/*
* @(#)ByteLookupTable.java 1.32 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.awt.image;
/**
* 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
*/
public class ByteLookupTable extends LookupTable {
/**
* Constants
*/
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 <code>offset</code> is
* is less than 0 or if the length of <code>data</code>
* is less than 1
*/
public ByteLookupTable(int offset, byte data[][]) {
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];
}
}
/**
* 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 <code>offset</code> is
* is less than 0 or if the length of <code>data</code>
* is less than 1
*/
public ByteLookupTable(int offset, byte data[]) {
super(offset,data.length);
numComponents = 1;
numEntries = data.length;
this.data = new byte[1][];
this.data[0] = data;
}
/**
* 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 <code>ByteLookupTable</code>.
*/
public final byte[][] getTable(){
return data;
}
/**
* Returns an array of samples of a pixel, translated with the lookup
* table. The source and destination array can be the same array.
* Array <code>dst</code> is returned.
*
* @param src the source array.
* @param dst the destination array. This array must be at least as
* long as <code>src</code>. If <code>dst</code> is
* <code>null</code>, a new array will be allocated having the
* same length as <code>src</code>.
* @return the array <code>dst</code>, an <code>int</code> array of
* samples.
* @exception ArrayIndexOutOfBoundsException if <code>src</code> is
* longer than <code>dst</code> or if for any element
* <code>i</code> of <code>src</code>,
* <code>src[i]-offset</code> is either less than zero or
* greater than or equal to the length of the lookup table
* for any band.
*/
public int[] lookupPixel(int[] src, int[] dst){
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;
}
/**
* Returns an array of samples of a pixel, translated with the lookup
* table. The source and destination array can be the same array.
* Array <code>dst</code> is returned.
*
* @param src the source array.
* @param dst the destination array. This array must be at least as
* long as <code>src</code>. If <code>dst</code> is
* <code>null</code>, a new array will be allocated having the
* same length as <code>src</code>.
* @return the array <code>dst</code>, an <code>int</code> array of
* samples.
* @exception ArrayIndexOutOfBoundsException if <code>src</code> is
* longer than <code>dst</code> or if for any element
* <code>i</code> of <code>src</code>,
* <code>(src[i]&0xff)-offset</code> is either less than
* zero or greater than or equal to the length of the
* lookup table for any band.
*/
public byte[] lookupPixel(byte[] src, byte[] dst){
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;
}
}
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