Browse Prior Art Database

Avoiding System Hangs when Using OS/2 2.1 Window Animation

IP.com Disclosure Number: IPCOM000113143D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Morgan, SA: AUTHOR

Abstract

In OS/2* 2.1, windows displayed using the Presentation Manager* (PM) graphical user interface have the ability to display window animation. Animation in this context is the appearance, when the window is being created, of the window frame expanding from a dot to the full window size. This animation feature provides an application with the desired sophisticated look of a state-of-the-art user interface.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Avoiding System Hangs when Using OS/2 2.1 Window Animation

      In OS/2* 2.1, windows displayed using the Presentation Manager*
(PM) graphical user interface have the ability to display window
animation.  Animation in this context is the appearance, when the
window is being created, of the window frame expanding from a dot to
the full window size.  This animation feature provides an application
with the desired sophisticated look of a state-of-the-art user
interface.

      Due to OS/2 system constraints, however, using this feature of
PM can sometimes cause the application to hang the PM desktop.  This
disclosure describes a technique that allows the application to
provide window animation while avoiding the system hangs that can
occur when user interaction causes a conflict in system resource
requirements.

      The animation feature provided by OS/2 is implemented using the
system tracking rectangle.  This is the same gray rectangle that is
displayed when a window is being moved or sized by the user.

      There is only one tracking rectangle resource in the system.
Before animation support, this did not present a problem, since only
one window could be moved or sized at any given time.  With the
tracking rectangle now also used to provide window animation,
however, a potential conflict arises.  While only the user is likely
to move or size a window once it is displayed, an application might
have cause to display a window at any time without user interaction,
such as a notification message of a system event.  A window can thus
be created using animation while another window is being moved or
sized.  This creates a situation where two windows both need to use a
single system resource, namely the tracking rectangle.  OS/2 does not
handle this gracefully, with the result being a system hang.

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