XtInstallAccelerators()XtInstallAccelerators()NameXtInstallAccelerators - install a widget's accelerators on another wid‐
get.
Synopsis
void XtInstallAccelerators(destination, source)
Widget destination;
Widget source;
Inputs
destination
Specifies the widget in which events specified in the accel‐
erator table will be detected. Must be of class Core or any
subclass thereof.
source Specifies the widget whose actions will be invoked when
events occur in destination. Must be of class Core or any
subclass thereof.
DescriptionXtInstallAccelerators() merges the accelerator table of source into the
translation table of destination. After this call, events in the des‐
tination widget will trigger actions in the source widget.
If the display_accelerator() method of source is non-NULL, XtInstallAc‐
celerators() calls it with source and a canonical representation of the
accelerator table that was installed. This method is a hook that is
intended to allow a widget to dynamically modify its appearance (a menu
button might display the key sequence that will invoke it, for example)
when an accelerator is installed.
Usage
It is often convenient to be able to bind events in one widget to
actions in another. In particular, it is often useful to be able to
invoke menu actions from the keyboard. The Intrinsics provide a facil‐
ity, called accelerators, that let you accomplish this. An accelerator
table is a translation table that binds events in the destination wid‐
get to actions in the source widget. The accelerator table can be
installed on one or more destination widgets. When an event sequence
in destination would cause an accelerator action to be invoked, and if
the source widget is sensitive, the actions are executed as though
triggered by the same event sequence in source. The event is passed to
the action procedure without modification. The action procedures used
within accelerators must assume neither that the source widget is real‐
ized, nor that any fields of the event are in reference to the source
widget's window if the widget is realized.
Every widget includes an XtNaccelerators resource, which is defined by
the Core widget class. The actual value of this resource can be hard‐
coded by the application or set in a resource file, just like any other
resource.
In order for the XtNaccelerators resource to actually be used, however,
the application must call XtInstallAccelerators() (or XtInstallAllAc‐
celerators()). This call takes two arguments. The destination widget
is the widget whose translation table will be augmented with the accel‐
erator table from the source widget.
It is difficult to remember which of the two widgets in this call is
which. If you want to install a keyboard accelerator so that a key‐
stroke in a text widget invokes an action in a menu button, then the
menu button is the source, and the text widget is the destination. You
must set the accelerator table in the XtNaccelerators resource of the
menu button, and then install those accelerators on the text widget.
If you are programming with the Motif widget set, you will generally
not be able to use accelerators as described here. Motif provides a
different (and incompatible) style of accelerators for use with menus;
see Volume 6, Motif Programming Manual for more information.
Example
Assume an application whose top-level shell widget is named topLevel,
and which contains a Command widget instance named quit. Further
assume that the quit widget has the following XtNaccelerators resource
defined for it:
*quit.accelerators: <KeyPress>q: notify()
The call:
XtInstallAccelerators (topLevel, quit);
would allow a "q" typed in the application's top-level window to invoke
the quit widget's notify action. The notify action invokes the call‐
back list of the button, and assuming that a quit callback was regis‐
tered, causes the application to terminate.
See AlsoXtInstallAllAccelerators(1),
display_accelerator(4).
Xt - Translations and Actions XtInstallAccelerators()
