The slides from my talk at WordCamp Torornto 30 Sept 2012

1. Daughter Themes
(aka: Child-Themes)
And why you need to know about them

2. Why
And
Ho

3. No theme will fit all sites

4. You can’t apply an update to a
theme without losing your
changes

5. Creating whole themes is hard

6. Daughter themes are easy

7. You can use framework themes
to save effort

8. You can brand a theme for your client

9. The code needed
/*
Theme Name: You Company Theme.
Theme URI: http://bearne.ca
Author: Paul Bearne
Template: twentyeleven
Author URI: http://bearne.ca/
Description: This is the special theme I created just for your company’s
website.
Version: 1.0
License: GNU General Public License
License URI: license.txt
Tags: dark, light, white, black, gray, one-column, two-columns, left-sidebar,
right-sidebar, fixed-width, flexible-width, custom-background, custom-colors,
custom-header, custom-menu, editor-style, featured-image-header, featured-
images, full-width-template, microformats, post-formats, rtl-language-support,
sticky-post, theme-options, translation-ready
*/
@import url('../twentyeleven/style.css');

10. How to install it
 Save as style.css
 In a new folder called "theme-name" ... for example:
" YourCompanyTheme"
 Create a zip of the folder - newTheme.zip (this zip
needs a subfolder with the style.css in it )
 Upload it

11. Or FTP it
 Upload it to the Themes folder in a new folder
which follows to show the theme folder as:
YourCompanyTheme

13. Add a thumbnail
 Upload an image screenshot.png

15. Replacing template files
 Copy just the files from parent theme that you
need to change to you daughter folder and edit
them.
 WordPress looks in the daughter folder first and
loads the file if found

16. functions.php
 WordPress will load BOTH function.php files
child function.php then the parent function.php
 So you only need to add the extra/replacement
functions
 Example:
<?php
add_action( 'after_setup_theme', 'CompanyNameTheme_setup' );
if ( ! function_exists( 'CompanyNameTheme_setup' ) ):
/**
* Sets up theme defaults and registers support for various WordPress features.
*/
function CompanyNameTheme_setup() {
// The default header text color
define( 'HEADER_TEXTCOLOR', 'fff' );
// By leaving empty, we allow for random image rotation.
define( 'HEADER_IMAGE', '' );
}
endif; // CompanyNameTheme setup

17. Page Templates
 Custom layout for pages
 Good for Coming soon
 Landing pages
 Galleries etc.
<?php
/*
Template Name: Homepage
*/
?>

18. Template Hierarchy
If your blog is at http://example.com/blog/ and a visitor clicks on a
link to a category page like
http://example.com/blog/category/your-cat/
WordPress looks for a template file in the current Theme's
directory that matches the category's ID.
 If the category's ID is 4, WordPress looks for a template file
named category-4.php.
 If it is missing, WordPress next looks for a generic category
template file, category.php.
 If this file does not exist either, WordPress looks for a generic
archive template, archive.php.
 If it is missing as well, WordPress falls back on the main Theme
template file, index.php.
http://codex.wordpress.org/Template_Hierarchy

20. Notes
 You can’t have a child of a child (1 layer only)
 There is a very small performance hit

21. Some links
 http://codex.wordpress.org/Child_Themes
 http://themeshaper.com/modify-wordpress-
themes/
 http://wpfirstaid.com/2011/04/wordpress-child-
themes/
 http://themeshaper.com/modify-wordpress-
themes/
 @pbearne