Theme XML Files

If you followed my previous topic about saving a theme, you know that your saved theme has the THMX file extension. THMX actually stands for an Office Theme Document file. However, what it hides is more important in this case than what it stands for.

A THMX file and any of the new file formats that Office 2007 and later use are actually XML based file formats. Also they are more like a wrapper that contain many disparate and related elements, as we will show you soon.

Brian Jones, a Program Manager for Microsoft Office has put up a detailed blog that discusses the new Office file formats. In addition to the file format itself, his blog talks about related stuff including ODF, OpenXML, etc. Here's a link to his blog.

And here's an interview with Brian Jones on the Channel9 site.

So how is a THMX file a wrapper? This one is easy. Just follow these steps:

1. Make a copy of any of the THMX files in your system, or just save a THMX file from within PowerPoint and save it to somewhere easy to locate such as your Desktop (see Figure 1).
2. 
   Figure 1: A THMX file placed on the Desktop
2. Now ensure that your system is set to show file extensions.
3. Now, right-click the file, and choose Rename, or just press F2. Add a ".zip" without the quotes right after the name of the file. For example if your original file name was:
4. indezine theme.thmx
5. It would be renamed to:
6. indezine theme.thmx.zip
7. Windows will warn you that renaming the file extension could render this file unusable -- but since you are just working on a test file for now, go ahead and ignore this error by clicking the Yes button that you can see in Figure 2.
8. 
   Figure 2: Ignore this warning
3. Now that you have renamed the THMX file with a ZIP extension, would you believe if we told you that the original THMX file was in fact just another ZIP file with a new extension? You may or may not believe that. The easiest way to find out is by double-clicking on the renamed ZIP file.
4. Depending upon whether you have a program like WinZip or similar installed or not, one of two things will happen:
5. If you have no extra zipping or archiving programs installed, then the new ZIP file will open just like a conventional folder that you can see in Figure 3.
6. 
   Figure 3: The Theme Zip files shows up like a folder
7. On the other hand if you have WinZip or another compression/archiving program installed, then the ZIP file will open in that program as you can see in Figure 4.
8. 
   Figure 4: The Theme ZIP file open in WinZip shows folders and files
4. Either way, you can now see that the original THMX file was actually nothing more than a collection of folders and files that comprise the Theme -- you'll find all sorts of files within the THMX wrapper including XML files, JPEG images, etc.
5. The cool part is that if you know what you are doing, you can actually edit these XML files, and even replace the JPEG files! There's no harm caused by playing with these files since you are just working with a test file.
5. Once you have made any changes, go ahead and rename the ZIP extension back to THMX. You should be able to use this Theme file in your Office documents.

Related Links: Theme Builder | Opening Existing Themes in Theme Builder