vtkCommand Class Reference

superclass for callback/observer methods More...

#include <vtkCommand.h>

Inheritance diagram for vtkCommand:

Collaboration diagram for vtkCommand:

List of all members.

Public Types
typedef vtkObjectBase	Superclass
Public Member Functions
virtual int	IsA (const char *type)
vtkCommand *	NewInstance () const
void	UnRegister ()
virtual void	UnRegister (vtkObjectBase *)
virtual void	Execute (vtkObject *caller, unsigned long eventId, void *callData)=0
void	SetAbortFlag (int f)
int	GetAbortFlag ()
void	AbortFlagOn ()
void	AbortFlagOff ()
void	SetPassiveObserver (int f)
int	GetPassiveObserver ()
void	PassiveObserverOn ()
void	PassiveObserverOff ()
Static Public Member Functions
static int	IsTypeOf (const char *type)
static vtkCommand *	SafeDownCast (vtkObjectBase *o)
static const char *	GetStringFromEventId (unsigned long event)
static unsigned long	GetEventIdFromString (const char *event)
Protected Member Functions
virtual vtkObjectBase *	NewInstanceInternal () const
vtkEventDeclarationMacro(EventIds) protected int	PassiveObserver
class	vtkSubjectHelper
	vtkCommand ()
virtual	~vtkCommand ()
	vtkCommand (const vtkCommand &c)
void	operator= (const vtkCommand &)

---

Detailed Description

superclass for callback/observer methods

vtkCommand is an implementation of the observer/command design pattern. In this design pattern, any instance of vtkObject can be "observed" for any events it might invoke. For example, vtkRenderer invokes a StartEvent as it begins to render and a EndEvent when it finishes rendering. Filters (subclasses of vtkProcessObject) invoke StartEvent, ProgressEvent, and EndEvent as the filter processes data. Observers of events are added with the AddObserver() method found in vtkObject. AddObserver(), besides requiring an event id or name, also takes an instance of vtkCommand (or a subclasses). Note that vtkCommand is meant to be subclassed, so that you can package the information necessary to support your callback.

Event processing can be organized in priority lists, so it is possible to truncate the processing of a particular event by setting the AbortFlag variable. The priority is set using the AddObserver() method. By default the priority is 0, events of the same priority are processed in last-in-first-processed order. The ordering/aborting of events is important for things like 3D widgets, which handle an event if the widget is selected (and then aborting further processing of that event). Otherwise. the event is passed along for further processing.

When an instance of vtkObject invokes an event, it also passes an optional void pointer to a callData. This callData is NULL most of the time. The callData is not specific to a type of event but specific to a type of vtkObject invoking a specific event. For instance, vtkCommand::PickEvent is invoked by vtkProp with a NULL callData but is invoked by vtkInteractorStyleImage with a pointer to the vtkInteractorStyleImage object itself.

Here is the list of events that may be invoked with a non-NULL callData.

