Class ArbitraryPaletteQuantizer
- java.lang.Object
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- net.sourceforge.jiu.ops.Operation
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- net.sourceforge.jiu.ops.ImageToImageOperation
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- net.sourceforge.jiu.color.quantization.ArbitraryPaletteQuantizer
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- All Implemented Interfaces:
RGBQuantizer
,RGBIndex
public class ArbitraryPaletteQuantizer extends ImageToImageOperation implements RGBIndex, RGBQuantizer
A color quantizer that maps anRGBImage
to any given palette. This operation is restricted to RGB24Image and palettes with up to 256 colors. It picks the color from the palette which is closest to the color to be quantized (with the minimum distance). This is a rather naive implementation which, for any given color to be quantized, computes the distance between it and each color in the palette (read: this operation is rather slow with a large palette and input image).It uses Manhattan distance (L1) instead of Euclidean distance (L2). This saves a square root operation per distance computation.
There are more sophisticated nearest neighbor algorithms available, left for future extensions.
Usage example
This example maps an RGB truecolor image to some palette we create.
RGB24Image image = ...; // initialize this // create some Palette object that you want to map the image to Palette palette = new Palette(3); // create palette with three entries palette.put(0, 33, 00, 244); // set first color palette.put(1, 0, 240, 193); // set second color palette.put(2, 245, 126, 136); // set third color ArbitraryPaletteQuantizer quantizer = new ArbitraryPaletteQuantizer(palette); quantizer.setInputImage(image); quantizer.process(); PixelImage quantizedImage = quantizer.getOutputImage();
- Since:
- 0.5.0
- Author:
- Marco Schmidt
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Field Summary
Fields Modifier and Type Field Description private int[]
BLUE
private int[]
GREEN
private int
numEntries
private Palette
palette
private int[]
RED
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Fields inherited from interface net.sourceforge.jiu.data.RGBIndex
INDEX_BLUE, INDEX_GREEN, INDEX_RED
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Constructor Summary
Constructors Constructor Description ArbitraryPaletteQuantizer(Palette palette)
Creates a quantizer that will be able to map pixels (or a complete image) to the argument palette.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Palette
createPalette()
Returns a copy of the palette that was given to the constructor of this class.int
map(int[] origRgb, int[] quantizedRgb)
This method maps a triplet of intensity values to its quantized counterpart and returns the palette index of that quantized color.int
map(int red, int green, int blue)
Finds the best match for the argument color in the palette and returns its index.void
process()
Maps the input image to an output image, using the palette given to the constructor.private void
process(RGB24Image in, Paletted8Image out)
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Methods inherited from class net.sourceforge.jiu.ops.ImageToImageOperation
canInputAndOutputBeEqual, ensureImagesHaveSameResolution, ensureInputImageIsAvailable, ensureOutputImageResolution, getInputImage, getOutputImage, setCanInputAndOutputBeEqual, setInputImage, setOutputImage
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Methods inherited from class net.sourceforge.jiu.ops.Operation
addProgressListener, addProgressListeners, getAbort, removeProgressListener, setAbort, setProgress, setProgress
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Field Detail
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RED
private final int[] RED
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GREEN
private final int[] GREEN
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BLUE
private final int[] BLUE
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palette
private Palette palette
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numEntries
private int numEntries
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Constructor Detail
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ArbitraryPaletteQuantizer
public ArbitraryPaletteQuantizer(Palette palette)
Creates a quantizer that will be able to map pixels (or a complete image) to the argument palette.
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Method Detail
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createPalette
public Palette createPalette()
Returns a copy of the palette that was given to the constructor of this class.- Specified by:
createPalette
in interfaceRGBQuantizer
- Returns:
- new copy of the palette this quantizer works on
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map
public int map(int[] origRgb, int[] quantizedRgb)
Description copied from interface:RGBQuantizer
This method maps a triplet of intensity values to its quantized counterpart and returns the palette index of that quantized color. The index values for the two arrays are taken from RGBIndex.- Specified by:
map
in interfaceRGBQuantizer
- Parameters:
origRgb
- the three samples red, green and blue for which a good match is searched in the palettequantizedRgb
- will hold the three samples found to be closest to origRgb after the call to this method- Returns:
- int index in the palette of the match quantizedRgb
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map
public int map(int red, int green, int blue)
Finds the best match for the argument color in the palette and returns its index. Similar tomap(int[], int[])
, the quantized color is not required and thus a few assignemnts are saved by this method.- Parameters:
red
- red sample of the pixel to be quantizedgreen
- green sample of the pixel to be quantizedblue
- blue sample of the pixel to be quantized- Returns:
- index of the color in the palette that is closest to the argument color
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process
private void process(RGB24Image in, Paletted8Image out)
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process
public void process() throws MissingParameterException, WrongParameterException
Maps the input image to an output image, using the palette given to the constructor.- Overrides:
process
in classOperation
- Throws:
MissingParameterException
- if any mandatory parameter was not given to the operationWrongParameterException
- if at least one of the input parameters was not initialized appropriately (values out of the valid interval, etc.)
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