gnb@bby.oz.au (Gregory N. Bond) (04/11/91)
Consider a subclass of a constraint widget that has three children
that are created in the parent widget initialize routine. The three
children are all the same class, but for one of them I want a
different default value for a constraint resource. (i.e. I want
children 1 and 2 to have "dislpayed: true" and child three to have
"displayed: false" as the default, where displayed is a constraint
resource).
I also want the resource database to be able to override the default,
as you would expect.
The default value for the displayed resource is true, so I don't need
anr args to the create call and children 1 and 2 work as expected -
they are normally displayed but the user can turn them off. How can I
specify the different default constraint resource for the third child?
If I specify it as an arg to the XtCreateManagedWidget() call, it
overrides the resource database and the user cannot change the
setting.
What I think I need is a way of asking the resource database what the
user wants for the displayed resource of the as-yet non-existant child
before calling XtCreateManagedWidget(), and set the resource to false
with an arglist if either the user hasn't specified or false is what
they want.
Is that clear?
Greg.
--
Gregory Bond, Burdett Buckeridge & Young Ltd, Melbourne, Australia
Internet: gnb@melba.bby.oz.au non-MX: gnb%melba.bby.oz@uunet.uu.net
Uucp: {uunet,pyramid,ubc-cs,ukc,mcvax,prlb2,nttlab...}!munnari!melba.bby.oz!gnbaw@jello.bae.bellcore.com (Andrew Wason) (04/13/91)
In article <GNB.91Apr11174058@leo.bby.oz.au>, gnb@bby.oz.au (Gregory N. Bond) writes: > Consider a subclass of a constraint widget that has three children > that are created in the parent widget initialize routine. The three > children are all the same class, but for one of them I want a > different default value for a constraint resource. (i.e. I want > children 1 and 2 to have "dislpayed: true" and child three to have > "displayed: false" as the default, where displayed is a constraint > resource). > > I also want the resource database to be able to override the default, > as you would expect. > > The default value for the displayed resource is true, so I don't need > anr args to the create call and children 1 and 2 work as expected - > they are normally displayed but the user can turn them off. How can I > specify the different default constraint resource for the third child? > If I specify it as an arg to the XtCreateManagedWidget() call, it > overrides the resource database and the user cannot change the > setting. I think you can do this by using XtGetSubresources for the display resource on widget three. Create a struct to hold the value of the XtNdisplay resource. Create a new XtResourceList with one entry for your XtNdisplay resource, but with default_addr set to False (instead of the normal default of True). (assume widgets 1,2,3 are of class "Display", class pointer displayWidgetClass). typedef struct { Boolean display; } ThreeDisplayStruct; ThreeDisplayStruct threeDisplay; XtResource displayResource[] = { { XtNdisplay, XtCDisplay, XtRBoolean, sizeof(Boolean), XtOffsetOf(ThreeDisplayStruct, display), XtRImmediate, (XtPointer)False } }; Now call XtGetSubresources to fetch this resource for your widget (parent is the constraint parent). XtGetSubresources(parent, (caddr_t)&threeDisplay, "three", "Display", displayResource, XtNumber(displayResource), NULL, 0); Now create your widget using the XtNdisplay resource you just fetched. three = XtVaCreateManagedWidget("three", displayWidgetClass, parent, XtNdisplay, threeDisplay.display, NULL); This would be even simpler if XtNdisplay wasn't a constraint resource (call it XtNnewDisplay), you could create the widget first and then refetch the XtNnewDisplay resource directly into the widget instance record. three = XtCreateManagedWidget("three", displayWidgetClass, parent, NULL, 0); XtGetSubresources(three, (caddr_t)&three, NULL, NULL, &resources[5], 1, NULL, 0); Where resources[5] is the entry for XtNnewDisplay in widget threes resource list (don't try this for callback resources though). I haven't actually tried any of this, but I think it will work. Let me know if you try it. Andrew _______________________________________________________________________________ Andrew Wason Bell Communications Research aw@bae.bellcore.com Piscataway, NJ bellcore!bae!aw