XtManageChildren, XtManageChild, XtUnmanageChildren,
XtUnmanageChild, XtChangeManagedSet, XtIsManaged - manage and unmanage
children
typedef Widget *WidgetList;
void XtManageChildren(WidgetList children, Cardinal
num_children);
void XtManageChild(Widget child);
void XtUnmanageChildren(WidgetList children, Cardinal
num_children);
void XtUnmanageChild(Widget child);
void XtChangeManagedSet(WidgetList unmanage_children,
Cardinal num_unmanage_children, XtDoChangeProc do_change_proc,
XtPointer client_data, WidgetList manage_children, Cardinal
num_manage_children);
Boolean XtIsManaged(Widget widget);
The XtManageChildren function performs the following:
- Issues an error if the children do not all have the same parent or if the
parent is not a subclass of compositeWidgetClass.
- Returns immediately if the common parent is being destroyed; otherwise,
for each unique child on the list, XtManageChildren ignores the
child if it already is managed or is being destroyed and marks it if
not.
- If the parent is realized and after all children have been marked, it
makes some of the newly managed children viewable:
- Calls the change_managed routine of the widgets' parent.
- Calls XtRealizeWidget on each previously unmanaged child that is
unrealized.
- Maps each previously unmanaged child that has map_when_managed
True.
Managing children is independent of the ordering of children and
independent of creating and deleting children. The layout routine of the
parent should consider children whose managed field is True and
should ignore all other children. Note that some composite widgets,
especially fixed boxes, call XtManageChild from their insert_child
procedure.
If the parent widget is realized, its change_managed procedure is
called to notify it that its set of managed children has changed. The parent
can reposition and resize any of its children. It moves each child as needed
by calling XtMoveWidget, which first updates the x and y fields and
then calls XMoveWindow if the widget is realized.
The XtManageChild function constructs a WidgetList
of length one and calls XtManageChildren.
The XtUnmanageChildren function performs the following:
- Issues an error if the children do not all have the same parent or if the
parent is not a subclass of compositeWidgetClass.
- Returns immediately if the common parent is being destroyed; otherwise,
for each unique child on the list, XtUnmanageChildren performs the
following:
- Ignores the child if it already is unmanaged or is being destroyed and
marks it if not.
- If the child is realized, it makes it nonvisible by unmapping it.
- •
- Calls the change_managed routine of the widgets' parent after all children
have been marked if the parent is realized.
XtUnmanageChildren does not destroy the children widgets.
Removing widgets from a parent's managed set is often a temporary
banishment, and, some time later, you may manage the children again.
The XtUnmanageChild function constructs a widget list of
length one and calls XtUnmanageChildren.
The XtChangeManagedSet function performs the following:
- Issues an error if the widgets specified in the manage_children and
the unmanage_children lists to no all have the same parent, or if
that parent is not a subclass of compositeWidgetClass.
- Returns immediately if the common parent is being destroyed.
- If no CompositeClassExtension is defined, or a
CompositeClassExtension is defined but with an
allows_change_managed_set field with a value of False, and
XtChangeManagedSet was invoked with a non-NULL
do_change_proc procedure then XtChangeManagedSet performs
the following:
- Calls XtUnmanageChildren (unmanage_children,
num_unmanage_children).
- Calls the do_change_proc specified.
- Calls XtManageChildren (manage_children,
num_manage_children) and then returns immediately.
- •
- Otherwise, if a CompositeClassExtension is defined with an
allows_change_managed_set field with a value of True, or if
no CompositeClassExtension is defined, and
XtChangeManagedSetwas do_change_proc procedure, then the
following is performed:
- For each child on the unmanage_children list; if the child is
already unmanaged or is being destroyed it is ignored, otherwise it is
marked as being unmanaged and if it is realized it is made nonvisible by
being unmapped.
- If the do_change_proc procedure is non-NULL then it is invoked as
specified.
- For each child on the manage_children list; if the child is already
managed or it is being destroyed it is ignored, otherwise it is marked as
managed
- •
- If the parent is realized and after all children have been marked, the
change_managed method of the parent is invoked and subsequently some of
the newly managed children are made viewable by:
- Calling XtRealizeWidget on each of the previously unmanaged child
that is unrealized.
- Mapping each previously unmanaged child that has map_when_managed
True.
The XtIsManaged function returns True if the
specified widget is of class RectObj or any subclass thereof and is managed,
or False otherwise.