1 /*
2 * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.imageio.plugins.png;
27
28 import java.awt.Point;
29 import java.awt.Rectangle;
30 import java.awt.color.ColorSpace;
31 import java.awt.image.BufferedImage;
32 import java.awt.image.DataBuffer;
33 import java.awt.image.DataBufferByte;
34 import java.awt.image.DataBufferUShort;
35 import java.awt.image.Raster;
36 import java.awt.image.WritableRaster;
37 import java.io.BufferedInputStream;
38 import java.io.ByteArrayInputStream;
39 import java.io.DataInputStream;
40 import java.io.EOFException;
41 import java.io.InputStream;
42 import java.io.IOException;
43 import java.io.SequenceInputStream;
44 import java.util.ArrayList;
45 import java.util.Arrays;
46 import java.util.Enumeration;
47 import java.util.Iterator;
48 import java.util.zip.Inflater;
49 import java.util.zip.InflaterInputStream;
50 import javax.imageio.IIOException;
51 import javax.imageio.ImageReader;
52 import javax.imageio.ImageReadParam;
53 import javax.imageio.ImageTypeSpecifier;
54 import javax.imageio.metadata.IIOMetadata;
55 import javax.imageio.spi.ImageReaderSpi;
56 import javax.imageio.stream.ImageInputStream;
57 import com.sun.imageio.plugins.common.InputStreamAdapter;
58 import com.sun.imageio.plugins.common.ReaderUtil;
59 import com.sun.imageio.plugins.common.SubImageInputStream;
60 import java.io.ByteArrayOutputStream;
61 import sun.awt.image.ByteInterleavedRaster;
62
63 class PNGImageDataEnumeration implements Enumeration<InputStream> {
64
65 boolean firstTime = true;
66 ImageInputStream stream;
67 int length;
68
69 public PNGImageDataEnumeration(ImageInputStream stream)
70 throws IOException {
71 this.stream = stream;
72 this.length = stream.readInt();
73 int type = stream.readInt(); // skip chunk type
74 }
75
76 public InputStream nextElement() {
77 try {
78 firstTime = false;
79 ImageInputStream iis = new SubImageInputStream(stream, length);
80 return new InputStreamAdapter(iis);
81 } catch (IOException e) {
82 return null;
83 }
84 }
85
86 public boolean hasMoreElements() {
87 if (firstTime) {
88 return true;
89 }
90
91 try {
92 int crc = stream.readInt();
93 this.length = stream.readInt();
94 int type = stream.readInt();
95 if (type == PNGImageReader.IDAT_TYPE) {
96 return true;
97 } else {
98 return false;
99 }
100 } catch (IOException e) {
101 return false;
102 }
103 }
104 }
105
106 public class PNGImageReader extends ImageReader {
107
108 /*
109 * Note: The following chunk type constants are autogenerated. Each
110 * one is derived from the ASCII values of its 4-character name. For
111 * example, IHDR_TYPE is calculated as follows:
112 * ('I' << 24) | ('H' << 16) | ('D' << 8) | 'R'
113 */
114
115 // Critical chunks
116 static final int IHDR_TYPE = 0x49484452;
117 static final int PLTE_TYPE = 0x504c5445;
118 static final int IDAT_TYPE = 0x49444154;
119 static final int IEND_TYPE = 0x49454e44;
120
121 // Ancillary chunks
122 static final int bKGD_TYPE = 0x624b4744;
123 static final int cHRM_TYPE = 0x6348524d;
124 static final int gAMA_TYPE = 0x67414d41;
125 static final int hIST_TYPE = 0x68495354;
126 static final int iCCP_TYPE = 0x69434350;
127 static final int iTXt_TYPE = 0x69545874;
