AIX Version 4.3 Differences Guide

8.3.4.14 Scrolled Window and Scroll Bar Enhancements
The Scrollbar widget has been extended to support a look and feel like
OpenStep, where both up and down controls are close together at one end of the
scroll bar, as opposed to one control at each end. A new resource was added to
give applications more control over the appearance of the slider.
It is practically impossible with Motif 1.2 for an application to implement a scrolled
window that has a fixed title or a status bar inside the scrolled window area. Motif
2.1 makes it possible to have one or more arbitrary controls be displayed as
non-scrollable in any direction.
Using this feature, users can simply implement a spreadsheet application with a
column title that cannot be scrolled out vertically, a rows title that cannot be
scrolled out horizontally, and a RowColumn widget for the cells. MainWindow, a
subclass of ScrolledWindow, inherits this feature too.
8.3.4.15 Drawing Area
The drawing area is now traversable with the keyboard, making it possible for
users to traverse to a drawing area and get its associated functions (for example,
pop-up menus).
8.3.4.16 Performance Enhancements
A number of performance enhancements have been made and are described
below.
XmString Performance
The memory used by an XmString that uses a single font and is smaller than 256
bytes (256 characters in Latin-based language environments) is less than it used
to be. Note that this kind of string represents the majority of strings displayed in a
typical user interface, for example, menu items, list items, and labels. The
memory size of every XmString has also been reduced by four bytes (from Motif
1.2). Every string that consists of less than 256 characters uses a single
encoding, single color, and single font.
Copying XmString is now managed by reference counting in 2.1, which makes
XmString copy much faster and uses no memory. Since Motif does a lot of
XmString copies internally, this should reduce the memory size used by many
applications that do not release the memory of an XmString after they have
passed it to a widget.
List Performance
The startup time for the List widget has been decreased compared to Motif 1.2.
This is particularly noticeable for applications that handle large lists of several
hundred items. See Section 8.3.4.10, “List Enhancements” on page 222.
X-Related Performance
In general, the amount of resources allocated in the X server, clients, and the
number of round trips between client and server has been decreased.
Client-side memory has been decreased by using bitmaps instead of pixmaps
whenever possible. In Motif 1.2, when a widget uses a background pixmap, a
pixmap is allocated using the available depth of the screen. In Motif 2.1, a bitmap
is used if only two colors are required.
224 AIX Version 4.3 Differences Guide