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SoHandleEventAction Class Reference
[Actions]

#include <Inventor/actions/SoHandleEventAction.h>

Inheritance diagram for SoHandleEventAction:

SoAction List of all members.

Detailed Description

The SoHandleEventAction class distributes user events to the scene.

This is the action used by the GUI viewer classes to pass interaction events from the window system to the nodes in the scene graph.

SoHandleEventAction also provides the functionality for tracking the object currently under the cursor, and functionality for "grabbing" the event focus.

See also:
SoEvent


Public Member Functions

virtual SoType getTypeId (void) const
 SoHandleEventAction (const SbViewportRegion &viewportregion)
virtual ~SoHandleEventAction ()
void setViewportRegion (const SbViewportRegion &newregion)
const SbViewportRegiongetViewportRegion (void) const
void setEvent (const SoEvent *ev)
const SoEventgetEvent (void) const
void setHandled (void)
SbBool isHandled (void) const
void setGrabber (SoNode *node)
void releaseGrabber (void)
SoNodegetGrabber (void) const
void setPickRoot (SoNode *node)
SoNodegetPickRoot (void) const
void setPickRadius (const float radiusinpixels)
const SoPickedPointgetPickedPoint (void)
const SoPickedPointListgetPickedPointList (void)

Static Public Member Functions

SoType getClassTypeId (void)
void addMethod (const SoType type, SoActionMethod method)
void enableElement (const SoType type, const int stackindex)
void initClass (void)

Protected Member Functions

virtual const SoEnabledElementsListgetEnabledElements (void) const
virtual void beginTraversal (SoNode *node)

Static Protected Member Functions

SoEnabledElementsListgetClassEnabledElements (void)
SoActionMethodListgetClassActionMethods (void)


Constructor & Destructor Documentation

SoHandleEventAction::SoHandleEventAction const SbViewportRegion viewportregion  ) 
 

Constructor.

SoHandleEventAction needs a viewportregion to pass on to the raypick action instance it uses for being able to track objects under the mouse cursor.

SoHandleEventAction::~SoHandleEventAction  )  [virtual]
 

Destructor.


Member Function Documentation

SoType SoHandleEventAction::getTypeId void   )  const [virtual]
 

Returns the type identification of an action derived from a class inheriting SoAction. This is used for run-time type checking and "downward" casting.

Usage example:

  void bar(SoAction * action)
  {
    if (action->getTypeId() == SoGLRenderAction::getClassTypeId()) {
      // safe downward cast, know the type
      SoGLRenderAction * glrender = (SoGLRenderAction *)action;
    }
    return; // ignore if not renderaction
  }

For application programmers wanting to extend the library with new actions: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through Inventor/nodes/SoSubAction.h: SO_ACTION_SOURCE, SO_ACTION_INIT_CLASS and SO_ACTION_CONSTRUCTOR.

For more information on writing Coin extensions, see the SoAction class documentation.

Implements SoAction.

SoType SoHandleEventAction::getClassTypeId void   )  [static]
 

Returns the run-time type object associated with instances of this class.

Reimplemented from SoAction.

void SoHandleEventAction::addMethod const SoType  type,
SoActionMethod  method
[static]
 

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

void SoHandleEventAction::enableElement const SoType  type,
const int  stackindex
[static]
 

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

const SoEnabledElementsList & SoHandleEventAction::getEnabledElements void   )  const [protected, virtual]
 

Returns a list of the elements used by action instances of this class upon traversal operations.

Reimplemented from SoAction.

SoEnabledElementsList * SoHandleEventAction::getClassEnabledElements void   )  [static, protected]
 

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

This method not available in the original OIV API, see SoSubAction.h for explanation.

Reimplemented from SoAction.

SoActionMethodList * SoHandleEventAction::getClassActionMethods void   )  [static, protected]
 

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

This method not available in the original OIV API, see SoSubAction.h for explanation.

Reimplemented from SoAction.

void SoHandleEventAction::initClass void   )  [static]
 

Initializes the run-time type system for this class, and sets up the enabled elements and action method list.

Reimplemented from SoAction.

void SoHandleEventAction::setViewportRegion const SbViewportRegion newregion  ) 
 

Set a new viewport region, replacing the one passed in the constructor.

const SbViewportRegion & SoHandleEventAction::getViewportRegion void   )  const
 

Returns the viewport region this action instance is using.

Advanced Usage:

You can also get the viewport region by accessing it through its element on the traversal state. You do that the following way:

  #include <Inventor/elements/SoViewportRegionElement.h>

    SoState * state = action->getState();
    SbViewportRegion vp = SoViewportRegionElement::get(state);

The reason for explaining this is that you can use this generic technique when you need access to state information when you can't seem to find the accessor function you need in the action implementation. You can use it to for instance retrieve the view volume information, for which there are no accessor methods:

  #include <Inventor/elements/SoViewVolumeElement.h>

    SoState * state = action->getState();
    SbViewVolume vv = SoViewVolumeElement::get(state);

When you do this on arbitrary action instances, you need to make sure that the given element is enabled for the action before you try to use it. The relevant functions for this are SoState::isElementEnabled() and SoElement::getClassStackIndex().

void SoHandleEventAction::setEvent const SoEvent ev  ) 
 

Set the event to distribute to the nodes of the scene.

const SoEvent * SoHandleEventAction::getEvent void   )  const
 

Returns the event this action is handling.

void SoHandleEventAction::setHandled void   ) 
 

Marks the action instance as handled, hence terminates the action.

The action is only marked as handled when a node in the graph "grabs" the event this action is carrying, so the handled flag will be FALSE after traversal if no nodes wanted the event.

See also:
isHandled()

SbBool SoHandleEventAction::isHandled void   )  const
 

Returns whether or not the event has been handled by a node during scene graph traversal.

See also:
setHandled()

void SoHandleEventAction::setGrabber SoNode node  ) 
 

Set a node pointer which will get all future events handled by this action until releaseGrabber() is called.

Note that since later SoHandleEventAction invokations are just applied directly on the grabber node, using SoHandleEventAction methods like getCurPath() will return bogus data.

void SoHandleEventAction::releaseGrabber void   ) 
 

Don't send the events to a "grabber" node anymore, use the default behavior of the action and pass them along to the scene graph again.

See also:
setGrabber()

SoNode * SoHandleEventAction::getGrabber void   )  const
 

Returns the grabber node, or NULL if no grabber is active.

void SoHandleEventAction::setPickRoot SoNode node  ) 
 

Sets the root node that is used for the pick action tracking the cursor.

SoNode * SoHandleEventAction::getPickRoot void   )  const
 

Returns the root node that is used by nodes that is tracking the cursor.

void SoHandleEventAction::setPickRadius const float  radiusinpixels  ) 
 

Sets the pick radius for cursor tracking.

const SoPickedPoint * SoHandleEventAction::getPickedPoint void   ) 
 

Returns the SoPickedPoint information for the intersection point below the cursor.

const SoPickedPointList & SoHandleEventAction::getPickedPointList void   ) 
 

Returns a list of all intersection points below the mouse cursor.

void SoHandleEventAction::beginTraversal SoNode node  )  [protected, virtual]
 

This virtual method is called from SoAction::apply(), and is the entry point for the actual scenegraph traversal.

It can be overridden to initialize the action at traversal start, for specific initializations in the action subclasses inheriting SoAction.

Default method just calls traverse(), which any overridden implementation of the method must do too (or call SoAction::beginTraversal()) to trigger the scenegraph traversal.

Reimplemented from SoAction.


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

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