XmTextGetCenterline — Return the height (length) of a character string when the writing direction is

XmTextGetCenterline accesses the x position of the centerline in the  Text  widget,  relative  to  the  x
       position of the top of the widget.

       widget    Specifies the Text widget ID.

XmTextGetCenterline  —  Return  the  height  (length) of a character string when the writing direction is
       vertical

       In the case of horizontal writing, this function accesses 0.

       In  the  case  of  vertical writing, this function accesses the x position of the first centerline in the
       Text widget, relative to the x position of the left of the widget.  The calculation  takes  into  account
       the  margin width, shadow thickness, highlight thickness, and a half of font width of the first font(set)
       in the fontlist used for drawing text.

XmText(3), XmTextGetBaseline(3)

                                                                                          XmTextGetCenterline(3)

       #include <Xm/Text.h>
       intXmTextGetCenterline(
       Widgetwidget);