Installing Drupal Themes
This article assumes you have a working Drupal installation, and that you have access to the files on your server.
The large and active community of developers that has formed around Drupal guarantees a steady flow of themes for this popular CMS. The diversity of that community also assures that there will be a wide variety of themes produced. Add into the equation the existence of a growing number of commercial and open source web designs and you can be certain that somewhere out there is a design that is close to what you want. The issue becomes identifying the sources of themes and designs, and determining how much work you want to do yourself.
You can find both design ideas and complete themes on the Web. You need to decide whether you want to work with an existing theme, or convert a design into a theme, or whether you want to start from scratch, unburdened by any preliminary constraints or alien code. For purposes of this article, we will be dealing with finding, installing, and then uninstalling an existing and current Drupal theme.
If you know your Drupal version, you can confirm whether the theme you are considering is usable on your system. If the theme you are looking at doesn't provide versioning information, assume the worst and make sure you back up your site before you install the questionable theme.
Once you're past the compatibility hurdle, your next concern is system requirements; does the theme require any additional extensions to work properly?
Some themes are ready to run with no additional extensions required. Many themes require that your Drupal installation include a particular templating engine. The most commonly required templating engine is PHPTemplate. If you are running a recent instance of Drupal, you will find that the PHPTemplate engine is installed by default. You can also download a variety of other popular templating engines, including Smarty and PHPTal from http://drupal.org/project/Theme+engines.Check carefully whether the theme you've chosen requires you to download and install other extensions. If so, track down the additional extensions and install them first, before you install your theme.
A good place to start looking for a complete Drupal theme is, perhaps not surprisingly, the official Drupal site. At Drupal.org, you can find a variety of downloads, including both themes and template engines. Go to http://drupal.org/project/Themes to find a listing of the current collection of themes. All the themes state very clearly the version compatibility and whether there are any prerequisites to run the theme.
In addition to the resources on the official Drupal site, there is an assortment of fan sites providing themes. Some sites are open source, others commercial, and a fair number are running unusual licenses (most frequently asking that footers be left intact with links back to their sites). Some of the themes available are great; most are average. If your firm is brand sensitive, or your design idiosyncratic, you will probably find yourself working from scratch.
Regardless of your particular needs, the theme repositories are a good place to start gathering ideas. Even if you cannot find exactly what you need, you sometimes find something with which you can work. An existing set of properly formed theme files can jump start your efforts and save you a ton of time.
If you wish to use an existing theme, pay attention to the terms of usage. You can save yourself (or your clients) major headaches by catching any unusual licensing provisions early in the process. There's nothing worse than spending hours on a theme only to discover its use is somehow restricted.
One source for designs with livable usage policies is the Open Source Web Design site, http://www.oswd.org, which includes a repository of designs, all governed by open source licensing terms. The down side of this resource is that all you get is the design—not the code, not a ready-made theme. You will need to convert the design into a usable theme.
For this article, let's search out a completed theme and for the sake of simplicity, let's take one from the official Drupal site. I am going to download the Gagarin theme from Drupal.org. I'll refer to this theme as a working example of some ofthe steps below. You can either grab a copy of the same theme or you can use another—the principles are the same regardless.
This article has been extracted from the book Drupal 5 Themes written by Ric Shreves and published by Packt Publishing. For more information about the article and book please visit www.PacktPub.com/Drupal-5-Themes/Book