrounds. Backwards compatible, but old methods will be deprecated. see #20249. see #17242. Custom header: Use add_theme_support('custom-header', $args) instead of add_custom_image_header(). Deprecates all use of constants. * HEADER_TEXTCOLOR is now (string) 'default-text-color'. * NO_HEADER_TEXT is nowi ! (bool) 'header-text'. * HEADER_IMAGE_WIDTH (and _HEIGHT) are now (int) 'width' and 'height'. * HEADER_IMAGE is now (string) 'default-image'. * The 3.4 arguments 'suggested-width' and 'suggested-height' are now just 'width' and 'height' (they are "suggested" when flex-width and flex-height are set). * Callback arguments for add_custom_image_header() can now be passed to add_theme_support(). Custom background: Use add_theme_support('custom-background, $args) instead of add_custom_background(). Deprecates all use of constants. * BACKGROUND_COLOR is now (string) 'default-color'. * BACKGROUND_IMAGE is now (string) 'default-image'. * Callback arguments for add_custom_background() can now be passed to add_theme_support(). Inheritance: add_theme_support() arguments for custom headers and custom backgrounds is a first-one-wins situation. This is not an unusual paradigm for theming as a child theme (which is included first) overrides a parent theme. * Once an argument is explicitly set, it cannot be overridden. You must hook in earlier and set it first. * Any argument that is not explicitly set before WP is loaded will inherit the default value for that argument. * It is therefore possible for a child theme to pass minimal arguments as long as the parent theme specifies others that may be necessary. * Allows for a child theme to alter callbacks for <head> and preview (previously, calling add_custom_image_header more than once broke things). * The just-in-time bits ensure that arguments fall back to default values, that the values of all constants are considered (such as one defined after an old add_custom_image_header call), and that all constants are defined (so as to be backwards compatible). get_theme_support(): Introduce new second argument, which headers and backgrounds leverage to return an argument. current_theme_supports() already supported checking the truthiness of the argument. * For example, get_theme_support( 'custom-header', 'width' ) will return the width specified during registration. * If you had wanted the default image, use get_theme_support( 'custom-header', 'default-image' ) instead of HEADER_IMAGE. Deprecate remove_custom_image_header(), remove_custom_background(). Use remove_theme_support('custom-header'), 'custom-background'. Deprecate short-lived custom-header-uploads internal support; this is now (bool) 'uploads' for add_theme_support(). New 3.4 functions renamed or removed: Rename get_current_header_data() to get_custom_header(). Remove get_header_image_width() and _height() in favor of get_custom_header()->width and height. git-svn-id: http://svn.automattic.com/wordpress/trunk@20212 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2012-03-19 13:12:44 -04:00
'default' => get_theme_support( 'custom-background', 'default-color' ),
'sanitize_callback' => 'sanitize_hexcolor',
'theme_supports' => 'custom-background',
) );
$this->add_control( 'background_color', array(
'label' => __( 'Background Color' ),
'section' => 'background',
'type' => 'color',
) );
$this->add_setting( 'background_image', array(
'default' => get_theme_support( 'custom-background', 'default-image' ),
'theme_supports' => 'custom-background',
) );
$this->add_control( new WP_Customize_Upload_Control( $this, 'background_image', array(
'label' => __( 'Background Image' ),
'section' => 'background',
'type' => 'upload',
'context' => 'custom-background',
) ) );
$this->add_setting( 'background_repeat', array(
'default' => 'repeat',
'theme_supports' => 'custom-background',
) );
$this->add_control( 'background_repeat', array(
'label' => __( 'Background Repeat' ),
'section' => 'background',
'visibility' => 'background_image',
'type' => 'radio',
'choices' => array(
'no-repeat' => __('No Repeat'),
'repeat' => __('Tile'),
'repeat-x' => __('Tile Horizontally'),
'repeat-y' => __('Tile Vertically'),
),
) );
$this->add_setting( 'background_position_x', array(
'default' => 'left',
'theme_supports' => 'custom-background',
) );
$this->add_control( 'background_position_x', array(
'label' => __( 'Background Position' ),
'section' => 'background',
'visibility' => 'background_image',
'type' => 'radio',
