XmDragContext(library call) XmDragContext(library call)
NAME [Toc] [Back]
XmDragContext - The DragContext widget class
SYNOPSIS [Toc] [Back]
#include <Xm/DragDrop.h>
DESCRIPTION [Toc] [Back]
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.
- 1 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
Classes [Toc] [Back]
DragContext inherits behavior and resources from Core.
The class pointer is xmDragContextClass.
The class name is XmDragContext.
New Resources [Toc] [Back]
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).
- 2 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
________________________________________________________________________________________________________________________
XmDragContext Resource Set
Name Class Type Default Access
________________________________________________________________________________________________________________________
XmNblendModel XmCBlendModel unsigned char XmBLEND_ALL CG
________________________________________________________________________________________________________________________
XmNclientData XmCClientData XtPointer NULL CSG
________________________________________________________________________________________________________________________
XmNconvertProc XmCConvertProc XtConvertSelectionIncrProc NULL CSG
________________________________________________________________________________________________________________________
XmNcursorBackground XmCCursorBackground Pixel dynamic CSG
________________________________________________________________________________________________________________________
XmNcursorForeground XmCCursorForeground Pixel dynamic CSG
________________________________________________________________________________________________________________________
XmNdragDropFinishCallback XmCCallback XtCallbackList NULL CSG
________________________________________________________________________________________________________________________
XmNdragMotionCallback XmCCallback XtCallbackList NULL C
________________________________________________________________________________________________________________________
XmNdragOperations XmCDragOperations unsigned char XmDROP_COPY | XmDROP_MOVE C
________________________________________________________________________________________________________________________
XmNdropFinishCallback XmCCallback XtCallbackList NULL C
________________________________________________________________________________________________________________________
XmNdropSiteEnterCallback XmCCallback XtCallbackList NULL C
________________________________________________________________________________________________________________________
XmNdropSiteLeaveCallback XmCCallback XtCallbackList NULL C
________________________________________________________________________________________________________________________
XmNdropStartCallback XmCCallback XtCallbackList NULL C
________________________________________________________________________________________________________________________
XmNexportTargets XmCExportTargets Atom * NULL CSG
________________________________________________________________________________________________________________________
XmNincremental XmCIncremental Boolean False CSG
________________________________________________________________________________________________________________________
XmNinvalidCursorForeground XmCCursorForeground Pixel dynamic CSG
________________________________________________________________________________________________________________________
XmNnoneCursorForeground XmCCursorForeground Pixel dynamic CSG
________________________________________________________________________________________________________________________
XmNnumExportTargets XmCNumExportTargets Cardinal 0 CSG
________________________________________________________________________________________________________________________
XmNoperationChangedCallback XmCCallback XtCallbackList NULL C
________________________________________________________________________________________________________________________
XmNoperationCursorIcon XmCOperationCursorIcon Widget dynamic CSG
________________________________________________________________________________________________________________________
XmNsourceCursorIcon XmCSourceCursorIcon Widget dynamic CSG
________________________________________________________________________________________________________________________
XmNsourcePixmapIcon XmCSourcePixmapIcon Widget dynamic CSG
________________________________________________________________________________________________________________________
XmNstateCursorIcon XmCStateCursorIcon Widget dynamic CSG
________________________________________________________________________________________________________________________
XmNtopLevelEnterCallback XmCCallback XtCallbackList NULL C
________________________________________________________________________________________________________________________
XmNtopLevelLeaveCallback XmCCallback XtCallbackList NULL C
- 3 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
________________________________________________________________________________________________________________________
|XmNvalidCursorForeground XmCCursorForeground Pixel dynamic CSG
|_______________________________________________________________________________________________________________________|
|____________________________|________________________|____________________________|___________________________|________|
| | | |
XmNblendModel [Toc] [Back]
Specifies which combination of DragIcons are blended to
produce a drag-over visual.
XmBLEND_ALL [Toc] [Back]
Blends all three DragIcons: the source, state and
operation icons. The icons are layered from top
to bottom with the operation icon on top and the
source icon on the bottom. The hotspot is derived
from the state icon.
XmBLEND_STATE_SOURCE [Toc] [Back]
Blends the state and source icons only. The
hotspot is derived from the state icon.
