TkXext "has the ability to send events to any window, embed windows in Tk, and send events to embedded or non-embedded windows." Unlike Android, it doesn't yet (as of September 2001) have capabilities for event recording and gathering information about the display.
GPS maintains TkXext at http://www.xmission.com/~georgeps/tkxext/ , with the help of several others.
TkXext is X-based; it's available only for Unix.
(more accurately, it's available as source, and good luck figuring out how to compile it under windows to work with Exceed [L1 ] or Reflection X [L2 ]... (do they even provide SDKs?) But if you do work it out, by all means let George know about it.)
GPS: I didn't hear from you about any problems. I'd be glad to help you, so please let me know what problems you ran into with Exceed or Reflections/X. BTW I'll add a configure option for X11 header and library directories, because I would imagine you have problems related to that. When I originally wrote the configure script I didn't plan on supporting many systems.
(problems? no, I was just commenting that it was theoretically possible, and saying 'good luck' to whoever tries it... while I do have access to both of the above-named products, they are not part of my development enviroment. My comment about letting you know is because I'm sure you'd like to hear about it if someone does do that, and so that you can add any necessary stuff to your makefile to support that configuration. I note with some amusement that after I added my comment yesterday, I revised it slightly to correct a product name and add URL for Reflection X, and your adding of your response managed to zap my revision.)
What about Cygwin? I'm running the Blackbox Window Manager [L3 ] using Cygwin/XFree86 [L4 ] on Cygwin [L5 ].
GPS: It probably would work under Cygwin's XFree86. I like Cygwin and their XFree86 port (used it for a while in NT 4), but for whatever reason the installer has a tendency to segfault in Windows XP Home. If it's fixed I may see what's needed (if anything) to make it work.
*Future goals
I would really like to take TkXext beyond ASCII. It currently has a table that associates X key symbols with ASCII characters (last I checked so does Android). There was some issue with XStringToKeysym last I tried to use it. I've also been curious about using the XTEST extension, which may make some things easier to do.