Table of contents

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Coding a theme

PrestaShop's theme system is based on a template engine, called Smarty, which allows web-designers and developers to easily build their own theme, with little technical knowledge.

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Concepts and technical information

What makes a PrestaShop theme

Thanks to PrestaShop's theming system, shop owners can easily customize their online shop.

The whole system is built upon the Smarty template engine, which enables HTML integrators to easily work their theme, witout any (or few) technical constraints.

The default PrestaShop theme is neutral, in gray tones, so as to enable shop owners to get started quickly whatever their business area.

More than 500 other themes have been created, and are available for free or for sale on PrestaShop Addons. They were either made by the PrestaShop team, or by members of the PrestaShop community.

As a developer/HTML integrator, you too can sell your themes on PrestaShop Addons, and earn 70% of your sales.

How a theme works

A PrestaShop theme is a set of files which you can edit in order to change the look of your online shop.

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• All themes have their files located in the /themes root folder.
• Each theme has its own sub-folder, in the main themes folder.
• Each theme is made of template files (/.tpl), image files (.gif, .jpg, .png), one or more CSS files (/.css), and sometimes even JavaScript files (.js).
• Each theme has a preview.jpg image file in its folder, enabling the shop-owner to see what the theme looks like directly from the back-office, and select the theme appropriately.

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All of your theme's text string should be enclosed in a Smarty function, like so:

{l s='My Text'}

This will enable anyone to translate the theme into his own language, using the internal translation tool, which you can find in the PrestaShop back-office, under the "Tools" tab and its "Translation" sub-tab. In the "Modify translations" section, use the drop-down menu, choose "Back Front Office translation", then click on the flag of the language you wish to translate strings into. All the backfront-office strings will then be displayed, and the strings for your theme are those whose sections are not prefixed with "Admin*".

h3 Transmitting data to a PrestaShop theme

The following graphic explains how data is transmitted from PrestaShop's core to its theme. Using the l() method enables the theme to display its text in the chosen language, if it has been translated beforehand.

Image Modified

Best practices

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1. Do not mix XHTML and PHP code.
2. Do not mix XHTML and CSS code, put the CSS code in a separate .css file.
3. Always validate your XHTML and CSS code using the W3C validators: XHTML validator, CSS validator.
4. Do not make SQL queries from a PHP controller ({{.php file at the root of PrestaShop); prefer the use of existing methods from the PrestaShop classes, or create new methods for these classes.
5. Always check if a method you need does not already exist in the available classes.
6. Always make sure to produce a clear and readable code, making it easy to maintain for anyone.
7. Do comment your code, in English.
8. When editing the theme on a production site, always first put the shop in maintenance mode via the back-office.
9. Use modern browsers, such as Firefox, Google Chrome or Opera, and make sure your friends do too.
10. Whenever possible, use CSS sprites (follow-up article).
11. If you wish to thank PrestaShop team for its hard work, please consider donating, or spread the good word!

Customizing the default theme

Follow the following steps below to create your own theme out of the PrestaShop default theme.

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That being said, it is highly discouraged to directly change the files for the default theme, the reason being that this could introduce news new bugs and no way to go back. You need to keep the default theme intact, so that you can switch between your theme and the default one in order to find out if the issue you are seeing is tied to your theme, or to a bug in another part of PrestaShop.

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A few advices

Firebug, Dragonyfly Dragonfly et al.: your work as a front-end developer can greatly helped with the right tools at hand, provided you test your design in a modern browser that provides such tools, either through a module (Firefox's FireBug) or directly embedded (Opera's Dragonfly, Chrome & Webkit's Web Inspector). Learn to master them, and you will quickly be amazed by their usefulness.

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preview.jpg file: Once your design is complete, you can create the preview image file. Take a screen shot, then resize it to 180px width in order to use it instead of the default preview.jpg file. You can either used the screenshot tool provided by your OS (Windows' Snipping Tool, OS X's Cmd+Shift+4 key combo), or install a browser extension, such as Firefox's FireShot or Screengrab.

Layered navigation: In order for a theme to be compatible with layered navigation, the /themes/themename/product-list.tpl file must have its product list area be encapsulated within a tag with the "product_list" id; otherwise, the layered navigation will not be able to update the product list.

<div id="product_list">

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<ul id="product_list">

Integration: where the hooks and modules are

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