Drupal front-end development or also know as Drupal theming was always a bit special craft. In order to be a good themer one needs to get his head around following topics:
- CSS (or preferably LESS and SASS)
Really a lot could be done in Drupal just by being very good (and creative) in writing CSS rules. The output of Drupal code is very classes and IDs rich, with wrappers wrapped with wrappers. This might be “ugly” by purists but can be advantage when you want to change the look and feel just with CSS.
- Understanding of Drupal output
In order to predict how the HTML outputed by Drupal will behave it is good to understand it. This means understanding how menus and links behave when they follow trail or how does Drupal contrib module Views list content in different formats.
- File template suggestions
After CSS it comes to altering the actual HTML. Here it is very important to now which tpl.php files a themer must create to override certain default output.
Before starting to building custom template files you have to know to write proper semantic HTML5. It’s the easies of traits in this list.
- Preprocess functions
There should be no logic in the TPL files. None at all. If there has to be some logic done, then it should be in the preprocess function. Every template file of theme function can have you implementation of the process and preprocess function. There you set your variables to use in the template.
- Theming function
When a certain output is not using a .tpl.php file, it means it is generated by a theme function. You can override theme functions, but it is not so recommended, since it can impact the output on more than one level.
If you are looking for a Drupal themer please contact us over agiledrop.com/contact. We have a Drupal theming team with experiences from over 100 Drupal websites. We know our craft.