<?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 );

}

?>