XmBLEND_JUST_SOURCE [Toc] [Back]
Specifies that only the source icon is used, which
the initiator updates as required.
XmBLEND_NONE [Toc] [Back]
Specifies that no drag-over visual is generated.
The client tracks the drop site status through
callback routines and updates the drag-over
visuals as necessary.
XmNclientData [Toc] [Back]
Specifies the client data to be passed to XmNconvertProc
when it is invoked.
XmNconvertProc [Toc] [Back]
If XmNincremental is True, specifies a procedure of type
XtConvertSelectionIncrProc that converts the source data to
the format(s) requested by the receiver client. The widget
argument passed to this procedure is the DragContext widget.
The selection atom passed is _MOTIF_DROP. If XmNincremental
is False, the procedure is an XtConvertSelectionProc, and
should ignore the max_length, client_data, and request_id
arguments and should handle the conversion atomically. Data
returned by XmNconvertProc must be allocated using XtMalloc,
and will be freed automatically by the toolkit after the
transfer. For additional information on selection
conversion procedures, see X Toolkit Intrinsics-C Language
Interface.
XmNcursorBackground [Toc] [Back]
Specifies the background pixel value of the cursor.
- 4 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
XmNcursorForeground [Toc] [Back]
Specifies the foreground pixel value of the cursor when the
state icon is not blended. This resource defaults to the
foreground color of the widget passed to the XmDragStart
function.
XmNdragDropFinishCallback [Toc] [Back]
Specifies the list of callbacks that are called when the
transaction is completed. The type of the structure whose
address is passed to this callback is
XmDragDropFinishCallbackStruct. The reason sent by the
callback is XmCR_DRAG_DROP_FINISH.
XmNdragMotionCallback [Toc] [Back]
Specifies the list of callbacks that are invoked when the
pointer moves. The type of structure whose address is
passed to this callback is XmDragMotionCallbackStruct. The
reason sent by the callback is XmCR_DRAG_MOTION.
XmNdragOperations [Toc] [Back]
Specifies the set of valid operations associated with an
initiator client for a drag transaction. This resource is a
bit mask that is formed by combining one or more of the
following values using a bitwise operation such as inclusive
OR (|): XmDROP_COPY, XmDROP_LINK, XmDROP_MOVE. The value
XmDROP_NOOP for this resource indicates that no operations
are valid. For Text and TextField widgets, this resource is
set to XmDROP_COPY | XmDROP_MOVE; for List widgets, it is
set to XmDROP_COPY.
XmNdropFinishCallback [Toc] [Back]
Specifies the list of callbacks that are invoked when the
drop is completed. The type of the structure whose address
is passed to this callback is XmDropFinishCallbackStruct.
The reason sent by the callback is XmCR_DROP_FINISH.
XmNdropSiteEnterCallback [Toc] [Back]
Specifies the list of callbacks that are invoked when the
pointer enters a drop site. The type of the structure whose
address is passed to this callback is
XmDropSiteEnterCallbackStruct. The reason sent by the
callback is XmCR_DROP_SITE_ENTER.
XmNdropSiteLeaveCallback [Toc] [Back]
Specifies the list of callbacks that are invoked when the
pointer leaves a drop site. The type of the structure whose
address is passed to this callback is
XmDropSiteLeaveCallbackStruct. The reason sent by the
callback is XmCR_DROP_SITE_LEAVE.
- 5 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
XmNdropStartCallback [Toc] [Back]
Specifies the list of callbacks that are invoked when a drop
is initiated. The type of the structure whose address is
passed to this callback is XmDropStartCallbackStruct. The
reason sent by the callback is XmCR_DROP_START.
XmNexportTargets [Toc] [Back]
Specifies the list of target atoms associated with this
source. This resource identifies the selection targets this
source can be converted to.
XmNincremental [Toc] [Back]
Specifies a Boolean value that indicates whether the
transfer on the initiator side uses the Xt incremental
selection transfer mechanism described in X Toolkit
Intrinsics-C Language Interface. If the value is True, the
initiator uses incremental transfer; if the value is False,
the initiator uses atomic transfer.
