com.hdcookbook.grin.features
Class Fade

java.lang.Object
  com.hdcookbook.grin.Feature
      com.hdcookbook.grin.features.Modifier
          com.hdcookbook.grin.features.Fade

All Implemented Interfaces:

Node

public class Fade
extends Modifier
implements Node

Modifies a child feature by applying an alpha value when drawing in it. This lets you animate a fade-in and fade-out effect. It works by specifying alpha values at a few keyframes, and doing linear interpolation between those keyframes.

Author:

Bill Foote (http://jovial.com)

Field Summary

protected Command[]	endCommands
protected int[]	keyAlphas
protected int[]	keyframes
protected int	loopCount
protected int	repeatFrame
protected boolean	srcOver

Fields inherited from class com.hdcookbook.grin.features.Modifier

activated, part

Fields inherited from class com.hdcookbook.grin.Feature

name, show

Constructor Summary

Fade(Show show)

Method Summary

void	addDisplayAreas(RenderContext context) Add all of the areas that are displayed for this feature with the current frame.
protected Feature	createClone(java.util.HashMap clones) This is an implementation method that should not be called direction by applications; applications should call cloneSubgraph().
void	initialize() Initialize this feature.
protected void	initializeClone(Feature original, java.util.HashMap clones) This is an implementation method that should not be called direction by applications; it is called from cloneSubgraph().
void	nextFrame() Called from Segment with the Show lock held, to advance us to the state we should be in for the next frame.
void	paintFrame(java.awt.Graphics2D gr) Paint the current state of this feature to gr.
void	readInstanceData(GrinDataInputStream in, int length) Reads in this node information from the binary file format.
protected void	setActivateMode(boolean mode) Change the activated mode of this feature.
void	setAlpha(java.awt.AlphaComposite ac) Sets the value of this fade's AlpahComposite to value.

Methods inherited from class com.hdcookbook.grin.features.Modifier

addSubgraph, destroy, getPart, getX, getY, markDisplayAreasChanged, needsMoreSetup, setChildChanged, setSetupMode, setup

Methods inherited from class com.hdcookbook.grin.Feature

activate, cloneCommands, clonedReference, cloneSubgraph, deactivate, destroyClonedSubgraph, getName, isSetup, makeNewClone, resetFeature, sendFeatureSetup, setName, setup, toString, unsetup

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

keyframes

protected int[] keyframes

keyAlphas

protected int[] keyAlphas

srcOver

protected boolean srcOver

repeatFrame

protected int repeatFrame

loopCount

protected int loopCount

endCommands

protected Command[] endCommands

Constructor Detail

Fade

public Fade(Show show)

Method Detail

createClone

protected Feature createClone(java.util.HashMap clones)

This is an implementation method that should not be called direction by applications; applications should call cloneSubgraph(). New subclasses of Feature that wish to support cloning must override this method.

Create a new clone of this feature. This method creates a new instance of this feature, and creates new instances of any sub-features, but it does not initialize the feature. This method is called from Feature.makeNewClone().

See the documentation of cloneSubgraph() for a list of runtime exceptions this method can throw. Subclasses that wish to support cloning must override this method.

Overrides:

createClone in class Feature

Parameters:

clones - A map from original feature to cloned feature. Entries are added by Feature.makeNewClone().

See Also:

Feature.makeNewClone(java.util.HashMap), Feature.cloneSubgraph(java.util.HashMap)

initializeClone

protected void initializeClone(Feature original,
                               java.util.HashMap clones)

This is an implementation method that should not be called direction by applications; it is called from cloneSubgraph(). New subclasses of Feature may override this method.

Initialize this cloned feature from its original. This is called after the entire subgraph has been cloned, so the HashMap containing the set of clones will be complete. See the documentation of cloneSubgraph() for a list of runtime exceptions this method can throw. Subclasses that wish to support cloning must override this method.

If this feature doesn't need initialization it's OK for a feature to not implement it; the default version of this method does nothing. Typically, you only need to implement this for features that have references to other features that aren't sub-features, or that have commands that might have references to other features.

Overrides:

initializeClone in class Feature

See Also:

Feature.cloneSubgraph(java.util.HashMap)

initialize

public void initialize()

Initialize this feature. This is called on show initialization. A show will initialize all of its features after it initializes the segments.

Overrides:

initialize in class Modifier

setAlpha

public final void setAlpha(java.awt.AlphaComposite ac)

Sets the value of this fade's AlpahComposite to value. This method may be called by xlet code, so long as it's called within a command body or inside of Director.notifyNextFrame(). It is an error to call this method if more than one keyframe is defined for this fade, and trying to do so may result in an assertion failure. In other words, if you want to programmatically control a value, don't also try to control it by defining multiple keyframes.

setActivateMode

protected void setActivateMode(boolean mode)

Change the activated mode of this feature. The new mode will always be different than the old. Clients of the GRIN framework should never call this method directly. Custom feature extensions must implement this method.

Overrides:

setActivateMode in class Modifier

nextFrame

public void nextFrame()

Called from Segment with the Show lock held, to advance us to the state we should be in for the next frame.

Overrides:

nextFrame in class Modifier

addDisplayAreas

public void addDisplayAreas(RenderContext context)

Add all of the areas that are displayed for this feature with the current frame. This will be called exactly once per frame displayed on each activated feature.

A feature that displays something needs to maintain a record of it in a DrawRecord. The animation framework uses this to track what needs to be erased and drawn from frame to frame.

Clients of the GRIN framework should not call this method directly. Feature subclasses must implement this method.

Subclasses will probably want to override this to account for changes in the drawing environment they make. The version in this class simply calls this method on the modified part.

Overrides:

addDisplayAreas in class Modifier

Parameters:

context - The context for tracking rendering state

See Also:

DrawRecord

paintFrame

public void paintFrame(java.awt.Graphics2D gr)

Paint the current state of this feature to gr. Clients of the GRIN framework should not call this method directly. Feature subclasses must implement this method.

Overrides:

paintFrame in class Modifier

Parameters:

gr - The place to paint to.

readInstanceData

public void readInstanceData(GrinDataInputStream in,
                             int length)
                      throws java.io.IOException

Description copied from interface: Node

Reads in this node information from the binary file format.

An implementation of this method is recommended to call in.readSuperClassData(this) as the first line of the method to read in information that is defined in the base class of this Node type.

This should only be called while initializing this object.

Specified by:

readInstanceData in interface Node

Parameters:

in - InputStream to read data from.

length - the number of bytes that this node's information occupies in the InputStream. The implementation of this method is expected to read exactly this number of bytes from the stream. This can be used for a debugging purpose.

Throws:

java.io.IOException - if error occurs.

See Also:

GrinDataInputStream.readSuperClassData(Feature), GrinDataInputStream.readSuperClassData(RCHandler), GrinDataInputStream.readSuperClassData(Segment), GrinDataInputStream.readSuperClassData(Command)