在Gallery Shortcode Callback 是一个过滤器挂钩：post_gallery
如果此过滤器返回任何非空/非null输出，则短代码将使用该输出，而不是默认生成。您可以复制Gallery Shortcode Callabck 并根据需要进行修改。
下面是一个过滤器挂钩，使用gallery回调的整个代码post_gallery 过滤器挂钩已拆除，以防止任何无限循环。
/**
* Custom Gallery Function for custom output
*
* @param string $output The gallery output. Default empty.
* @param array $attr Attributes of the gallery shortcode.
* @param int $instance Unique numeric ID of this gallery shortcode instance.
*
* @return String $output
*/
function my_custom_gallery( $output, $attr, $instance ) {
$post = get_post();
static $instance = 0;
$instance++;
if ( ! empty( $attr[\'ids\'] ) ) {
// \'ids\' is explicitly ordered, unless you specify otherwise.
if ( empty( $attr[\'orderby\'] ) ) {
$attr[\'orderby\'] = \'post__in\';
}
$attr[\'include\'] = $attr[\'ids\'];
}
$html5 = current_theme_supports( \'html5\', \'gallery\' );
$atts = shortcode_atts(
array(
\'order\' => \'ASC\',
\'orderby\' => \'menu_order ID\',
\'id\' => $post ? $post->ID : 0,
\'itemtag\' => $html5 ? \'figure\' : \'dl\',
\'icontag\' => $html5 ? \'div\' : \'dt\',
\'captiontag\' => $html5 ? \'figcaption\' : \'dd\',
\'columns\' => 3,
\'size\' => \'thumbnail\',
\'include\' => \'\',
\'exclude\' => \'\',
\'link\' => \'\',
),
$attr,
\'gallery\'
);
$id = intval( $atts[\'id\'] );
if ( ! empty( $atts[\'include\'] ) ) {
$_attachments = get_posts(
array(
\'include\' => $atts[\'include\'],
\'post_status\' => \'inherit\',
\'post_type\' => \'attachment\',
\'post_mime_type\' => \'image\',
\'order\' => $atts[\'order\'],
\'orderby\' => $atts[\'orderby\'],
)
);
$attachments = array();
foreach ( $_attachments as $key => $val ) {
$attachments[ $val->ID ] = $_attachments[ $key ];
}
} elseif ( ! empty( $atts[\'exclude\'] ) ) {
$attachments = get_children(
array(
\'post_parent\' => $id,
\'exclude\' => $atts[\'exclude\'],
\'post_status\' => \'inherit\',
\'post_type\' => \'attachment\',
\'post_mime_type\' => \'image\',
\'order\' => $atts[\'order\'],
\'orderby\' => $atts[\'orderby\'],
)
);
} else {
$attachments = get_children(
array(
\'post_parent\' => $id,
\'post_status\' => \'inherit\',
\'post_type\' => \'attachment\',
\'post_mime_type\' => \'image\',
\'order\' => $atts[\'order\'],
\'orderby\' => $atts[\'orderby\'],
)
);
}
if ( empty( $attachments ) ) {
return \'\';
}
if ( is_feed() ) {
$output = "\\n";
foreach ( $attachments as $att_id => $attachment ) {
$output .= wp_get_attachment_link( $att_id, $atts[\'size\'], true ) . "\\n";
}
return $output;
}
$itemtag = tag_escape( $atts[\'itemtag\'] );
$captiontag = tag_escape( $atts[\'captiontag\'] );
$icontag = tag_escape( $atts[\'icontag\'] );
$valid_tags = wp_kses_allowed_html( \'post\' );
if ( ! isset( $valid_tags[ $itemtag ] ) ) {
$itemtag = \'dl\';
}
if ( ! isset( $valid_tags[ $captiontag ] ) ) {
$captiontag = \'dd\';
}
if ( ! isset( $valid_tags[ $icontag ] ) ) {
$icontag = \'dt\';
}
$columns = intval( $atts[\'columns\'] );
$itemwidth = $columns > 0 ? floor( 100 / $columns ) : 100;
$float = is_rtl() ? \'right\' : \'left\';
$selector = "gallery-{$instance}";
$gallery_style = \'\';
/**
* Filters whether to print default gallery styles.
*
* @since 3.1.0
*
* @param bool $print Whether to print default gallery styles.
* Defaults to false if the theme supports HTML5 galleries.
* Otherwise, defaults to true.
*/
if ( apply_filters( \'use_default_gallery_style\', ! $html5 ) ) {
$gallery_style = "
<style type=\'text/css\'>
#{$selector} {
margin: auto;
}
#{$selector} .gallery-item {
float: {$float};
margin-top: 10px;
text-align: center;
width: {$itemwidth}%;
}
#{$selector} img {
border: 2px solid #cfcfcf;
}
#{$selector} .gallery-caption {
margin-left: 0;
}
/* see gallery_shortcode() in wp-includes/media.php */
</style>\\n\\t\\t";
}
$size_class = sanitize_html_class( $atts[\'size\'] );
$gallery_div = "<div id=\'$selector\' class=\'gallery galleryid-{$id} gallery-columns-{$columns} gallery-size-{$size_class}\'>";
/**
* Filters the default gallery shortcode CSS styles.
*
* @since 2.5.0
*
* @param string $gallery_style Default CSS styles and opening HTML div container
* for the gallery shortcode output.
*/
$output = apply_filters( \'gallery_style\', $gallery_style . $gallery_div );
$i = 0;
foreach ( $attachments as $id => $attachment ) {
$attr = ( trim( $attachment->post_excerpt ) ) ? array( \'aria-describedby\' => "$selector-$id" ) : \'\';
if ( ! empty( $atts[\'link\'] ) && \'file\' === $atts[\'link\'] ) {
$image_output = wp_get_attachment_link( $id, $atts[\'size\'], false, false, false, $attr );
} elseif ( ! empty( $atts[\'link\'] ) && \'none\' === $atts[\'link\'] ) {
$image_output = wp_get_attachment_image( $id, $atts[\'size\'], false, $attr );
} else {
$image_output = wp_get_attachment_link( $id, $atts[\'size\'], true, false, false, $attr );
}
$image_meta = wp_get_attachment_metadata( $id );
$orientation = \'\';
if ( isset( $image_meta[\'height\'], $image_meta[\'width\'] ) ) {
$orientation = ( $image_meta[\'height\'] > $image_meta[\'width\'] ) ? \'portrait\' : \'landscape\';
}
$output .= "<{$itemtag} class=\'gallery-item\'>";
$output .= "
<{$icontag} class=\'gallery-icon {$orientation}\'>
$image_output
</{$icontag}>";
if ( $captiontag && trim( $attachment->post_excerpt ) ) {
$output .= "
<{$captiontag} class=\'wp-caption-text gallery-caption\' id=\'$selector-$id\'>
" . wptexturize( $attachment->post_excerpt ) . "
</{$captiontag}>";
}
$output .= "</{$itemtag}>";
if ( ! $html5 && $columns > 0 && ++$i % $columns == 0 ) {
$output .= \'<br style="clear: both" />\';
}
}
if ( ! $html5 && $columns > 0 && $i % $columns !== 0 ) {
$output .= "
<br style=\'clear: both\' />";
}
$output .= "
</div>\\n";
return $output;
}
add_filter( \'post_gallery\', \'my_custom_gallery\', 10, 3 );
