WordPress/wp-includes/media.php

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<?php
/**
* WordPress API for media display.
*
* @package WordPress
*/
/**
* Scale down the default size of an image.
*
* This is so that the image is a better fit for the editor and theme.
*
* The $size parameter accepts either an array or a string. The supported string
* values are 'thumb' or 'thumbnail' for the given thumbnail size or defaults at
* 128 width and 96 height in pixels. Also supported for the string value is
* 'medium' and 'full'. The 'full' isn't actually supported, but any value other
* than the supported will result in the content_width size or 500 if that is
* not set.
*
* Finally, there is a filter named, 'editor_max_image_size' that will be called
* on the calculated array for width and height, respectively. The second
* parameter will be the value that was in the $size parameter. The returned
* type for the hook is an array with the width as the first element and the
* height as the second element.
*
* @since 2.5.0
* @uses wp_constrain_dimensions() This function passes the widths and the heights.
*
* @param int $width Width of the image
* @param int $height Height of the image
* @param string|array $size Size of what the result image should be.
* @return array Width and height of what the result image should resize to.
*/
function image_constrain_size_for_editor($width, $height, $size = 'medium') {
global $content_width;
if ( is_array($size) ) {
$max_width = $size[0];
$max_height = $size[1];
}
elseif ( $size == 'thumb' || $size == 'thumbnail' ) {
$max_width = intval(get_option('thumbnail_size_w'));
$max_height = intval(get_option('thumbnail_size_h'));
// last chance thumbnail size defaults
if ( !$max_width && !$max_height ) {
$max_width = 128;
$max_height = 96;
}
}
elseif ( $size == 'medium' ) {
$max_width = intval(get_option('medium_size_w'));
$max_height = intval(get_option('medium_size_h'));
// if no width is set, default to the theme content width if available
}
elseif ( $size == 'large' ) {
// we're inserting a large size image into the editor. if it's a really
// big image we'll scale it down to fit reasonably within the editor
// itself, and within the theme's content width if it's known. the user
// can resize it in the editor if they wish.
$max_width = intval(get_option('large_size_w'));
$max_height = intval(get_option('large_size_h'));
if ( intval($content_width) > 0 )
$max_width = min( intval($content_width), $max_width );
}
// $size == 'full' has no constraint
else {
$max_width = $width;
$max_height = $height;
}
list( $max_width, $max_height ) = apply_filters( 'editor_max_image_size', array( $max_width, $max_height ), $size );
return wp_constrain_dimensions( $width, $height, $max_width, $max_height );
}
/**
* Retrieve width and height attributes using given width and height values.
*
* Both attributes are required in the sense that both parameters must have a
* value, but are optional in that if you set them to false or null, then they
* will not be added to the returned string.
*
* You can set the value using a string, but it will only take numeric values.
* If you wish to put 'px' after the numbers, then it will be stripped out of
* the return.
*
* @since 2.5.0
*
* @param int|string $width Optional. Width attribute value.
* @param int|string $height Optional. Height attribute value.
* @return string HTML attributes for width and, or height.
*/
function image_hwstring($width, $height) {
$out = '';
if ($width)
$out .= 'width="'.intval($width).'" ';
if ($height)
$out .= 'height="'.intval($height).'" ';
return $out;
}
/**
* Scale an image to fit a particular size (such as 'thumb' or 'medium').
*
* Array with image url, width, height, and whether is intermediate size, in
* that order is returned on success is returned. $is_intermediate is true if
* $url is a resized image, false if it is the original.
*
* The URL might be the original image, or it might be a resized version. This
* function won't create a new resized copy, it will just return an already
* resized one if it exists.
*
* A plugin may use the 'image_downsize' filter to hook into and offer image
* resizing services for images. The hook must return an array with the same
* elements that are returned in the function. The first element being the URL
* to the new image that was resized.
*
* @since 2.5.0
* @uses apply_filters() Calls 'image_downsize' on $id and $size to provide
* resize services.
*
* @param int $id Attachment ID for image.
* @param string $size Optional, default is 'medium'. Size of image, can be 'thumbnail'.
* @return bool|array False on failure, array on success.
