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From: aw@KITCHEN.BELLCORE.COM (Andrew Wason, aw@cellar.bae.bellcore.com)
Newsgroups: comp.windows.x.motif
Subject: Re: Resizing with an XmScrolledWindow
Message-ID: <9010311757.AA03169@bellcore.bellcore.com>
Date: 31 Oct 90 16:07:36 GMT
References: <3659@stl.stc.co.uk>
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: inet
Organization: The Internet
Lines: 71

mcsun!ukc!stl!tap@uunet.uu.net writes:
>    I am trying to get an XmScrolledWindow to size itself correctly to
> a given child widget. What I mean by correctly is :-
> 
>    1) if only vertical scrolling enabled, size the clip window to
>       the width of the child widget. Leave the clip window height
>       to whatever default is set.
> 
>    2) if only horizontal scrolling enabled, size the clip window
>       to the height of the child widget. Leave the width alone
> 
>    3) if scrolling in both directions is enabled, set the width
>       and height of the clip window to some specified value

I don't know what you mean by "enabled". If your XmNscrollBarDisplayPolicy
is XmAS_NEEDED (see below) then the scrollbars will only be displayed
if your work area widget is too big.  When using XmAUTOMATIC mode,
you don't explicitly enable/disable the scrollbars - they get enabled/disabled
depending on the size of the work area child.


> [...]
>   static Arg ViewportArgs[] = {
>      {XmNscrollBarPlacement,XmTOP_LEFT},
>      {XmNspacing,0},
>      {XmNscrollingPolicy,XmAUTOMATIC},
>      {XmNscrollBarDisplayPolicy,XmSTATIC},
>      {XmNvisualPolicy,XmCONSTANT}
>   };

XmNscrollBarDisplayPolicy should be XmAS_NEEDED or else the
scrollbars will always be displayed.

For your item #1, you want only the vertical scrollbar,
so you must set the width of the XmScrolledWindow to be
the width of the work area. Since you must take into account
the width of the vertical scrollbar too, it is best to use
XtQueryGeometry as the manual suggests:

    intended.request_mode = CWHeight | XtCWQueryOnly;
    intended.height = 75;
    XtQueryGeometry(scrolledWin, &intended, &preferred);
    XtVaSetValues(scrolledWin,
        XmNwidth,   preferred.width,
        NULL);

The XtQueryGeometry will cause scrolledWin to return the correct
width in preferred.width (this is the width which will cause the
horizontal scrollbar to disappear).

For your item #2, you want only the horizontal scrollbar.
You need to do basically the same thing as above, but set
the height of the scrolledWin:

    intended.request_mode = CWWidth | XtCWQueryOnly;
    intended.width = 75;
    XtQueryGeometry(scrolledWin, &intended, &preferred);
    XtVaSetValues(scrolledWin,
        XmNheight,   preferred.height,
        NULL);

For item #3, you want both scrollbars, so just set
the width/height of scrolledWin to be less than the width/height
of your work area child.

Andrew

--------------------------------------------------------------------------------
Andrew Wason                                        Bell Communications Research
aw@cellar.bae.bellcore.com                          Piscataway, NJ
bellcore!cellar!aw