org.jfree.chart.util
Class PaintAlpha

java.lang.Object
  org.jfree.chart.util.PaintAlpha

public class PaintAlpha
extends Object

This class contains static methods for the manipulation of objects of type Paint

The intention is to honour the alpha-channel in the process. PaintAlpha was originally conceived to improve the rendering of 3D Shapes with transparent colours and to allow invisible bars by making them completely transparent.

In, for example StackedBarRenderer3D, bars are rendered with 6 faces. The front face is rendered with the Paint requested. The other 5 faces are rendered darker to achieve the 3D effect.

Previously Color.darker() was used for this, which always returns an opaque colour.

Additionally there are methods to control the behaviour and in particular a cloneImage(..) method which is needed to darken objects of type TexturePaint.

Author:

DaveLaw

Constructor Summary

PaintAlpha()

Method Summary

static BufferedImage	cloneImage(BufferedImage image) Clone a BufferedImage.
static Paint	darker(Paint paint) Create a new (if possible, darker) Paint of the same Type.
static boolean	setLegacyAlpha(boolean legacyAlpha) Per default PaintAlpha will try to honour alpha-channel information.

Methods inherited from class java.lang.Object

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

Constructor Detail

PaintAlpha

public PaintAlpha()

Method Detail

setLegacyAlpha

public static boolean setLegacyAlpha(boolean legacyAlpha)

Per default PaintAlpha will try to honour alpha-channel information. In the past this was not the case. If you wish legacy functionality for your application you can request this here.

Parameters:

legacyAlpha - boolean

Returns:

the previous setting

darker

public static Paint darker(Paint paint)

Create a new (if possible, darker) Paint of the same Type. If the Type is not supported, the original Paint is returned.

Parameters:

paint - a Paint implementation (e.g. Color, GradientPaint, TexturePaint,..)

Returns:

a (usually new, see above) Paint

cloneImage

public static BufferedImage cloneImage(BufferedImage image)

Clone a BufferedImage.

Note: when constructing the clone, the original Colour Model Object is reused.
That keeps things simple & should not be a problem, as all known Colour Models
(IndexColorModel, DirectColorModel, ComponentColorModel) are immutable.

Parameters:

image - original BufferedImage to clone

Returns:

a new BufferedImage reusing the original's Colour Model & containing a clone of its pixels