JIU 0.12.0 Homepage

net.sourceforge.jiu.color.dithering
Class OrderedDither

java.lang.Object
  extended bynet.sourceforge.jiu.ops.Operation
      extended bynet.sourceforge.jiu.ops.ImageToImageOperation
          extended bynet.sourceforge.jiu.color.dithering.OrderedDither
All Implemented Interfaces:
RGBIndex

public class OrderedDither
extends ImageToImageOperation
implements RGBIndex

This operation reduces the color depth of RGB truecolor images and grayscale images by applying ordered dithering. A relatively nice output image (for a human observer) will be created at the cost of introducing noise into the output image. The algorithm is relatively fast, but its quality is usually inferior to what can be reached by using ErrorDiffusionDithering or similar other methods.

Supported conversions

Usage example

The following code snippet demonstrates how to create a paletted image with 256 colors, using three bits for red and green and two bits for blue, from an RGB truecolor image.
 OrderedDither od = new OrderedDither();
 od.setRgbBits(3, 3, 2);
 od.setInputImage(image);
 od.process();
 Paletted8Image ditheredImage = (Paletted8Image)od.getOutputImage();
 

Author:
Marco Schmidt

Field Summary
 
Fields inherited from interface net.sourceforge.jiu.data.RGBIndex
INDEX_BLUE, INDEX_GREEN, INDEX_RED
 
Constructor Summary
OrderedDither()
           
 
Method Summary
 void process()
          This method does the actual work of the operation.
 void setOutputBits(int bits)
           
 void setRgbBits(int red, int green, int blue)
          Sets the number of bits to be used for each RGB component in the output image.
 void setStandardThresholdValues()
          Calls setThresholdValues(int[], int, int) with a 16 x 16 matrix.
 void setThresholdValues(int[] values, int valueWidth, int valueHeight)
          Defines a matrix of threshold values that will be used for grayscale dithering.
 
Methods inherited from class net.sourceforge.jiu.ops.ImageToImageOperation
canInputAndOutputBeEqual, ensureImagesHaveSameResolution, ensureInputImageIsAvailable, ensureOutputImageResolution, getInputImage, getOutputImage, setCanInputAndOutputBeEqual, setInputImage, setOutputImage
 
Methods inherited from class net.sourceforge.jiu.ops.Operation
addProgressListener, addProgressListeners, getAbort, removeProgressListener, setAbort, setProgress, setProgress
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

OrderedDither

public OrderedDither()
Method Detail

process

public void process()
             throws MissingParameterException,
                    WrongParameterException
Description copied from class: Operation
This method does the actual work of the operation. It must be called after all parameters have been given to the operation object.

Overrides:
process in class Operation
Throws:
MissingParameterException - if any mandatory parameter was not given to the operation
WrongParameterException - if at least one of the input parameters was not initialized appropriately (values out of the valid interval, etc.)

setOutputBits

public void setOutputBits(int bits)

setRgbBits

public void setRgbBits(int red,
                       int green,
                       int blue)
Sets the number of bits to be used for each RGB component in the output image. Each argument must be one or larger. The values defined by this method are only used if the input image implements RGBIntegerImage. Later, in process(), these values are checked against the actual number of bits per component in the input image. If any of the arguments of this method is equal to or larger than those actual bits per channel values, a WrongParameterException will then be thrown. Right now, there is no way how this can be checked, because the input image may not have been defined yet.

Parameters:
red - number of bits for the red channel in the output image
green - number of bits for the green channel in the output image
blue - number of bits for the blue channel in the output image
Throws:
IllegalArgumentException - if at least one argument is smaller than 1

setStandardThresholdValues

public void setStandardThresholdValues()
Calls setThresholdValues(int[], int, int) with a 16 x 16 matrix.


setThresholdValues

public void setThresholdValues(int[] values,
                               int valueWidth,
                               int valueHeight)
Defines a matrix of threshold values that will be used for grayscale dithering.

Parameters:
values - the int values to use for comparing
valueWidth -
valueHeight -

JIU 0.12.0 Homepage

Copyright © 2000, 2001, 2002, 2003, 2004 Marco Schmidt