128 static final int pHYs_TYPE = 0x70485973;
129 static final int sBIT_TYPE = 0x73424954;
130 static final int sPLT_TYPE = 0x73504c54;
131 static final int sRGB_TYPE = 0x73524742;
132 static final int tEXt_TYPE = 0x74455874;
133 static final int tIME_TYPE = 0x74494d45;
134 static final int tRNS_TYPE = 0x74524e53;
135 static final int zTXt_TYPE = 0x7a545874;
136
137 static final int PNG_COLOR_GRAY = 0;
138 static final int PNG_COLOR_RGB = 2;
139 static final int PNG_COLOR_PALETTE = 3;
140 static final int PNG_COLOR_GRAY_ALPHA = 4;
141 static final int PNG_COLOR_RGB_ALPHA = 6;
142
143 // The number of bands by PNG color type
144 static final int[] inputBandsForColorType = {
145 1, // gray
146 -1, // unused
147 3, // rgb
148 1, // palette
149 2, // gray + alpha
150 -1, // unused
151 4 // rgb + alpha
152 };
153
154 static final int PNG_FILTER_NONE = 0;
155 static final int PNG_FILTER_SUB = 1;
156 static final int PNG_FILTER_UP = 2;
157 static final int PNG_FILTER_AVERAGE = 3;
158 static final int PNG_FILTER_PAETH = 4;
159
160 static final int[] adam7XOffset = { 0, 4, 0, 2, 0, 1, 0 };
161 static final int[] adam7YOffset = { 0, 0, 4, 0, 2, 0, 1 };
162 static final int[] adam7XSubsampling = { 8, 8, 4, 4, 2, 2, 1, 1 };
163 static final int[] adam7YSubsampling = { 8, 8, 8, 4, 4, 2, 2, 1 };
164
165 private static final boolean debug = true;
166
167 ImageInputStream stream = null;
168
169 boolean gotHeader = false;
170 boolean gotMetadata = false;
171
172 ImageReadParam lastParam = null;
173
174 long imageStartPosition = -1L;
175
176 Rectangle sourceRegion = null;
177 int sourceXSubsampling = -1;
178 int sourceYSubsampling = -1;
179 int sourceMinProgressivePass = 0;
180 int sourceMaxProgressivePass = 6;
181 int[] sourceBands = null;
182 int[] destinationBands = null;
183 Point destinationOffset = new Point(0, 0);
184
185 PNGMetadata metadata = new PNGMetadata();
186
187 DataInputStream pixelStream = null;
188
189 BufferedImage theImage = null;
190
191 // The number of source pixels processed
192 int pixelsDone = 0;
193
194 // The total number of pixels in the source image
195 int totalPixels;
196
197 public PNGImageReader(ImageReaderSpi originatingProvider) {
198 super(originatingProvider);
199 }
200
201 public void setInput(Object input,
202 boolean seekForwardOnly,
203 boolean ignoreMetadata) {
204 super.setInput(input, seekForwardOnly, ignoreMetadata);
205 this.stream = (ImageInputStream)input; // Always works
206
207 // Clear all values based on the previous stream contents
208 resetStreamSettings();
209 }
210
211 private String readNullTerminatedString(String charset, int maxLen) throws IOException {
212 ByteArrayOutputStream baos = new ByteArrayOutputStream();
213 int b = 0;
214 int count = 0;
215 while ((maxLen > count++) && ((b = stream.read()) != 0)) {
216 if (b == -1) throw new EOFException();
217 baos.write(b);
218 }
219 if (b != 0) {
220 throw new IIOException("Found non null terminated string");
221 }
222 return new String(baos.toByteArray(), charset);
223 }
224
225 private void readHeader() throws IIOException {
226 if (gotHeader) {
227 return;
228 }
229 if (stream == null) {
