How to Insert my Code Between Zoom Text and Windows?

I am writing an application whose users will use ZoomText and a tablet PC. ZoomText is screen magnification software. However ZoomText has a bug that prevents tablet tracking from working correctly, meaning finger and pen interaction with the screen is incorrect. When you zoom in on a rectangle in the screen and tap on something, you are actually tapping on the absolute coordinates, as if ZoomText was not running.

I a开发者_如何转开发m trying to write a program that will correct this behavior. ZoomText has a COM API which allows me to know the zoom amount and location. This means that if I were able to get between ZoomText and the operating system, I could intercept the pen/touch input, translate the coordinates taking into account ZoomText's zoom and location, and then pass the input back to the operating system.

Where should I begin? I don't even know where to start looking for how to implement this.

I think the way to go about this is a low level mouse hook. Use SetWindowsHookEx with a hook type of WH_MOUSE_LL.