International Language Environments Guide

Changes in Motif to Support CTL Technology

XmDirection

The XmNlayoutDirection resource [See section 11.3 of the Motif Programmer's Guide (Release 2.1) for an overview of XmNlayoutDirection, and especially for a description of the interaction between XmStringDirection and XmNlayoutDirection.] controls object layout. It interacts with the orientation value of the LayoutObject in the manner described below.

Layout Direction

First, when XmNlayoutDirection is specified as XmDEFAULT_DIRECTION, then the widget's layout direction is set at creation time from the governing pseudo-XOC. In the case of dynamic text (XmText and XmTextField), the governing pseudo-XOC is the one that is associated with the XmRendition used for the widget. In the case of static text (XmList, XmLabel, XmLabelG), the layout direction is set from the first compound string component that specifies a direction. This specification happens in one of two ways:

Directly, if the component is of type XmSTRING_COMPONENT_LAYOUT_PUSH or XmSTRING_COMPONENT_DIRECTION
Indirectly, if the component is of type XmSTRING_COMPONENT_LOCALE_TEXT, XmSTRING_COMPONENT_WIDECHAR_TEXT, or XmSTRING_COMPONENT_TEXT, from the component's associated XmRendition's and associated LayoutObject.

Second, if XmNlayoutDirection is not specified as XmDEFAULT_DIRECTION, and the XmNlayoutModifier @ls orientation value is not specified explicitly in the layout modifier string, then the XmNlayoutDirection value is passed through to the XOC and its LayoutObject.

If both XmNlayoutDirection and the XmNlayoutModifier @ls orientation value are explicitly specified, then the behavior is mixed; the XmNlayoutDirection controls widget object layout, and the XmNlayoutModifier @ls orientation value controls layout transformations.

For More Information

For more information, see CAE Specification: Portable Layout Services: Context-dependent and Directional Text. The Open Group: Feb 1997; ISBN 1-85912-142-X; document number C616.

This document describes a set of portable functions for handling context-dependent and bidirectional text transformations as a logical extension to the existing POSIX locale model. It is intended for system and application programmers who want to provide support for complex-text languages.