230 throw new IllegalStateException("Input source not set!");
231 }
232
233 try {
234 byte[] signature = new byte[8];
235 stream.readFully(signature);
236
237 if (signature[0] != (byte)137 ||
238 signature[1] != (byte)80 ||
239 signature[2] != (byte)78 ||
240 signature[3] != (byte)71 ||
241 signature[4] != (byte)13 ||
242 signature[5] != (byte)10 ||
243 signature[6] != (byte)26 ||
244 signature[7] != (byte)10) {
245 throw new IIOException("Bad PNG signature!");
246 }
247
248 int IHDR_length = stream.readInt();
249 if (IHDR_length != 13) {
250 throw new IIOException("Bad length for IHDR chunk!");
251 }
252 int IHDR_type = stream.readInt();
253 if (IHDR_type != IHDR_TYPE) {
254 throw new IIOException("Bad type for IHDR chunk!");
255 }
256
257 this.metadata = new PNGMetadata();
258
259 int width = stream.readInt();
260 int height = stream.readInt();
261
262 // Re-use signature array to bulk-read these unsigned byte values
263 stream.readFully(signature, 0, 5);
264 int bitDepth = signature[0] & 0xff;
265 int colorType = signature[1] & 0xff;
266 int compressionMethod = signature[2] & 0xff;
267 int filterMethod = signature[3] & 0xff;
268 int interlaceMethod = signature[4] & 0xff;
269
270 // Skip IHDR CRC
271 stream.skipBytes(4);
272
273 stream.flushBefore(stream.getStreamPosition());
274
275 if (width <= 0) {
276 throw new IIOException("Image width <= 0!");
277 }
278 if (height <= 0) {
279 throw new IIOException("Image height <= 0!");
280 }
281 if (bitDepth != 1 && bitDepth != 2 && bitDepth != 4 &&
282 bitDepth != 8 && bitDepth != 16) {
283 throw new IIOException("Bit depth must be 1, 2, 4, 8, or 16!");
284 }
285 if (colorType != 0 && colorType != 2 && colorType != 3 &&
286 colorType != 4 && colorType != 6) {
287 throw new IIOException("Color type must be 0, 2, 3, 4, or 6!");
288 }
289 if (colorType == PNG_COLOR_PALETTE && bitDepth == 16) {
290 throw new IIOException("Bad color type/bit depth combination!");
291 }
292 if ((colorType == PNG_COLOR_RGB ||
293 colorType == PNG_COLOR_RGB_ALPHA ||
294 colorType == PNG_COLOR_GRAY_ALPHA) &&
295 (bitDepth != 8 && bitDepth != 16)) {
296 throw new IIOException("Bad color type/bit depth combination!");
297 }
298 if (compressionMethod != 0) {
299 throw new IIOException("Unknown compression method (not 0)!");
300 }
301 if (filterMethod != 0) {
302 throw new IIOException("Unknown filter method (not 0)!");
303 }
304 if (interlaceMethod != 0 && interlaceMethod != 1) {
305 throw new IIOException("Unknown interlace method (not 0 or 1)!");
306 }
307
308 metadata.IHDR_present = true;
309 metadata.IHDR_width = width;
310 metadata.IHDR_height = height;
311 metadata.IHDR_bitDepth = bitDepth;
312 metadata.IHDR_colorType = colorType;
313 metadata.IHDR_compressionMethod = compressionMethod;
314 metadata.IHDR_filterMethod = filterMethod;
315 metadata.IHDR_interlaceMethod = interlaceMethod;
316 gotHeader = true;
317 } catch (IOException e) {
318 throw new IIOException("I/O error reading PNG header!", e);
319 }
320 }
321
322 private void parse_PLTE_chunk(int chunkLength) throws IOException {
323 if (metadata.PLTE_present) {
324 processWarningOccurred(
325 "A PNG image may not contain more than one PLTE chunk.\n" +
