NAME

       SoHandleEventAction -

       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.

SYNOPSIS

       #include <Inventor/actions/SoHandleEventAction.h>

       Inherits SoAction.

   Public Member Functions
       virtual SoType getTypeId (void) const
       SoHandleEventAction (const SbViewportRegion &viewportregion)
       virtual ~SoHandleEventAction (void)
       void setViewportRegion (const SbViewportRegion &newregion)
       const SbViewportRegion & getViewportRegion (void) const
       void setEvent (const SoEvent *ev)
       const SoEvent * getEvent (void) const
       void setHandled (void)
       SbBool isHandled (void) const
       void setGrabber (SoNode *node)
       void releaseGrabber (void)
       SoNode * getGrabber (void) const
       void setPickRoot (SoNode *node)
       SoNode * getPickRoot (void) const
       void setPickRadius (const float radiusinpixels)
       const SoPickedPoint * getPickedPoint (void)
       const SoPickedPointList & getPickedPointList (void)

   Static Public Member Functions
       static SoType getClassTypeId (void)
       static void addMethod (const SoType type, SoActionMethod method)
       static void enableElement (const SoType type, const int stackindex)
       static void initClass (void)

   Protected Member Functions
       virtual const
           SoEnabledElementsList & getEnabledElements (void) const "
       virtual void beginTraversal (SoNode *node)

   Static Protected Member Functions
       static SoEnabledElementsList * getClassEnabledElements (void)
       static SoActionMethodList * getClassActionMethods (void)

   Additional Inherited 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

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 (void) [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.

       Returns the actual type id of an object derived from a class inheriting SoAction. Needs to
       be overridden in all subclasses.

       Implements SoAction.

   void SoHandleEventAction::addMethod (const SoTypetype, SoActionMethodmethod) [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 SoTypetype, const intstackindex) [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.

   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 floatradiusinpixels)
       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.

Author

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