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vtkCommand Class Reference

#include <vtkCommand.h>

Inheritance diagram for vtkCommand:

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Collaboration diagram for vtkCommand:

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List of all members.

Detailed Description

superclass for callback/observer methods

Date:
2002/11/10 18:26:32
Revision:
1.42

vtkCommand is an implementation of the observer/command design pattern. In this design pattern, any instance of vtkObject can be "observered" 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.

See also:
vtkObject vtkCallbackCommand vtkOldStyleCallbackCommand vtkInteractorObserver vtk3DWidget
Created by:
  • Gobbi, David
  • Martin, Ken
CVS contributions (if > 5%):
  • Martin, Ken (28%)
  • Gobbi, David (25%)
  • Schroeder, Will (17%)
  • Cedilnik, Andy (12%)
  • Lorensen, Bill (9%)
CVS logs (CVSweb):
  • .h (/Common/vtkCommand.h)
  • .cxx (/Common/vtkCommand.cxx)

Definition at line 73 of file vtkCommand.h.

Public Types

enum  EventIds {
  NoEvent = 0, AnyEvent, DeleteEvent, StartEvent,
  EndEvent, ProgressEvent, PickEvent, StartPickEvent,
  EndPickEvent, AbortCheckEvent, ExitEvent, LeftButtonPressEvent,
  LeftButtonReleaseEvent, MiddleButtonPressEvent, MiddleButtonReleaseEvent, RightButtonPressEvent,
  RightButtonReleaseEvent, EnterEvent, LeaveEvent, KeyPressEvent,
  KeyReleaseEvent, CharEvent, ExposeEvent, ConfigureEvent,
  TimerEvent, MouseMoveEvent, ResetCameraEvent, ResetCameraClippingRangeEvent,
  ModifiedEvent, WindowLevelEvent, StartWindowLevelEvent, EndWindowLevelEvent,
  ResetWindowLevelEvent, NextDataEvent, PushDataStartEvent, SetOutputEvent,
  EndOfDataEvent, ErrorEvent, WarningEvent, StartInteractionEvent,
  InteractionEvent, EndInteractionEvent, EnableEvent, DisableEvent,
  CreateTimerEvent, DestroyTimerEvent, PlaceWidgetEvent, CursorChangedEvent,
  ExecuteInformationEvent, RenderWindowMessageEvent, UserEvent = 1000
}

Public Methods

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 ()

Static Public Methods

const char * GetStringFromEventId (unsigned long event)
unsigned long GetEventIdFromString (const char *event)

Protected Methods

 vtkCommand ()
virtual ~vtkCommand ()
void SetAbortFlagPointer (int *f)
 vtkCommand (const vtkCommand &c)
void operator= (const vtkCommand &)

Protected Attributes

int * AbortFlag

Friends

class vtkSubjectHelper


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.

Enumeration values:
NoEvent 
AnyEvent 
DeleteEvent 
StartEvent 
EndEvent 
ProgressEvent 
PickEvent 
StartPickEvent 
EndPickEvent 
AbortCheckEvent 
ExitEvent 
LeftButtonPressEvent 
LeftButtonReleaseEvent 
MiddleButtonPressEvent 
MiddleButtonReleaseEvent 
RightButtonPressEvent 
RightButtonReleaseEvent 
EnterEvent 
LeaveEvent 
KeyPressEvent 
KeyReleaseEvent 
CharEvent 
ExposeEvent 
ConfigureEvent 
TimerEvent 
MouseMoveEvent 
ResetCameraEvent 
ResetCameraClippingRangeEvent 
ModifiedEvent 
WindowLevelEvent 
StartWindowLevelEvent 
EndWindowLevelEvent 
ResetWindowLevelEvent 
NextDataEvent 
PushDataStartEvent 
SetOutputEvent 
EndOfDataEvent 
ErrorEvent 
WarningEvent 
StartInteractionEvent 
InteractionEvent 
EndInteractionEvent 
EnableEvent 
DisableEvent 
CreateTimerEvent 
DestroyTimerEvent 
PlaceWidgetEvent 
CursorChangedEvent 
ExecuteInformationEvent 
RenderWindowMessageEvent 
UserEvent 

Definition at line 125 of file vtkCommand.h.


Constructor & Destructor Documentation

vtkCommand::vtkCommand   [protected]
 

virtual vtkCommand::~vtkCommand   [inline, protected, virtual]
 

Definition at line 184 of file vtkCommand.h.

vtkCommand::vtkCommand const vtkCommand &    c [inline, protected]
 

Definition at line 192 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 81 of file vtkCommand.h.

References vtkObjectBase::UnRegister().

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, and vtkOldStyleCallbackCommand.

const char* vtkCommand::GetStringFromEventId unsigned long    event [static]
 

Convenience methods for translating between event names and event ids.

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 109 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 111 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 113 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 115 of file vtkCommand.h.

void vtkCommand::SetAbortFlagPointer int *    f [inline, protected]
 

Definition at line 187 of file vtkCommand.h.

void vtkCommand::operator= const vtkCommand &    [inline, protected]
 

Definition at line 193 of file vtkCommand.h.


Friends And Related Function Documentation

friend class vtkSubjectHelper [friend]
 

Definition at line 190 of file vtkCommand.h.


Member Data Documentation

int* vtkCommand::AbortFlag [protected]
 

Definition at line 182 of file vtkCommand.h.


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