*/
function image_downsize($id, $size = 'medium') {
if ( !wp_attachment_is_image($id) )
return false;
$img_url = wp_get_attachment_url($id);
$meta = wp_get_attachment_metadata($id);
$width = $height = 0;
$is_intermediate = false;
// plugins can use this to provide resize services
if ( $out = apply_filters('image_downsize', false, $id, $size) )
return $out;
// try for a new style intermediate size
if ( $intermediate = image_get_intermediate_size($id, $size) ) {
$img_url = str_replace(basename($img_url), $intermediate['file'], $img_url);
$width = $intermediate['width'];
$height = $intermediate['height'];
$is_intermediate = true;
}
elseif ( $size == 'thumbnail' ) {
// fall back to the old thumbnail
if ( ($thumb_file = wp_get_attachment_thumb_file($id)) && $info = getimagesize($thumb_file) ) {
$img_url = str_replace(basename($img_url), basename($thumb_file), $img_url);
$width = $info[0];
$height = $info[1];
$is_intermediate = true;
}
}
if ( !$width && !$height && isset($meta['width'], $meta['height']) ) {
// any other type: use the real image
$width = $meta['width'];
$height = $meta['height'];
}
if ( $img_url) {
// we have the actual image size, but might need to further constrain it if content_width is narrower
list( $width, $height ) = image_constrain_size_for_editor( $width, $height, $size );
return array( $img_url, $width, $height, $is_intermediate );
}
return false;
}
/**
* An <img src /> tag for an image attachment, scaling it down if requested.
*
* The filter 'get_image_tag_class' allows for changing the class name for the
* image without having to use regular expressions on the HTML content. The
* parameters are: what WordPress will use for the class, the Attachment ID,
* image align value, and the size the image should be.
*
* The second filter 'get_image_tag' has the HTML content, which can then be
* further manipulated by a plugin to change all attribute values and even HTML
* content.
*
* @since 2.5.0
*
* @uses apply_filters() The 'get_image_tag_class' filter is the IMG element
* class attribute.
* @uses apply_filters() The 'get_image_tag' filter is the full IMG element with
* all attributes.
*
* @param int $id Attachment ID.
* @param string $alt Image Description for the alt attribute.
* @param string $title Image Description for the title attribute.
* @param string $align Part of the class name for aligning the image.
* @param string $size Optional. Default is 'medium'.
* @return string HTML IMG element for given image attachment
*/
function get_image_tag($id, $alt, $title, $align, $size='medium') {
list( $img_src, $width, $height ) = image_downsize($id, $size);
$hwstring = image_hwstring($width, $height);
$class = 'align'.attribute_escape($align).' size-'.attribute_escape($size).' wp-image-'.$id;
$class = apply_filters('get_image_tag_class', $class, $id, $align, $size);
$html = '<img src="'.attribute_escape($img_src).'" alt="'.attribute_escape($alt).'" title="'.attribute_escape($title).'" '.$hwstring.'class="'.$class.'" />';
$html = apply_filters( 'get_image_tag', $html, $id, $alt, $title, $align, $size );
return $html;
}
/**
* Calculates the new dimentions for a downsampled image.
*
* Same as {@link wp_shrink_dimensions()}, except the max parameters are
* optional. If either width or height are empty, no constraint is applied on
* that dimension.
*
* @since 2.5.0
*
* @param int $current_width Current width of the image.
* @param int $current_height Current height of the image.
* @param int $max_width Optional. Maximum wanted width.
* @param int $max_height Optional. Maximum wanted height.
* @return array First item is the width, the second item is the height.
*/
function wp_constrain_dimensions( $current_width, $current_height, $max_width=0, $max_height=0 ) {
if ( !$max_width and !$max_height )
return array( $current_width, $current_height );
$width_ratio = $height_ratio = 1.0;
if ( $max_width > 0 && $current_width > 0 && $current_width > $max_width )
$width_ratio = $max_width / $current_width;
if ( $max_height > 0 && $current_height > 0 && $current_height > $max_height )
$height_ratio = $max_height / $current_height;
// the smaller ratio is the one we need to fit it to the constraining box
$ratio = min( $width_ratio, $height_ratio );
return array( intval($current_width * $ratio), intval($current_height * $ratio) );
}
/**
* Retrieve calculated resized dimensions for use in imagecopyresampled().
*
* Calculate dimensions and coordinates for a resized image that fits within a
* specified width and height. If $crop is true, the largest matching central
* portion of the image will be cropped out and resized to the required size.
*
* @since 2.5.0
*
* @param int $orig_w Original width.
* @param int $orig_h Original height.
* @param int $dest_w New width.
