WordPress/wp-includes/post-thumbnail-template.php

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<?php
/**
* WordPress Post Thumbnail Template Functions.
*
* Support for post thumbnails.
* Theme's functions.php must call add_theme_support( 'post-thumbnails' ) to use these.
*
* @package WordPress
* @subpackage Template
*/
/**
Docs: Link to the "Conditional Tags" article in the Theme Developer Handbook from the descriptions for a variety of core conditional tag functions. These notations largely serve to direct consumers (of both the source and the parsed code reference) to extended information on individual and related conditional tags throughout WordPress. The changeset also standardizes corresponding DocBlock summaries to use third-person singular verbs. Notations been added for the following functions: * comments_open() * email exists() * has_excerpt() * has_post_thumbnail() * has_tag() * in_category() * in_the_loop() * is_404() * is_active_sidebar() * is_active_widget() * is_admin() * is_admin_bar_showing() * is_archive() * is_attachment() * is_author() * is_blog_installed() * is_category() * is_comments_popup() * is_date() * is_day() * is_dynamic_sidebar() * is_feed() * is_front_page() * is_home() * is_local_attachment() * is_main_query * is_month() * is_multi_author * is_new_day() * is_page() * is_page_template() * is_paged() * is_plugin_active() * is_plugin_active_for_network() * is_plugin_inactive() * is_plugin_page() * is_post_type_archive() * is_preview() * is_rtl() * is_search() * is_single() * is_singular() * is_sticky() * is_tag() * is_tax() * is_taxonomy_hierarchical() * is_time() * is_trackback() * is_user_logged_in() * is_year() * pings_open() * post_type_exists() * taxonomy_exists() * term_exists() * username exists() * wp_attachment_is_image() * wp_script_is() Props janalwin. Fixes #43254. Built from https://develop.svn.wordpress.org/trunk@42710 git-svn-id: http://core.svn.wordpress.org/trunk@42538 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2018-02-13 17:54:31 +01:00
* Determines whether a post has an image attached.
*
Docs: Link to the "Conditional Tags" article in the Theme Developer Handbook from the descriptions for a variety of core conditional tag functions. These notations largely serve to direct consumers (of both the source and the parsed code reference) to extended information on individual and related conditional tags throughout WordPress. The changeset also standardizes corresponding DocBlock summaries to use third-person singular verbs. Notations been added for the following functions: * comments_open() * email exists() * has_excerpt() * has_post_thumbnail() * has_tag() * in_category() * in_the_loop() * is_404() * is_active_sidebar() * is_active_widget() * is_admin() * is_admin_bar_showing() * is_archive() * is_attachment() * is_author() * is_blog_installed() * is_category() * is_comments_popup() * is_date() * is_day() * is_dynamic_sidebar() * is_feed() * is_front_page() * is_home() * is_local_attachment() * is_main_query * is_month() * is_multi_author * is_new_day() * is_page() * is_page_template() * is_paged() * is_plugin_active() * is_plugin_active_for_network() * is_plugin_inactive() * is_plugin_page() * is_post_type_archive() * is_preview() * is_rtl() * is_search() * is_single() * is_singular() * is_sticky() * is_tag() * is_tax() * is_taxonomy_hierarchical() * is_time() * is_trackback() * is_user_logged_in() * is_year() * pings_open() * post_type_exists() * taxonomy_exists() * term_exists() * username exists() * wp_attachment_is_image() * wp_script_is() Props janalwin. Fixes #43254. Built from https://develop.svn.wordpress.org/trunk@42710 git-svn-id: http://core.svn.wordpress.org/trunk@42538 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2018-02-13 17:54:31 +01:00
* For more information on this and similar theme functions, check out
* the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
Docs: Link to the "Conditional Tags" article in the Theme Developer Handbook from the descriptions for a variety of core conditional tag functions. These notations largely serve to direct consumers (of both the source and the parsed code reference) to extended information on individual and related conditional tags throughout WordPress. The changeset also standardizes corresponding DocBlock summaries to use third-person singular verbs. Notations been added for the following functions: * comments_open() * email exists() * has_excerpt() * has_post_thumbnail() * has_tag() * in_category() * in_the_loop() * is_404() * is_active_sidebar() * is_active_widget() * is_admin() * is_admin_bar_showing() * is_archive() * is_attachment() * is_author() * is_blog_installed() * is_category() * is_comments_popup() * is_date() * is_day() * is_dynamic_sidebar() * is_feed() * is_front_page() * is_home() * is_local_attachment() * is_main_query * is_month() * is_multi_author * is_new_day() * is_page() * is_page_template() * is_paged() * is_plugin_active() * is_plugin_active_for_network() * is_plugin_inactive() * is_plugin_page() * is_post_type_archive() * is_preview() * is_rtl() * is_search() * is_single() * is_singular() * is_sticky() * is_tag() * is_tax() * is_taxonomy_hierarchical() * is_time() * is_trackback() * is_user_logged_in() * is_year() * pings_open() * post_type_exists() * taxonomy_exists() * term_exists() * username exists() * wp_attachment_is_image() * wp_script_is() Props janalwin. Fixes #43254. Built from https://develop.svn.wordpress.org/trunk@42710 git-svn-id: http://core.svn.wordpress.org/trunk@42538 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2018-02-13 17:54:31 +01:00
* Conditional Tags} article in the Theme Developer Handbook.
