vtkCommand Class Reference
#include <vtkCommand.h>
Detailed Description
superclass for callback/observer methodsvtkCommand 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 none 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 int values (startPosition[2],endPosition[2], and selection type {SELECT_UNION|SELECT_NORMAL})
- Rendering/vtkInteractorStyleRubberBand3D returns an array of 5 unsigned int values (startPosition[2],endPosition[2], and selection type {SELECT_UNION|SELECT_NORMAL})
- Graphics/vtkSelectionLink returns NULL
- 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::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
- 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::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
Definition at line 198 of file vtkCommand.h.
Member Enumeration Documentation
| enum vtkCommand::EventIds |
All the currently defined events are listed here. Developers can use -- vtkCommand::UserEvent + int to specify their own event ids. If this list is adjusted, be sure to adjust vtkCommandEventStrings in vtkCommand.cxx to match.
- Enumerator:
Definition at line 265 of file vtkCommand.h.
Constructor & Destructor Documentation
| vtkCommand::vtkCommand | ( | ) | [protected] |
| virtual vtkCommand::~vtkCommand | ( | ) | [inline, protected, virtual] |
Definition at line 350 of file vtkCommand.h.
| vtkCommand::vtkCommand | ( | const vtkCommand & | c | ) | [inline, protected] |
Definition at line 354 of file vtkCommand.h.
Member Function Documentation
| 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 206 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 vtkCallbackCommand, vtkEventForwarderCommand, and vtkOldStyleCallbackCommand.
| 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 234 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 236 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 238 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 240 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 249 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 251 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 253 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 255 of file vtkCommand.h.
| void vtkCommand::operator= | ( | const vtkCommand & | ) | [inline, protected] |
Definition at line 355 of file vtkCommand.h.
Friends And Related Function Documentation
friend class vtkSubjectHelper [friend] |
Definition at line 352 of file vtkCommand.h.
Member Data Documentation
int vtkCommand::AbortFlag [protected] |
Definition at line 346 of file vtkCommand.h.
int vtkCommand::PassiveObserver [protected] |
Definition at line 347 of file vtkCommand.h.
The documentation for this class was generated from the following file:
- dox/Common/vtkCommand.h
