Volume 6A: Motif Programming Manual

15.5.4 Focus Callbacks

The XmNfocusCallback and XmNlosingFocusCallback callback routines can be used to monitor when a

Text widget gains and loses the keyboard focus. A Text widget can receive the input focus if the user intentionally

shifts the focus to the widget or if the application moves the focus using XmProcessTraversal(). When a

widget gains the input focus and the insertion cursor is not visible, we can make it visible and cause the widget to

automatically scroll to the current cursor location by installing an XmNfocusCallback routine that calls

XmTextShowCursorPosition(), as shown in the following code fragment:

{

Widget text_w;

extern void gain_focus();

...

text_w = XmCreateScrolledText(...);

XtAddCallback(text_w, XmNfocusCallback, gain_focus, NULL);

...

}

void

gain_focus(text_w, client_data, call_data)

Widget text_w;

XtPointer client_data;

XtPointer call_data;

{

XmTextShowCursorPosition (text_w, XmTextGetCursorPosition (text_w));

}

The XmNfocusCallback is passed a callback structure of type XmAnyCallbackStruct with the callback

reason set to XmCR_FOCUS.

The XmNlosingFocusCallback callback can be used to monitor when the Text widget loses its focus. The

callback structure passed to the callback function is an XmTextVerifyCallbackStruct. All of the fields except

the text field are valid, and the reason field is set to XmCR_LOSING_FOCUS.

15.6 Text Widget Internationalization

In Motif 1.2, the Text and TextField widgets have been modified to support internationalized input and output. ...