Composite widgets are intended to be containers for other widgets and can
have an arbitrary number of children. Their responsibilities (implemented
either directly by the widget class or indirectly by Intrinsics
functions) include:
Overall management of children from creation to destruction.
Destruction of descendants when the composite widget is destroyed.
Physical arrangement (geometry management) of a displayable subset of
managed children.
Mapping and unmapping of a subset of the managed children.
Instances of composite widgets need to specify the order in which
their children are kept. For example, an application may want a set of
command buttons in some logical order grouped by function, and it may want
buttons that represent filenames to be kept in alphabetical order.
Classes
Composite inherits behavior and resources from Core.
The class pointer is compositeWidgetClass.
The class name is Composite.
New resources
The following table defines a set of widget resources used by the programmer
to specify data. The programmer can also set the resource values for the
inherited classes to set attributes for this widget. To reference a
resource by name or by class in a .Xdefaults file,
remove the ``XmN'' or ``XmC'' prefix and use the remaining
letters. To specify one of the defined values for a resource in a
.Xdefaults file, remove the ``Xm'' prefix and use
the remaining letters (in either lowercase or uppercase, but include any
underscores between words).
The codes in the access column indicate if the given resource can be
set at creation time (C), set by using
XtSetValues (S), retrieved by using
XtGetValues (G), or is not applicable (N/A).
Composite resource set
Name
Class
Type
Default
Access
XmNchildren
XmCReadOnly
WidgetList
NULL
G
XmNinsertPosition
XmCInsertPosition
XtOrderProc
NULL
CSG
XmNnumChildren
XmCReadOnly
Cardinal
0
G
XmNchildren
A read-only list of the children of the widget.
XmNinsertPosition
Points to the XtOrderProc function described below.
XmNnumChildren
A read-only resource specifying the length of the list of children in
XmNchildren.
The following procedure pointer in a composite widget instance is of type
XtOrderProc:
Cardinal (* XtOrderProc) (widget)
Widget w;
w
Specifies the widget.
Composite widgets that allow clients to order their children (usually
homogeneous boxes) can call their widget instance's insert_position
procedure from the class's insert_child procedure to determine where a new
child should go in its children array. Thus, a client of a composite class
can apply different sorting criteria to widget instances of the class,
passing in a different insert_position procedure when it creates each
composite widget instance.
The return value of the insert_position procedure indicates how many children
should go before the widget. Returning zero indicates that the
widget should go before all other children; returning num_children indicates
that it should go after all other children. The default insert_position
function returns num_children and can be overridden by a specific composite
widget's resource list or by the argument list provided when the composite
widget is created.
Inherited resources
Composite inherits behavior and resources from the following superclass.
For a complete description of each resource, refer to the manual page for
that superclass.
