Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!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: XtSetValues / geometry_manager problem Message-ID: <8809211310.AA09341@LYRE.MIT.EDU> Date: 21 Sep 88 13:10:01 GMT References: <6365@batcomputer.tn.cornell.edu> Sender: daemon@bloom-beacon.MIT.EDU Organization: DEC/MIT Project Athena Lines: 38 Date: 21 Sep 88 01:48:42 GMT From: gdykes@tcgould.tn.cornell.edu (Gene Dykes) 1) How is a geometry manager supposed to make a good layout when it is given Widget and constraint values which point to outdated information? It can't. You are 100% correct in your analysis of this problem. See below. 2) A GeometryManager may also be affected by certain constraints of a widget. If one of these constraints is changed by XtSetValues, there is no mechanism for telling XtSetValues that the geometry manager needs to be called. This is a corollary of (1). If ConstraintSetValues were able to modify the geometry and constraints of the widget passed to the Geometry Manager, then your problems would be over. See below. What I would like is for XtSetValues to pass the correct (new) information to the geometry manager Done. The R3 Intrinsics specification changes the values passed to the set_values method so that the real widget is in the 'new' argument. Semantically, this is equivalent to assuming that all requested changes will be accepted (rather than denied). When the Geometry Manager is invoked (on the real widget) it therefore sees all the new state. (This is one of 3 non-source-compatible changes for widgets; it will affect widgets which had to implement gross work-arounds in their set_values procedures.) and to allow the ConstraintSetValues procedure to be able to return a code that means, "The Geometry Will Change", so that XtSetValues will call the geometry manager even if x,y,width,height haven't changed. I'm not sure why you want this. If the widget geometry (you left out border_width) hasn't changed, then why is there a need for a re-layout? In R3, ConstraintSetValues can modify any parts of the (new) widget geometry and thereby cause the Geometry Manager to be invoked. -Ralph