Volume 6A: Motif Programming Manual

in the figure.

Output of action_area.c

In order to distribute the PushButtons evenly across the action area, we use the XmN-fractionBase resource of the

Form widget to segment the widget into equal portions. The value of the resource is based on the value of the

TIGHTNESS definition, which controls the spacing between buttons. A higher value causes the PushButtons to be

closer together, while a lower value spaces them further apart. We use the value 20 for purely aesthetic reasons. As

each button is created, its attachments are set. The left side of the first button and right side of the last button are

attached to the left and right edges of the Form, respectively, while all of the other left and right edges are attached to

positions.

The callback routine and associated client data for each button are added using XtAddCallback(). The first button

in the action area is specified as the default button for the dialog. The XmNdefaultButton resource indicates

which button is designated as the default button for certain actions that take place in the control area of the dialog. The

XmN-activateCallback of the TextField widget in the control area uses the resource to activate the default

button when the user presses the RETURN key in the TextField.

The CreateActionArea() function also sets XmNpaneMaximum and XmNpaneMinimum constraint resources

on the action area. These are PanedWindow constraint resources ...