Now that we've examined the various elements of the GUI, we can ask a question that is essential to the concept of skinning Windows XP. Why is the Windows XP GUI such a robust stage for redefining the look and feel of the OS environment?
Microsoft XP is designed differently from previous versions of the Windows OS. Microsoft XP actually contains its own built-in visual style (or skinning) engine that allows you to dramatically change the look and feel of the interface. The engine comes in the form of a dynamic link library (DLL; code that is shared by Windows programs) called uxtheme.dll. Skins that can be loaded by the engine come in the form of a file with an extension of .msstyles.
We discuss some of the issues related to hacking Windows resources and ResHacker in Appendix A. For the most part, we take a conservative approach to skinning Windows in this book, so most of our discussion of skinning covers third-party products that enable you to skin Windows without compromising the Windows system itself.
Unfortunately, Microsoft XP's visual style engine accepts only digitally signed .msstyles files. So, without actually hacking the digital security of a .msstyles file, you are stuck with two visual styles: Windows Classic and Windows XP.
When you do a search on a Windows XP computer for *.msstyles, your search results show that Windows XP provides one skin called luna.msstyles (see Figure 1.14). This file is actually the Windows XP skin that is applied to the Windows environment by default.
Figure 1.14. Search results of luna by entering in *.msstyles.
When you select the Windows Classic theme on the Themes tab of the Display Properties dialog box (see Figure 1.15), you are actually turning off the Windows XP theme (or skin) by unloading luna.msstyles from the skinning engine (uxtheme.dll).
Figure 1.15. Changing the theme in the Display Properties dialog box.
Now you can add digitally signed themes to your Windows installation by purchasing Windows XP Plus. This add-on package provides a number of new themes that add new visual styles, backgrounds, color schemes, and sound schemes.
However, let's say you want to create your own themes, visual styles, and skins for Windows XP (and is the reason you purchased this book). You actually have a couple of alternatives for editing the Windows GUI. Let's take a moment to define the differences between a theme, visual style, and skin; then we can discuss the possibilities for creating these GUI modifications.