XtManageChildren(3Xt)
NAME
XtManageChildren, XtManageChild, XtUnmanageChildren,
XtUnmanageChild, XtChangeManagedSet, XtIsManaged - manage
and unmanage children
SYNTAX
typedef Widget *WidgetList;
void XtManageChildren(children, num_children)
WidgetList children;
Cardinal num_children;
void XtManageChild(child)
Widget child;
void XtUnmanageChildren(children, num_children)
WidgetList children;
Cardinal num_children;
void XtUnmanageChild(child)
Widget child;
void XtChangeManagedSet(unmanage_children, num_unman-
age_children, manage_children, num_manage_children,
post_unmanage_pre_manage_hook, client_data)
WidgetList unmanage_children;
Cardinal num_unmanage_children;
WidgetList manage_children;
Cardinal num_manage_children;
XtCSMProc post_unmanage_pre_manage_hook;
XtPointer client_data;
Boolean XtIsManaged(widget)
Widget widget
ARGUMENTS
child Specifies the child.
children Specifies a list of child widgets.
num_children
Specifies the number of children.
widget Specifies the widget.
manage_children
Specifies the list of widget children to add to
the managed set.
num_manage_children
Specifies the number of entries in the man-
age_children list.
unmanage_children
Specifies the list of widget children to remove
from the managed set.
num_unmanage_children
Specifies the number of entries in the unman-
age_children list.
post_unmanage_pre_manage_hook
Specifies the post unmanage, pre manage hook
procedure to invoke.
client_data
Specifies the client data to be passed to the
hook precedure.
DESCRIPTION
The XtManageChildren function performs the following:
+o Issues an error if the children do not all have the
same parent or if the parent is not a subclass of
compositeWidgetClass.
+o 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.
+o If the parent is realized and after all children have
been marked, it makes some of the newly managed chil-
dren viewable:
- Calls the change_managed routine of the widgets'
parent.
- Calls XtRealizeWidget on each previously unman-
aged child that is unrealized.
- Maps each previously unmanaged child that has
map_when_managed True.
Managing children is independent of the ordering of chil-
dren 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 pro-
cedure 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 real-
ized.
The XtManageChild function constructs a WidgetList of
length one and calls XtManageChildren.
The XtUnmanageChildren function performs the following:
+o Issues an error if the children do not all have the
same parent or if the parent is not a subclass of
compositeWidgetClass.
+o 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.
+o Calls the change_managed routine of the widgets' par-
ent 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:
+o Issues an error if the widgets specified in the man-
age_children and the unmanage_children lists to no
all have the same parent, or if that parent is not a
subclass of compositeWidgetClass.
+o Returns immediately if the common parent is being
destroyed.
+o If no CompositeClassExtension is defined, or a Com-
positeClassExtension is defined but with an
allows_change_managed_set field with a value of
False, and XtChangeManagedSet was invoked with a non-
NULL post_unmanage_pre_manage_hook procedure then
XtChangeManagedSet performs the following:
- Calls XtUnmanageChildren (unmanage_children,
num_unmanage_children).
- Calls the post_unmanage_pre_manage_hook speci-
fied.
- Calls XtManageChildren (manage_children,
num_manage_children) and then returns immedi-
ately.
+o 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 post_unmanage_pre_man-
age_hook 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 post_unmanage_pre_manage_hook procdedure
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
+o 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 previ-
ously 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.
SEE ALSO
XtMapWidget(3Xt) XtRealizeWidget(3Xt)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface