be.hogent.tarsos.ui.pitch
Class ShadowFactory

java.lang.Object
  be.hogent.tarsos.ui.pitch.ShadowFactory

public class ShadowFactory
extends java.lang.Object

A shadow factory generates a drop shadow for any given picture, respecting the transparency channel if present. The resulting picture contains the shadow only and to create a drop shadow effect you will need to stack the original picture and the shadow generated by the factory. If you are using Swing you can get this done very easily with the layout.

Shadow Properties

A shadow is defined by three properties:

• size: The size, in pixels, of the shadow. This property also defines the fuzzyness.
• opacity: The opacity, between 0.0 and 1.0, of the shadow.
• color: The color of the shadow. Shadows are not meant to be black only.

You can set these properties using the provided mutaters or the appropriate constructor. Here are two ways of creating a green shadow of size 10 and with an opacity of 50%:

 ShadowFactory factory = new ShadowFactory(10, 0.5f, Color.GREEN);
 // ..
 factory = new ShadowFactory();
 factory.setSize(10);
 factory.setOpacity(0.5f);
 factory.setColor(Color.GREEN);
 

The default constructor provides the following default values:

• size: 5 pixels
• opacity: 50%
• color: Black

Shadow Quality

The factory provides two shadow generation algorithms: fast quality blur and high quality blur. You can select your preferred algorithm by setting the appropriate rendering hint:

 ShadowFactory factory = new ShadowFactory();
 factory.setRenderingHint(ShadowFactory.KEY_BLUR_QUALITY, ShadowFactory.VALUE_BLUR_QUALITY_HIGH);
 

The default rendering algorihtm is VALUE_BLUR_QUALITY_FAST.

The current implementation should provide the same quality with both algorithms but performances are guaranteed to be better (about 30 times faster) with the fast quality blur.

Generating a Shadow

A shadow is generated as a BufferedImage from another BufferedImage. Once the factory is set up, you must call createShadow(java.awt.image.BufferedImage) to actually generate the shadow:

 ShadowFactory factory = new ShadowFactory();
 // factory setup
 BufferedImage shadow = factory.createShadow(bufferedImage);
 

The resulting image is of type BufferedImage.TYPE_INT_ARGB. Both dimensions of this image are larger than original image's:

• new width = original width + 2 * shadow size
• new height = original height + 2 * shadow size

This must be taken into account when you need to create a drop shadow effect.

Properties Changes

This factory allows to register property change listeners with addPropertyChangeListener(java.beans.PropertyChangeListener). Listening to properties changes is very useful when you emebed the factory in a graphical component and give the API user the ability to access the factory. By listening to properties changes, you can easily repaint the component when needed.

Threading Issues

ShadowFactory is not guaranteed to be thread-safe.

Author:

Romain Guy , Sébastien Petrucci

Field Summary

static java.lang.String	COLOR_CHANGED_PROPERTY Identifies a change to the color used to render the shadow.
static java.lang.String	KEY_BLUR_QUALITY Key for the blur quality rendering hint.
static java.lang.String	OPACITY_CHANGED_PROPERTY Identifies a change to the opacity used to render the shadow.
static java.lang.String	SIZE_CHANGED_PROPERTY Identifies a change to the size used to render the shadow.
static java.lang.String	VALUE_BLUR_QUALITY_FAST Selects the fast rendering algorithm.
static java.lang.String	VALUE_BLUR_QUALITY_HIGH Selects the high quality rendering algorithm.

Constructor Summary

ShadowFactory()
Creates a default good looking shadow generator.

ShadowFactory(int size, float opacity, java.awt.Color color)
A shadow factory needs three properties to generate shadows.

Method Summary

void	addPropertyChangeListener(java.beans.PropertyChangeListener listener) Add a PropertyChangeListener to the listener list.
java.awt.image.BufferedImage	createShadow(java.awt.image.BufferedImage image) Generates the shadow for a given picture and the current properties of the factory.
java.awt.Color	getColor() Gets the color used by the factory to generate shadows.
float	getOpacity() Gets the opacity used by the factory to generate shadows.
int	getSize() Gets the size in pixel used by the factory to generate shadows.
void	removePropertyChangeListener(java.beans.PropertyChangeListener listener) Remove a PropertyChangeListener from the listener list.
void	setColor(java.awt.Color shadowColor) Sets the color used by the factory to generate shadows.
void	setOpacity(float shadowOpacity) Sets the opacity used by the factory to generate shadows.
void	setRenderingHint(java.lang.Object key, java.lang.Object value) Maps the specified rendering hint key to the specified value in this SahdowFactory object.
void	setSize(int shadowSize) Sets the size, in pixels, used by the factory to generate shadows.

Methods inherited from class java.lang.Object

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

Field Detail

KEY_BLUR_QUALITY

public static final java.lang.String KEY_BLUR_QUALITY

Key for the blur quality rendering hint.

See Also:

Constant Field Values

VALUE_BLUR_QUALITY_FAST

public static final java.lang.String VALUE_BLUR_QUALITY_FAST

Selects the fast rendering algorithm. This is the default rendering hint for KEY_BLUR_QUALITY.

