XmDisplay(3X) SDK X11 R4.11MU05 XmDisplay(3X)
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 |
+------------------------------+-------------------------------+---------------+---------------------------+--------+
|Name | Class | Type | Default | Access |
+------------------------------+-------------------------------+---------------+---------------------------+--------+
+------------------------------+-------------------------------+---------------+---------------------------+--------+
|XmNdefaultVirtualBindings | DefaultVirtualBindings | String | dynamic | CG |
+------------------------------+-------------------------------+---------------+---------------------------+--------+
|XmNdragInitiatorProtocolStyle | XmCDragInitiatorProtocolStyle | unsigned char | XmDRAG_PREFER_RECEIVER | CG |
+------------------------------+-------------------------------+---------------+---------------------------+--------+
|XmNdragReceiverProtocolStyle | XmCDragReceiverProtocolStyle | unsigned char | XmDRAG_PREFER_PREREGISTER | 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
XmDRAGPREREGISTER
As an initiator, this client does not use the dynamic protocol and
can only arrange visual effects with receivers who provide
preregistered information.
XmDRAGDYNAMIC
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.
XmDRAGNONE
Specifies that drag and drop is disabled for this client.
XmDRAGDROPONLY
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.
XmDRAGPREFERDYNAMIC
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.
XmDRAGPREFERPREREGISTER
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.
XmDRAGPREFERRECEIVER
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
XmDRAGPREREGISTER
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.
XmDRAGDYNAMIC
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.
XmDRAGNONE
Specifies that drag and drop is disabled for this client.
XmDRAGDROPONLY
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.
XmDRAGPREFERDYNAMIC
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.
XmDRAGPREFERPREREGISTER
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 +-------------+--------------------+----------------+-----------+
| | Preregister | Prefer Preregister | Prefer Dynamic | Dynamic |
+-------------------+-------------+--------------------+----------------+-----------+
| Preregister | Preregister | Preregister | Preregister | Drop Only |
+-------------------+-------------+--------------------+----------------+-----------+
|Prefer Preregister | Preregister | Preregister | Preregister | Dynamic |
+-------------------+-------------+--------------------+----------------+-----------+
| Prefer Receiver | Preregister | Preregister | Dynamic | Dynamic |
+-------------------+-------------+--------------------+----------------+-----------+
| Prefer Dynamic | Preregister | Dynamic | Dynamic | Dynamic |
+-------------------+-------------+--------------------+----------------+-----------+
| Dynamic | Drop Only | Dynamic | Dynamic | Dynamic |
+-------------------+-------------+--------------------+----------------+-----------+
The value XmDRAGNONE does not appear in the above matrix. When
specified for either the initiator or receiver side, XmDRAGNONE
implies that drag and drop transactions are not supported. A value
of XmDRAGDROPONLY (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 XmDRAGDROPONLY.
Inherited Resources
All of the superclass resources inherited by XmDisplay are designated
N/A (not applicable).
RELATED INFORMATION
ApplicationShell(3X), Composite(3X), Core(3X), TopLevelShell(3X),
VendorShell(3X), WMShell(3X), XmGetXmDisplay(3X), and XmScreen(3X).
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