/**
* WordPress Post Thumbnail Template Functions.
*
- * Support for post thumbnails
- * Themes function.php must call add_theme_support( 'post-thumbnails' ) to use these.
+ * Support for post thumbnails.
+ * Theme's functions.php must call add_theme_support( 'post-thumbnails' ) to use these.
*
* @package WordPress
* @subpackage Template
/**
* Check if post has an image attached.
- *
+ *
* @since 2.9.0
*
* @param int $post_id Optional. Post ID.
- * @return bool Whether post has an image attached (true) or not (false).
+ * @return bool Whether post has an image attached.
*/
-function has_post_thumbnail( $post_id = NULL ) {
- global $id;
- $post_id = ( NULL === $post_id ) ? $id : $post_id;
- return !! get_post_thumbnail_id( $post_id );
+function has_post_thumbnail( $post_id = null ) {
+ return (bool) get_post_thumbnail_id( $post_id );
}
/**
* Retrieve Post Thumbnail ID.
- *
+ *
* @since 2.9.0
*
- * @param int $post_id Optional. Post ID.
- * @return int
+ * @param int|null $post_id Optional. Post ID.
+ * @return mixed
*/
-function get_post_thumbnail_id( $post_id = NULL ) {
- global $id;
- $post_id = ( NULL === $post_id ) ? $id : $post_id;
+function get_post_thumbnail_id( $post_id = null ) {
+ $post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
return get_post_meta( $post_id, '_thumbnail_id', true );
}
/**
- * Display Post Thumbnail.
- *
+ * 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
*
- * @param int $size Optional. Image size. Defaults to 'post-thumbnail', which theme sets using set_post_thumbnail_size( $width, $height, $crop_flag );.
- * @param string|array $attr Optional. Query string or array of attributes.
+ * @see get_the_post_thumbnail()
+ *
+ * @param string|array $size Optional. Registered image size to use, or flat array of height
+ * and width values. 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 );
+ echo get_the_post_thumbnail( null, $size, $attr );
}
/**
- * Retrieve Post Thumbnail.
- *
+ * Update cache for thumbnails in the current loop
+ *
+ * @since 3.2.0
+ *
+ * @global WP_Query $wp_query
+ *
+ * @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 ) {
+ if ( $id = get_post_thumbnail_id( $post->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
*
- * @param int $post_id Optional. Post ID.
- * @param string $size Optional. Image size. Defaults to 'thumbnail'.
- * @param string|array $attr Optional. Query string or array of attributes.
- */
-function get_the_post_thumbnail( $post_id = NULL, $size = 'post-thumbnail', $attr = '' ) {
- global $id;
- $post_id = ( NULL === $post_id ) ? $id : $post_id;
+ * @param int $post_id Post ID. Default is the ID of the `$post` global.
+ * @param string|array $size Optional. Registered image size to use, or flat array of height
+ * and width values. Default 'post-thumbnail'.
+ * @param string|array $attr Optional. Query string or array of attributes. Default empty.
+ * @return string
+ */
+function get_the_post_thumbnail( $post_id = null, $size = 'post-thumbnail', $attr = '' ) {
+ $post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
$post_thumbnail_id = get_post_thumbnail_id( $post_id );
+
+ /**
+ * Filter the post thumbnail size.
+ *
+ * @since 2.9.0
+ *
+ * @param string $size The post thumbnail size.
+ */
$size = apply_filters( 'post_thumbnail_size', $size );
+
if ( $post_thumbnail_id ) {
- do_action( 'begin_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size ); // for "Just In Time" filtering of all of wp_get_attachment_image()'s filters
+
+ /**
+ * 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 string $post_id The post ID.
+ * @param string $post_thumbnail_id The post thumbnail ID.
+ * @param string $size The post thumbnail size.
+ */
+ 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 string $post_id The post ID.
+ * @param string $post_thumbnail_id The post thumbnail ID.
+ * @param string $size The post thumbnail size.
+ */
do_action( 'end_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size );
+
} else {
$html = '';
}
+ /**
+ * Filter the post thumbnail HTML.
+ *
+ * @since 2.9.0
+ *
+ * @param string $html The post thumbnail HTML.
+ * @param string $post_id The post ID.
+ * @param string $post_thumbnail_id The post thumbnail ID.
+ * @param string $size The post thumbnail size.
+ * @param string $attr Query string of attributes.
+ */
return apply_filters( 'post_thumbnail_html', $html, $post_id, $post_thumbnail_id, $size, $attr );
}
-
-?>
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