See Also:

Constant Field Values

VALUE_BLUR_QUALITY_HIGH

public static final java.lang.String VALUE_BLUR_QUALITY_HIGH

Selects the high quality rendering algorithm. With current implementation, This algorithm does not guarantee a better rendering quality and should not be used.

See Also:

Constant Field Values

SIZE_CHANGED_PROPERTY

public static final java.lang.String SIZE_CHANGED_PROPERTY

Identifies a change to the size used to render the shadow.

When the property change event is fired, the old value and the new value are provided as Integer instances.

See Also:

Constant Field Values

OPACITY_CHANGED_PROPERTY

public static final java.lang.String OPACITY_CHANGED_PROPERTY

Identifies a change to the opacity used to render the shadow.

When the property change event is fired, the old value and the new value are provided as Float instances.

See Also:

Constant Field Values

COLOR_CHANGED_PROPERTY

public static final java.lang.String COLOR_CHANGED_PROPERTY

Identifies a change to the color used to render the shadow.

See Also:

Constant Field Values

Constructor Detail

ShadowFactory

public ShadowFactory()

Creates a default good looking shadow generator. The default shadow factory provides the following default values:

• size: 5 pixels
• opacity: 50%
• color: Black
• rendering quality: VALUE_BLUR_QUALITY_FAST

These properties provide a regular, good looking shadow.

ShadowFactory

public ShadowFactory(int size,
                     float opacity,
                     java.awt.Color color)

A shadow factory needs three properties to generate shadows. These properties are:

• size: The size, in pixels, of the shadow. This property also defines the fuzzyness.
• opacity: The opacity, between 0.0 and 1.0, of the shadow.
• color: The color of the shadow. Shadows are not meant to be black only.

Besides these properties you can set rendering hints to control the rendering process. The default rendering hints let the factory use the fastest shadow generation algorithm.

Parameters:

size - The size of the shadow in pixels. Defines the fuzziness.

opacity - The opacity of the shadow.

color - The color of the shadow.

See Also:

setRenderingHint(Object, Object)

Method Detail

addPropertyChangeListener

public void addPropertyChangeListener(java.beans.PropertyChangeListener listener)

Add a PropertyChangeListener to the listener list. The listener is registered for all properties. The same listener object may be added more than once, and will be called as many times as it is added. If listener is null, no exception is thrown and no action is taken.

Parameters:

listener - the PropertyChangeListener to be added

removePropertyChangeListener

public void removePropertyChangeListener(java.beans.PropertyChangeListener listener)

Remove a PropertyChangeListener from the listener list. This removes a PropertyChangeListener that was registered for all properties. If listener was added more than once to the same event source, it will be notified one less time after being removed. If listener is null, or was never added, no exception is thrown and no action is taken.

Parameters:

listener -

setRenderingHint

public void setRenderingHint(java.lang.Object key,
                             java.lang.Object value)

Maps the specified rendering hint key to the specified value in this SahdowFactory object.

Parameters:

key - The rendering hint key

value - The rendering hint value

getColor

public java.awt.Color getColor()

Gets the color used by the factory to generate shadows.

Returns:

this factory's shadow color

setColor

public void setColor(java.awt.Color shadowColor)

Sets the color used by the factory to generate shadows.

Consecutive calls to createShadow(java.awt.image.BufferedImage) will all use this color until it is set again.

If the color provided is null, the previous color will be retained.

Parameters:

shadowColor - the generated shadows color

getOpacity

public float getOpacity()

Gets the opacity used by the factory to generate shadows.

The opacity is comprised between 0.0f and 1.0f; 0.0f being fully transparent and 1.0f fully opaque.

Returns:

this factory's shadow opacity

setOpacity

public void setOpacity(float shadowOpacity)

Sets the opacity used by the factory to generate shadows.

Consecutive calls to createShadow(java.awt.image.BufferedImage) will all use this color until it is set again.

The opacity is comprised between 0.0f and 1.0f; 0.0f being fully transparent and 1.0f fully opaque. If you provide a value out of these boundaries, it will be restrained to the closest boundary.

Parameters:

shadowOpacity - the generated shadows opacity

getSize

public int getSize()

Gets the size in pixel used by the factory to generate shadows.

Returns:

this factory's shadow size

setSize

public void setSize(int shadowSize)

Sets the size, in pixels, used by the factory to generate shadows.

The size defines the blur radius applied to the shadow to create the fuzziness.

There is virtually no limit to the size but it has an impact on shadow generation performances. The greater this value, the longer it will take to generate the shadow. Remember the generated shadow image dimensions are computed as follow:

• new width = original width + 2 * shadow size
• new height = original height + 2 * shadow size

The size cannot be negative. If you provide a negative value, the size will be 0 instead.

Parameters:

shadowSize - the generated shadows size in pixels (fuzziness)

createShadow

public java.awt.image.BufferedImage createShadow(java.awt.image.BufferedImage image)

Generates the shadow for a given picture and the current properties of the factory.

The generated shadow image dimensions are computed as follow:

• new width = original width + 2 * shadow size
• new height = original height + 2 * shadow size

The time taken by a call to this method depends on the size of the shadow, the larger the longer it takes, and on the selected rendering algorithm.

Parameters:

image - the picture from which the shadow must be cast

Returns:

the picture containing the shadow of image