SoSelection(3IV)

NAME
SoSelection — manages a list of selected objects

INHERITS FROM
SoBase > SoFieldContainer > SoNode > SoGroup > SoSeparator > SoSelection

SYNOPSIS
#include <Inventor/nodes/SoSelection.h>

typedef void
SoSelectionPathCB(void *userData, SoPath *path)
typedef void
SoSelectionClassCB(void *userData, SoSelection *sel)
typedef SoPath *
SoSelectionPickCB(void *userData, const SoPickedPoint *pick)

enum Policy {
SoSelection::SINGLE
Left mouse pick on object clears selection, then selects object. Left mouse pick on nothing clears selection. Only one object may be selected at a time.
SoSelection::TOGGLE
Left mouse pick on object toggles its selection status. Left mouse pick on nothing does nothing. Multiple objects may be selected.
SoSelection::SHIFT
When shift key is down, selection policy is TOGGLE. When shift key is up, selection policy is SINGLE. Multiple objects may be selected.
}

Fields from class SoSelection:

SoSFEnum
policy

Fields from class SoSeparator:

SoSFEnum
renderCaching
SoSFEnum
boundingBoxCaching
SoSFEnum
renderCulling
SoSFEnum
pickCulling

Methods from class SoSelection:

SoSelection()

SoSelection(int nChildren)
static SoType
getClassTypeId()
void
select(const SoPath *path)
void
select(SoNode *node)
void
deselect(const SoPath *path)
void
deselect(int which)
void
deselect(SoNode *node)
void
toggle(const SoPath *path)
void
toggle(SoNode *node)
SbBool
isSelected(const SoPath *path) const
SbBool
isSelected(SoNode *node) const
void
deselectAll()
int
getNumSelected() const
const SoPathList *
getList() const
SoPath *
getPath(int index) const
SoPath *
operator [](int i) const
void
addSelectionCallback(SoSelectionPathCB *f, void *userData = NULL)
void
removeSelectionCallback(SoSelectionPathCB *f, void *userData = NULL)
void
addDeselectionCallback(SoSelectionPathCB *f, void *userData = NULL)
void
removeDeselectionCallback(SoSelectionPathCB *f, void *userData = NULL)
void
addStartCallback(SoSelectionClassCB *f, void *userData = NULL)
void
removeStartCallback(SoSelectionClassCB *f, void *userData = NULL)
void
addFinishCallback(SoSelectionClassCB *f, void *userData = NULL)
void
removeFinishCallback(SoSelectionClassCB *f, void *userData = NULL)
void
setPickFilterCallback(SoSelectionPickCB *f, void *userData = NULL, SbBool callOnlyIfSelectable = TRUE)
void
setPickMatching(SbBool pickTwice)
SbBool
getPickMatching() const

Methods from class SoSeparator:

static void
setNumRenderCaches(int howMany)
static int
getNumRenderCaches()

Methods from class SoGroup:

void
addChild(SoNode *child)
void
insertChild(SoNode *child, int newChildIndex)
SoNode *
getChild(int index) const
int
findChild(const SoNode *child) const
int
getNumChildren() const
void
removeChild(int index)
void
removeChild(SoNode *child)
void
removeAllChildren()
void
replaceChild(int index, SoNode *newChild)
void
replaceChild(SoNode *oldChild, SoNode *newChild)

Methods from class SoNode:

void
setOverride(SbBool state)
SbBool
isOverride() const
SoNode *
copy(SbBool copyConnections = FALSE) const
virtual SbBool
affectsState() const
static SoNode *
getByName(const SbName &name)
static int
getByName(const SbName &name, SoNodeList &list)

Methods from class SoFieldContainer:

void
setToDefaults()
SbBool
hasDefaultValues() const
SbBool
fieldsAreEqual(const SoFieldContainer *fc) const
void
copyFieldValues(const SoFieldContainer *fc, SbBool copyConnections = FALSE)
SbBool
set(const char *fieldDataString)
void
get(SbString &fieldDataString)
virtual int
getFields(SoFieldList &resultList) const
virtual SoField *
getField(const SbName &fieldName) const
SbBool
getFieldName(const SoField *field, SbName &fieldName) const
SbBool
isNotifyEnabled() const
SbBool
enableNotify(SbBool flag)

Methods from class SoBase:

void
ref()
void
unref() const
void
unrefNoDelete() const
void
touch()
virtual SoType
getTypeId() const
SbBool
isOfType(SoType type) const
virtual void
setName(const SbName &name)
virtual SbName
getName() const

DESCRIPTION
SoSelection defines a node which can be inserted into a scene graph and will generate and manage a selection list from picks on any node in the subgraph below it. Nodes are selected based on a current selection policy. Callback functions report back to the application when a path has been selected or deselected. The selection list can also be managed programmatically.

When handling events, SoSelection makes sure that the mouse release event was over the same object as the mouse press event before changing the list of selected objects. This allows users to mouse down on an object, change their mind and move the cursor off the object, then release the mouse button without altering the selection.

The selection can be highlighted automatically through the SoXtRenderArea, or the application can provide custom highlights. Please see the chapter "Creating a Selection Highlight Style" in the Inventor Toolmaker.

FIELDS
SoSFEnum
policy
Selection policy that is followed in response to user interaction. This can be set to SoSelection::SINGLE, SoSelection::TOGGLE, or SoSelection::SHIFT.

METHODS

SoSelection()
Creates a selection node with the default settings.

