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Pause Preview: A Technique for Improving the Interactivity of Direct Manipulation

IP.com Disclosure Number: IPCOM000122357D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 6 page(s) / 266K

Publishing Venue

IBM

Related People

Alpert, SR: AUTHOR [+3]

Abstract

Users of direct manipulation user interfaces may be uncertain of the effects of some manipulation, for a variety of reasons. Pause Preview is a technique for providing visual feedback before a direct manipulation is completed. Pause Preview allows costly do/undo/redo sequences to be replaced by conversation-like preview/reject/continue sequences.

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Pause Preview: A Technique for Improving the Interactivity of Direct
Manipulation

      Users of direct manipulation user interfaces may be
uncertain of the effects of some manipulation, for a variety of
reasons.  Pause Preview is a technique for providing visual feedback
before a direct manipulation is completed. Pause Preview allows
costly do/undo/redo sequences to be replaced by conversation-like
preview/reject/continue sequences.

      Current direct manipulation interfaces allow many user actions,
like move, copy and delete, to be accomplished by "dragging"
interface objects with a mouse.  In a typical design, an object is
first "picked up", by some sequence that ends with a mouse button
depressed.  "Dragging" means moving the mouse with this button still
depressed. Releasing the mouse button at a target location completes
the action specification.

      This interaction design allows separate effects to be realized
by a consistent action sequence and has been widely touted as a
successful piece of interface technology. However, it leads to some
problems for the user.

      The user cannot see what will actually happen until releasing
the dragged object.  Even when the command semantics are directly
related to the action, such as with moving and copying, the user is
typically only shown some impoverished representation of the
picked-up object, such as a shimmering outline.  When the command
semantics are more dependent on the destination, as with deletion,
the same model is used, and now the intended effect only becomes
visible at all on completion of the action, i.e., on release of the
mouse button.  This is particularly problematic if (a) the
specification of the destination must be precise, such as when moving
a graphic object to align with another, or (b) when the boundaries of
meaningful destination locations on the screen are not clearly marked
(this problem is exacerbated if adjacent locations have very
different effects), or (c) when the user is uncertain of the
semantics of moving to some destination. Furthermore, inaccurate or
inadvertent actions can often only be repaired, if at all, by undoing
the entire sequence, which imposes a substantial redo cost: a
correction move to a different, nearby destination will often involve
undoing, reselecting, and redragging.  To overcome these interactive
problems with direct manipulation, we suggest that any graphic
effects of actions should be visible before button release (or
whatever action is the syntactic marker of action- completion).  The
problem this raises is one of computational cost - the graphic
computations required to show the effects changing as the mouse is
moved are prohibitive, and would, in any case, present a confusing,
unstable display.

      To solve this problem this article reveals a technique in which
previews of results are driven by the rhythm of user actions.  If the
user pauses for some criterion time in a mouse movement, then...