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From: raveling@VAXA.ISI.EDU (Paul Raveling)
Newsgroups: comp.windows.x
Subject: Re: Warping the pointer for a reconfigured widget
Message-ID: <8711240223.AA01873@>
Date: Mon, 23-Nov-87 21:23:19 EST
Article-I.D.: .8711240223.AA01873
Posted: Mon Nov 23 21:23:19 1987
Date-Received: Fri, 27-Nov-87 01:12:49 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 40



Regarding the following recent exchange . . .

  >> First of all, I view the user as "owning" the pointer and not the system,
  >> suggesting that it is almost never the right thing to do to change the location
  >> of the pointer unless the user moves it.  Assuming we disagree on that
  >> religious point, ...

  > Sigh.., it certainly does appear to be a religious issue.


	My religious faith says that there if my widget (or window,
	or whatever) moves, the mouse had better move with it in order
	to maintain the same dialog state.  Keeping the mouse stable
	over the screen often would represent motion in a semantic
	reference frame.

	Taking an example from a schematic editor, the cursor may be
	positioned over a pin on one corner of an IC chip.  If the
	chip is rotated 90 degrees, I want the cursor to move with
	it in order to continue marking the same pin, which is likely
	to be the subject of the next editing operation.  If the
	cursor position doesn't move, both the pin and the entire
	IC move from under the mouse, and the entire context is lost.

	In other cases the interactive context would dictate the
	opposite approach (not warping the mouse).  I think it's
	appropriate for the level of processing which is "aware"
	of the semantic consequences to decide whether to warp the
	mouse and if so how.  For toolkit widgets, the code
	supporting the widget should often be able to make this
	decision.  I vote for having the ability to do this, even
	if the code often wisely elects to let the user make the
	moves.


---------------------
Paul Raveling
Raveling@vaxa.isi.edu