SoSelection(int nChildren)
Constructor that specifies the approximate number of children.

static SoType
getClassTypeId()
Return the type id for the SoSelection class.

void
select(const SoPath *path)
Select the passed path by adding it to the selection list. The selection node must lie in the path. The path is copied and truncated such that the selection node is the head of the path. If the selection node does not lie in the path, the selection list remains unchanged. This method ignores the current selection policy.

void
select(SoNode *node)
Select the passed node by creating a path to it, and adding the path to the selection list by calling select(path). If there is more than one instance of node beneath the selection node, the created path will be the first instance found.

void
deselect(const SoPath *path)
Deselect the passed path by removing it from the selection list.

void
deselect(int which)
Deselect a path by removing it from the selection list. The argument which specifies which path in the list to be removed.

void
deselect(SoNode *node)
Deselect the passed node by creating a path to it, and removing the node from the selection list by calling deselect(path). If there is more than one instance of node beneath the selection node, the created path will be the first instance found.

void
toggle(const SoPath *path)
Toggle the selection status of the passed path — if the path is in the selection list, it is removed; if not in the list, it is added.

void
toggle(SoNode *node)
Toggle the selection status of the passed node by creating a path to it, then calling toggle(path). If there is more than one instance of node beneath the selection node, the created path will be the first instance found.

SbBool
isSelected(const SoPath *path) const
Returns TRUE if the passed path is selected, that is, if it is in the selection list.

SbBool
isSelected(SoNode *node) const
Returns TRUE if the passed node is selected by creating a path to it, then calling isSelected(). If there is more than one instance of node beneath the selection node, the created path will be the first instance found.

void
deselectAll()
Deselect all paths in the selection list, that is, clear the list.

int
getNumSelected() const
Return the number of paths in the selection list.

const SoPathList *
getList() const
Return the list of selected paths.

SoPath *
getPath(int index) const
SoPath *
operator [](int i) const
Return the ith path in the selection list.

void
addSelectionCallback(SoSelectionPathCB *f, void *userData = NULL)
void
removeSelectionCallback(SoSelectionPathCB *f, void *userData = NULL)
The selection callbacks are invoked every time an object is selected, whether it be from user interaction or from method call. The callbacks are invoked after the object has been added to the selection list.

void
addDeselectionCallback(SoSelectionPathCB *f, void *userData = NULL)
void
removeDeselectionCallback(SoSelectionPathCB *f, void *userData = NULL)
The deselection callbacks are invoked every time an object is deselected, whether it be from user interaction or from method call. This is invoked after the object has been removed from the selection list.

void
addStartCallback(SoSelectionClassCB *f, void *userData = NULL)
void
removeStartCallback(SoSelectionClassCB *f, void *userData = NULL)
The start callbacks are invoked when the user has initiated an interactive change to the selection list (by picking objects). This will be followed by invocations of the select and/or deselect callbacks, finally followed by each finish callback. A start callback can be used, for instance, to save the current selection for later restoration (e.g. undo/redo). The start callbacks are not called when the selection list is changed programmatically.

void
addFinishCallback(SoSelectionClassCB *f, void *userData = NULL)
void
removeFinishCallback(SoSelectionClassCB *f, void *userData = NULL)
The finish callbacks are invoked when the user has finished interactively changing the selection list (by picking objects). This was preceded by an invocation of each start callback, and invocations of the select and/or deselect callbacks. The finish callbacks are not called when the selection list is changed programmatically.

void
setPickFilterCallback(SoSelectionPickCB *f, void *userData = NULL, SbBool callOnlyIfSelectable = TRUE)
The pick filter callback is invoked when a pick has occurred and the selection node is about to change the selection list. The callback function returns the path that the selection node should use when selecting and deselecting. If no pick callback is registered (the default), the selection node will use the path returned by SoPickedPoint::getPath() on the picked point associated with the event being processed. The returned path should not be ref'd - selection will ref() and unref() it. (See SoPath::unrefNoDelete().)

Note that a picked object may or may not be a child of the selection node. A selection node will only select paths that pass through it. Possible return values from the callback:

[a] NULL — selection behaves as if nothing was picked (i.e. for SINGLE and SHIFT policies, this clears the selection list). Handle event action traversal halts.

[b] Path — this path will be selected/deselected according to the selection policy (it must lie under the selection node). Handle event action traversal halts.

[c] Path containing only the selection node — apply the selection policy as if nothing was picked. Handle event action traversal continues.

[d] Path not passing through the selection node — selection ignores this pick event and no change is made to the selection list. Handle event action traversal continues.

A simple way to tell selection to ignore the pick is to return an SoPath with no nodes in it. (i.e. return new SoPath;) Selection will always ref the path returned by the callback, make a copy of the path, then unref the path.

The callOnlyIfSelectable argument, when set to TRUE, means the pick callback function will only be invoked on picks which pass through the selection node. When FALSE, all picks will be passed to the callback whether they pass through the selection or not.

void
setPickMatching(SbBool pickTwice)
SbBool
getPickMatching() const
SoSelection will pick once on mouse down and once on mouse up, and make sure the picks match before changing the selection list. This allows the user to pick down on an object, change their mind and drag off the object, release the mouse button and not affect the selection. Pass TRUE to enable this behavior. Pass FALSE to disable this, meaning whatever is picked on a mouse release is added to/removed from the selection list. Default is pick-matching on.

FILE FORMAT/DEFAULTS
Selection {
renderCaching	AUTO
boundingBoxCaching	AUTO
renderCulling	AUTO
pickCulling	AUTO
policy	SHIFT
}

SEE ALSO
SoEventCallback, SoXtRenderArea, SoBoxHighlightRenderAction, SoLineHighlightRenderAction