XmNinvalidCursorForeground [Toc] [Back]
Specifies the foreground pixel value of the cursor when the
state is invalid. This resource defaults to the value of the
XmNcursorForeground resource.
XmNnoneCursorForeground [Toc] [Back]
Specifies the foreground pixel value of the cursor when the
state is none. This resource defaults to the value of the
XmNcursorForeground resource.
XmNnumExportTargets [Toc] [Back]
Specifies the number of entries in the list of export
targets.
XmNoperationChangedCallback [Toc] [Back]
Specifies the list of callbacks that are invoked when the
drag is started and when the user requests that a different
operation be applied to the drop. The type of the structure
whose address is passed to this callback is
XmOperationChangedCallbackStruct. The reason sent by the
callback is XmCR_OPERATION_CHANGED.
XmNoperationCursorIcon [Toc] [Back]
Specifies the cursor icon used to designate the type of
operation performed by the drag transaction. If NULL,
XmScreen resources provide default icons for copy, link, and
move operations.
XmNsourceCursorIcon [Toc] [Back]
Specifies the cursor icon used to represent the source when
a dynamic visual style is used. If NULL, the
XmNdefaultSourceCursorIcon resource of XmScreen provides a
- 6 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
default cursor icon.
XmNsourcePixmapIcon [Toc] [Back]
Specifies the pixmap icon used to represent the source when
a preregister visual style is used. The icon is used in
conjunction with the colormap of the widget passed to
XmDragStart. If NULL, XmNsourceCursorIcon is used.
XmNstateCursorIcon [Toc] [Back]
Specifies the cursor icon used to designate the state of a
drop site. If NULL, XmScreen resources provide default
icons for a valid, invalid, and no drop site condition.
XmNtopLevelEnterCallback [Toc] [Back]
Specifies the list of callbacks that are called when the
pointer enters a top-level window or root window (due to
changing screens). The type of the structure whose address
is passed to this callback is XmTopLevelEnterCallbackStruct.
The reason sent by the callback is XmCR_TOP_LEVEL_ENTER.
XmNtopLevelLeaveCallback [Toc] [Back]
Specifies the list of callbacks that are called when the
pointer leaves a top level window or the root window (due to
changing screens). The type of the structure whose address
is passed to this callback is XmTopLevelLeaveCallbackStruct.
The reason sent by the callback is XmCR_TOP_LEVEL_LEAVE.
XmNvalidCursorForeground [Toc] [Back]
Specifies the foreground pixel value of the cursor
designated as a valid cursor icon.
Inherited Resources [Toc] [Back]
DragContext inherits behavior and resources from the superclass
described in the following table. For a complete description of each
resource, refer to the Core reference page.
- 7 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
________________________________________________________________________________________________________________
| Core Resource Set |
|Name Class Type Default Access |
|______________________________|_______________________________|________________|______________________|________|
|XmNaccelerators | XmCAccelerators | XtAccelerators | dynamic | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNancestorSensitive | XmCSensitive | Boolean | dynamic | G |
|______________________________|_______________________________|________________|______________________|________|
|XmNbackground | XmCBackground | Pixel | dynamic | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNbackgroundPixmap | XmCPixmap | Pixmap | XmUNSPECIFIED_PIXMAP | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNborderColor | XmCBorderColor | Pixel | XtDefaultForeground | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNborderPixmap | XmCPixmap | Pixmap | XmUNSPECIFIED_PIXMAP | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNborderWidth | XmCBorderWidth | Dimension | 0 | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNcolormap | XmCColormap | Colormap | dynamic | CG |
|______________________________|_______________________________|________________|______________________|________|
|XmNdepth | XmCDepth | int | dynamic | CG |
|______________________________|_______________________________|________________|______________________|________|
|XmNdestroyCallback | XmCCallback | XtCallbackList | NULL | C |
|______________________________|_______________________________|________________|______________________|________|
|XmNheight | XmCHeight | Dimension | dynamic | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNinitialResourcesPersistent | XmCInitialResourcesPersistent | Boolean | True | C |
|______________________________|_______________________________|________________|______________________|________|
|XmNmappedWhenManaged | XmCMappedWhenManaged | Boolean | True | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNscreen | XmCScreen | Screen * | dynamic | CG |
|______________________________|_______________________________|________________|______________________|________|
|XmNsensitive | XmCSensitive | Boolean | True | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNtranslations | XmCTranslations | XtTranslations | dynamic | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNwidth | XmCWidth | Dimension | dynamic | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNx | XmCPosition | Position | 0 | CSG |
|______________________________|_______________________________|________________|______________________|________|
|XmNy | XmCPosition | Position | 0 | CSG |
|______________________________|_______________________________|________________|______________________|________|
|______________________________|_______________________________|________________|______________________|________|
Callback Information [Toc] [Back]
Each of the DragContext callbacks has an associated callback
structure.
