Provided by: libmotif-dev_2.3.8-4_amd64 
NAME
XmDropSite — The DropSite Registry "XmDropSite"
SYNOPSIS
#include <Xm/DragDrop.h>
DESCRIPTION
A client registers a widget or gadget as a drop site using the XmDropSiteRegister function. In addition,
this routine defines the behavior and capabilities of a drop site by specifying appropriate resources.
For example, the XmNimportTargets and XmNnumImportTargets resources identify respectively the selection
target types and number of types supported by a drop site. The visual animation effects associated with a
drop site are also described with DropSite resources.
Drop site animation effects that occur in response to the pointer entering a valid drop site are called
drag-under effects. A receiver can select from several animation styles supplied by the toolkit or can
provide customized animation effects. Drag-under effects supplied by the toolkit include border
highlighting, shadow in/out drawing, and pixmap representation.
When a preregister drag protocol style is used, the toolkit generates drag-under visual effects based on
the value of the XmNanimationStyle resource. In dynamic mode, if the drop site XmNdragProc resource is
NULL, the toolkit also provides animation effects based on the XmNanimationStyle resource. Otherwise, if
the XmNdragProc routine is specified, the receiver can either assume responsibility for animation effects
(through the XmNdragProc routine) or rely on the toolkit to provide animation. An application can either
handle all or none of the animation effects for a particular drop site. That is, an application should
never do a partial job of animation on a particular drop site.
Drop sites may overlap. The initial stacking order corresponds to the order in which the drop sites were
registered. When a drop site overlaps another drop site, the drag-under effects of the drop site
underneath are clipped by the obscuring drop site(s).
The XmDropSiteUpdate routine sets resources for a widget that is registered as a drop site.
XmDropSiteRetrieve gets drop site resource values previously specified for a registered widget. These
routines are used instead of XtSetValues and XtGetValues.
Classes
XmDropSite does not inherit from any widget class.
New Resources
The following table defines a set of widget resources used by the programmer to specify data. 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 XmDropSiteUpdate (S), retrieved by using XmDropSiteRetrieve (G), or is not applicable
(N/A).
┌─────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ │ XmDropSite│Resource Set │ │ │
│ Name │ Class │ Type │ Default │ Access │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNanimationMask │ XmCAnimationMask │ Pixmap │ XmUNSPECIFIED_PIXMAP │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNanimationPixmap │ XmCAnimationPixmap │ Pixmap │ XmUNSPECIFIED_PIXMAP │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNanimationPixmapDepth │ XmCAnimationPixmapDepth │ int │ 0 │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNanimationStyle │ XmCAnimationStyle │ unsigned char │ XmDRAG_UNDER_HIGHLIGHT │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNdragProc │ XmCDragProc │ XtCallbackProc │ NULL │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNdropProc │ XmCDropProc │ XtCallbackProc │ NULL │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNdropRectangles │ XmCDropRectangles │ XRectangle * │ dynamic │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNdropSiteActivity │ XmCDropSiteActivity │ unsigned char │ XmDROP_SITE_ACTIVE │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNdropSiteOperations │ XmCDropSiteOperations │ unsigned char │ XmDROP_MOVE | XmDROP_COPY │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNdropSiteType │ XmCDropSiteType │ unsigned char │ XmDROP_SITE_SIMPLE │ CG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNimportTargets │ XmCImportTargets │ Atom * │ NULL │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNnumDropRectangles │ XmCNumDropRectangles │ Cardinal │ 1 │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
│ XmNnumImportTargets │ XmCNumImportTargets │ Cardinal │ 0 │ CSG │
├─────────────────────────┼─────────────────────────┼────────────────┼───────────────────────────┼────────┤
└─────────────────────────┴─────────────────────────┴────────────────┴───────────────────────────┴────────┘
XmNanimationMask
Specifies a mask to use with the pixmap specified by XmNanimationPixmap when the animation
style is XmDRAG_UNDER_PIXMAP.
XmNanimationPixmap
Specifies a pixmap for drag-under animation when the animation style is XmDRAG_UNDER_PIXMAP.
The pixmap is drawn with its origin at the upper left corner of the bounding box of the drop
site. If the drop site window is larger than the animation pixmap, the portion of the window
not covered by the pixmap will be tiled with the window's background color.
XmNanimationPixmapDepth
Specifies the depth of the pixmap specified by the XmNanimationPixmap resource. When the depth
is 1, the colors are taken from the foreground and background of the drop site widget. For any
other value, drop site animation occurs only if the XmNanimationPixmapDepth matches the depth
of the drop site window. Colors are derived from the current colormap.
