Path: utzoo!attcan!uunet!lll-winken!ncis.llnl.gov!helios.ee.lbl.gov!pasteur!ucbvax!tut.cis.ohio-state.edu!bloom-beacon!ATHENA.MIT.EDU!swick
From: swick@ATHENA.MIT.EDU (Ralph R Swick)
Newsgroups: comp.windows.x
Subject: Re: XTranslateCoordinates
Message-ID: <8903171727.AA13677@LYRE.MIT.EDU>
Date: 17 Mar 89 17:27:38 GMT
References: <8903171621.AA18094@litsun5.litsun2.epfl.ch>
Sender: daemon@bloom-beacon.MIT.EDU
Organization: DEC/MIT Project Athena
Lines: 19

>        XTranslateCoordinates takes among other inputs the screen
> number.  How does an application find the screen number?  For example,
> I have the following line of code:
>
>    XTranslateCoordinates( XtDisplay(widget), XtWindow(widget),
>                    RootWindow( XtDisplay(widget), SCREEN_NUMBER),
>                        0, 0, &shellx, &shelly, &w );

If you really want the screen number, you'll have to code your own
loop that compares XtScreen(widget) with
ScreenOfDisplay(XtDisplay(widget), loop_index).

In the example you give, a much simpler solution is to use
RootWindowOfScreen(XtScreen(widget)) instead of RootWindow().

> I know about XtTranslateCoords(), but it doesn't work (see next
> posting).

This is a known bug (under some window managers, e.g. uwm).