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From: marbru@attc.UUCP (Martin Brunecky)
Newsgroups: comp.windows.x
Subject: Re: XWarpPointer revisited.....
Message-ID: <977@attc.UUCP>
Date: 18 Jan 91 22:41:32 GMT
References: <9945@ncar.ucar.edu> <100920272@hpcvlx.cv.hp.com>
Reply-To: marbru@auto-trol.UUCP (Martin Brunecky)
Organization: Auto-trol Technology, Denver
Lines: 57

In article <100920272@hpcvlx.cv.hp.com> ben@hpcvlx.cv.hp.com (Benjamin Ellsworth) writes:
>
>> Is it simply because the user can become confused with the visual
>> effects?
>
>I think so.  The problem is that it seriously disturbs the "direct
>manipulation" paradigm.  The cursor is always attached to the
>mouse--moving the mouse moves the cursor.  When you warp the cursor, you
>have caused the cursor to move without moving the mouse.  This weakens
>the perception that the two are connected.
>
>There are also perceptual issues regarding "Where'd that darn cursor
>get to anyway?!"....

   I think that one more thing to *consider* is the "lifetime" of the
   warp and the context. For example:

   Application responds to the user's action, which caused an error,
   by poping-up a message box with application modal and "acknowledge"
   button on it.

   Under the current thinking, the user must:
   - move the pointer to the "acknowledge" button
   - click the button
   - remember where he was before the disaster happened
   - move the pointer back
    (sure, in click-to-focus mode you could use the keyboard, 
     but thet's another issue).

   Now. If the application would:
   - popup the box
   - warp the pointer into the "acknowledge" button
   - wait for reply
   - warp pointer to the *original* position

   In this scenario, the user would *only* have to click the button to
   acknowledge the message. He von't be lost, since the application would
   return the pointer where it was before...
   Naturally, this should ONLY be done if the pointer *was* in the application's
   window to start.


   So, I think that again and again, we should never make general absolute
   statements. Sure, warping the pointer disturbs the "direct manipulation"
   paradigm. However, there may be circumstances where such a "disruption"
   is justified and welcome.
   Besides, anytimes an application uses an Application or System Modal
   (to use Motif terms), it has *already* disturbed the direct manipulation
   paradigm, as it is forcing the user into something he did not want to do.



-- 
=*= Opinions presented here are solely of my own and not those of Auto-trol =*=
Martin Brunecky                           {...}sunpeaks!auto-trol!marbru
(303) 252-2499                        (sometimes also:  marbru@auto-trol.COM )
Auto-trol Technology Corp. 12500 North Washington St., Denver, CO 80241-2404