Gallery Replaccment

wpse-gallery-replacement.php

<?php
/*
Plugin Name: WPSE-45326 Gallery Replacement example
Plugin URI: http://wordpress.stackexchange.com/questions/45326
Description: A plugin to demonstrate how to replace the default 'gallery' shortcode and add additional HTML tags for more customization.
Version: 1.0
Author: Tom Auger
Author URI: http://www.tomauger.com
License: GPL2
*/

class wpse_45326_Gallery_Replacement {
    function __construct(){
        // Hook on the plugins-loaded action since it's the first real action hook that's available to us.
        // However, if you're using a theme and want to replace that theme's `gallery` custom shortcode,
        // you may need to use another action. Search through your parent theme's files for 'gallery' and see
        // what hook it's using to define it's gallery shortcode, so you can make sure this code runs AFTER their code.
        add_action( "init", array( __CLASS__, "init" ) );
    }

    function init(){
        remove_shortcode( 'gallery' ); // Remove the default gallery shortcode implementation
        add_shortcode( 'gallery', array( __CLASS__, "gallery_shortcode" ) ); // And replace it with our own!
    }

    /**
    * The Gallery shortcode.
    *
    * This has been taken verbatim from wp-includes/media.php. There's a lot of good stuff in there.
    * All you want to do is add some more HTML to it, and since (for some reason) they didn't provide more
    * filters to be able to add, we have to replace the Gallery shortcode wholesale.
    *
    * @param array $attr Attributes of the shortcode.
    * @return string HTML content to display gallery.
    */
    function gallery_shortcode($attr) {
        global $post;

        static $instance = 0;
        $instance++;

        $output = apply_filters('post_gallery', '', $attr);
        if ( $output != '' )
            return $output;

        if ( isset( $attr['orderby'] ) ) {
            $attr['orderby'] = sanitize_sql_orderby( $attr['orderby'] );
            if ( !$attr['orderby'] )
                unset( $attr['orderby'] );
        }

        // NOTE: These are all the 'options' you can pass in through the shortcode definition, eg: [gallery itemtag='p']
        extract(shortcode_atts(array(
            'order'      => 'DESC',
            'orderby'    => 'menu_order ID',
            'id'         => $post->ID,
            'itemtag'    => 'dl',
            'icontag'    => 'dt',
            'captiontag' => 'dd',
            'columns'    => 3,
            'size'       => 'thumbnail',
            'include'    => '',
            'exclude'    => '',
            // Here's the new options stuff we added to the shortcode defaults
            'titletag'  => 'p',
            'descriptiontag' => 'p'
        ), $attr));

        $id = intval($id);
        if ( 'RAND' == $order )
            $orderby = 'none';

        if ( !empty($include) ) {
            $include = preg_replace( '/[^0-9,]+/', '', $include );
            $_attachments = get_posts( array(   'include'       => $include, 
                                                'post_status'   => 'inherit', 
                                                'post_type'     => 'attachment', 
                                                'post_mime_type'=> 'image', 
                                                'order'         => $order, 
                                                'orderby'       => $orderby) );

            $attachments = array();
            foreach ( $_attachments as $key => $val ) {
                $attachments[$val->ID] = $_attachments[$key];
            }
        } elseif ( !empty($exclude) ) {
            $exclude = preg_replace( '/[^0-9,]+/', '', $exclude );
            $attachments = get_children( array('post_parent' => $id, 'exclude' => $exclude, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby) );
        } else {
            $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 $att_id => $attachment )
                $output .= wp_get_attachment_link($att_id, $size, true) . "\n";
            return $output;
        }

        $itemtag    = tag_escape($itemtag);
        $captiontag = tag_escape($captiontag);
        $columns    = intval($columns);
        $itemwidth  = $columns > 0 ? floor(100/$columns) : 100;
        $float      = is_rtl() ? 'right' : 'left';

        $selector = "gallery-{$instance}";

        $gallery_style = $gallery_div = '';
        if ( apply_filters( 'use_default_gallery_style', true ) )
            $gallery_style = "
            <style type='text/css'>
                #{$selector} {
                    margin: auto;
                }
                #{$selector} .gallery-item {
                    float: {$float};
                    margin-top: 10px;
                    text-align: center;
                    width: {$itemwidth}%;
                }
                #{$selector} .gallery-item-title {
                    margin: 0;
                }
                #{$selector} .gallery-item-description {
                    margin: 0;
                }
                #{$selector} img {
                    border: 0;
                }
                #{$selector} .gallery-caption {
                    margin-left: 0;
                }
            </style>
            <!-- see gallery_shortcode() in wp-includes/media.php -->";
        $size_class = sanitize_html_class( $size );
        $gallery_div = "<div id='$selector' class='gallery galleryid-{$id} gallery-columns-{$columns} gallery-size-{$size_class}'>";
        $output = apply_filters( 'gallery_style', $gallery_style . "\n\t\t" . $gallery_div );

        $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}>";

            // MODIFICATION: include the title and description HTML if we've supplied the relevant shortcode parameters (titletag, descriptiontag)
            if ( $captiontag ) {
                $output .= "
                    <{$captiontag} class='wp-caption-text gallery-caption'>";
                
                // The CAPTION, if there is one
                //if ( trim( $attachment->post_excerpt ) ) {
                //    $output .= "
                //       " . wptexturize($attachment->post_excerpt);
                //}

                // The TITLE, if we've not made the 'titletag' param blank
                if ( $titletag ){
                    $output .= "
                        <{$titletag} class=\"gallery-item-title\">" . $attachment->post_title . "</{$titletag}>";
                }

                // The DESCRIPTION, if we've not specified a blank 'descriptiontag'
                if ( $descriptiontag ){
                    $output .= "
                        <{$descriptiontag} class=\"gallery-item-description\">" . wptexturize( $attachment->post_content ) . "</{$descriptiontag}>";
                }

                $option .= "
                    </{$captiontag}>";
            }
            $output .= "</{$itemtag}>";
            if ( $columns > 0 && ++$i % $columns == 0 )
                $output .= '<br style="clear: both" />';
        }

        $output .= "
                <br style='clear: both;' />
            </div>\n";

        return $output;
    }
}

new wpse_45326_Gallery_Replacement();