XmDisplay(library call) XmDisplay(library call)

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. The two basic protocol
types are 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 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).

+-----------------------------------------------------------------------------------------------------------------+
| XmDisplay Resource Set |
|Name | Class | Type | Default | Access |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNdefaultButtonEmphasis | XmCDefaultButtonEmphasis | XtEnum | XmEXTERNAL_HIGHLIGHT | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNdefaultVirtualBindings | XmCDefaultVirtualBindings | String | dynamic | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNdragInitiatorProtocolStyle | XmCDragInitiatorProtocolStyle | unsigned char | XmDRAG_PREFER_RECEIVER | CG |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNdragReceiverProtocolStyle | XmCDragReceiverProtocolStyle | unsigned char | XmDRAG_PREFER_DYNAMIC | CG |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNdragStartCallback | XmCCallback | XtCallbackList | NULL | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNenableBtn1Transfer | XmCEnableBtn1Transfer | XtEnum | XmOFF | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNenableButtonTab | XmCEnableButtonTab | Boolean | False | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNenableDragIcon | XmCEnableDragIcon | Boolean | False | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNenableEtchedInMenu | XmCEnableEtchedInMenu | Boolean | False | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNenableToggleColor | XmCEnableToggleColor | Boolean | False | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNenableToggleVisual | XmCEnableToggleVisual | Boolean | False | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNenableUnselectableDrag | XmCEnableUnselectableDrag | Boolean | True | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNenableWarp | XmCEnableWarp | XtEnum | True | CSG |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNmotifVersion | XmCMotifVersion | int | XmVERSION | CSG |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNnoFontCallback | XmCCallback | XtCallbackList | NULL | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNnoRenditionCallback | XmCCallback | XtCallbackList | NULL | C |
+------------------------------+-------------------------------+----------------+------------------------+--------+
|XmNuserData | XmCUserData | XtPointer | NULL | CSG |
+------------------------------+-------------------------------+----------------+------------------------+--------+
+------------------------------+-------------------------------+----------------+------------------------+--------+
XmNdefaultButtonEmphasis
Specifies whether to change the look of the PushButton
widget and gadget that have the XmNshowAsDefault resource
set. When the PushButton is the default, it has an etched
out button which is enclosed with another etched in border.
The XmNdefaultButtonEmphasis has the follow possible
values, which affect the location cursor:

XmINTERNAL_HIGHLIGHT
Causes the location cursor to appear in between
the two etched borders to minimize the space
required.

XmEXTERNAL_HIGHLIGHT
Causes the PushButton to draw the location cursor
outside the second border.

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 \n\
...
osfLeft: <Key>left, Ctrl<Key>H

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 the 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 default value of this resource is dependent on the
capabilities of the display. If the display supports the
shape extension, allowing the dynamic protocol to use
arbitrarily sized drag cursors, the default of this
resource is XmDRAG_PREFER_DYNAMIC, otherwise the default is
XmDRAG_PREFER_PREREGISTER.


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 described in the
following table.

+---------------+------------------------------------------------------------------------------------+
|Drag Initiator | | | | |
| | Drag Receiver Protocol Style | | | |
+---------------+------------------------------+--------------------+----------------+---------- --+
| | Preregister | Prefer Preregister | Prefer Dynamic | Dynamic |
+---------------+------------------------------+--------------------+----------------+---------- --+
| | Preregister | Preregister | Preregister | Drop Only |
+---------------+------------------------------+--------------------+----------------+---------- --+
| | Preregister | Preregister | Preregister | Dynamic |
+---------------+------------------------------+--------------------+----------------+---------- --+
| | Preregister | Preregister | Dynamic | Dynamic |
+---------------+------------------------------+--------------------+----------------+---------- --+
| | Preregister | Dynamic | Dynamic | Dynamic |
+---------------+------------------------------+--------------------+----------------+---------- --+
| | Drop Only | Dynamic | Dynamic | Dynamic |
+---------------+------------------------------+--------------------+----------------+---------------+

The value XmDRAG_NONE does not appear in the 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.

XmNdragStartCallback
Specifies the list of callbacks that are invoked when the
XmDragStart function is called. The type of structure whose
address is passed to this callback is
XmDragStartCallbackStruct. The callback reason is
XmCR_DRAG_START.

XmNenableBtn1Transfer
Specifies if selection and transfer actions are integrated
on Btn1 and extend actions are activated on Btn2. This
resource can take the following values:

XmOFF Disables integration and selection activation on
Btn1.

XmBUTTON2_TRANSFER
Enables integration and selection activation on
Btn1 and transfer on Btn2.

XmBUTTON2_ADJUST
Enables integration and selection activation on
Btn1 and adjust on Btn2.


This resource affects the actions of Text, TextField, List,
and Container.

XmNenableButtonTab
Specifies if the action for the <Tab> key (KNextField and
KPrevField actions) is to be modified. A value of True
modifies the key to move as an arrow key until the boundary
of a tab group is reached. Then, at the boundary of the tab
group, KNextField and KPrevField will move to the next or
previous tab group, respectively. A value of False does not
cause modification.

XmNenableDragIcon
Specifies which set of icons are to be used for system
default cursors during drag and drop operations. A value of
False specifies that earlier versions of Motif release
icons are used, a value of True specifies that alternate
icons are used. This resource affects both the 16x16 and
the 32x32 icons that the system defaults for each of the
Screen objects associated with this display.

