# Class ByteLookupTable

java.lang.Object
java.awt.image.LookupTable
java.awt.image.ByteLookupTable

public class ByteLookupTable extends LookupTable
This class defines a lookup table object. The output of a lookup operation using an object of this class is interpreted as an unsigned byte quantity. The lookup table contains byte data arrays for one or more bands (or components) of an image, and it contains an offset which will be subtracted from the input values before indexing the arrays. This allows an array smaller than the native data size to be provided for a constrained input. If there is only one array in the lookup table, it will be applied to all bands.

See Also:
  - `ShortLookupTable`
  - `LookupOp`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `ByteLookupTable(int offset, byte[] data)`
  Constructs a ByteLookupTable object from an array of bytes representing a lookup table to be applied to all bands.
  `ByteLookupTable(int offset, byte[][] data)`
  Constructs a ByteLookupTable object from an array of byte arrays representing a lookup table for each band.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `final byte[][]`
  `getTable()`
  Returns the lookup table data by reference.
  `byte[]`
  `lookupPixel(byte[] src, byte[] dst)`
  Returns an array of samples of a pixel, translated with the lookup table.
  `int[]`
  `lookupPixel(int[] src, int[] dst)`
  Returns an array of samples of a pixel, translated with the lookup table.

  ### Methods declared in class java.awt.image.LookupTable

  `getNumComponents, getOffset`

  ### Methods declared in class java.lang.Object

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

- ## Constructor Details

  - ### ByteLookupTable

    public ByteLookupTable(int offset, byte[][] data)
    Constructs a ByteLookupTable object from an array of byte arrays representing a lookup table for each band. The offset will be subtracted from input values before indexing into the arrays. The number of bands is the length of the data argument. The data array for each band is stored as a reference.
    Parameters:
      `offset` - the value subtracted from the input values before indexing into the arrays
      `data` - an array of byte arrays representing a lookup table for each band
    Throws:
      `IllegalArgumentException` - if `offset` is is less than 0 or if the length of `data` is less than 1

  - ### ByteLookupTable

    public ByteLookupTable(int offset, byte[] data)
    Constructs a ByteLookupTable object from an array of bytes representing a lookup table to be applied to all bands. The offset will be subtracted from input values before indexing into the array. The data array is stored as a reference.
    Parameters:
      `offset` - the value subtracted from the input values before indexing into the array
      `data` - an array of bytes
    Throws:
      `IllegalArgumentException` - if `offset` is is less than 0 or if the length of `data` is less than 1

- ## Method Details

  - ### getTable

    public final byte[][] getTable()
    Returns the lookup table data by reference. If this ByteLookupTable was constructed using a single byte array, the length of the returned array is one.
    Returns:
      the data array of this `ByteLookupTable`.

  - ### lookupPixel

    public int[] lookupPixel(int[] src, int[] dst)
    Returns an array of samples of a pixel, translated with the lookup table. The source and destination array can be the same array. Array `dst` is returned.
    Specified by:
      `lookupPixel` in class `LookupTable`
    Parameters:
      `src` - the source array.
      `dst` - the destination array. This array must be at least as long as `src`. If `dst` is `null`, a new array will be allocated having the same length as `src`.
    Returns:
      the array `dst`, an `int` array of samples.
    Throws:
      `ArrayIndexOutOfBoundsException` - if `src` is longer than `dst` or if for any element `i` of `src`, `src[i]-offset` is either less than zero or greater than or equal to the length of the lookup table for any band.

  - ### lookupPixel

    public byte[] lookupPixel(byte[] src, byte[] dst)
    Returns an array of samples of a pixel, translated with the lookup table. The source and destination array can be the same array. Array `dst` is returned.
    Parameters:
      `src` - the source array.
      `dst` - the destination array. This array must be at least as long as `src`. If `dst` is `null`, a new array will be allocated having the same length as `src`.
    Returns:
      the array `dst`, an `int` array of samples.
    Throws:
      `ArrayIndexOutOfBoundsException` - if `src` is longer than `dst` or if for any element `i` of `src`, `(src[i]&0xff)-offset` is either less than zero or greater than or equal to the length of the lookup table for any band.