Modern WordPress Themeing

*Actually, there is no Lisa. That's a picture of Amancay Maahs from flickr I found by searching for photos of photographers under the creative commons license. She's a fake friend. UX designers have lots of these fake friends. We call them "personas". Sometimes, when nobody is looking, we sit them up around a table and serve them fake tea while crying silently because we have no real friends. Well, no we don't. But thank you for reading this footnote! Remind me to give you a cookie.

Making a child theme is very simple. Create a directory, put a properly formatted style.css file in it, and you have a child theme! ...child themes are the recommended way of making modifications to a theme. WordPress Codex: Child Themes

Formatting the child theme's style.css

/*
Theme Name:     Name of Child Theme
Theme URI:      http://example.com/
Description:    Child theme for foobar theme 
Author:         Your name here
Author URI:     http://example.com/about/
Template:       twentyten
Version:        0.1.0
*/

Import Your Parent Theme's Styles

@import url("../parent-theme/style.css");

A Post Format is a piece of meta information that can be used by a theme to customize its presentation of a post. ...(A) blogger can change how each post looks by choosing a Post Format from a radio-button list. WordPress Codex: Post Formats

Enabling Post Formats

add_theme_support('post-formats', array('aside', 'chat', 'gallery', 'image', 'link', 'quote', 'status', 'video', 'audio'));

add_action( 'init', 'namespace_create_post_type' );
function namespace_create_post_type() {
	register_post_type( 'acme_product',
		array(
			'labels' => array(
				'name' => __( 'Products' ),
				'singular_name' => __( 'Product' )
			),
		    'description' => 'A short description of this post type.',
			'public' => true,
			'has_archive' => true,
			'rewrite' => array(
            	'slug' => 'products',
                'with_front' => false // if your permalink structure is /blog/, then your links will be: false->/news/, true->/blog/news/) - defaults to true
			),
            'hierarchical' => false, // set to true to "nest" like pages
			'menu_position' => null, // where on the menu it should appear; 5 = below posts, 10 = below media, etc
            'supports' => array('title','editor','author','thumbnail','excerpt','comments')
		)
	);
}

In WordPress, a "taxonomy" is a grouping mechanism for some posts (or links or custom post types). WordPress Codex: Taxonomies

//hook into the init action and call create_book_taxonomies when it fires
add_action( 'init', 'create_book_taxonomies', 0 );

//create two taxonomies, genres and writers for the post type "book"
function create_book_taxonomies() 
{
  // Add new taxonomy
  $labels = array(
    'name' => _x( 'Writers', 'taxonomy general name' ),
    'singular_name' => _x( 'Writer', 'taxonomy singular name' ),
    'search_items' =>  __( 'Search Writers' ),
    'popular_items' => __( 'Popular Writers' ),
    'all_items' => __( 'All Writers' ),
    'parent_item' => null, //null for non-hierarchical, defaults to "Parent Category" otherwise
    'parent_item_colon' => null, // same as above, but with a colon! Like "Parent Category:"
    'edit_item' => __( 'Edit Writer' ), 
    'update_item' => __( 'Update Writer' ),
    'add_new_item' => __( 'Add New Writer' ),
    'new_item_name' => __( 'New Writer Name' ),
    'separate_items_with_commas' => __( 'Separate writers with commas' ),
    'add_or_remove_items' => __( 'Add or remove writers' ),
    'choose_from_most_used' => __( 'Choose from the most used writers' ),
    'menu_name' => __( 'Writers' )
  ); 

  register_taxonomy('writer','book',array( // 'book' here is the name of your custom post type you want to associate this with
    'hierarchical' => false, // creates tag-like taxonomy. Set to true for category-like taxonomy
    'labels' => $labels,
    'show_ui' => true,
    'update_count_callback' => '_update_post_term_count', //only necessary for non-hierarchicals
    'query_var' => true,
    'rewrite' => array( 'slug' => 'writer' ) //this is used in the archive and page URLs!
  ));
  