A pointer to the following structure is passed to the
XmNdragDropFinishCallback callback:
- 8 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
}XmDragDropFinishCallbackStruct, *XmDragDropFinishCallback;
reason Indicates why the callback was invoked
event Points to the XEvent that triggered the callback
timeStamp Specifies the time at which either the drag or the drop was
completed
A pointer to the following structure is passed to callbacks for
XmNdragMotionCallback:
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
unsigned char operation;
unsigned char operations;
unsigned char dropSiteStatus;
Position x;
Position y;
}XmDragMotionCallbackStruct, *XmDragMotionCallback;
reason Indicates why the callback was invoked.
event Points to the XEvent that triggered the callback.
timeStamp Specifies the timestamp of the logical event.
operation Identifies an operation.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes operation to the value of the operation
member of the XmDragProcCallbackStruct at the time the
DropSite's XmNdragProc returns.
If the toolkit has not called an XmNdragProc and the pointer
is within an active drop site, the toolkit initializes
operation by selecting an operation from the bitwise AND of
the initial value of the operations member and the value of
the DropSite's XmNdropSiteOperations resource. The toolkit
searches this set first for XmDROP_MOVE, then for
XmDROP_COPY, then for XmDROP_LINK, and initializes operation
to the first operation it finds in the set. If the toolkit
finds none of these operations in the set, it initializes
- 9 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
operation to XmDROP_NOOP.
If the toolkit has not called an XmNdragProc and the pointer
is not within an active drop site, the toolkit initializes
operation by selecting an operation from the initial value
of the operations member. The toolkit searches this set
first for XmDROP_MOVE, then for XmDROP_COPY, then for
XmDROP_LINK, and initializes operation to the first
operation it finds in the set. If the toolkit finds none of
these operations in the set, it initializes operation to
XmDROP_NOOP.
operations
Indicates the set of operations supported for the source
data.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes operations to the bitwise AND of the
DropSite's XmNdropOperations and the value of the operations
member of the XmDragProcCallbackStruct at the time the
DropSite's XmNdragProc returns. If the resulting set of
operations is empty, the toolkit initializes operations to
XmDROP_NOOP.
If the toolkit has not called an XmNdragProc and the user
does not select an operation (by pressing a modifier key),
the toolkit initializes operations to the value of the
DragContext's XmNdragOperations resource.
If the toolkit has not called an XmNdragProc and the user
does select an operation, the toolkit initializes operations
to the bitwise AND of the corresponding operation and the
value of the DragContext's XmNdragOperations resource. If
the resulting set of operations is empty, the toolkit
initializes operations to XmDROP_NOOP.
dropSiteStatus
Indicates whether or not a drop site is valid.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes dropSiteStatus to the value of the
dropSiteStatus member of the XmDragProcCallbackStruct at the
time the DropSite's XmNdragProc returns.
If the toolkit has not called an XmNdragProc, it initializes
dropSiteStatus as follows: the toolkit initializes
dropSiteStatus to XmNO_DROP_SITE if the pointer is over an
inactive drop site or is not over a drop site. The toolkit
initializes dropSiteStatus to XmDROP_SITE_VALID if all the
following conditions are met:
- 10 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
+ The pointer is over an active drop site.
+ The DragContext's XmNexportTargets and the DropSite's
XmNimportTargets are compatible.
+ The initial value of the operation member is not
XmDROP_NOOP.
Otherwise, the toolkit initializes dropSiteStatus to
XmDROP_SITE_INVALID.
