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

76 lines
2.2 KiB
PHP

<?php
/**
* WordPress Post Thumbnail Template Functions.
*
* Support for post thumbnails
* Themes function.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).
*/
function has_post_thumbnail( $post_id = NULL ) {
global $id;
$post_id = ( NULL === $post_id ) ? $id : $post_id;
return !! get_post_thumbnail_id( $post_id );
}
/**
* Retrieve Post Thumbnail ID.
*
* @since 2.9.0
*
* @param int $post_id Optional. Post ID.
* @return int
*/
function get_post_thumbnail_id( $post_id = NULL ) {
global $id;
$post_id = ( NULL === $post_id ) ? $id : $post_id;
return get_post_meta( $post_id, '_thumbnail_id', true );
}
/**
* Display Post Thumbnail.
*
* @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.
*/
function the_post_thumbnail( $size = 'post-thumbnail', $attr = '' ) {
echo get_the_post_thumbnail( NULL, $size, $attr );
}
/**
* Retrieve Post Thumbnail.
*
* @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;
$post_thumbnail_id = get_post_thumbnail_id( $post_id );
$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
$html = wp_get_attachment_image( $post_thumbnail_id, $size, false, $attr );
do_action( 'end_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size );
} else {
$html = '';
}
return apply_filters( 'post_thumbnail_html', $html, $post_id, $post_thumbnail_id, $size, $attr );
}
?>