🚀 go-pugleaf

gnb@bby.oz.au (Gregory N. Bond) writes
>One of our users is writing an application that has a List widget
>inside a viewport widget.  He wants to be able to scroll a particular
>line of the list to the (top,center,bottom) of the viewport, but I
>can't see any calls &/| resources to do this.
>
>Hints gladly accepted.  Should this go in the FAQ?

The following allows one to change the position of a viewport
to some absolute position over its child. (Note: bounds checking 
should also be done).

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ViewportWidget viewport;
Widget child;
Widget w;
Position vport_vpos,	/* where the viewport is */
	 absolute_vpos; /* absolute position to move to */
Arg arg;

absolute_vpos = 111;	/* to move to position 111 */
w = XtNameToWidget(viewport,"vertical");
XtSetArg(arg,XtNy,&vport_vpos);
XtGetValues(child,&arg,1);

XtCallCallbacks(w,XtNscrollProc,absolute_vpos+vport_vpos);
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Yes, this should go in the FAQ

-Afzal