FileDocCategorySizeDatePackage
ByteLookupTable.javaAPI DocJava SE 5 API7541Fri Aug 26 14:56:52 BST 2005java.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
ShortLookupTable
see
LookupOp
version
10 Feb 1997

Fields Summary
byte[]
data
Constants
Constructors Summary
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.

param
offset the value subtracted from the input values before indexing into the arrays
param
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

        super(offset,data.length);
        numComponents = data.length;
        numEntries    = data[0].length;
        this.data = new byte[numComponents][];
        // Allocate the array and copy the data reference
        for (int i=0; i < numComponents; i++) {
            this.data[i] = data[i];
        }
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.

param
offset the value subtracted from the input values before indexing into the array
param
data an array of bytes
throws
IllegalArgumentException if offset is is less than 0 or if the length of data is less than 1

        super(offset,data.length);
        numComponents = 1;
        numEntries    = data.length;
        this.data = new byte[1][];
        this.data[0] = data;
Methods Summary
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.

return
the data array of this ByteLookupTable.

        return data;
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.

param
src the source array.
param
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.
return
the array dst, an int array of samples.
exception
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.

        if (dst == null) {
            // Need to alloc a new destination array
            dst = new int[src.length];
        }
        
        if (numComponents == 1) {
            // Apply one LUT to all bands
            for (int i=0; i < src.length; i++) {
                int s = src[i] - offset;
                if (s < 0) {
                    throw new ArrayIndexOutOfBoundsException("src["+i+
                                                             "]-offset is "+
                                                             "less than zero");
                }
                dst[i] = (int) data[0][s];
            }
        }
        else {
            for (int i=0; i < src.length; i++) {
                int s = src[i] - offset;
                if (s < 0) {
                    throw new ArrayIndexOutOfBoundsException("src["+i+
                                                             "]-offset is "+
                                                             "less than zero");
                }
                dst[i] = (int) data[i][s];
            }
        }
        return dst;
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.

param
src the source array.
param
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.
return
the array dst, an int array of samples.
exception
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.

        if (dst == null) {
            // Need to alloc a new destination array
            dst = new byte[src.length];
        }
        
        if (numComponents == 1) {
            // Apply one LUT to all bands
            for (int i=0; i < src.length; i++) {
                int s = (src[i]&0xff) - offset;
                if (s < 0) {
                    throw new ArrayIndexOutOfBoundsException("src["+i+
                                                             "]-offset is "+
                                                             "less than zero");
                }
                dst[i] = data[0][s];
            }
        }
        else {
            for (int i=0; i < src.length; i++) {
                int s = (src[i]&0xff) - offset;
                if (s < 0) {
                    throw new ArrayIndexOutOfBoundsException("src["+i+
                                                             "]-offset is "+
                                                             "less than zero");
                }
                dst[i] = data[i][s];
            }
        }
        return dst;