XmNanimationStyle
Specifies the drag-under animation style used when a drag enters a valid drop site. The
possible values are
XmDRAG_UNDER_HIGHLIGHT
The drop site uses highlighting effects.
XmDRAG_UNDER_SHADOW_OUT
The drop site uses an outset shadow.
XmDRAG_UNDER_SHADOW_IN
The drop site uses an inset shadow.
XmDRAG_UNDER_PIXMAP
The drop site uses the pixmap specified by XmNanimationPixmap to indicate that it can
receive the drop.
XmDRAG_UNDER_NONE
The drop site does not use animation effects. A client using a dynamic protocol, may
provide drag-under effects in its XmNdragProc routine.
XmNdragProc
Specifies the procedure that is invoked when the drop site receives a crossing, motion, or
operation changed message. This procedure is called only when a dynamic protocol is used. The
type of structure whose address is passed to this procedure is XmDragProcCallbackStruct. The
reason sent to the procedure is one of the following:
• XmCR_DROP_SITE_ENTER_MESSAGE
• XmCR_DROP_SITE_LEAVE_MESSAGE
• XmCR_DRAG_MOTION
• XmCR_OPERATION_CHANGED
The drag procedure may change the values of some members of the XmDragProcCallbackStruct passed
to it. After the drag procedure returns, the toolkit uses the final values in initializing
some members of the callback structure passed to the appropriate callbacks of the initiator
(the DragContext's XmNdropSiteEnterCallback, XmNdropSiteLeaveCallback, XmNdragMotionCallback,
or XmNoperationChangedCallback callbacks).
XmNdropProc
Specifies the procedure that is invoked when a drop (excluding a cancel or interrupt action)
occurs on a drop site regardless of the status of the drop site. The type of the structure
whose address is passed to this procedure is XmDropProcCallbackStruct. The reason sent to the
procedure is XmCR_DROP_MESSAGE.
The drop procedure may change the values of some members of the XmDropProcCallbackStruct passed
to it. After the drop procedure returns, the toolkit uses the final values in initializing
some members of the XmDropStartCallbackStruct passed to the initiator's drop start callbacks
(the DragContext's XmNdropStartCallback callbacks).
XmNdropRectangles
Specifies a list of rectangles that describe the shape of a drop site. The locations of the
rectangles are relative to the origin of the enclosing object. When XmNdropRectangles is NULL,
the drop site is assumed to be the sensitive area of the enclosing widget. If XmNdropSiteType
is XmDROP_SITE_COMPOSITE, this resource cannot be specified by the application.
Retrieving this resource returns allocated memory that needs to be freed with the XtFree
function.
XmNdropSiteActivity
Indicates whether a drop site is active or inactive. The values are XmDROP_SITE_ACTIVE,
XmDROP_SITE_INACTIVE, and XmDROP_SITE_IGNORE. An active drop site can receive a drop, whereas
an inactive drop site is dormant. An inactive drop site is treated as if it was not a
registered drop site and any drag-under visuals associated with entering or leaving the drop
site do not occur. However, it is still used for clipping drag-under effects. A value of
XmDROP_SITE_IGNORE indicates that a drop site should be ignored for all purposes.
XmNdropSiteOperations
Specifies the set of valid operations associated with a drop site. 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, and XmDROP_MOVE. The value XmDROP_NOOP for this
resource indicates that no operations are valid.
XmNdropSiteType
Specifies the type of the drop site. The possible values are
XmDROP_SITE_SIMPLE
The widget does not have any additional children that are registered as drop sites.
XmDROP_SITE_COMPOSITE
The widget will have children that are registered as drop sites.
XmNimportTargets
Specifies the list of target atoms that this drop site accepts.
XmNnumDropRectangles
Specifies the number of rectangles in the XmNdropRectangles list. If the drop site type is
XmDROP_SITE_COMPOSITE, this resource can not be specified by the application.
XmNnumImportTargets
Specifies the number of atoms in the target atom list.
Callback Information
A pointer to the following structure is passed to the XmNdragProc routine when the drop site receives
crossing, motion, or operation changed messages:
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
Widget dragContext;
Position x;
Position y;
unsigned char dropSiteStatus;
unsigned char operation;
unsigned char operations;
Boolean animate;
} XmDragProcCallbackStruct, *XmDragProcCallback;
reason Indicates why the callback was invoked.
event Points to the XEvent that triggered the callback.
timeStamp Specifies the timestamp of the logical event.
dragContext
Specifies the ID of the DragContext widget associated with the transaction.
x Indicates the x-coordinate of the pointer relative to the drop site.
y Indicates the y-coordinate of the pointer relative to the drop site.
dropSiteStatus
An IN/OUT member that indicates whether or not a drop site is valid.