* @param int $dest_h New height.
* @param bool $crop Optional, default is false. Whether to crop image or resize.
* @return bool|array False, on failure. Returned array matches parameters for imagecopyresampled() PHP function.
*/
function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop=false) {
if ($orig_w <= 0 || $orig_h <= 0)
return false;
// at least one of dest_w or dest_h must be specific
if ($dest_w <= 0 && $dest_h <= 0)
return false;
if ( $crop ) {
// crop the largest possible portion of the original image that we can size to $dest_w x $dest_h
$aspect_ratio = $orig_w / $orig_h;
$new_w = min($dest_w, $orig_w);
$new_h = min($dest_h, $orig_h);
if (!$new_w) {
$new_w = intval($new_h * $aspect_ratio);
}
if (!$new_h) {
$new_h = intval($new_w / $aspect_ratio);
}
$size_ratio = max($new_w / $orig_w, $new_h / $orig_h);
$crop_w = ceil($new_w / $size_ratio);
$crop_h = ceil($new_h / $size_ratio);
$s_x = floor(($orig_w - $crop_w)/2);
$s_y = floor(($orig_h - $crop_h)/2);
}
else {
// don't crop, just resize using $dest_w x $dest_h as a maximum bounding box
$crop_w = $orig_w;
$crop_h = $orig_h;
$s_x = 0;
$s_y = 0;
list( $new_w, $new_h ) = wp_constrain_dimensions( $orig_w, $orig_h, $dest_w, $dest_h );
}
// if the resulting image would be the same size or larger we don't want to resize it
if ($new_w >= $orig_w && $new_h >= $orig_h)
return false;
// the return array matches the parameters to imagecopyresampled()
// int dst_x, int dst_y, int src_x, int src_y, int dst_w, int dst_h, int src_w, int src_h
return array(0, 0, $s_x, $s_y, $new_w, $new_h, $crop_w, $crop_h);
}
/**
* Scale down an image to fit a particular size and save a new copy of the image.
*
* The PNG transparency will be preserved using the function, as well as the
* image type. If the file going in is PNG, then the resized image is going to
* be PNG. The only supported image types are PNG, GIF, and JPEG.
*
* Some functionality requires API to exist, so some PHP version may lose out
* support. This is not the fault of WordPress (where functionality is
* downgraded, not actual defects), but of your PHP version.
*
* @since 2.5.0
*
* @param string $file Image file path.
* @param int $max_w Maximum width to resize to.
* @param int $max_h Maximum height to resize to.
* @param bool $crop Optional. Whether to crop image or resize.
* @param string $suffix Optional. File Suffix.
* @param string $dest_path Optional. New image file path.
* @param int $jpeg_quality Optional, default is 90. Image quality percentage.
* @return mixed WP_Error on failure. String with new destination path. Array of dimensions from {@link image_resize_dimensions()}
*/
function image_resize( $file, $max_w, $max_h, $crop=false, $suffix=null, $dest_path=null, $jpeg_quality=90) {
$image = wp_load_image( $file );
if ( !is_resource( $image ) )
return new WP_Error('error_loading_image', $image);
list($orig_w, $orig_h, $orig_type) = getimagesize( $file );
$dims = image_resize_dimensions($orig_w, $orig_h, $max_w, $max_h, $crop);
if (!$dims)
return $dims;
list($dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h) = $dims;
$newimage = imagecreatetruecolor( $dst_w, $dst_h);
// preserve PNG transparency
if ( IMAGETYPE_PNG == $orig_type && function_exists( 'imagealphablending' ) && function_exists( 'imagesavealpha' ) ) {
imagealphablending( $newimage, false);
imagesavealpha( $newimage, true);
}
imagecopyresampled( $newimage, $image, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h);
// we don't need the original in memory anymore
imagedestroy( $image );
// $suffix will be appended to the destination filename, just before the extension
if ( !$suffix )
$suffix = "{$dst_w}x{$dst_h}";
$info = pathinfo($file);
$dir = $info['dirname'];
$ext = $info['extension'];
$name = basename($file, ".{$ext}");
if ( !is_null($dest_path) and $_dest_path = realpath($dest_path) )
$dir = $_dest_path;
$destfilename = "{$dir}/{$name}-{$suffix}.{$ext}";
if ( $orig_type == IMAGETYPE_GIF ) {
if (!imagegif( $newimage, $destfilename ) )
return new WP_Error('resize_path_invalid', __( 'Resize path invalid' ));
}
elseif ( $orig_type == IMAGETYPE_PNG ) {
if (!imagepng( $newimage, $destfilename ) )
return new WP_Error('resize_path_invalid', __( 'Resize path invalid' ));
}
else {
// all other formats are converted to jpg
$destfilename = "{$dir}/{$name}-{$suffix}.jpg";
if (!imagejpeg( $newimage, $destfilename, apply_filters( 'jpeg_quality', $jpeg_quality ) ) )
return new WP_Error('resize_path_invalid', __( 'Resize path invalid' ));
}
imagedestroy( $newimage );
// Set correct file permissions
$stat = stat( dirname( $destfilename ));
$perms = $stat['mode'] & 0000666; //same permissions as parent folder, strip off the executable bits
@ chmod( $destfilename, $perms );
return $destfilename;
}
/**
* Resize an image to make a thumbnail or intermediate size.
*
* The returned array has the file size, the image width, and image height. The
* filter 'image_make_intermediate_size' can be used to hook in and change the
* values of the returned array. The only parameter is the resized file path.
*
* @since 2.5.0
*
* @param string $file File path.
* @param int $width Image width.
* @param int $height Image height.
* @param bool $crop Optional, default is false. Whether to crop image to specified height and width or resize.
* @return bool|array False, if no image was created. Metadata array on success.
*/
function image_make_intermediate_size($file, $width, $height, $crop=false) {
if ( $width || $height ) {
$resized_file = image_resize($file, $width, $height, $crop);
if ( !is_wp_error($resized_file) && $resized_file && $info = getimagesize($resized_file) ) {
$resized_file = apply_filters('image_make_intermediate_size', $resized_file);
return array(
'file' => basename( $resized_file ),
'width' => $info[0],
'height' => $info[1],
);
}
}
return false;
}
/**
* Retrieve the image's intermediate size (resized) path, width, and height.
*
* The $size parameter can be an array with the width and height respectively.
* If the size matches the 'sizes' metadata array for width and height, then it
* will be used. If there is no direct match, then the nearest image size larger
* than the specified size will be used. If nothing is found, then the function
* will break out and return false.
*
* The metadata 'sizes' is used for compatible sizes that can be used for the
* parameter $size value.
*
* The url path will be given, when the $size parameter is a string.
*
* @since 2.5.0
*
* @param int $post_id Attachment ID for image.
* @param array|string $size Optional, default is 'thumbnail'. Size of image, either array or string.
* @return bool|array False on failure or array of file path, width, and height on success.
*/
function image_get_intermediate_size($post_id, $size='thumbnail') {
if ( !is_array( $imagedata = wp_get_attachment_metadata( $post_id ) ) )
return false;
// get the best one for a specified set of dimensions
if ( is_array($size) && !empty($imagedata['sizes']) ) {
foreach ( $imagedata['sizes'] as $_size => $data ) {
// already cropped to width or height; so use this size
if ( ( $data['width'] == $size[0] && $data['height'] <= $size[1] ) || ( $data['height'] == $size[1] && $data['width'] <= $size[0] ) ) {
$file = $data['file'];
list($width, $height) = image_constrain_size_for_editor( $data['width'], $data['height'], $size );
return compact( 'file', 'width', 'height' );
}
// add to lookup table: area => size
$areas[$data['width'] * $data['height']] = $_size;
}
if ( !$size || !empty($areas) ) {
// find for the smallest image not smaller than the desired size
ksort($areas);
foreach ( $areas as $_size ) {
$data = $imagedata['sizes'][$_size];
if ( $data['width'] >= $size[0] || $data['height'] >= $size[1] ) {
$file = $data['file'];
list($width, $height) = image_constrain_size_for_editor( $data['width'], $data['height'], $size );
return compact( 'file', 'width', 'height' );
}
}
}
}
if ( is_array($size) || empty($size) || empty($imagedata['sizes'][$size]) )
return false;
$data = $imagedata['sizes'][$size];
// include the full filesystem path of the intermediate file
if ( empty($data['path']) && !empty($data['file']) ) {
$file_url = wp_get_attachment_url($post_id);
$data['path'] = path_join( dirname($imagedata['file']), $data['file'] );
$data['url'] = path_join( dirname($file_url), $data['file'] );
}
return $data;
}
/**
* Retrieve an image to represent an attachment.
