Locate DirectX viewport

How do I locate the coordinates and size of a DirectX game?

My current code uses window sizes (user32.dll, GetWindowRect), which includes window chrome, but I want it to work accurately even if chrome is customized or if there is no chrome (e.g. fullscreen).

As an example, Fraps can create an overlay of the FPS of a game in a parti开发者_如何转开发cular corner. If I wanted to do that, how do I find that window viewport?

Thanks in advance for your insight.

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There is a GetDisplayMode function.