Source code

001/*
002 * $RCSfile: TIFFT4Compressor.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: 1.2 $
042 * $Date: 2006/04/11 22:10:37 $
043 * $State: Exp $
044 */
045package com.github.jaiimageio.impl.plugins.tiff;
046
047import java.io.IOException;
048
049import javax.imageio.IIOException;
050import javax.imageio.metadata.IIOMetadata;
051
052import com.github.jaiimageio.plugins.tiff.BaselineTIFFTagSet;
053import com.github.jaiimageio.plugins.tiff.TIFFField;
054import com.github.jaiimageio.plugins.tiff.TIFFTag;
055
056/**
057 *
058 */
059public class TIFFT4Compressor extends TIFFFaxCompressor {
060
061    private boolean is1DMode = false;
062    private boolean isEOLAligned = false;
063
064    public TIFFT4Compressor() {
065        super("CCITT T.4", BaselineTIFFTagSet.COMPRESSION_CCITT_T_4, true);
066    }
067
068    /**
069     * Sets the value of the <code>metadata</code> field.
070     *
071     * <p> The implementation in this class also sets local options
072     * from the T4_OPTIONS field if it exists, and if it doesn't, adds
073     * it with default values.</p>
074     *
075     * @param metadata the <code>IIOMetadata</code> object for the
076     * image being written.
077     *
078     * @see #getMetadata()
079     */
080    public void setMetadata(IIOMetadata metadata) {
081        super.setMetadata(metadata);
082
083        if (metadata instanceof TIFFImageMetadata) {
084            TIFFImageMetadata tim = (TIFFImageMetadata)metadata;
085            TIFFField f = tim.getTIFFField(BaselineTIFFTagSet.TAG_T4_OPTIONS);
086            if (f != null) {
087                int options = f.getAsInt(0);
088                is1DMode = (options & 0x1) == 0;
089                isEOLAligned = (options & 0x4) == 0x4;
090            } else {
091                long[] oarray = new long[1];
092                oarray[0] = (isEOLAligned ? 0x4 : 0x0) |
093                    (is1DMode ? 0x0 : 0x1);
094                
095                BaselineTIFFTagSet base = BaselineTIFFTagSet.getInstance();
096                TIFFField T4Options =
097                  new TIFFField(base.getTag(BaselineTIFFTagSet.TAG_T4_OPTIONS),
098                                TIFFTag.TIFF_LONG,
099                                1,
100                                oarray);
101                tim.rootIFD.addTIFFField(T4Options);
102            }
103        }
104    }
105
106    /**
107     * Encode a buffer of data using CCITT T.4 Compression also known as
108     * Group 3 facsimile compression.
109     *
110     * @param is1DMode     Whether to perform one-dimensional encoding.
111     * @param isEOLAligned Whether EOL bit sequences should be padded.
112     * @param data         The row of data to compress.
113     * @param lineStride   Byte step between the same sample in different rows.
114     * @param colOffset    Bit offset within first <code>data[rowOffset]</code>.
115     * @param width        Number of bits in the row.
116     * @param height       Number of rows in the buffer.
117     * @param compData     The compressed data.
118     *
119     * @return The number of bytes saved in the compressed data array.
120     */
121    public int encodeT4(boolean is1DMode,
122                        boolean isEOLAligned,
123                        byte[] data,
124                        int lineStride,
125                        int colOffset,
126                        int width,
127                        int height,
128                        byte[] compData)
129    {
130        //
131        // ao, a1, a2 are bit indices in the current line
132        // b1 and b2  are bit indices in the reference line (line above)
133        // color is the current color (WHITE or BLACK)
134        //
135        byte[] refData = data;
136        int lineAddr = 0;
137        int outIndex = 0;
138
139        initBitBuf();
140
141        int KParameter = 2;
142        for(int numRows = 0; numRows < height; numRows++) {
143            if(is1DMode || (numRows % KParameter) == 0) { // 1D encoding
144                // Write EOL+1
145                outIndex += addEOL(is1DMode, isEOLAligned, true,
146                                   compData, outIndex);
147
148                // Encode row
149                outIndex += encode1D(data, lineAddr, colOffset, width,
150                                      compData, outIndex);
151            } else { // 2D encoding.
152                // Write EOL+0
153                outIndex += addEOL(is1DMode, isEOLAligned, false,
154                                   compData, outIndex);
155
156                // Set reference to previous line
157                int refAddr = lineAddr - lineStride;
158
159                // Encode row
160                int a0   = colOffset;
161                int last = a0 + width;
162
163                int testbit =
164                    ((data[lineAddr + (a0>>>3)]&0xff) >>>
165                     (7-(a0 & 0x7))) & 0x1;
166                int a1 = testbit != 0 ?