A pointer to the following structure is passed for the
XmNdropFinishCallback callback:
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
unsigned char operation;
unsigned char operations;
unsigned char dropSiteStatus;
unsigned char dropAction;
unsigned char completionStatus;
}XmDropFinishCallbackStruct, *XmDropFinishCallback;
reason Indicates why the callback was invoked.
event Points to the XEvent that triggered the callback.
timeStamp Specifies the time at which the drop was completed.
operation Identifies an operation.
If the pointer is over an active drop site when the drop
begins, the toolkit initializes operation to the value of
the operation member of the XmDropProcCallbackStruct at the
time the DropSite's XmNdropProc returns.
If the pointer is not over an active drop site when the drop
begins, the toolkit initializes operation by selecting an
operation from the initial value of the operations member.
The toolkit searches this set first for XmDROP_MOVE, then
for XmDROP_COPY, then for XmDROP_LINK, and initializes
operation to the first operation it finds in the set. If it
finds none of these operations in the set, it initializes
operation to XmDROP_NOOP.
operations
Indicates the set of operations supported for the source
data.
- 11 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
If the pointer is over an active drop site when the drop
begins, the toolkit initializes operations to the bitwise
AND of the DropSite's XmNdropOperations and the value of the
operations member of the XmDropProcCallbackStruct at the
time the DropSite's XmNdropProc returns. If the resulting
set of operations is empty, the toolkit initializes
operations to XmDROP_NOOP.
If the pointer is not over an active drop site when the drop
begins and if the user does not select an operation (by
pressing a modifier key), the toolkit initializes operations
to the value of the DragContext's XmNdragOperations
resource.
If the pointer is not over an active drop site when the drop
begins and if the user does select an operation, the toolkit
initializes operations to the bitwise AND of the
corresponding operation and the value of the DragContext's
XmNdragOperations resource. If the resulting set of
operations is empty, the toolkit initializes operations to
XmDROP_NOOP.
dropSiteStatus
Indicates whether or not a drop site is valid.
If the pointer is over an active drop site when the drop
begins, the toolkit initializes dropSiteStatus to the value
of the dropSiteStatus member of the XmDropProcCallbackStruct
at the time the DropSite's XmNdropProc returns.
If the pointer is not over an active drop site when the drop
begins, the toolkit initializes dropSiteStatus to
XmNO_DROP_SITE.
dropAction
Identifies the drop action. The values are XmDROP,
XmDROP_CANCEL, XmDROP_HELP, and XmDROP_INTERRUPT. The
XmDROP_INTERRUPT value is currently unsupported; if
specified, it will be interpreted as an XmDROP_CANCEL.
completionStatus
An IN/OUT member that indicates the status of the drop
action. After the last callback procedure has returned, the
final value of this member determines what visual transition
effects will be applied. There are two values:
XmDROP_SUCCESS [Toc] [Back]
The drop was successful.
XmDROP_FAILURE [Toc] [Back]
The drop was unsuccessful.
- 12 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
A pointer to the following structure is passed to callbacks for
XmNdropSiteEnterCallback:
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
unsigned char operation;
unsigned char operations;
unsigned char dropSiteStatus;
Position x;
Position y;
}XmDropSiteEnterCallbackStruct, *XmDropSiteEnterCallback;
reason Indicates why the callback was invoked.
event Points to the XEvent that triggered the callback.
timeStamp Specifies the time the crossing event occurred.
operation Identifies an operation.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes operation to the value of the operation
member of the XmDragProcCallbackStruct at the time the
DropSite's XmNdragProc returns.
If the toolkit has not called an XmNdragProc, it initializes
operation by selecting an operation from the bitwise AND of
the initial value of the operations member and the value of
the DropSite's XmNdropSiteOperations resource. The toolkit
searches this set first for XmDROP_MOVE, then for
XmDROP_COPY, then for XmDROP_LINK, and initializes operation
to the first operation it finds in the set. If the toolkit
finds none of these operations in the set, it initializes
operation to XmDROP_NOOP.
operations
Indicates the set of operations supported for the source
data.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes operations to the bitwise AND of the
DropSite's XmNdropOperations and the value of the operations
member of the XmDragProcCallbackStruct at the time the
DropSite's XmNdragProc returns. If the resulting set of
operations is empty, the toolkit initializes operations to
XmDROP_NOOP.
