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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package com.sun.imageio.plugins.tiff;

import javax.imageio.plugins.tiff.BaselineTIFFTagSet;
import java.io.IOException;
import java.util.zip.Deflater;
import javax.imageio.ImageWriteParam;

Compressor superclass for Deflate and ZLib compression.
/** * Compressor superclass for Deflate and ZLib compression. */
public class TIFFDeflater extends TIFFCompressor { Deflater deflater; int predictor; public TIFFDeflater(String compressionType, int compressionTagValue, ImageWriteParam param, int predictorValue) { super(compressionType, compressionTagValue, true); this.predictor = predictorValue; // Set the deflate level. int deflateLevel; if(param != null && param.getCompressionMode() == ImageWriteParam.MODE_EXPLICIT) { float quality = param.getCompressionQuality(); deflateLevel = (int)(1 + 8*quality); } else { deflateLevel = Deflater.DEFAULT_COMPRESSION; } this.deflater = new Deflater(deflateLevel); } public int encode(byte[] b, int off, int width, int height, int[] bitsPerSample, int scanlineStride) throws IOException { int inputSize = height*scanlineStride; int blocks = (inputSize + 32767)/32768; // Worst case for Zlib deflate is input size + 5 bytes per 32k // block, plus 6 header bytes byte[] compData = new byte[inputSize + 5*blocks + 6]; int numCompressedBytes = 0; if(predictor == BaselineTIFFTagSet.PREDICTOR_HORIZONTAL_DIFFERENCING) { int samplesPerPixel = bitsPerSample.length; int bitsPerPixel = 0; for (int i = 0; i < samplesPerPixel; i++) { bitsPerPixel += bitsPerSample[i]; } int bytesPerRow = (bitsPerPixel*width + 7)/8; byte[] rowBuf = new byte[bytesPerRow]; int maxRow = height - 1; for(int i = 0; i < height; i++) { // Cannot modify b[] in place as it might be a data // array from the image being written so make a copy. System.arraycopy(b, off, rowBuf, 0, bytesPerRow); for(int j = bytesPerRow - 1; j >= samplesPerPixel; j--) { rowBuf[j] -= rowBuf[j - samplesPerPixel]; } deflater.setInput(rowBuf); if(i == maxRow) { deflater.finish(); } int numBytes = 0; while((numBytes = deflater.deflate(compData, numCompressedBytes, compData.length - numCompressedBytes)) != 0) { numCompressedBytes += numBytes; } off += scanlineStride; } } else { deflater.setInput(b, off, height*scanlineStride); deflater.finish(); numCompressedBytes = deflater.deflate(compData); } deflater.reset(); stream.write(compData, 0, numCompressedBytes); return numCompressedBytes; } }