167                    a0 : nextState(data, lineAddr, a0, last);
168
169                testbit = ((refData[refAddr + (a0>>>3)]&0xff) >>>
170                           (7-(a0 & 0x7))) & 0x1;
171                int b1 = testbit != 0 ?
172                    a0 : nextState(refData, refAddr, a0, last);
173
174                // The current color is set to WHITE at line start
175                int color = WHITE;
176
177                while(true) {
178                    int b2 = nextState(refData, refAddr, b1, last);
179                    if(b2 < a1) {          // pass mode
180                        outIndex += add2DBits(compData, outIndex, pass, 0);
181                        a0 = b2;
182                    } else {
183                        int tmp = b1 - a1 + 3;
184                        if((tmp <= 6) && (tmp >= 0)) { // vertical mode
185                            outIndex +=
186                                add2DBits(compData, outIndex, vert, tmp);
187                            a0 = a1;
188                        } else {            // horizontal mode
189                            int a2 = nextState(data, lineAddr, a1, last);
190                            outIndex +=
191                                add2DBits(compData, outIndex, horz, 0);
192                            outIndex +=
193                                add1DBits(compData, outIndex, a1-a0, color);
194                            outIndex +=
195                                add1DBits(compData, outIndex, a2-a1, color^1);
196                            a0 = a2;
197                        }
198                    }
199                    if(a0 >= last) {
200                        break;
201                    }
202                    color = ((data[lineAddr + (a0>>>3)]&0xff) >>>
203                             (7-(a0 & 0x7))) & 0x1;
204                    a1 = nextState(data, lineAddr, a0, last);
205                    b1 = nextState(refData, refAddr, a0, last);
206                    testbit = ((refData[refAddr + (b1>>>3)]&0xff) >>>
207                               (7-(b1 & 0x7))) & 0x1;
208                    if(testbit == color) {
209                        b1 = nextState(refData, refAddr, b1, last);
210                    }
211                }
212            }
213
214            // Skip to next line.
215            lineAddr += lineStride;
216        }
217
218        for(int i = 0; i < 6; i++) {
219            outIndex += addEOL(is1DMode, isEOLAligned, true,
220                               compData, outIndex);
221        }
222
223        //
224        // flush all pending bits
225        //
226        while(ndex > 0) {
227            compData[outIndex++] = (byte)(bits >>> 24);
228            bits <<= 8;
229            ndex -= 8;
230        }
231
232        // Flip the bytes if inverse fill was requested.
233        if(inverseFill) {
234            for(int i = 0; i < outIndex; i++) {
235                compData[i] = TIFFFaxDecompressor.flipTable[compData[i]&0xff];
236            }
237        }
238
239        return outIndex;
240    }
241
242    public int encode(byte[] b, int off,
243                      int width, int height,
244                      int[] bitsPerSample,
245                      int scanlineStride) throws IOException {
246        if (bitsPerSample.length != 1 || bitsPerSample[0] != 1) {
247            throw new IIOException(
248                             "Bits per sample must be 1 for T4 compression!"); 
249        }
250
251        // This initial buffer size is based on an alternating 1-0
252        // pattern generating the most bits when converted to code
253        // words: 12 bits out for each pair of bits in. So the number
254        // of bit pairs is determined, multiplied by 12, converted to
255        // bytes, and a ceil() is taken to account for fill bits at the
256        // end of each line.  The "2" addend accounts for the case
257        // of the pattern beginning with black.  The buffer is intended
258        // to hold only a single row.
259        
260        // Note: the max pattern len is 12: Horizontal mode 001 + M(a0a1) + M(a1a2)
261        // where for 2 bits M(a0a1) and M(a1a2) can be 9
262
263        int maxBits = 12*((width + 1)/2) + 2;
264        int bufSize = (maxBits + 7)/8;
265
266        // Calculate the maximum row as the G3-1D size plus the EOL,
267        // multiply this by the number of rows in the tile, and add
268        // 6 EOLs for the RTC (return to control).
269        bufSize = height*(bufSize + 2) + 12;
270
271        byte[] compData = new byte[bufSize];
272
273        int bytes = encodeT4(is1DMode,
274                             isEOLAligned,
275                             b, scanlineStride, 8*off,
276                             width, height,
277                             compData);
278
279        stream.write(compData, 0, bytes);
280        return bytes;
281    }
282}