• vtkCommand::ProgressEvent
  • most of the objects return a pointer to a double value ranged between 0.0 and 1.0
  • Infovis/vtkFixedWidthTextReader returns a pointer to a float value equal to the number of lines read so far.
• vtkCommand::ErrorEvent
  • an error message as a const char * string
• vtkCommand::WarningEvent
  • a warning message as a const char * string
• vtkCommand::StartAnimationCueEvent
  • a pointer to a vtkAnimationCue::AnimationCueInfo object
• vtkCommand::EndAnimationCueEvent
  • a pointer to a vtkAnimationCue::AnimationCueInfo object
• vtkCommand::AnimationCueTickEvent
  • a pointer to a vtkAnimationCue::AnimationCueInfo object
• vtkCommand::PickEvent
  • Common/vtkProp returns NULL
  • Rendering/vtkInteractorStyleImage returns a pointer to itself
• vtkCommand::StartPickEvent
  • Rendering/vtkPropPicker returns NULL
  • Rendering/vtkInteractorStyleImage returns a pointer to itself
• vtkCommand::EndPickEvent
  • Rendering/vtkPropPicker returns NULL
  • Rendering/vtkInteractorStyleImage returns a pointer to itself
• vtkCommand::WrongTagEvent
  • Parallel/vtkSocketCommunicator returns a received tag as a char *
• vtkCommand::SelectionChangedEvent
  • Views/vtkView returns NULL
  • Views/vtkDataRepresentation returns a pointer to a vtkSelection
  • Rendering/vtkInteractorStyleRubberBand2D returns an array of 5 unsigned integers (p1x, p1y, p2x, p2y, mode), where mode is vtkInteractorStyleRubberBand2D::SELECT_UNION or vtkInteractorStyleRubberBand2D::SELECT_NORMAL
• vtkCommand::AnnotationChangedEvent
  • GUISupport/Qt/vtkQtAnnotationView returns a pointer to a vtkAnnotationLayers
• vtkCommand::PlacePointEvent
  • Widgets/vtkSeedWidget returns a pointer to an int, being the current handle number
• vtkCommand::ResetWindowLevelEvent
  • Widgets/vtkImagePlaneWidget returns an array of 2 double values (window and level)
  • Rendering/vtkInteractorStyleImage returns a pointer to itself
• vtkCommand::StartWindowLevelEvent
  • Widgets/vtkImagePlaneWidget returns an array of 2 double values (window and level)
  • Rendering/vtkInteractorStyleImage returns a pointer to itself
• vtkCommand::EndWindowLevelEvent
  • Widgets/vtkImagePlaneWidget returns an array of 2 double values (window and level)
  • Rendering/vtkInteractorStyleImage returns a pointer to itself
• vtkCommand::WindowLevelEvent
  • Widgets/vtkImagePlaneWidget returns an array of 2 double values (window and level)
  • Rendering/vtkInteractorStyleImage returns a pointer to itself
• vtkCommand::CharEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QKeyEvent *
• vtkCommand::TimerEvent
  • most of the objects return a to an int representing a timer id
  • Rendering/vtkXRenderWindowTclInteractor returns NULL
  • Widgets/vtkHoverWidget returns NULL
• vtkCommand::CreateTimerEvent
  • Rendering/vtkGenericRenderWindowInteractor returns a to an int representing a timer id
• vtkCommand::DestroyTimerEvent
  • Rendering/vtkGenericRenderWindowInteractor returns a to an int representing a timer id
• vtkCommand::UserEvent
  • most of the objects return NULL
  • Infovis/vtkInteractorStyleTreeMapHover returns a pointer to a vtkIdType representing a pedigree id
• vtkCommand::KeyPressEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QKeyEvent*
• vtkCommand::KeyReleaseEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QKeyEvent*
• vtkCommand::LeftButtonPressEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QMouseEvent*
• vtkCommand::LeftButtonReleaseEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QMouseEvent*
• vtkCommand::MouseMoveEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QMouseEvent*
• vtkCommand::MouseWheelForwardEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QWheelEvent*
• vtkCommand::MouseWheelBackwardEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QWheelEvent*
• vtkCommand::RightButtonPressEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QMouseEvent*
• vtkCommand::RightButtonReleaseEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QMouseEvent*
• vtkCommand::MiddleButtonPressEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QMouseEvent*
• vtkCommand::MiddleButtonReleaseEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QMouseEvent*
• vtkCommand::CursorChangedEvent
  • most of the objects return a pointer to an int representing a shape
  • Rendering/vtkInteractorObserver returns NULL
• vtkCommand::ResetCameraEvent
  • Rendering/vtkRenderer returns a pointer to itself
• vtkCommand::ResetCameraClippingRangeEvent
  • Rendering/vtkRenderer returns a pointer to itself
• vtkCommand::ActiveCameraEvent
  • Rendering/vtkRenderer returns a pointer to the active camera
• vtkCommand::CreateCameraEvent
  • Rendering/vtkRenderer returns a pointer to the created camera
• vtkCommand::EnterEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QEvent*
• vtkCommand::LeaveEvent
  • most of the objects return NULL
  • GUISupport/Qt/QVTKWidget returns a QEvent*
• vtkCommand::RenderWindowMessageEvent
  • Rendering/vtkWin32OpenGLRenderWindow return a pointer to a UINT message
• vtkCommand::ComputeVisiblePropBoundsEvent
  • Rendering/vtkRenderer returns a pointer to itself
• QVTKWidget::ContextMenuEvent
  • GUISupport/Qt/QVTKWidget returns a QContextMenuEvent*
• QVTKWidget::DragEnterEvent
  • GUISupport/Qt/QVTKWidget returns a QDragEnterEvent*
• QVTKWidget::DragMoveEvent
  • GUISupport/Qt/QVTKWidget returns a QDragMoveEvent*
• QVTKWidget::DragLeaveEvent
  • GUISupport/Qt/QVTKWidget returns a QDragLeaveEvent*
• QVTKWidget::DropEvent
  • GUISupport/Qt/QVTKWidget returns a QDropEvent*
• vtkCommand::ViewProgressEvent
  • View/vtkView returns a ViewProgressEventCallData*
• vtkCommand::VolumeMapperRenderProgressEvent
  • A pointer to a double value between 0.0 and 1.0
• vtkCommand::VolumeMapperComputeGradientsProgressEvent
  • A pointer to a double value between 0.0 and 1.0
• vtkCommand::TDxMotionEvent (TDx=3DConnexion)
  • A vtkTDxMotionEventInfo*
• vtkCommand::TDxButtonPressEvent
  • A int* being the number of the button
• vtkCommand::TDxButtonReleaseEvent

