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From: tap@stl.stc.co.uk
Newsgroups: comp.windows.x.motif
Subject: Resizing with an XmScrolledWindow
Message-ID: <3659@stl.stc.co.uk>
Date: 30 Oct 90 16:21:41 GMT
Sender: news@stl.stc.co.uk
Reply-To: tap@stl.stc.co.uk ()
Organization: STC Technology Limited, London Road, Harlow, Essex, UK
Lines: 127

Hi All,

   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

   In all of the above I don't muck around with any sizing of the 
ScrollBars. Currently all that happens is that the clipping window
remains it's default size (width = 81, height = 95) whatever I do !


   My application does the following :-

   1) create the XmScrolledWindow widget


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

  ...

   widpar = /* parent for the ScrolledWindow, usually an XmRowColumn widget */
   widgetID = (id)XmCreateScrolledWindow(widpar,"Scrollport",
      	       	  ViewportArgs,XtNumber(ViewportArgs));


   2) create the child widget (usually an XmRowColumn) and all subtree widgets


   3) call XtRealizeWidget on the application toplevel widget

   4) get the size of the child widget

      i = 0;
      XtSetArg(args[i],XmNwidth,&width);i++;
      XtSetArg(args[i],XmNheight,&height);i++;
      XtGetValues(child,args,i);


   5) size the ScrolledWindow as stated above, so that it shows the
      required ScrollBars and sizes the clip window correctly

   Part 5) is the bit I can't get right. I have tried :-

   a) get the width/height of the relevent ScrollBars, add this
      to the child width/height and set the XmNwidth,XmNheight
      resources on the ScrolledWindow accordingly

   b) get the value of XmNclipWindow (I think this is an XmDrawingArea widget)
      and set the width/height resources on that widget

   c) set the XmNresizePolicy of the clip window to XmRESIZE_ANY and
      try b). When I ask for the current value of XmNresizePolicy I
      get a value which isn't any of XmRESIZE_NONE,XmRESIZE_GROW,XmRESIZE_ANY !

   d) try a) and b) together

   e) try a) and c) together

   f) muck about with XtQueryGeometry as suggested in the Programmer's
      Reference Manual (p355)

      ...

      XtWidgetGeometry intendedSize,preferredSize;
      XtGeometryMask sizeMask = CWWidth | CWHeight;
      XtGeometryResult geoResult;

      ...

      intendedSize.request_mode = sizeMask;
      intendedSize.width = childWidth;
      intendedSize.height = childHeight;
      XtQueryGeometry(widgetID,&intendedSize,&preferredSize);

      printf("Viewport::realize : preferred size %d %d\n",
      	    preferredSize.width,preferredSize.height);

      geoResult = XtMakeResizeRequest(widgetID,
      	       	     preferredSize.width,preferredSize.height,
      	       	     &(intendedSize.width),&(intendedSize.height));

      printf("Viewport::realize : result %d intended size %d %d\n",
      	       	     geoResult,intendedSize.width,intendedSize.height);

      ...

      I get reasonable values for the preferred size, but the clip window
      doesn't re-size. I don't like this anyway 'cos I am under the
      impression that the QueryGeometry stuff is for internal widget
      implementation not for general application use. While we're here
      the description for XmNvisualPolicy in the Programmer's Reference
      says (p353) :-

      "When the policy is XmCONSTANT ... The only time the viewing area
       can grow is in response to a resize from the ScrolledWindow's
       parent."

      How do/Can/Should I get the parent to issue such a resize request to
      it's child ?


   Any help/ideas on this gratefully accepted. If I'm being dumb, tell me.
   Which brings me to another point. Our bean-counters have cut our Usenet
   feed (in an effort to save some money), so currently if you reply to
   the net I won't see it ! So please reply by e-mail to :-

      T.A.Plant@stl.stc.co.uk

   Thanks


   Environment : Sun 3/60, X11R3 and Motif 1.0