When reason is XmCR_DROP_SITE_ENTER_MESSAGE or XmCR_OPERATION_CHANGED, or reason is
XmCR_DRAG_MOTION or XmCR_DROP_SITE_LEAVE_MESSAGE and the pointer is not in the same drop site
as on the previous invocation of the drag procedure, the toolkit 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.
When the reason is XmCR_DRAG_MOTION or XmCR_DROP_SITE_LEAVE_MESSAGE and the pointer is within
the same drop site as on the previous invocation of the drag procedure, the toolkit initializes
dropSiteStatus to the value of dropSiteStatus at the time the previous invocation of the drag
procedure returns.
The drag procedure may change the value of this member. After the drag procedure returns, the
toolkit uses the final value in initializing the dropSiteStatus member of the callback struct
passed to the appropriate callbacks of the initiator.
operation An IN/OUT member that identifies an operation.
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.
The drag procedure may change the value of this member. After the drag procedure returns, the
toolkit uses the final value in initializing the operation member of the callback struct passed
to the appropriate callbacks of the initiator.
operations
An IN/OUT member that indicates the set of operations supported for the source data.
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 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.
The drag procedure may change the value of this member. After the drag procedure returns, the
toolkit uses the final value in initializing the operations member of the callback struct
passed to the appropriate callbacks of the initiator.
animate An OUT member that indicates whether the toolkit or the receiver client provides drag-under
effects for a valid drop site. If animate is set to True, the toolkit provides drop site
animation per the XmNanimationStyle resource value; if it is set to False, the receiver
generates drag-under animation effects.
A pointer to the following structure is passed to the XmNdropProc routine when the drop site receives a
drop message:
typedef struct
{
int reason;
XEvent *event;
Time timeStamp;
Widget dragContext;
Position x;
Position y;
unsigned char dropSiteStatus;
unsigned char operation;
unsigned char operations;
unsigned char dropAction;
} XmDropProcCallbackStruct, *XmDropProcCallback;
reason Indicates why the callback was invoked.
event Specifies the XEvent that triggered the callback.
timeStamp Specifies the timestamp of the logical event.
dragContext
Specifies the ID of the DragContext widget associated with the transaction.
x Indicates the x-coordinate of the pointer relative to the drop site.
y Indicates the y-coordinate of the pointer relative to the drop site.
dropSiteStatus
An IN/OUT member that indicates whether or not a drop site is valid.
The toolkit 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.
The drop procedure may change the value of this member. After the drop procedure returns, the
toolkit uses the final value in initializing the dropSiteStatus member of the
XmDropStartCallbackStruct passed to the initiator's drop start callbacks (the DragContext's
XmNdropStartCallback callbacks).
operation An IN/OUT member that identifies an operation.
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 it finds
none of these operations in the set, it initializes operation to XmDROP_NOOP.
The drop procedure may change the value of this member. After the drop procedure returns, the
toolkit uses the final value in initializing the operation member of the
XmDropStartCallbackStruct passed to the initiator's drop start callbacks (the DragContext's
XmNdropStartCallback callbacks).
operations
An IN/OUT member that indicates the set of operations supported for the source data.
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 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.
The drop procedure may change the value of this member. After the drop procedure returns, the
toolkit uses the final value in initializing the operations member of the
XmDropStartCallbackStruct passed to the initiator's drop start callbacks (the DragContext's
XmNdropStartCallback callbacks).
dropAction
An IN/OUT member that identifies the action associated with the drop. The possible values are
XmDROP A drop was attempted. If the drop site is valid, drop transfer handling proceeds.
XmDROP_HELP
The user has requested help on the drop site.
The drop procedure may change the value of this member. After the drop procedure returns, the
toolkit uses the final value in initializing the dropAction member of the
XmDropStartCallbackStruct passed to the initiator's drop start callbacks (the DragContext's
XmNdropStartCallback callbacks).
RELATED INFORMATION
XmDragContext(3), XmDragIcon(3), XmDropSiteConfigureStackingOrder(3), XmDropSiteEndUpdate(3),
XmDropSiteQueryStackingOrder(3), XmDropSiteRegister(3), XmDropSiteStartUpdate(3), XmDropSiteUpdate(3),
XmDropSiteUnregister(3), XmDropTransfer(3), and XmTargetsAreCompatible(3).
XmDropSite(3)