- 13 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
If the toolkit has not called an XmNdragProc and the user
does not select an operation (by pressing a modifier key),
the toolkit initializes operations to the value of the
DragContext's XmNdragOperations resource.
If the toolkit has not called an XmNdragProc and the user
does select an operation, the toolkit initializes operations
to the bitwise AND of the corresponding operation and the
value of the DragContext's XmNdragOperations resource. If
the resulting set of operations is empty, the toolkit
initializes operations to XmDROP_NOOP.
dropSiteStatus
Indicates whether or not a drop site is valid.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes dropSiteStatus to the value of the
dropSiteStatus member of the XmDragProcCallbackStruct at the
time the DropSite's XmNdragProc returns.
If the toolkit has not called XmNdragProc, it initializes
dropSiteStatus to XmDROP_SITE_VALID if the DragContext's
XmNexportTargets and the DropSite's XmNimportTargets are
compatible and if the initial value of the operation member
is not XmDROP_NOOP. Otherwise, the toolkit initializes
dropSiteStatus to XmDROP_SITE_INVALID.
x Indicates the x-coordinate of the pointer in root window
coordinates.
y Indicates the y-coordinate of the pointer in root window
coordinates.
A pointer to the following structure is passed to callbacks for
XmNdropSiteLeaveCallback:
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
}XmDropSiteLeaveCallbackStruct, *XmDropSiteLeaveCallback;
reason Indicates why the callback was invoked
event Points to the XEvent that triggered the callback
timeStamp Specifies the timestamp of the logical event
A pointer to the following structure is passed for the
XmNdropStartCallback callback:
- 14 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
unsigned char operation;
unsigned char operations;
unsigned char dropSiteStatus;
unsigned char dropAction;
Position x;
Position y;
}XmDropStartCallbackStruct, *XmDropStartCallback;
reason Indicates why the callback was invoked.
event Points to the XEvent that triggered the callback.
timeStamp Specifies the time at which the drag was completed.
operation Identifies an operation.
If the pointer is over an active drop site when the drop
begins, the toolkit initializes operation to the value of
the operation member of the XmDropProcCallbackStruct at the
time the DropSite's XmNdropProc returns.
If the pointer is not over an active drop site when the drop
begins, the toolkit initializes operation by selecting an
operation from the initial value of the operations member.
The toolkit searches this set first for XmDROP_MOVE, then
for XmDROP_COPY, then for XmDROP_LINK, and initializes
operation to the first operation it finds in the set. If it
finds none of these operations in the set, it initializes
operation to XmDROP_NOOP.
operations
Indicates the set of operations supported for the source
data.
If the pointer is over an active drop site when the drop
begins, the toolkit initializes operations to the bitwise
AND of the DropSite's XmNdropOperations and the value of the
operations member of the XmDropProcCallbackStruct at the
time the DropSite's XmNdropProc returns. If the resulting
set of operations is empty, the toolkit initializes
operations to XmDROP_NOOP.
If the pointer is not over an active drop site when the drop
begins and if the user does not select an operation (by
pressing a modifier key), the toolkit initializes operations
to the value of the DragContext's XmNdragOperations
- 15 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
resource.
If the pointer is not over an active drop site when the drop
begins and if the user does select an operation, the toolkit
initializes operations to the bitwise AND of the
corresponding operation and the value of the DragContext's
XmNdragOperations resource. If the resulting set of
operations is empty, the toolkit initializes operations to
XmDROP_NOOP.
dropSiteStatus
Indicates whether or not a drop site is valid.
If the pointer is over an active drop site when the drop
begins, the toolkit initializes dropSiteStatus to the value
of the dropSiteStatus member of the XmDropProcCallbackStruct
at the time the DropSite's XmNdropProc returns.
If the pointer is not over an active drop site when the drop
begins, the toolkit initializes dropSiteStatus to
XmNO_DROP_SITE.
