Adding color module support to your theme in Drupal 7

I have been playing about with creating my own base theme which I can use to easily roll out new sites quickly and easily for those who don't want to pay for a bespoke design.

The main problem with this is ending up with one theme for all, to get around this with out having to do any development work is use Drupal's core colour module which allows the user to select the colours of certain areas.

This will just show you the basic code that is required for use with a theme using the PHPTempalte engine with some comments on what the code is doing at parts.

Sorry but I will be using the English spelling, too used to typing with the 'u'.

Enable colour module

First things first, the colour module needs to be enabled.

Create an empty CSS file to store all your colours

I have found that it is a lot easier to create a single CSS file for your the colours which you are going to want to change through the colour module. So create a file (I will call mine colour.css within your theme directory, it can be in a subdirectory if you like to keep your theme directory tidy). This then needs to be defined in your theme's info file.

Create a directory for your colour files

Within your theme you will need a directory called color (notice the US spelling).

Bartik and Garland go about integrating with the colour module slightly differently. For this tutorial I will be using the Bartik module (more code than design).

Garland uses a PNG with alpha channels to show a preview and create graphics required for any colour changes then that PNG is sliced by the colour module and used when users view the site. Bartik on the other hand uses a few extra files by having an HTML, CSS and JS files to show the preview (but can also slice up a base image, but I won't be using that).

So I copy all the files from the bartik/color directory in to my themes color directory.

Modify the color.inc file

In the color.inc file, the first thing to change is the theme name in the drupal_add_js() call to the name of your theme.

Below this we have an array which is used to store our preset colour packages. For the time being we will skip this and move down to below the array where you will have the following:

This should be an array of CSS files that you want the colour module to modify the colours.

I won't be using anything else so I will change the gradient to an empty array as I won't be using it, the key must be there otherwise you will get PHP errors.

Everything else in the file must remain.

Going back to the top of the file with the $info array, you should be able to see two keyed arrays. The first one is fields where you can define the types/areas of the page that can be changed through the colour module.

The schemes array is where you can set the colours for each scheme. The colours under the default scheme need to be the same colours as are in the CSS file(s) that you specified.

Preview

The preview within Bartik works very simply. The HTML file contains a rough structure of your theme (in this case it matches Bartik with the tabs, sidebar block etc). You can change this as you want and update the preview.css file to make the layout as similar to your theme as possible.

Updates to the preview are made from the javascript file, preview.js. You should be able to see what does what.

The currently selected colours can be taken from:

$('#palette input[name="palette[link]"]', form).val()

Where link is the field key name defined within the color.inc file. The jQuery selectors should change the elements that would be changing through your colour.css file.

Changes to the template.php file

There are two changes that need to be made to the template.php file in the themename_process_html() and themename_process_page() functions. Note that they are not preprocess functions.

Problems

For some reason if there isn't a field called base, I get errors coming up, I haven't had a good look to see why, but it is easy enough to create one called base and use that as the background colour. Garland has base defined but Bartik doesn't, so I don't know what is going on with that.

Colour contrast is another problem. It is all very well giving the user the option of changing the colour of the footer and links but sometimes you want the footer background to be blue and the default link colour to be blue in which case the links are impossible to see. So you will need to either hard code link colours for these areas within one of your other files and hope that the user doesn't select a different non-contrasting colour or you will need to provide more options to allow the user to change different link colours depending on regions.

The colour module updates the colours based on colour matches between the default scheme defined in the color.inc file and your colour.css file. So if by default your link colour is #126ac2 and your header background is #126ac2 then in the colour settings for your theme, you change the header to #000000 and the link colour to #cc0000. You will end up with everything being in one of those colours.

So for very simple changes to your themes colour scheme which if you have a simple theme can be pretty easy to set up, the colour module is great. For anything that is remotely starting to get complex you will be better off creating separate CSS files for different colour schemes which you can turn on or off with in the themes info file or through other means such as using the theme-settings.php file to let the user decide.