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Class quicktime.app.actions.MatrixAction

java.lang.Object
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   +----quicktime.app.actions.PeriodicAction
           |
           +----quicktime.app.actions.MatrixAction

public abstract class MatrixAction
extends PeriodicAction
implements Targetable

This class provides the means for a basic Matrix actions. Each time the tickle method is called, it will retrieve the matrix from the target and invoke the transformMatrix method, which the subclass must implement. The subclass defines the transformMatrix method to apply a transformation to the matrix of the target of the action.

The MatrixAction will also notify the subclass of any changes of rate direction and if the subclass is interested in constraint testing will notify the subclass which side(s) a targets matrix has collided with after the transformation has been applied. These two states are notified with the rateDirectionChanged and boundsReached methods respectively.

Though the Space is generally specified it is only used in the bounds testing.

doConstraintBoundsTesting: Set this boolean to true or false to perform bounds testing of the target within the bounds of its enclosing Space.
kBottomSide: These constants are used in the boundsReached call to indicate to the subclass which edge the target has collided with.
kLeftSide: These constants are used in the boundsReached call to indicate to the subclass which edge the target has collided with.
kRightSide: These constants are used in the boundsReached call to indicate to the subclass which edge the target has collided with.
kTopSide: These constants are used in the boundsReached call to indicate to the subclass which edge the target has collided with.
target: The target of the matrix transformations

MatrixAction(int, int, QTDrawable, Transformable): Create a PeriodicAction that will act upon a Matrix.

boundsReached(int)

If the Matrix action is doing constraint bounds testing and a bounding condition is reached the Matrix action calls this method with one of four flags to indicate which side of the enclosing space the target collided with.

constraintReached()

doAction(float, int)

When called it performs three primary tasks:

(1) Checks to see if rate direction has changed - if so calls the rateDirectionChanged method
(2) Calls the transformMatrix method which the subclass defines
(3) If doConstraintBoundsTesting is true does bounds testing of the target within the enclosing space and notifies of any collisions of the target with the space's sides.
equals(Object)
Returns true if the incoming object is a Matrix action with the same target.
getSpace()
The space which is the space that the transformable object is a member of.
getTarget()
Returns the current target of the action.
rateDirectionChanged(boolean)
The Matrix action notifies subclasses when the rate at which an action is tickled changes from positive to negative or vice versa.
setSpace(QTDrawable)
Set the space which is the space that the transformable target is a member of.
setTarget(Object)
Sets the target of the action.
setTargetMatrix(Matrix)
This method is invoked by the doAction method once the matrix has been transformed.
toString()
Return a string representation of this class.
transformMatrix(Matrix)
The Matrix action calls the transformMatrix method with a Matrix that the subclass should transform according to the particular transformation of the subclass.

kLeftSide

 protected static final int kLeftSide

These constants are used in the boundsReached call to indicate to the subclass which edge the target has collided with. Horizontal and Vertical sides are provided as a means for testing for both left and right, up and down respectively.

kRightSide

 protected static final int kRightSide

kTopSide

 protected static final int kTopSide

kBottomSide

 protected static final int kBottomSide

target

 protected Transformable target

The target of the matrix transformations

doConstraintBoundsTesting

 protected boolean doConstraintBoundsTesting

Set this boolean to true or false to perform bounds testing of the target within the bounds of its enclosing Space. Default is false. If true the enclosing Space must be specified.

MatrixAction

 protected MatrixAction(int scale,
                        int period,
                        QTDrawable space,
                        Transformable t) throws QTException

Create a PeriodicAction that will act upon a Matrix.

Parameters:: scale - the amount with which a second is divided into at a rate of one; period - the number of scale ticks that elapse between invocations of the action.; space - the QTDrawable object that is the enclosing space of the Transformable target.; t - a transformable object that will have its display matrix altered by the deltaMatrix

setTarget

 public void setTarget(Object target)

Sets the target of the action. The target must be some kind of Transformable object.

Parameters:: target - a Transformable object

getTarget

 public Object getTarget()

Returns the current target of the action.

Returns:: the current target

getSpace

 public QTDrawable getSpace()

The space which is the space that the transformable object is a member of.

Returns:: the enclosing space.

setSpace

 public void setSpace(QTDrawable space)

Set the space which is the space that the transformable target is a member of.

Parameters:: space - the enclosing space.

doAction

 protected void doAction(float er,
                         int t) throws QTException

When called it performs three primary tasks:

(1) Checks to see if rate direction has changed - if so calls the rateDirectionChanged method
(2) Calls the transformMatrix method which the subclass defines
(3) If doConstraintBoundsTesting is true does bounds testing of the target within the enclosing space and notifies of any collisions of the target with the space's sides.

Once these tasks are performed the target's matrix is set to the transformed matrix through calling the setTargetMatrix with the transformed matrix.

Parameters:: er - the rate at which the action was invoked.; t - the time at which the action was invoked.
Overrides:: doAction in class PeriodicAction

rateDirectionChanged

 protected void rateDirectionChanged(boolean forwards) throws QTException

The Matrix action notifies subclasses when the rate at which an action is tickled changes from positive to negative or vice versa.

transformMatrix

 protected abstract void transformMatrix(Matrix theMatrix) throws QTException

The Matrix action calls the transformMatrix method with a Matrix that the subclass should transform according to the particular transformation of the subclass.

Parameters:: theMatrix - the matrix to transform.

boundsReached

 protected void boundsReached(int whichSide)

Parameters:: whichSide - a flag that indicates which side

setTargetMatrix

 protected void setTargetMatrix(Matrix transformedMatrix) throws QTException

This method is invoked by the doAction method once the matrix has been transformed. The default behaviour of this method is to just call the target's setMatrix method with the transformed matrix.

Parameters:: transformedMatrix - the new matrix for the target

constraintReached

 protected boolean constraintReached()

Subclasses should return true if after an action is triggered (the doAction method is called) the action has reached one of its specified constraint conditions and the actionable object should be triggered. How this is defined is determined totally by the subclass. This method will only be called by the tickle method if the Action has an Actionable actor.

Returns:: true if the actionable object (if set) should be triggered
Overrides:: constraintReached in class PeriodicAction

toString

 public String toString()

Return a string representation of this class.

Overrides:: toString in class PeriodicAction

equals

 public boolean equals(Object obj)

Returns true if the incoming object is a Matrix action with the same target.

Parameters:: obj - the object to test
Returns:: true if equal, false if not
Overrides:: equals in class PeriodicAction

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