hpux man page for constraintd

Constraint set_values() 												   Constraint set_values()

Name
  Constraint set_values - Constraint class method called to handle changes to constraint resources.

Synopsis
  typedef Boolean (*XtSetValuesFunc)(Widget, Widget, Widget, ArgList,
  Cardinal *);
	 Widget current;
	 Widget request;
	 Widget set;
	 ArgList args;
	 Cardinal *num-args;

Inputs
  current   Specifies a copy of the child widget (and that widget's constraint record) made by XtSetValues() before any resources are changed
	    or any class methods are called.

  request   Specifies a copy of the child widget (and that widget's constraint record) made by XtSetValues() after the constraint and  normal
	    resources are changed as requested, but before any class set_values() methods are called.

  set	    Specifies  the  child  widget  with  constraint and normal resources set and as modified by any superclass methods that have been
	    called by XtSetValues().

  args	    Specifies the argument list passed to XtSetValues().

  num_args  Specifies the number of arguments in the args.

Returns
  True if the resource changes require the child widget to be redrawn; False otherwise.

Description
  The Constraint set_values() method is registered on the set_value field of the Constraint class part structure.  It is invoked when  XtSet-
  Values()  is called on a child of the constraint widget to do any processing necessary to handle resource changes in the child's constraint
  record.

  The arguments to the Constraint set_values() method are the same as those passed to the  child's  Object,  RectObj,  or  Core  set_values()
  method.   The constraints field of each of the widget arguments points to a copy of the child's constraints procedure made at the appropri-
  ate point by XtSetValues().  The Constraint set_values() procedure must perform the same sort of processing on this record  as  the  normal
  set_values() method performs on the widget instance record itself.

  The Constraint set_values() method will deal primarily with the fields of the constraint record, but may also modify widget instance fields
  as necessary.  If the constraint for the maximum height of a child is changed to a value that is less than the current height of the child,
  for  example,  the  Constraint set_values() method may change the height instance field of the child widget.	If the parent needs to change
  the geometry of the child, it needn't call XtConfigureWidget() directly; if any child geometry fields are changed by this or other set_val-
  ues()  methods, XtSetValues() will call XtMakeGeometryRequest(), which will invoke the parent's geometry_manager() method, which can do any
  necessary processing.

  As with the Object set_values() method, the Constraint set_values() method should return True if the widget should be redrawn.  Unless this
  method  actually  modifies  fields  in  the  widget  instance  structure itself, however, a redraw will never be useful because the child's
  expose() method cannot take constraint fields into account.

  The Constraint set_values() method should not assume that the child widget is realized.

  The args and num_args arguments were added in Release 4.

  The Constraint set_values() method is chained in superclass-to-subclass order, and cannot be inherited.  If none  of	the  resources	in  a
  class's constraint record need special processing when their values are changed, this method may be NULL.

  See  set_values(4)  for information on the arguments to this function, and a discussion of the typical tasks of a set_values() method.  See
  XtSetValues(1) for full details on the widget creation process.

Example
  The following procedure is the Constraint set_values() method, lightly edited, of the Xaw Paned widget class.  Note  that  it  obtains  the
  constraint  records  of  the	current  and set arguments (which are named old and new here) and compares their fields to determine what has
  changed.  Note also that "new" is a reserved word in C++, and your C code will be more portable if you avoid using it as an argument name.

     #define PaneInfo(w)     ((Pane)(w)->core.constraints)

     /* ARGSUSED */
     static Boolean
     PaneSetValues(old, request, new, args, num_args)
     Widget old, request, new;
     ArgList args;
     Cardinal *num_args;
     {
	 Pane old_pane = PaneInfo(old);
	 Pane new_pane = PaneInfo(new);

	 /* Check for new min and max. */

	 if (old_pane->min != new_pane->min    old_pane->max != new_pane->max)
	     XawPanedSetMinMax(new, (int)new_pane->min, (int)new_pane->max);

	 /* Check for change in XtNshowGrip. */

	 if (old_pane->show_grip != new_pane->show_grip)
	     if (new_pane->show_grip == TRUE) {
		 CreateGrip(new);
		 if (XtIsRealized(XtParent(new))) {
		     if (XtIsManaged(new)) /* if paned is unrealized this will
					    happen automatically at realize time.*/
			 XtManageChild(PaneInfo(new)->grip); /* manage the grip. */
		     CommitNewLocations( (PanedWidget) XtParent(new) );
		 }
	     }
	     else if ( HasGrip(old) ) {
		 XtDestroyWidget( old_pane->grip );
		 new_pane->grip = NULL;
	     }

	 return(False);
     }

See Also
  XtSetValues(1),
  Constraint(3), Core(3),
  set_values(4).

Xt - Intrinsics Methods 												   Constraint set_values()