The days of ugly Linux desktops are a thing of the past. Modern distros include many tools and options that enable them to look good and be more useful.

Unlike Windows, Linux has several different widget toolkits. The most well-known widget engines are GTK+, (distributed with GNOME) and QT. (pronounced “cute”) Widgets are the various elements which make up a program's GUI: scrollbars, arrows, checkboxes, etc. However, take note that QT or GTK widgets are not the same thing as desktop widgets.

Widgets and other things like window chrome (the toolbars, panels, etc. of a programs interface) and window decoration (the window's title bar, minimize/maximize/close buttons, and the window border) are the various elements that, when joined together, create a theme for QT or GTK. It is possible to modify the various themes in Linux to change how they look or even create your own. This article will address the various resources that are out there to help make your desktop look its best and help you get the most out of it.

Manipulating GTK Themes

GTK themes are among the most versatile when it comes to customization. Originally created for the GIMP, (GNU Image Manipulation Program) GTK is used in many applications, especially in the GNOME desktop environment. Some of the more elaborate GTK themes use rasterized PNG graphics to create the visual appearance of the widgets, but most GTK themes use effects created by the GTK engine itself. Each installed GTK theme is stored in its own folder in /usr/share/themes and has a gtkrc file that is used to store the parameters of the theme, such as element colors, size, position, etc. Although gtkrc files are plain text and are therefore human-readable, there is still a small learning curve in relation to working with them.

Fortunately, GNOME's Appearance module has a built-in tool to allow you to create your own themes in an easy-to-use interface. (To access the Appearance module in GNOME, go to System → Preferences → Appearance → Customize) This tool uses themes that have already been installed and allows you to mix and match parts from different themes to create your own hybrid designs; you can use icons from one theme, widgets from another, window decorations from yet another, etc. The more themes you have installed, the more versatile this tool can be, since the possible number of combinations can rise exponentially if you install only a few extra themes. For this reason, it is a good idea to install as many themes as possible, since each theme (even ones you don't like) can provide a larger inventory of spare parts to work with.

This tool is best for those who don't know how to work with gtkrc files directly or don't want to spend too much time creating their own theme. If you're more artistically inclined, you may wish to create your own themes from scratch. Since themes can be image-based, you are limited only by your creativity. A good way for beginners to learn how to create themes is to download a few and then analyze them to see how other artists made theirs. By using pre-existing themes as a guide, you can then create one of your own.

Plasma Themes

Unlike GTK themes, Plasma themes used in KDE4 are predominately made up of scalable vector graphics. (SVG) These are made in vector graphics editing software like Inkscape, Karbon, or anything else that can export SVG. (even Adobe Illustrator)

KDE4's appearance management system is much less straightforward than GNOME. While GNOME has one interface module to control its appearance, KDE4 has several. The modules which allow you to switch between themes is located on the desktop right-click menu instead of the control center, so newbies may be confused at first about how to switch between different themes.

Most Plasma themes are quite simple, (mostly glass-like with a few minimalistic and metallic variants) and only affect desktop widgets, the taskbar, etc. Windows are not affected by the Plasma theme you use, since they are not part of the Plasma system. Rather, window appearance is governed through choosing a color scheme and a widget/window decoration style just like in classic KDE. This is done through the Appearance module in the KDE4 control center and is rather straightforward. KDE has a built-in tool to acquire new wallpapers, Plasma themes, etc. so adding additional Plasma themes is simple.

Next, how to troubleshoot some common theme-related problems.