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XmDisplay(3X)


OSF/Motif


NAME

  XmDisplay - The Display widget class


SYNOPSIS

  #include <Xm/Display.h>


DESCRIPTION

  The XmDisplay object is used by the Motif widgets to store information that
  is specific to a display.  It also allows the toolkit to access certain
  information on widget hierarchies that would otherwise be unavailable.
  Each client has one XmDisplay object for each display it accesses.

  An XmDisplay object is automatically created when the application creates
  the first shell on a display (usually accomplished by a call to
  XtAppInitialize or XtAppCreateShell). It is not necessary to create an
  XmDisplay object by any other means. An application can use the function
  XmGetXmDisplay to obtain the widget ID of the XmDisplay object for a given
  display.

  An application cannot supply initial values for XmDisplay resources as
  arguments to a call to any function that creates widgets. The application
  or user can supply initial values in a resource file. After creating the
  first shell on the display, the application can use XmGetXmDisplay to
  obtain the widget ID of the XmDisplay object and then call XtSetValues to
  set the XmDisplay resources.

  XmDisplay resources specify the drag protocol style for a client
  participating in drag and drop transactions.	There are two basic protocol
  types, preregister and dynamic.  When a preregister protocol is used, the
  toolkit handles any communication between the initiator and receiver
  clients, and displays the appropriate drag-over and drag-under visual
  effects.  A client registers its drop sites in advance and this information
  is stored in a property for each top-level window.  When the drag pointer
  enters a top level window, the drop site information is read by the
  initiator.  A dynamic protocol allows the source and destination clients to
  dynamically communicate drag and drop state information between each other,
  and to update their respective visuals accordingly.  The toolkit provides
  drop site information as the pointer passes over any given drop site. In
  this mode, a receiver can supply a procedure to generate its own drag-under
  effects.

  Classes

  Display inherits behavior and resources from Core, Composite, Shell,
  WMShell, VendorShell, TopLevelShell, and ApplicationShell classes.

  The class pointer is xmDisplayClass.

  The class name is XmDisplay.

  New Resources

  The following table defines a set of widget resources used by the
  programmer to specify data.  The programmer can also set the resource
  values for the inherited classes to set attributes for this widget. To
  reference a resource by name or by class in an .Xdefaults file, remove the
  XmN or XmC prefix and use the remaining letters.  To specify one of the
  defined values for a resource in an .Xdefaults file, remove the Xm prefix
  and use the remaining letters (in either lowercase or uppercase, but
  include any underscores between words).  The codes in the access column
  indicate if the given resource can be set at creation time (C), set by
  using XtSetValues (S), retrieved by using XtGetValues (G), or is not
  applicable (N/A).

  XmDisplay Resource Set

  XmNdefaultVirtualBindings
       Class: DefaultVirtualBindings
       Default: dynamic
       Type:  String
       Access: CG

  XmNdragInitiatorProtocolStyle
       Class: XmCDragInitiatorProtocolStyle
       Default: XmDRAG_PREFER_RECEIVER
       Type:  unsigned char
       Access: CG

  XmNdragReceiverProtocolStyle
       Class: XmCDragReceiverProtocolStyle
       Default: XmDRAG_PREFER_PREREGISTER
       Type:  unsigned char
       Access: CG

  XmNdefaultVirtualBindings
      Specifies the default virtual bindings for the display. Following is an
      example of a specification for the defaultVirtualBindings resource in a
      resource file:

	   *defaultVirtualBindings: \
		osfBackSpace   :    <Key>BackSpace\n\
		osfInsert      :    <Key>InsertChar\n\
	   ...
		osfDelete      :    <Key>DeleteChar

  XmNdragInitiatorProtocolStyle
      Specifies the drag and drop protocol requirements or preference when
      the client is an initiator.  The possible values are:

      XmDRAG_PREREGISTER
	  As an initiator, this client does not use the dynamic protocol and
	  can only arrange visual effects with receivers who provide
	  preregistered information.

      XmDRAG_DYNAMIC
	  As an initiator, this client does not make use of any preregistered
	  drop site information made available by other clients, and can only
	  arrange visual effects with receivers who use the dynamic protocol.

      XmDRAG_NONE
	  Specifies that drag and drop is disabled for this client.

      XmDRAG_DROP_ONLY
	  As an initiator, this client does not use either the preregistered
	  drop site information or the dynamic protocol.  It supports
	  dragging, and any time the cursor is over a client that supports
	  drag and drop, valid feedback is provided.  There are no other
	  visual effects.

      XmDRAG_PREFER_DYNAMIC
	  As an initiator, this client can support both the preregister and
	  dynamic protocols, but prefers to use dynamic protocols whenever
	  possible in order to provide high-quality drag-under feedback.

      XmDRAG_PREFER_PREREGISTER
	  As an initiator, this client can support both the preregister and
	  dynamic protocols, but prefers to use the preregister protocol
	  whenever possible in order to accommodate performance needs or to
	  provide consistent drag-over feedback.

      XmDRAG_PREFER_RECEIVER
	  Indicates that this client can support both preregister and dynamic
	  protocols, but will defer to the preference of the receiver client.
	  This value is valid only for the XmNdragInitiatorProtocolStyle
	  resource, and is its default value.

  XmNdragReceiverProtocolStyle
      Specifies the drag and drop protocol requirements or preference when
      this client is a receiver.  The values are:

      XmDRAG_PREREGISTER
	  As a receiver, this client preregisters drop site information and
	  does not use the dynamic protocol.  It can only arrange visual
	  effects with initiators who make use of the preregistered
	  information.

      XmDRAG_DYNAMIC
	  As a receiver, this client uses the dynamic protocol and does not
	  preregister drop site information.  It can only arrange visual
	  effects with initiators who use the dynamic protocol.

      XmDRAG_NONE
	  Specifies that drag and drop is disabled for this client.

      XmDRAG_DROP_ONLY
	  As a receiver, this client neither uses the dynamic protocol nor
	  preregisters drop site information.  It supports dropping, and when
	  dragging over this client, valid feedback is always provided, but
	  there are no other visual effects.

      XmDRAG_PREFER_DYNAMIC
	  As a receiver, this client can support both the preregister and
	  dynamic protocols, but prefers to use dynamic protocol whenever
	  possible in order to provide high-quality drag-under feedback.

      XmDRAG_PREFER_PREREGISTER
	  As a receiver, this client can support both the preregister and
	  dynamic protocols, but prefers to use the preregister protocol
	  whenever possible in order to accommodate performance needs.

  The actual protocol used between an initiator and a receiver is based on
  the protocol style of the receiver and initiator.  The decision matrix is
  as follows:

       _______________________________________________________
		      |
       Drag Initiator |	      Drag Receiver Protocol Style
       Protocol Style |
       ---------------|---------------------------------------
		      |
		      | Pre    Prefer Pre    Prefer Dyn	   Dyn
       ---------------|---------------------------------------
	Pre	      | Pre    Pre	     Pre	   D-O
		      |
	Prefer Pre    | Pre    Pre	     Pre	   Dyn
		      |
	Prefer Rec    | Pre    Pre	     Dyn	   Dyn
		      |
	Prefer Dyn    | Pre    Dyn	     Dyn	   Dyn
		      |
	Dyn	      | D-O    Dyn	     Dyn	   Dyn
       _______________|_______________________________________

	  Pre = Preregister
	  Dyn = Dynamic
	  D-P = Drop Only

  The value XmDRAG_NONE does not appear in the above matrix.  When specified
  for either the initiator or receiver side, XmDRAG_NONE implies that drag
  and drop transactions are not supported.  A value of XmDRAG_DROP_ONLY (Drop
  Only) results when an initiator and receiver cannot compromise protocol
  styles, that is, one client requires dynamic mode while the other can only
  support preregister mode, or if either explicitly has specified
  XmDRAG_DROP_ONLY.

  Inherited Resources

  All of the superclass resources inherited by XmDisplay are designated N/A
  (not applicable).


SEE ALSO

  ApplicationShell(3X), Composite(3X), Core(3X), TopLevelShell(3X),
  VendorShell(3X), WMShell(3X), XmGetXmDisplay(3X), XmScreen(3X)

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