  • A int* being the number of the button

    See also:

    vtkObject vtkCallbackCommand vtkOldStyleCallbackCommand vtkInteractorObserver vtk3DWidget

Definition at line 325 of file vtkCommand.h.

---

Member Typedef Documentation

typedef vtkObjectBase vtkCommand::Superclass

Reimplemented in vtkCallbackCommand, vtkOldStyleCallbackCommand, vtkEventForwarderCommand, and vtkPythonCommand.

Definition at line 328 of file vtkCommand.h.

---

Constructor & Destructor Documentation

vtkCommand::vtkCommand

(

)

virtual vtkCommand::~vtkCommand

(

)

[inline, virtual]

Definition at line 404 of file vtkCommand.h.

vtkCommand::vtkCommand

(

const vtkCommand &

c

)

[inline]

Definition at line 408 of file vtkCommand.h.

---

Member Function Documentation

static int vtkCommand::IsTypeOf

(

const char *

name

)

[static]

Return 1 if this class type is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkObjectBase.

Reimplemented in vtkCallbackCommand, vtkOldStyleCallbackCommand, vtkEventForwarderCommand, and vtkPythonCommand.

virtual int vtkCommand::IsA

(

const char *

name

)

[virtual]

Return 1 if this class is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkObjectBase.

Reimplemented in vtkCallbackCommand, vtkOldStyleCallbackCommand, vtkEventForwarderCommand, and vtkPythonCommand.

static vtkCommand* vtkCommand::SafeDownCast

(

vtkObjectBase *

o

)

[static]

Reimplemented in vtkCallbackCommand, vtkOldStyleCallbackCommand, vtkEventForwarderCommand, and vtkPythonCommand.

virtual vtkObjectBase* vtkCommand::NewInstanceInternal

(

)

const [protected, virtual]

Reimplemented in vtkCallbackCommand, vtkOldStyleCallbackCommand, vtkEventForwarderCommand, and vtkPythonCommand.

vtkCommand* vtkCommand::NewInstance

(

)

const

Reimplemented in vtkCallbackCommand, vtkOldStyleCallbackCommand, vtkEventForwarderCommand, and vtkPythonCommand.

void vtkCommand::UnRegister

(

)

Decrease the reference count (release by another object). This has the same effect as invoking Delete() (i.e., it reduces the reference count by 1).

virtual void vtkCommand::UnRegister

(

vtkObjectBase *

)

[inline, virtual]

Decrease the reference count (release by another object). This has the same effect as invoking Delete() (i.e., it reduces the reference count by 1).

