org.geotools.image.palette

Class EfficientInverseColorMapComputation

Object

EfficientInverseColorMapComputation

public final class EfficientInverseColorMapComputation
extends Object

This class is responsible for computing efficiently an inverse color map for a given color map.

This algorithm is adapted from the algorithm found in Graphics Gems volume 2 by Spencer W. Thomas "Efficient Inverse Color Map Computation".

Author:

Simone Giannecchini, GeoSolutions SAS

Field Summary

Fields

Modifier and Type	Field and Description
protected int	bits Number of most significant bits we are going to use from the input color in order to quantize them.
protected int	blueQuantizationMask
protected byte[][]	colorMap Forward color map.
protected int	greenQuantizationMask
protected byte[]	mapBuf inverse rgb color map
protected int	redQuantizationMask
protected int	truncationBits

Constructor Summary

Constructors

Constructor and Description
EfficientInverseColorMapComputation(byte[][] rgbColorMap, int quantizationBits) EfficientInverseColorMapComputation that allows us to specify the number of bits we are going to save from the quantization.

Method Summary

Modifier and Type	Method and Description
int	getIndexNearest(int red, int green, int blue) This method is responsible for doing the actual lookup that given an rgb triple returns the best, taking into account quantization, index in the forward color map.

Methods inherited from class Object

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

Field Detail

bits

protected final int bits

Number of most significant bits we are going to use from the input color in order to quantize them.

truncationBits

protected final int truncationBits

blueQuantizationMask

protected final int blueQuantizationMask

greenQuantizationMask

protected final int greenQuantizationMask

redQuantizationMask

protected final int redQuantizationMask

colorMap

protected final byte[][] colorMap

Forward color map. Is a 3*numcolors array.

mapBuf

protected final byte[] mapBuf

inverse rgb color map

Constructor Detail

EfficientInverseColorMapComputation

public EfficientInverseColorMapComputation(byte[][] rgbColorMap,
                                           int quantizationBits)

EfficientInverseColorMapComputation that allows us to specify the number of bits we are going to save from the quantization.

Method Detail

getIndexNearest

public int getIndexNearest(int red,
                           int green,
                           int blue)

This method is responsible for doing the actual lookup that given an rgb triple returns the best, taking into account quantization, index in the forward color map.

Parameters:

red - component.

green - component.

blue - component.

Returns:

the best, taking into account quantization, index in the forward color map for the provided triple.