Path: utzoo!mnetor!uunet!husc6!cmcl2!nrl-cmf!ames!ucbcad!pasteur!ucbvax!ZERMATT.LCS.MIT.EDU!RWS
From: RWS@ZERMATT.LCS.MIT.EDU (Robert Scheifler)
Newsgroups: comp.windows.x
Subject: GrabPointer again
Message-ID: <880119192340.1.RWS@KILLINGTON.LCS.MIT.EDU>
Date: 20 Jan 88 00:23:00 GMT
References: <880107-095710-7037@Xerox>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 33


    Sender: Michael_K._Powers.WBST139@Xerox.COM
    Date: Thu, 7 Jan 88 12:56 EST

				Now I want to temporarily ask for a button down
    event anywhere on the area defined by window A ignoring any siblings request for
    said event. Once I get the button down (I want to ignore the release) I wish to
    take that point and use it for the stake point of a rubberbanding line. I then
    wish to grab, for the area defined by A, all motion and button down events. The
    track point of the line will follow the pointer. Then when another button down
    is recieved the rubber line is done and things, event-wise, should return to the
    way they were before the first down event. 

The key thing here is that you want to ignore what your subwindows are
asking for.  Had you brought this up about a year ago, and got me
thinking in the same direction, I would have suggested that perhaps the
right thing would be to add a new window attribute
	do-not-descend: SETofDEVICEEVENT
that was like the opposite of do-not-propagate, i.e., have the server
walk down the tree first to figure out where the effective "source"
window for the event was, stopping at the first window with a matching
do-not-descend.  For your scenario, you could then simply turn Button
related events on and off in this mask on window A.  Even though it is
too late for 11.0, it still seems like an idea worth someone fleshing
out (there are lots of interactions with other mechanisms that need to
be considered).

As it is, your choices seem limited to grabbing the pointer (which is
inconsiderate of other applications, I agree) or getting whatever
toolkit layer or widgets you are using to cooperate in within-client
transformation of the events, to have them automatically propagated up
the widget hierarchy (with coordinates appropriately massaged) to the
desired parent.