Class PopularityQuantizer

  • All Implemented Interfaces:
    RGBQuantizer, RGBIndex

    public class PopularityQuantizer
    extends ImageToImageOperation
    implements RGBIndex, RGBQuantizer
    Performs the popularity color quantization algorithm that maps an image to the colors occurring most frequently in the input image. The number of colors in the palette can be defined by the user of this operation with setPaletteSize(int).

    Supported image types

    The input image must implement RGB24Image, the output image must be of type Paletted8Image.

    Usage example

    The following code snippet uses the default settings with a palette of 256 entries.
     PopularityQuantizer quantizer = new PopularityQuantizer();
     quantizer.setInputImage(image);
     quantizer.setPaletteSize(256);
     quantizer.process();
     PixelImage quantizedImage = quantizer.getOutputImage();
     
    Since:
    0.11.0
    Author:
    Marco Schmidt
    See Also:
    ArbitraryPaletteQuantizer
    • Constructor Detail

      • PopularityQuantizer

        public PopularityQuantizer()
    • Method Detail

      • createPalette

        public Palette createPalette()
        Description copied from interface: RGBQuantizer
        Return a Palette object with the list of colors to be used in the quantization process. That palette may be fixed or created specifically for a given input image.
        Specified by:
        createPalette in interface RGBQuantizer
        Returns:
        Palette object for destination image
      • getPaletteSize

        public int getPaletteSize()
        Returns the number of colors in the destination image. If output is paletted, this is also the number of entries in the palette.
        Returns:
        number of colors in the destination
        See Also:
        setPaletteSize(int)
      • 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 interface RGBQuantizer
        Parameters:
        origRgb - the three samples red, green and blue for which a good match is searched in the palette
        quantizedRgb - 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
      • setMapping

        public void setMapping​(boolean newValue)
        Specifies whether this operation will map the image to the new palette (true) or not (false). The latter may be interesting if only the palette is required. By default, this operation does map.
        Parameters:
        newValue - map to new image (true) or just search palette (false)
      • setPaletteSize

        public void setPaletteSize​(int newPaletteSize)
        Sets the number of colors that this operations is supposed to reduce the original image to.
        Parameters:
        newPaletteSize - the number of colors
        Throws:
        IllegalArgumentException - if the argument is smaller than 1 or larger than 256
        See Also:
        getPaletteSize()