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From: davis@gauss.enet.dec.com (Peter Davis)
Newsgroups: comp.windows.x
Subject: Re: How to simulate mouse events from a data tablet
Message-ID: <1991May30.135144.5884@engage.pko.dec.com>
Date: 30 May 91 13:44:05 GMT
Sender: newsdaemon@engage.pko.dec.com (USENET News Daemon)
Distribution: usa
Organization: Digital Equipment Corporation
Lines: 44


In article <1991May30.022513.15790@auto-trol.com>, marbru@auto-trol.com (Martin Brunecky) writes...
>
>    Can you elaborate on why you have to XGrabPointer ? (I don't, and have
>    no problems I can see - so far).
>
	I thought I had to grab the pointer in order to be able to move
	it around in windows outside my control.  I don't remember testing
	this, however, so perhaps it's not necessary.
>
>    Plus, I also found I have to look at what events those windows are
>    interested in. The "propagate" mechanism did not work for me, so I am
>    looking for the "topmost" window containing the pointer AND interested
>    in a particular event.
>
	As far as I know, there's no way, or at least, no easy way to find
	out which window to send the events to.  Using the lowest window
	containing the pointer seems to work most of the time, but not
	always.  As I mentioned. I still don't have my code completely
	working yet, so I don't know all the ramifications.  Maybe I should
	try your approach.
> 
>    I found I can easily send a button event. The problems arise when the
>    client receiving this button event either:
>    - assumes a passive grab
>    - grabs the button explicitly.
> 
>    For example, trying to resize window from a "simulated" mouse under
>    most widnow managers won't work - those guys grab the "real" mouse
>    button - which is not depressed.
>    Grabbing the pointer for motions might help, but I am worried it will
>    confuse other things ....
>
	It may be that there's no way to really do this other than through
	some X extension, such as the input extension. This would require
	rebuilding the X server and possibly the operating system kernel
	as well, so it's not well suited for quick testing and prototyping
	of different input devices.

	I'd be interested in seeing what you're doing.  If you want to
	exchange code, we can do it here or by mail.

	Thanks.
	-pd