*
* @since 2.9.0
* @since 4.4.0 `$post` can be a post ID or WP_Post object.
*
* @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
* @return bool Whether the post has an image attached.
*/
function has_post_thumbnail( $post = null ) {
$thumbnail_id = get_post_thumbnail_id( $post );
$has_thumbnail = (bool) $thumbnail_id;
/**
* Filters whether a post has a post thumbnail.
*
* @since 5.1.0
*
* @param bool $has_thumbnail true if the post has a post thumbnail, otherwise false.
* @param int|WP_Post|null $post Post ID or WP_Post object. Default is global `$post`.
* @param int|string $thumbnail_id Post thumbnail ID or empty string.
*/
return (bool) apply_filters( 'has_post_thumbnail', $has_thumbnail, $post, $thumbnail_id );
}
/**
* Retrieve post thumbnail ID.
*
* @since 2.9.0
* @since 4.4.0 `$post` can be a post ID or WP_Post object.
* @since 5.5.0 The return value for a non-existing post
* was changed to false instead of an empty string.
*
* @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
* @return int|false Post thumbnail ID (which can be 0 if the thumbnail is not set),
* or false if the post does not exist.
*/
function get_post_thumbnail_id( $post = null ) {
$post = get_post( $post );
if ( ! $post ) {
return false;
}
return (int) get_post_meta( $post->ID, '_thumbnail_id', true );
}
/**
* Display the post thumbnail.
*
* When a theme adds 'post-thumbnail' support, a special 'post-thumbnail' image size
* is registered, which differs from the 'thumbnail' image size managed via the
* Settings > Media screen.
*
* When using the_post_thumbnail() or related functions, the 'post-thumbnail' image
* size is used by default, though a different size can be specified instead as needed.
*
* @since 2.9.0
*
* @see get_the_post_thumbnail()
*
* @param string|array $size Optional. Image size to use. Accepts any valid image size, or
* an array of width and height values in pixels (in that order).
* Default 'post-thumbnail'.
* @param string|array $attr Optional. Query string or array of attributes. Default empty.
*/
function the_post_thumbnail( $size = 'post-thumbnail', $attr = '' ) {
echo get_the_post_thumbnail( null, $size, $attr );
}
/**
* Update cache for thumbnails in the current loop.
*
* @since 3.2.0
*
* @global WP_Query $wp_query WordPress Query object.
*
* @param WP_Query $wp_query Optional. A WP_Query instance. Defaults to the $wp_query global.
*/
function update_post_thumbnail_cache( $wp_query = null ) {
if ( ! $wp_query ) {
$wp_query = $GLOBALS['wp_query'];
}
if ( $wp_query->thumbnails_cached ) {
return;
}
$thumb_ids = array();
foreach ( $wp_query->posts as $post ) {
$id = get_post_thumbnail_id( $post->ID );
if ( $id ) {
$thumb_ids[] = $id;
}
}
if ( ! empty( $thumb_ids ) ) {
_prime_post_caches( $thumb_ids, false, true );
}
$wp_query->thumbnails_cached = true;
}
/**
* Retrieve the post thumbnail.
*
* When a theme adds 'post-thumbnail' support, a special 'post-thumbnail' image size
* is registered, which differs from the 'thumbnail' image size managed via the
* Settings > Media screen.
*
* When using the_post_thumbnail() or related functions, the 'post-thumbnail' image
* size is used by default, though a different size can be specified instead as needed.
*
* @since 2.9.0
* @since 4.4.0 `$post` can be a post ID or WP_Post object.