  //repeat the above for genres, only use hierarchical options
}

• You create a new kind of archive for every custom post type and taxonomy you generate.
• Custom post type pages can be targeted with single-postype.php, and archived with archive-posttype.php.
• Otherwise custom post types will use single.php and archive.php just like blog posts.
• Taxonomy archives will also use archive.php by default.
• But you can get more granular with them, too: taxonomy.php < taxonomy-taxonomy.php < taxonomy-taxonomy-term.php

Listing your Taxonomy Terms

<?php get_the_term_list( $id, $taxonomy, $before, $sep, $after ); ?>

Activating Post Thumbnails in Older WordPress Themes

add_theme_support( 'post-thumbnails' );

set_post_thumbnail_size( 200, 200 ); //add a default size

Adding Post Thumbnails to WordPress Templates

<?php the_post_thumbnail(); ?>

Defining Thumbnail Dimensions

add_image_size( 'koi_art_full', 500, 9000, false );

<?php the_post_thumbnail('medium'); ?>

 <?php if ( has_post_thumbnail()) : ?>
   <a href="<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>" >
   <?php the_post_thumbnail(); ?>
 </a>
   
 <?php endif; ?> 

add_filter( 'post_thumbnail_html', 'my_post_image_html', 10, 3 );

function my_post_image_html( $html, $post_id, $post_image_id ) {

  $html = '<a href="' . get_permalink( $post_id ) . '" title="' . esc_attr( get_post_field( 'post_title', $post_id ) ) . '">' . $html . '</a>';
  return $html;

}

Adding a class to Post Thumbnails

<?php the_post_thumbnail('thumbnail', array('class' => 'gallery-tn')); ?>

if (function_exists('register_sidebar')) {
  register_sidebar(array(
    'name' => 'Widgetized Area', //the name of this area, as used in the WP admin
    'id'   => 'widgetized-area', //a unique identifier for your widgetized area
    'description'   => 'This is a widgetized area.',
    'before_widget' => '<div id="%1$s" class="widget %2$s">',
    'after_widget'  => '</div>',
    'before_title'  => '<h4>', //note, titles sit outside of widgets
    'after_title'   => '</h4>'
  ));
}

        
<?php if (function_exists('dynamic_sidebar') && dynamic_sidebar('widgetized-area')) : else : ?>

	<h4>Widgetized Area</h4>
	<div class="widget">
		<p>This panel is active and ready for you to add some widgets via the WP Admin</p>
	</div>

<?php endif; ?>

Reminding admins to edit things

<?php if (current_user_can('edit_theme_options') ) : ?>

if ( function_exists( 'register_nav_menu' ) ) {
	register_nav_menu( 'koi-art_menu', 'Arty Menu' );
}

<?php wp_nav_menu( array( 'theme_location' => 'koi-art_menu' ) ); ?>

function myfeed_request($qv) {
	if (isset($qv['feed']))
		$qv['post_type'] = get_post_types();
	return $qv;
}
add_filter('request', 'myfeed_request');

http://www.yoursite.com/feed/?post_type=book

http://www.yoursite.com/feed/?post_type=book&genre=romance

Adding a sidebar to your theme templates

<?php get_sidebar( 'primary' ); ?>

A WordPress Plugin is a program, or a set of one or more functions, written in the PHP scripting language, that adds a specific set of features or services to the WordPress weblog WordPress Codex: Writing a Plugin

Initiating a plugin

<?php
/*
Plugin Name: Name Of The Plugin
Plugin URI: http://URI_Of_Page_Describing_Plugin_and_Updates
Description: A brief description of the Plugin.
Version: The Plugin's Version Number, e.g.: 1.0
Author: Name Of The Plugin Author
Author URI: http://URI_Of_The_Plugin_Author
License: A "Slug" license name e.g. GPL2
*/
?>

Here's the ridiculously easy part. Grab all the functions from your functions.php that you want to put in your plugin, and put them in your new plugin file. Seriously. That's it.

Congratulations. You are now a plugin author. Have some chocolate or a beer or something, and pat yourself on the back.