Class Palette

  • All Implemented Interfaces:
    RGBIndex

    public class Palette
    extends Object
    implements RGBIndex
    This class represents a palette, a list of RGB colors. An RGB color here has three int values for its red, green and blue intensity. Each intensity value must be larger than or equal to zero and smaller than or equal to the maximum intensity value that can be given to the constructor Palette(int, int). This maximum value is typically 255. Note that the number of entries in a palette is restricted only by the element index type int so that palettes with more than 256 entries are no problem. When accessing (reading or writing) samples of this palette, use the constants RGBIndex.INDEX_RED, RGBIndex.INDEX_GREEN and RGBIndex.INDEX_BLUE of this class to define a color channel.
    Author:
    Marco Schmidt
    See Also:
    PalettedImage
    • Constructor Summary

      Constructors 
      Constructor Description
      Palette​(int numEntries)
      Create a palette with the given number of entries and a maximum value of 255.
      Palette​(int numEntries, int maxValue)
      Create a palette with the given number of entries and a maximum value for each sample.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      Object clone()
      Creates a copy of this palette, allocating a new Palette object and copying each RGB triplet to the new palette.
      long getAllocatedMemory()
      Returns the amount of memory in bytes allocated for this palette.
      int getMaxValue()
      Returns the maximum value allowed for a sample.
      int getNumEntries()
      Returns the number of entries in this palette.
      int getSample​(int channelIndex, int entryIndex)
      Returns one of the samples of this palette.
      int[] getSamples​(int channelIndex)
      Returns all samples of one channel as an int array.
      boolean isBlackAndWhite()
      Checks if all entries of this palette are either black or white.
      boolean isGray()
      Checks if this palette is gray, i.e., checks if all entries are gray.
      void put​(int entryIndex, int red, int green, int blue)  
      void putSample​(int channelIndex, int entryIndex, int newValue)
      Sets one sample of one color entry in the palette to a new value.
    • Field Detail

      • data

        private int[][] data
      • numEntries

        private int numEntries
      • maxValue

        private int maxValue
    • Constructor Detail

      • Palette

        public Palette​(int numEntries,
                       int maxValue)
        Create a palette with the given number of entries and a maximum value for each sample.
        Parameters:
        numEntries - the number of entries to be accessible in this palette
        maxValue - the maximum value to be allowed for each sample
      • Palette

        public Palette​(int numEntries)
        Create a palette with the given number of entries and a maximum value of 255.
        Parameters:
        numEntries - the number of entries to be accessible in this palette
    • Method Detail

      • clone

        public Object clone()
        Creates a copy of this palette, allocating a new Palette object and copying each RGB triplet to the new palette. Then returns the new palette. Thus, a "deep" copy of this Palette object is created, not a "shallow" one.
        Overrides:
        clone in class Object
        Returns:
        newly-created palette
      • getAllocatedMemory

        public long getAllocatedMemory()
        Returns the amount of memory in bytes allocated for this palette.
      • getMaxValue

        public int getMaxValue()
        Returns the maximum value allowed for a sample.
        Returns:
        the maximum sample value
      • getNumEntries

        public int getNumEntries()
        Returns the number of entries in this palette.
        Returns:
        the number of entries in this palette
      • getSample

        public int getSample​(int channelIndex,
                             int entryIndex)
        Returns one of the samples of this palette.
        Parameters:
        entryIndex - the index of the color to be addressed, must be from 0 to getNumEntries() - 1
        channelIndex - one of the three channels; must be RGBIndex.INDEX_RED, RGBIndex.INDEX_GREEN or RGBIndex.INDEX_BLUE
        Returns:
        the requested sample
      • getSamples

        public int[] getSamples​(int channelIndex)
        Returns all samples of one channel as an int array.
        Parameters:
        channelIndex - index of the channel, one of the RGBIndex constants
        Returns:
        array with samples
      • isBlackAndWhite

        public boolean isBlackAndWhite()
        Checks if all entries of this palette are either black or white. An entry is black if all three intensitites (red, green and blue) are 0, it is white if they are all equal to getMaxValue(). No particular order of entries (e.g. first color black, second white) is demanded and no specific number of entries (e.g. 2). This means that a palette is black and white if it contains ten entries that are all black.
        Returns:
        if the palette contains only the colors black and white
      • isGray

        public boolean isGray()
        Checks if this palette is gray, i.e., checks if all entries are gray. This is the case if for all entries red, green and blue have the same intensity.
        Returns:
        if the palette contains only shades of gray
      • put

        public void put​(int entryIndex,
                        int red,
                        int green,
                        int blue)
      • putSample

        public void putSample​(int channelIndex,
                              int entryIndex,
                              int newValue)
        Sets one sample of one color entry in the palette to a new value.
        Parameters:
        channelIndex -