*
* @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
* @param string|array $size Optional. Image size to use. Accepts any valid image size, or
* an array of width and height values in pixels (in that order).
* Default 'post-thumbnail'.
* @param string|array $attr Optional. Query string or array of attributes. Default empty.
* @return string The post thumbnail image tag.
*/
function get_the_post_thumbnail( $post = null, $size = 'post-thumbnail', $attr = '' ) {
$post = get_post( $post );
if ( ! $post ) {
return '';
}
$post_thumbnail_id = get_post_thumbnail_id( $post );
/**
* Filters the post thumbnail size.
*
* @since 2.9.0
* @since 4.9.0 Added the `$post_id` parameter.
*
* @param string|array $size The post thumbnail size. Image size or array of width and height
* values (in that order). Default 'post-thumbnail'.
* @param int $post_id The post ID.
*/
$size = apply_filters( 'post_thumbnail_size', $size, $post->ID );
if ( $post_thumbnail_id ) {
/**
* Fires before fetching the post thumbnail HTML.
*
* Provides "just in time" filtering of all filters in wp_get_attachment_image().
*
* @since 2.9.0
*
* @param int $post_id The post ID.
* @param string $post_thumbnail_id The post thumbnail ID.
* @param string|array $size The post thumbnail size. Image size or array of width
* and height values (in that order). Default 'post-thumbnail'.
*/
do_action( 'begin_fetch_post_thumbnail_html', $post->ID, $post_thumbnail_id, $size );
if ( in_the_loop() ) {
update_post_thumbnail_cache();
}
$html = wp_get_attachment_image( $post_thumbnail_id, $size, false, $attr );
/**
* Fires after fetching the post thumbnail HTML.
*
* @since 2.9.0
*
* @param int $post_id The post ID.
* @param string $post_thumbnail_id The post thumbnail ID.
* @param string|array $size The post thumbnail size. Image size or array of width
* and height values (in that order). Default 'post-thumbnail'.
*/
do_action( 'end_fetch_post_thumbnail_html', $post->ID, $post_thumbnail_id, $size );
} else {
$html = '';
}
/**
* Filters the post thumbnail HTML.
*
* @since 2.9.0
*
* @param string $html The post thumbnail HTML.
* @param int $post_id The post ID.
* @param string $post_thumbnail_id The post thumbnail ID.
* @param string|array $size The post thumbnail size. Image size or array of width and height
* values (in that order). Default 'post-thumbnail'.
* @param string $attr Query string of attributes.
*/
return apply_filters( 'post_thumbnail_html', $html, $post->ID, $post_thumbnail_id, $size, $attr );
}
/**
* Return the post thumbnail URL.
*
* @since 4.4.0
*
* @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
* @param string|array $size Optional. Registered image size to retrieve the source for or a flat
* array of height and width dimensions. Default 'post-thumbnail'.
* @return string|false Post thumbnail URL or false if no URL is available.
*/
function get_the_post_thumbnail_url( $post = null, $size = 'post-thumbnail' ) {
$post_thumbnail_id = get_post_thumbnail_id( $post );
if ( ! $post_thumbnail_id ) {
return false;
}
return wp_get_attachment_image_url( $post_thumbnail_id, $size );
}
/**
* Display the post thumbnail URL.
*
* @since 4.4.0
*
* @param string|array $size Optional. Image size to use. Accepts any valid image size,
* or an array of width and height values in pixels (in that order).
* Default 'post-thumbnail'.
*/
function the_post_thumbnail_url( $size = 'post-thumbnail' ) {
$url = get_the_post_thumbnail_url( null, $size );
if ( $url ) {
echo esc_url( $url );
}
}
/**
* Returns the post thumbnail caption.
*
* @since 4.6.0
*
* @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
* @return string Post thumbnail caption.
*/
function get_the_post_thumbnail_caption( $post = null ) {
$post_thumbnail_id = get_post_thumbnail_id( $post );
if ( ! $post_thumbnail_id ) {
return '';
}
$caption = wp_get_attachment_caption( $post_thumbnail_id );
if ( ! $caption ) {
$caption = '';
}
return $caption;
}
/**
* Displays the post thumbnail caption.
*
* @since 4.6.0
*
* @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
*/
function the_post_thumbnail_caption( $post = null ) {
/**
* Filters the displayed post thumbnail caption.
*
* @since 4.6.0
*
* @param string $caption Caption for the given attachment.
*/
echo apply_filters( 'the_post_thumbnail_caption', get_the_post_thumbnail_caption( $post ) );
}