326 "The chunk wil be ignored.");
327 return;
328 } else if (metadata.IHDR_colorType == PNG_COLOR_GRAY ||
329 metadata.IHDR_colorType == PNG_COLOR_GRAY_ALPHA) {
330 processWarningOccurred(
331 "A PNG gray or gray alpha image cannot have a PLTE chunk.\n" +
332 "The chunk wil be ignored.");
333 return;
334 }
335
336 byte[] palette = new byte[chunkLength];
337 stream.readFully(palette);
338
339 int numEntries = chunkLength/3;
340 if (metadata.IHDR_colorType == PNG_COLOR_PALETTE) {
341 int maxEntries = 1 << metadata.IHDR_bitDepth;
342 if (numEntries > maxEntries) {
343 processWarningOccurred(
344 "PLTE chunk contains too many entries for bit depth, ignoring extras.");
345 numEntries = maxEntries;
346 }
347 numEntries = Math.min(numEntries, maxEntries);
348 }
349
350 // Round array sizes up to 2^2^n
351 int paletteEntries;
352 if (numEntries > 16) {
353 paletteEntries = 256;
354 } else if (numEntries > 4) {
355 paletteEntries = 16;
356 } else if (numEntries > 2) {
357 paletteEntries = 4;
358 } else {
359 paletteEntries = 2;
360 }
361
362 metadata.PLTE_present = true;
363 metadata.PLTE_red = new byte[paletteEntries];
364 metadata.PLTE_green = new byte[paletteEntries];
365 metadata.PLTE_blue = new byte[paletteEntries];
366
367 int index = 0;
368 for (int i = 0; i < numEntries; i++) {
369 metadata.PLTE_red[i] = palette[index++];
370 metadata.PLTE_green[i] = palette[index++];
371 metadata.PLTE_blue[i] = palette[index++];
372 }
373 }
374
375 private void parse_bKGD_chunk() throws IOException {
376 if (metadata.IHDR_colorType == PNG_COLOR_PALETTE) {
377 metadata.bKGD_colorType = PNG_COLOR_PALETTE;
378 metadata.bKGD_index = stream.readUnsignedByte();
379 } else if (metadata.IHDR_colorType == PNG_COLOR_GRAY ||
380 metadata.IHDR_colorType == PNG_COLOR_GRAY_ALPHA) {
381 metadata.bKGD_colorType = PNG_COLOR_GRAY;
382 metadata.bKGD_gray = stream.readUnsignedShort();
383 } else { // RGB or RGB_ALPHA
384 metadata.bKGD_colorType = PNG_COLOR_RGB;
385 metadata.bKGD_red = stream.readUnsignedShort();
386 metadata.bKGD_green = stream.readUnsignedShort();
387 metadata.bKGD_blue = stream.readUnsignedShort();
388 }
389
390 metadata.bKGD_present = true;
391 }
392
393 private void parse_cHRM_chunk() throws IOException {
394 metadata.cHRM_whitePointX = stream.readInt();
395 metadata.cHRM_whitePointY = stream.readInt();
396 metadata.cHRM_redX = stream.readInt();
397 metadata.cHRM_redY = stream.readInt();
398 metadata.cHRM_greenX = stream.readInt();
399 metadata.cHRM_greenY = stream.readInt();
400 metadata.cHRM_blueX = stream.readInt();
401 metadata.cHRM_blueY = stream.readInt();
402
403 metadata.cHRM_present = true;
404 }
405
406 private void parse_gAMA_chunk() throws IOException {
407 int gamma = stream.readInt();
408 metadata.gAMA_gamma = gamma;
409
410 metadata.gAMA_present = true;
411 }
412
413 private void parse_hIST_chunk(int chunkLength) throws IOException,
414 IIOException
415 {
416 if (!metadata.PLTE_present) {
417 throw new IIOException("hIST chunk without prior PLTE chunk!");
418 }
419
420 /* According to PNG specification length of
421 * hIST chunk is specified in bytes and
422 * hIST chunk consists of 2 byte elements
423 * (so we expect length is even).