*
* A mime icon for files, thumbnail or intermediate size for images.
*
* @since 2.5.0
*
* @param int $attachment_id Image attachment ID.
* @param string $size Optional, default is 'thumbnail'.
* @param bool $icon Optional, default is false. Whether it is an icon.
* @return bool|array Returns an array (url, width, height), or false, if no image is available.
*/
function wp_get_attachment_image_src($attachment_id, $size='thumbnail', $icon = false) {
// get a thumbnail or intermediate image if there is one
if ( $image = image_downsize($attachment_id, $size) )
return $image;
if ( $icon && $src = wp_mime_type_icon($attachment_id) ) {
$icon_dir = apply_filters( 'icon_dir', ABSPATH . WPINC . '/images/crystal' );
$src_file = $icon_dir . '/' . basename($src);
@list($width, $height) = getimagesize($src_file);
}
if ( $src && $width && $height )
return array( $src, $width, $height );
return false;
}
/**
* Retrieve img HTML content for an image to represent an attachment.
*
* @see wp_get_attachment_image_src() Returns img HTML element based on array.
* @since 2.5.0
*
* @param int $attachment_id Image attachment ID.
* @param string $size Optional, default is 'thumbnail'.
* @param bool $icon Optional, default is false. Whether it is an icon.
* @return string HTML img element or empty string on failure.
*/
function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = false) {
$html = '';
$image = wp_get_attachment_image_src($attachment_id, $size, $icon);
if ( $image ) {
list($src, $width, $height) = $image;
$hwstring = image_hwstring($width, $height);
if ( is_array($size) )
$size = join('x', $size);
$html = '<img src="'.attribute_escape($src).'" '.$hwstring.'class="attachment-'.attribute_escape($size).'" alt="" />';
}
return $html;
}
add_shortcode('wp_caption', 'img_caption_shortcode');
add_shortcode('caption', 'img_caption_shortcode');
/**
* The Caption shortcode.
*
* Allows a plugin to replace the content that would otherwise be returned. The
* filter is 'img_caption_shortcode' and passes an empty string, the attr
* parameter and the content parameter values.
*
* The supported attributes for the shortcode are 'id', 'align', 'width', and
* 'caption'.
*
* @since 2.6.0
*
* @param array $attr Attributes attributed to the shortcode.
* @param string $content Optional. Shortcode content.
* @return string
*/
function img_caption_shortcode($attr, $content = null) {
// Allow plugins/themes to override the default caption template.
$output = apply_filters('img_caption_shortcode', '', $attr, $content);
if ( $output != '' )
return $output;
extract(shortcode_atts(array(
'id' => '',
'align' => 'alignnone',
'width' => '',
'caption' => ''
), $attr));
if ( 1 > (int) $width || empty($caption) )
return $content;
if ( $id ) $id = 'id="' . $id . '" ';
return '<div ' . $id . 'class="wp-caption ' . $align . '" style="width: ' . (10 + (int) $width) . 'px">'
. do_shortcode( $content ) . '<p class="wp-caption-text">' . $caption . '</p></div>';
}
add_shortcode('gallery', 'gallery_shortcode');
/**
* The Gallery shortcode.
*
* This implements the functionality of the Gallery Shortcode for displaying
* WordPress images on a post.
*
* @since 2.5.0
*
* @param array $attr Attributes attributed to the shortcode.
* @return string HTML content to display gallery.
*/
function gallery_shortcode($attr) {
global $post;
// Allow plugins/themes to override the default gallery template.