Reimplemented from vtkObjectBase.

Definition at line 335 of file vtkCommand.h.

virtual void vtkCommand::Execute	(	vtkObject *	caller,
		unsigned long	eventId,
		void *	callData
	)		[pure virtual]

All derived classes of vtkCommand must implement this method. This is the method that actually does the work of the callback. The caller argument is the object invoking the event, the eventId parameter is the id of the event, and callData parameter is data that can be passed into the execute method. (Note: vtkObject::InvokeEvent() takes two parameters: the event id (or name) and call data. Typically call data is NULL, but the user can package data and pass it this way. Alternatively, a derived class of vtkCommand can be used to pass data.)

Implemented in vtkJavaCommand, vtkTclCommand, vtkCallbackCommand, vtkOldStyleCallbackCommand, vtkEventForwarderCommand, and vtkPythonCommand.

static const char* vtkCommand::GetStringFromEventId

(

unsigned long

event

)

[static]

Convenience methods for translating between event names and event ids.

static unsigned long vtkCommand::GetEventIdFromString

(

const char *

event

)

[static]

Convenience methods for translating between event names and event ids.

void vtkCommand::SetAbortFlag

(

int

f

)

[inline]

Set/Get the abort flag. If this is set to true no further commands are executed.

Definition at line 363 of file vtkCommand.h.

int vtkCommand::GetAbortFlag

(

)

[inline]

Set/Get the abort flag. If this is set to true no further commands are executed.

Definition at line 365 of file vtkCommand.h.

void vtkCommand::AbortFlagOn

(

)

[inline]

Set/Get the abort flag. If this is set to true no further commands are executed.

Definition at line 367 of file vtkCommand.h.

void vtkCommand::AbortFlagOff

(

)

[inline]

Set/Get the abort flag. If this is set to true no further commands are executed.

Definition at line 369 of file vtkCommand.h.

void vtkCommand::SetPassiveObserver

(

int

f

)

[inline]

Set/Get the passive observer flag. If this is set to true, this indicates that this command does not change the state of the system in any way. Passive observers are processed first, and are not called even when another command has focus.

Definition at line 378 of file vtkCommand.h.

int vtkCommand::GetPassiveObserver

(

)

[inline]

Set/Get the passive observer flag. If this is set to true, this indicates that this command does not change the state of the system in any way. Passive observers are processed first, and are not called even when another command has focus.

Definition at line 380 of file vtkCommand.h.

void vtkCommand::PassiveObserverOn

(

)

[inline]

Set/Get the passive observer flag. If this is set to true, this indicates that this command does not change the state of the system in any way. Passive observers are processed first, and are not called even when another command has focus.

Definition at line 382 of file vtkCommand.h.

void vtkCommand::PassiveObserverOff

(

)

[inline]

Set/Get the passive observer flag. If this is set to true, this indicates that this command does not change the state of the system in any way. Passive observers are processed first, and are not called even when another command has focus.

Definition at line 384 of file vtkCommand.h.

void vtkCommand::operator=

(

const vtkCommand &

)

[inline]

Definition at line 409 of file vtkCommand.h.

---

Friends And Related Function Documentation

friend class vtkSubjectHelper [friend]

Definition at line 406 of file vtkCommand.h.

---

Member Data Documentation

vtkEventDeclarationMacro (EventIds) protected int vtkCommand::PassiveObserver

Definition at line 394 of file vtkCommand.h.

---

The documentation for this class was generated from the following file:

• dox/Common/Core/vtkCommand.h