001: /*
002: * $RCSfile: TIFFLZWCompressor.java,v $
003: *
004: *
005: * Copyright (c) 2005 Sun Microsystems, Inc. All Rights Reserved.
006: *
007: * Redistribution and use in source and binary forms, with or without
008: * modification, are permitted provided that the following conditions
009: * are met:
010: *
011: * - Redistribution of source code must retain the above copyright
012: * notice, this list of conditions and the following disclaimer.
013: *
014: * - Redistribution in binary form must reproduce the above copyright
015: * notice, this list of conditions and the following disclaimer in
016: * the documentation and/or other materials provided with the
017: * distribution.
018: *
019: * Neither the name of Sun Microsystems, Inc. or the names of
020: * contributors may be used to endorse or promote products derived
021: * from this software without specific prior written permission.
022: *
023: * This software is provided "AS IS," without a warranty of any
024: * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
025: * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
026: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
027: * EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL
028: * NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF
029: * USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
030: * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR
031: * ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
032: * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
033: * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
034: * INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
035: * POSSIBILITY OF SUCH DAMAGES.
036: *
037: * You acknowledge that this software is not designed or intended for
038: * use in the design, construction, operation or maintenance of any
039: * nuclear facility.
040: *
041: * $Revision: 1.1 $
042: * $Date: 2005/02/11 05:01:48 $
043: * $State: Exp $
044: */
045: package com.sun.media.imageioimpl.plugins.tiff;
046:
047: import java.io.IOException;
048: import javax.imageio.stream.ImageOutputStream;
049: import com.sun.media.imageio.plugins.tiff.BaselineTIFFTagSet;
050: import com.sun.media.imageio.plugins.tiff.TIFFCompressor;
051: import com.sun.media.imageioimpl.common.LZWCompressor;
052:
053: /**
054: * LZW Compressor.
055: */
056: public class TIFFLZWCompressor extends TIFFCompressor {
057:
058: int predictor;
059:
060: public TIFFLZWCompressor(int predictorValue) {
061: super ("LZW", BaselineTIFFTagSet.COMPRESSION_LZW, true);
062: this .predictor = predictorValue;
063: }
064:
065: public void setStream(ImageOutputStream stream) {
066: super .setStream(stream);
067: }
068:
069: public int encode(byte[] b, int off, int width, int height,
070: int[] bitsPerSample, int scanlineStride) throws IOException {
071:
072: LZWCompressor lzwCompressor = new LZWCompressor(stream, 8, true);
073:
074: int samplesPerPixel = bitsPerSample.length;
075: int bitsPerPixel = 0;
076: for (int i = 0; i < samplesPerPixel; i++) {
077: bitsPerPixel += bitsPerSample[i];
078: }
079: int bytesPerRow = (bitsPerPixel * width + 7) / 8;
080:
081: long initialStreamPosition = stream.getStreamPosition();
082:
083: boolean usePredictor = predictor == BaselineTIFFTagSet.PREDICTOR_HORIZONTAL_DIFFERENCING;
084:
085: if (bytesPerRow == scanlineStride && !usePredictor) {
086: lzwCompressor.compress(b, off, bytesPerRow * height);
087: } else {
088: byte[] rowBuf = usePredictor ? new byte[bytesPerRow] : null;
089: for (int i = 0; i < height; i++) {
090: if (usePredictor) {
091: // Cannot modify b[] in place as it might be a data
092: // array from the image being written so make a copy.
093: System.arraycopy(b, off, rowBuf, 0, bytesPerRow);
094: for (int j = bytesPerRow - 1; j >= samplesPerPixel; j--) {
095: rowBuf[j] -= rowBuf[j - samplesPerPixel];
096: }
097: lzwCompressor.compress(rowBuf, 0, bytesPerRow);
098: } else {
099: lzwCompressor.compress(b, off, bytesPerRow);
100: }
101: off += scanlineStride;
102: }
103: }
104:
105: lzwCompressor.flush();
106:
107: int bytesWritten = (int) (stream.getStreamPosition() - initialStreamPosition);
108:
109: return bytesWritten;
110: }
111: }
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