NAME
XtAddGrab, XtRemoveGrab - redirect user input to a modal widget
SYNTAX
void XtAddGrab(Widget w, Boolean exclusive, Boolean
spring_loaded);
void XtRemoveGrab(Widget w);
ARGUMENTS
exclusive
Specifies whether user events should be dispatched exclusively to this widget
or also to previous widgets in the cascade.
spring_loaded
Specifies whether this widget was popped up because the user pressed
a pointer button.
w
Specifies the widget .
DESCRIPTION
The
function appends the widget (and associated parameters) to the modal cascade
and checks that exclusive is
if spring_loaded is
If these are not
generates an error.
The modal cascade is used by
when it tries to dispatch a user event.
When at least one modal widget is in the widget cascade,
first determines if the event should be delivered.
It starts at the most recent cascade entry and follows the cascade up to and
including the most recent cascade entry added with the exclusive parameter
This subset of the modal cascade along with all descendants of these widgets
comprise the active subset.
User events that occur outside the widgets in this subset are ignored
or remapped.
Modal menus with submenus generally add a submenu widget to the cascade
with exclusive
Modal dialog boxes that need to restrict user input to the most deeply nested
dialog box add a subdialog widget to the cascade with exclusive
User events that occur within the active subset are delivered to the
appropriate widget, which is usually a child or further descendant of the modal
widget.
Regardless of where on the screen they occur,
remap events are always delivered to the most recent widget in the active
subset of the cascade that has spring_loaded
if any such widget exists.
The
function removes widgets from the modal cascade starting
at the most recent widget up to and including the specified widget.
It issues an error if the specified widget is not on the modal cascade.
SEE ALSO
