NAME

       XmDragContext — The DragContext widget class "XmDragContext" "widget class" "DragContext"

SYNOPSIS

       #include <Xm/DragDrop.h>

DESCRIPTION

       DragContexts  are  special  widgets  used in drag and drop transactions.  A DragContext is
       implemented as a widget, but a client does not explicitly  create  a  DragContext  widget.
       Instead,  a  client initiates a drag and drop transaction by calling XmDragStart, and this
       routine initializes and returns a DragContext widget. There is a  unique  DragContext  for
       each  drag  operation.  The  toolkit  frees  a DragContext when a transaction is complete;
       therefore, an application programmer should not explicitly destroy a DragContext.

       Initiator and receiver clients both use DragContexts to track the state of a  transaction.
       When  the  initiator  and receiver of a transaction are in the same client, they share the
       same DragContext instance. If they are  in  different  clients,  there  are  two  separate
       DragContexts.  In  this  case,  the initiator calls XmDragStart and the toolkit provides a
       DragContext for the receiver client. The only resources  pertinent  to  the  receiver  are
       XmNexportTargets  and  XmNnumExportTargets.  These  can both be passed as arguments to the
       XmDropSiteRetrieve function to obtain information about the current drop site.

       In general, in order to receive data, a drop site must share at least one target type  and
       operation  in  common  with  a  drag  source.  The DragContext resource, XmNexportTargets,
       identifies the selection targets for the drag source. These export  targets  are  compared
       with  the  XmNimportTargets  resource  list  specified  by  a  drop site.  The DragContext
       resource, XmNdragOperations, identifies the valid operations that can be  applied  to  the
       source data by the initiator. The drop site counterpart resource is XmNdropSiteOperations,
       which indicates a drop site's supported operations.

       A client uses DragIcon widgets to define the drag-over animation effects associated with a
       given  drag  and  drop transaction.  An initiator specifies a set of drag icons, selects a
       blending model,  and  sets  foreground  and  background  cursor  colors  with  DragContext
       resources.

       The  type  of  drag-over  visual  used  to  represent a drag operation depends on the drag
       protocol style. In preregister mode, the server is grabbed,  and  either  a  cursor  or  a
       pixmap  may  be  used  as  a  drag-over visual. In dynamic mode, drag-over visuals must be
       implemented with the X cursor. If the resulting drag protocol style is Drop Only  or  None
       and  the  XmNdragInitiatorProtocolStyle is XmDRAG_DYNAMIC or XmDRAG_PREFER_DYNAMIC, then a
       dynamic visual style (cursor) is used. Otherwise, a preregister visual style is used.

   Classes
       DragContext inherits behavior and resources from Core.

       The class pointer is xmDragContextClass.

       The class name is XmDragContext.

   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  a  .Xdefaults
       file,  remove  the  XmN or XmC prefix and use the remaining letters. To specify one of the
       defined values for a resource in a .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).

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RELATED INFORMATION

       Core(3),  XmDisplay(3),  XmDragCancel(3),  XmDragIcon(3),  XmDragStart(3),  XmDropSite(3),
       XmDropTransfer(3), and XmScreen(3).

                                                                                 XmDragContext(3)