XmNenableEtchedInMenu
Specifies the shadowing of the button widgets and gadgets
in menus when the control is activated. A value of True
causes the selected menu to be drawn with the shadow etched
in; this shadow style is consistent with the selected
appearance of other button widgets outside of menus. A
value of False causes the selected menu to be draw with the
shadow etched out. This resource affects the actions of
PushButton, ToggleButton, and CascadeButton widgets and
gadgets when they are children of Menu.


When this resource is set, the background of a button in a
menu uses the XmNselectColor (derived from the
XmNselectPixel) when armed as a default. A PushButton uses
the XmNarmColor if it is defined. A ToggleButton uses the
XmNselectColor if XmNindicatorOn is False and
XmNfillOnSelect is True.

XmNenableToggleColor
Specifies how to determine the default value of the
XmNselectColor resource of ToggleButton and
ToggleButtonGadget. A value of True causes the default
value of XmNselectColor to be set to the value of
XmNhighlightColor. A value of False causes the default
value of XmNselectColor to be set to the value of
XmNbackground. This resource only affects the appearance
of ToggleButton widgets and gadgets that are in
XmONE_OF_MANY or XmONE_OF_MANY_ROUND mode. In addition,
XmNenableToggleColor only influences the default value of
XmNselectColor. That is, if the user or application sets a
value for XmNselectColor, then XmNenableToggleColor is
ignored.

XmNenableToggleVisual
Specifies the visual appearance of the ToggleButton widget
and/or gadget. This resource affects the default value of
the ToggleButton[Gadget] XmNindicatorType and
XmNindicatorOn resources. When the ToggleButton is in a
RadioBox, a value of True causes the XmONE_OF_MANY_ROUND (a
shadowed circle) to be the default. Otherwise, when this
resource is True, the ToggleButton XmNindicatorOn resource
causes a default of XmN_OF_MANY, which will be a shadowed
square with a check mark (check box).


A value of False causes the following:

XmONE_OF_MANY
Is a shadowed diamond.

XmN_OF_MANY
Is a shadowed square.

XmNenableUnselectableDrag
Specifies whether or not it is possible to drag from Label
and Scale. A value of True enables the drag; a value of
False disables it.

XmNenableWarp
Specifies if an application is allowed to warp the pointer
from the user. A value of True enables warping, a value of
False does not.

XmNmotifVersion
Specifies the current version of Motif that the current
implementation is supposed to behave like. By default, this
resource gets its value from release values in Xm.h.

XmNnoFontCallback
This callback is called whenever a rendition attempts to
load a font or fontset and fails. This can happen on
creation if the font is specified as XmLOAD_IMMEDIATE or
when an attempt is made to render an XmString using a font
specified as XmLOAD_DEFERRED. An application can have this
callback attempt to remedy this problem by calling
XmRenditionUpdate on the input rendition to provide a font
for the widget to use. This may be done by either providing
an an alternative font name to be loaded using the
XmNfontName and XmNfontType resources or with an already
loaded font using the XmNfont resource. The callback reason
is XmCR_NO_FONT. This callback uses the
XmDisplayCallbackStruct structure.

XmNnoRenditionCallback
This callback is called whenever an attempt is made to
render a segment with a RENDITION tag which does not match
any renditions in a given render table. The callback reason
is XmCR_NO_RENDITION. This callback uses the
XmDisplayCallbackStruct structure.


An application can have this callback attempt to remedy
this problem by creating a new rendition with the given tag
and adding it to render_table.


The XmNnoRenditionCallback should deallocate the render
table passed in in the render_table field of the callback
structure. Note that the table will automatically be
deallocated if the XmRenderTableAddRenditions function is
called on it. The callback should NOT deallocate the
modified render table that is passed back to Motif in the
render_table field. If the application wishes to manipulate
this render table further, it should make a copy with the
XmRenderTableCopy function before returning from the
callback.

XmNuserData
Specifies a client data pointer for applications. An
internally unused resource.

Inherited Resources

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

Callback Information

A pointer to the following structure is passed to the
XmNdragStartCallback callback:

typedef struct
{
int reason;
XEvent *event;
Widget timeStamp;
Boolean doit;
}XmDragStartCallbackStruct;

reason Indicates why the callback was invoked

event Points to the XEvent that triggered the callback

widget Indicates the ID of the widget from which the drag was
initiated.

doit Is an IN/OUT member that allows the callback to determine
whether to continue with the drag or cancel. Setting doit
to False will cancel the drag. The default value is NULL.

A pointer to the following structure is passed to the
XmNnoFontCallback and XmNnoRenditionCallback callbacks:

typedef struct
{
int reason;
XEvent *event;
XmRendition rendition;
char *font_name;
XmRenderTable render_table;
XmStringTag tag;
}XmDisplayCallbackStruct;

reason Indicates why the callback was invoked.

event Points to the XEvent that triggered the callback. It can be
NULL.

rendition Specifies the rendition with the missing font.

font_name Specifies the name of the font or font set which could not
be loaded.

render_table
Specifies the render table with the missing rendition.

tag Specifies the tag of the missing rendition.

The following table describes the reasons for which the individual
callback structure fields are valid.

+------------------+----------------------+
|Reason | Valid Fields |
+------------------+----------------------+
|XmCR_NO_FONT | rendition, font_name |
+------------------+----------------------+
|XmCR_NO_RENDITION | render_table, tag |
+------------------+----------------------+
+------------------+----------------------+

RELATED

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

XmDisplay(library call)