$output = apply_filters('post_gallery', '', $attr);
if ( $output != '' )
return $output;
// We're trusting author input, so let's at least make sure it looks like a valid orderby statement
if ( isset( $attr['orderby'] ) ) {
$attr['orderby'] = sanitize_sql_orderby( $attr['orderby'] );
if ( !$attr['orderby'] )
unset( $attr['orderby'] );
}
extract(shortcode_atts(array(
'order' => 'ASC',
'orderby' => 'menu_order ID',
'id' => $post->ID,
'itemtag' => 'dl',
'icontag' => 'dt',
'captiontag' => 'dd',
'columns' => 3,
'size' => 'thumbnail'
), $attr));
$id = intval($id);
$attachments = get_children( array('post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby) );
if ( empty($attachments) )
return '';
if ( is_feed() ) {
$output = "\n";
foreach ( $attachments as $id => $attachment )
$output .= wp_get_attachment_link($id, $size, true) . "\n";
return $output;
}
$itemtag = tag_escape($itemtag);
$captiontag = tag_escape($captiontag);
$columns = intval($columns);
$itemwidth = $columns > 0 ? floor(100/$columns) : 100;
$output = apply_filters('gallery_style', "
<style type='text/css'>
.gallery {
margin: auto;
}
.gallery-item {
float: left;
margin-top: 10px;
text-align: center;
width: {$itemwidth}%; }
.gallery img {
border: 2px solid #cfcfcf;
}
.gallery-caption {
margin-left: 0;
}
</style>
<!-- see gallery_shortcode() in wp-includes/media.php -->
<div class='gallery'>");
$i = 0;
foreach ( $attachments as $id => $attachment ) {
$link = isset($attr['link']) && 'file' == $attr['link'] ? wp_get_attachment_link($id, $size, false, false) : wp_get_attachment_link($id, $size, true, false);
$output .= "<{$itemtag} class='gallery-item'>";
$output .= "
<{$icontag} class='gallery-icon'>
$link
</{$icontag}>";
if ( $captiontag && trim($attachment->post_excerpt) ) {
$output .= "
<{$captiontag} class='gallery-caption'>
{$attachment->post_excerpt}
</{$captiontag}>";
}
$output .= "</{$itemtag}>";
if ( $columns > 0 && ++$i % $columns == 0 )
$output .= '<br style="clear: both" />';
}
$output .= "
<br style='clear: both;' />
</div>\n";
return $output;
}
/**
* Display previous image link that has the same post parent.
*
* @since 2.5.0
* @param string $size Optional, default is 'thumbnail'. Size of image, either array or string. 0 or 'none' will default to post_title or $text;
* @param string $text Optional, default is false. If included, link will reflect $text variable.
* @return string HTML content.
*/
function previous_image_link($size = 'thumbnail', $text = false) {
adjacent_image_link(true, $size, $text);
}
/**
* Display next image link that has the same post parent.
*
* @since 2.5.0
* @param string $size Optional, default is 'thumbnail'. Size of image, either array or string. 0 or 'none' will default to post_title or $text;
* @param string $text Optional, default is false. If included, link will reflect $text variable.
* @return string HTML content.
*/
function next_image_link($size = 'thumbnail', $text = false) {
adjacent_image_link(false, $size, $text);
}
/**
* Display next or previous image link that has the same post parent.
*
* Retrieves the current attachment object from the $post global.
*
* @since 2.5.0
*
* @param bool $prev Optional. Default is true to display previous link, true for next.
*/
function adjacent_image_link($prev = true, $size = 'thumbnail', $text = false) {
global $post;
$post = get_post($post);
$attachments = array_values(get_children( array('post_parent' => $post->post_parent, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => 'ASC', 'orderby' => 'menu_order ID') ));
foreach ( $attachments as $k => $attachment )
if ( $attachment->ID == $post->ID )
break;
$k = $prev ? $k - 1 : $k + 1;
if ( isset($attachments[$k]) )
echo wp_get_attachment_link($attachments[$k]->ID, $size, true, false, $text);
}
/**
* Retrieve taxonomies attached to the attachment.
*
* @since 2.5.0
*
* @param int|array|object $attachment Attachment ID, Attachment data array, or Attachment data object.
* @return array Empty array on failure. List of taxonomies on success.
*/
function get_attachment_taxonomies($attachment) {
if ( is_int( $attachment ) )
$attachment = get_post($attachment);
else if ( is_array($attachment) )
$attachment = (object) $attachment;
if ( ! is_object($attachment) )
return array();
$filename = basename($attachment->guid);
$objects = array('attachment');
if ( false !== strpos($filename, '.') )
$objects[] = 'attachment:' . substr($filename, strrpos($filename, '.') + 1);
if ( !empty($attachment->post_mime_type) ) {
$objects[] = 'attachment:' . $attachment->post_mime_type;
if ( false !== strpos($attachment->post_mime_type, '/') )
foreach ( explode('/', $attachment->post_mime_type) as $token )
if ( !empty($token) )
$objects[] = "attachment:$token";
}
$taxonomies = array();
foreach ( $objects as $object )
if ( $taxes = get_object_taxonomies($object) )
$taxonomies = array_merge($taxonomies, $taxes);
return array_unique($taxonomies);
}
?>