'choices' => array(
'left' => __('Left'),
'center' => __('Center'),
'right' => __('Right'),
),
) );
$this->add_setting( 'background_attachment', array(
'default' => 'fixed',
'theme_supports' => 'custom-background',
) );
$this->add_control( 'background_attachment', array(
'label' => __( 'Background Attachment' ),
'section' => 'background',
'visibility' => 'background_image',
'type' => 'radio',
'choices' => array(
'fixed' => __('Fixed'),
'scroll' => __('Scroll'),
),
) );
/* Nav Menus */
$locations = get_registered_nav_menus();
$menus = wp_get_nav_menus();
$menu_locations = get_nav_menu_locations();
$num_locations = count( array_keys( $locations ) );
$this->add_section( 'nav', array(
'title' => __( 'Navigation' ),
'theme_supports' => 'menus',
'priority' => 40,
'description' => sprintf( _n('Your theme supports %s menu. Select which menu you would like to use.', 'Your theme supports %s menus. Select which menu appears in each location.', $num_locations ), number_format_i18n( $num_locations ) ),
) );
foreach ( $locations as $location => $description ) {
$choices = array( 0 => '' );
foreach ( $menus as $menu ) {
$truncated_name = wp_html_excerpt( $menu->name, 40 );
$truncated_name == $menu->name ? $menu->name : trim( $truncated_name ) . '&hellip;';
$choices[ $menu->term_id ] = $truncated_name;
}
$menu_setting_id = "nav_menu_locations[{$location}]";
$this->add_setting( $menu_setting_id, array(
'sanitize_callback' => 'absint',
'theme_supports' => 'menus',
) );
$this->add_control( $menu_setting_id, array(
'label' => $description,
'section' => 'nav',
'type' => 'select',
'choices' => $choices,
) );
}
/* Static Front Page */
// #WP19627
$this->add_section( 'static_front_page', array(
'title' => __( 'Static Front Page' ),
// 'theme_supports' => 'static-front-page',
'priority' => 50,
'description' => __( 'Your theme supports a static front page.' ),
) );
$this->add_setting( 'show_on_front', array(
'default' => get_option( 'show_on_front' ),
'capability' => 'manage_options',
'type' => 'option',
// 'theme_supports' => 'static-front-page',
) );
$this->add_control( 'show_on_front', array(
'label' => __( 'Front page displays' ),
'section' => 'static_front_page',
'type' => 'radio',
'choices' => array(
'posts' => __( 'Your latest posts' ),
'page' => __( 'A static page' ),
),
) );
$this->add_setting( 'page_on_front', array(
'type' => 'option',
'capability' => 'manage_options',
// 'theme_supports' => 'static-front-page',
) );
$this->add_control( 'page_on_front', array(
'label' => __( 'Front page' ),
'section' => 'static_front_page',
'type' => 'dropdown-pages',
'visibility' => array( 'show_on_front', 'page' ),
) );
$this->add_setting( 'page_for_posts', array(
'type' => 'option',
'capability' => 'manage_options',
// 'theme_supports' => 'static-front-page',
) );
$this->add_control( 'page_for_posts', array(
'label' => __( 'Posts page' ),
'section' => 'static_front_page',
'type' => 'dropdown-pages',
'visibility' => array( 'show_on_front', 'page' ),
) );
/* Site Title & Tagline */
$this->add_section( 'strings', array(
'title' => __( 'Site Title & Tagline' ),
'priority' => 5,
) );
$this->add_setting( 'blogname', array(
'default' => get_option( 'blogname' ),
'type' => 'option',
'capability' => 'manage_options',
) );
$this->add_control( 'blogname', array(
'label' => __( 'Site Title' ),
'section' => 'strings',
) );
$this->add_setting( 'blogdescription', array(
'default' => get_option( 'blogdescription' ),
'type' => 'option',
'capability' => 'manage_options',
) );
$this->add_control( 'blogdescription', array(
'label' => __( 'Tagline' ),
'section' => 'strings',
) );
}
};
// Callback function for sanitizing a hex color
function sanitize_hexcolor( $color ) {
$color = preg_replace( '/[^0-9a-fA-F]/', '', $color );
if ( preg_match('|[A-Fa-f0-9]{3,6}|', $color ) )
return $color;
return $color;
}
function wp_customize_print_uploaded_headers() {
$headers = get_uploaded_header_images();
foreach ( $headers as $header ) : ?>
<a href="<?php echo esc_url( $header['url'] ); ?>">
<img src="<?php echo esc_url( $header['thumbnail_url'] ); ?>" />
</a>
<?php endforeach;
}
function wp_customize_print_included_headers() {
global $custom_image_header;
$custom_image_header->process_default_headers();
foreach ( $custom_image_header->default_headers as $header ) : ?>
<a href="<?php echo esc_url( $header['url'] ); ?>">
<img src="<?php echo esc_url( $header['thumbnail_url'] ); ?>" />
</a>
<?php endforeach;
}