This field is invalid if the dropAction field is set to
XmDROP_CANCEL.
dropAction
An IN/OUT member that identifies the drop action. The
values are XmDROP, XmDROP_CANCEL, XmDROP_HELP, and
XmDROP_INTERRUPT. The value of dropAction can be modified to
change the action actually initiated. The value
XmDROP_INTERRUPT is currently unsupported; if specified, it
will be interpreted as an XmDROP_CANCEL.
x Indicates the x-coordinate of the pointer in root window
coordinates.
y Indicates the y-coordinate of the pointer in root window
coordinates.
A pointer to the following structure is passed to the
XmNoperationChangedCallback callback:
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
unsigned char operation;
unsigned char operations;
unsigned char dropSiteStatus;
}XmOperationChangedCallbackStruct, *XmOperationChangedCallback;
- 16 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
reason Indicates why the callback was invoked.
event Points to the XEvent that triggered the callback.
timeStamp Specifies the time at which the crossing event occurred.
operation Identifies an operation.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes operation to the value of the operation
member of the XmDragProcCallbackStruct at the time the
DropSite's XmNdragProc returns.
If the toolkit has not called an XmNdragProc, and the
pointer is within an active drop site, the toolkit
initializes operation by selecting an operation from the
bitwise AND of the initial value of the operations member
and the value of the DropSite's XmNdropSiteOperations
resource. The toolkit searches this set first for
XmDROP_MOVE, then for XmDROP_COPY, then for XmDROP_LINK, and
initializes operation to the first operation it finds in the
set. If the toolkit finds none of these operations in the
set, it initializes operation to XmDROP_NOOP.
If the toolkit has not called an XmNdragProc, and the
pointer is not within an active drop site, the toolkit
initializes operation by selecting an operation from the
initial value of the operations member. The toolkit
searches this set first for XmDROP_MOVE, then for
XmDROP_COPY, then for XmDROP_LINK, and initializes operation
to the first operation it finds in the set. If the toolkit
finds none of these operations in the set, it initializes
operation to XmDROP_NOOP.
operations
Indicates the set of operations supported for the source
data.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes operations to the bitwise AND of the
DropSite's XmNdropOperations and the value of the operations
member of the XmDragProcCallbackStruct at the time the
DropSite's XmNdragProc returns. If the resulting set of
operations is empty, the toolkit initializes operations to
XmDROP_NOOP.
If the toolkit has not called an XmNdragProc, and the user
does not select an operation (by pressing a modifier key),
the toolkit initializes operations to the value of the
DragContext's XmNdragOperations resource.
- 17 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
If the toolkit has not called an XmNdragProc, and the user
does select an operation, the toolkit initializes operations
to the bitwise AND of the corresponding operation and the
value of the DragContext's XmNdragOperations resource. If
the resulting set of operations is empty, the toolkit
initializes operations to XmDROP_NOOP.
dropSiteStatus
Indicates whether or not a drop site is valid.
If the toolkit has just called a DropSite's XmNdragProc, the
toolkit initializes dropSiteStatus to the value of the
dropSiteStatus member of the XmDragProcCallbackStruct at the
time the DropSite's XmNdragProc returns.
If the toolkit has not called an XmNdragProc it initializes
dropSiteStatus to XmNO_DROP_SITE if the pointer is over an
inactive drop site or is not over a drop site. The toolkit
initializes dropSiteStatus to XmDROP_SITE_VALID if all the
following conditions are met:
+ The pointer is over an active drop site
+ The DragContext's XmNexportTargets and the DropSite's
XmNimportTargets are compatible
+ The initial value of the operation member is not
XmDROP_NOOP
Otherwise, the toolkit initializes dropSiteStatus to
XmDROP_SITE_INVALID.
A pointer to the following structure is passed to callbacks for
XmNtopLevelEnterCallback:
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
Screen screen;
Window window;
Position x;
Position y;
unsigned char dragProtocolStyle;
}XmTopLevelEnterCallbackStruct, *XmTopLevelEnterCallback;
reason Indicates why the callback was invoked.
event Points to the XEvent that triggered the callback.
- 18 - Formatted: January 24, 2005
XmDragContext(library call) XmDragContext(library call)
timeStamp Specifies the timestamp of the logical event.
screen Specifies the screen associated with the top-level window or
root window being entered.
window Specifies the ID of the top-level window or
|
