I am looking for good resources for learning to use the Win32/GDI APIs or whatever supercedes it to draw and paint directly using the Win32 API to a glass form.
While I am using Delphi, I tagged this as Delphi or Visual C++. Any code samples and articles that you can find would be appreciated. MSDN articles do not seem to be written about this.
As a goal, let's imagine you want to either: (a) Reproduce what Google Chrome does (tabs as part of the glass frame) (b) Reproduce what MS Office 2010 does (save button on the glass frame, referred to in MFC for VS 2010, as "Quick Access Toolbar" (see picture below).
I am not using MFC, but if examining the MFC sources would be a good source of information, I am curious to know where in the MFC sources or BCG original sources (I have both) are implemented the Quick Access Toolbar rendering/painting code.
Update: A related neato link from one of the answers below shows the NC (nonclient) Paint message, and how to handle it when painting on a glass frame, and an MSDN article about it here.
I'm sure you've found the MSDN page about the DWM. It has jumps many topics and a few examples. Some of the "overview" articles there have examples (like the DWM Blur Behind Overview).
Unfortunately, other than the documentation, there are precious few good articles. You can start with Using glass on codeproject, and take a look at a detecting glass in delphi - after that using the functions straight from the docs is not too bad. Luckily they are all pretty straight-forward in practice.
Good web site for glass components, including a Glass button:
http://rmklever.com/
This is a subset of my "Glass" bookmarks folder, the result of a lot of research / searching on this topic. I've found all of these useful for learning about glass and solving various problems drawing on it. Most of these include Delphi code, but I've noted where it's for another language.
Plain Glass links
Advanced, or tangentially related:
In addition, these old articles may help you:
These posts on drawing a custom title bar under Vista/Windows 7 might interest you.
Sample image: