Volume 6A: Motif Programming Manual

reject the resize request of the child that started all the negotiation. Geometry management is by no means a simple

task; it is explained more completely in Volume Four, X Toolkit Intrinsics Programming Manual.

9.4 The Form Widget

The Form widget is subclassed from the BulletinBoard class, so it inherits all of the resources that the BulletinBoard

has to offer. Accordingly, the children of a Form can be placed at specific x,y coordinates and geometry management

can be performed as in the source code However, the Form provides additional geometry management features that

allow its children to be positioned relative to one another and relative to specific locations in the Form.

In order to use a Form, you must include the file <Xm/Form.h>. A Form is created in a similar way to other manager

widgets, as shown below:

Widget form;

form = XtVaCreateWidget ("name",

xmFormWidgetClass, parent,

resource−value−list,

NULL);

/* create children */

XtManageChild (form);

9.4.1 Form Attachments

Geometry management in a Form is done using attachment resources. These resources are constraint resources, which

means that they are specified for the children of the Form. The resources provide various ways of specifying the

position of a child of a Form by attaching each of the four sides of the child to another entity. The side of a widget can

be attached to another widget, to a fixed position in the Form, to a flexible position in the Form, to the Form itself, or

to nothing at all. These attachments can be considered ...