Package 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.

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 Details

  • Method Details

    • 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 Color Model Object is reused.
      That keeps things simple and should not be a problem, as all known Color Models
      (IndexColorModel, DirectColorModel, ComponentColorModel) are immutable.

      Parameters:
      image - original BufferedImage to clone
      Returns:
      a new BufferedImage reusing the original's Color Model and containing a clone of its pixels