424 */
425 metadata.hIST_histogram = new char[chunkLength/2];
426 stream.readFully(metadata.hIST_histogram,
427 0, metadata.hIST_histogram.length);
428
429 metadata.hIST_present = true;
430 }
431
432 private void parse_iCCP_chunk(int chunkLength) throws IOException {
433 String keyword = readNullTerminatedString("ISO-8859-1", 80);
434 int compressedProfileLength = chunkLength - keyword.length() - 2;
435 if (compressedProfileLength <= 0) {
436 throw new IIOException("iCCP chunk length is not proper");
437 }
438 metadata.iCCP_profileName = keyword;
439
440 metadata.iCCP_compressionMethod = stream.readUnsignedByte();
441
442 byte[] compressedProfile =
443 new byte[compressedProfileLength];
444 stream.readFully(compressedProfile);
445 metadata.iCCP_compressedProfile = compressedProfile;
446
447 metadata.iCCP_present = true;
448 }
449
450 private void parse_iTXt_chunk(int chunkLength) throws IOException {
451 long chunkStart = stream.getStreamPosition();
452
453 String keyword = readNullTerminatedString("ISO-8859-1", 80);
454 metadata.iTXt_keyword.add(keyword);
455
456 int compressionFlag = stream.readUnsignedByte();
457 metadata.iTXt_compressionFlag.add(Boolean.valueOf(compressionFlag == 1));
458
459 int compressionMethod = stream.readUnsignedByte();
460 metadata.iTXt_compressionMethod.add(Integer.valueOf(compressionMethod));
461
462 long pos = stream.getStreamPosition();
463 int remainingLen = (int)(chunkStart + chunkLength - pos);
464 String languageTag = readNullTerminatedString("UTF8", remainingLen);
465 metadata.iTXt_languageTag.add(languageTag);
466
467 pos = stream.getStreamPosition();
468 remainingLen = (int)(chunkStart + chunkLength - pos);
469 if (remainingLen < 0) {
470 throw new IIOException("iTXt chunk length is not proper");
471 }
472 String translatedKeyword =
473 readNullTerminatedString("UTF8", remainingLen);
474 metadata.iTXt_translatedKeyword.add(translatedKeyword);
475
476 String text;
477 pos = stream.getStreamPosition();
478 int textLength = (int)(chunkStart + chunkLength - pos);
479 if (textLength < 0) {
480 throw new IIOException("iTXt chunk length is not proper");
481 }
482 byte[] b = new byte[textLength];
483 stream.readFully(b);
484
485 if (compressionFlag == 1) { // Decompress the text
486 text = new String(inflate(b), "UTF8");
487 } else {
488 text = new String(b, "UTF8");
489 }
490 metadata.iTXt_text.add(text);
491
492 // Check if the text chunk contains image creation time
493 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) {
494 // Update Standard/Document/ImageCreationTime from text chunk
495 int index = metadata.iTXt_text.size() - 1;
496 metadata.decodeImageCreationTimeFromTextChunk(
497 metadata.iTXt_text.listIterator(index));
498 }
499 }
500
501 private void parse_pHYs_chunk() throws IOException {
502 metadata.pHYs_pixelsPerUnitXAxis = stream.readInt();
503 metadata.pHYs_pixelsPerUnitYAxis = stream.readInt();
504 metadata.pHYs_unitSpecifier = stream.readUnsignedByte();
505
506 metadata.pHYs_present = true;
507 }
508
509 private void parse_sBIT_chunk() throws IOException {
510 int colorType = metadata.IHDR_colorType;
511 if (colorType == PNG_COLOR_GRAY ||
512 colorType == PNG_COLOR_GRAY_ALPHA) {
513 metadata.sBIT_grayBits = stream.readUnsignedByte();
514 } else if (colorType == PNG_COLOR_RGB ||
515 colorType == PNG_COLOR_PALETTE ||
516 colorType == PNG_COLOR_RGB_ALPHA) {
517 metadata.sBIT_redBits = stream.readUnsignedByte();
518 metadata.sBIT_greenBits = stream.readUnsignedByte();
519 metadata.sBIT_blueBits = stream.readUnsignedByte();
520 }
521
522 if (colorType == PNG_COLOR_GRAY_ALPHA ||
523 colorType == PNG_COLOR_RGB_ALPHA) {
524 metadata.sBIT_alphaBits = stream.readUnsignedByte();
525 }
526
527 metadata.sBIT_colorType = colorType;
528 metadata.sBIT_present = true;
529 }
530
531 private void parse_sPLT_chunk(int chunkLength)
532 throws IOException, IIOException {
533 metadata.sPLT_paletteName = readNullTerminatedString("ISO-8859-1", 80);
534 int remainingChunkLength = chunkLength -
535 (metadata.sPLT_paletteName.length() + 1);
536 if (remainingChunkLength <= 0) {
537 throw new IIOException("sPLT chunk length is not proper");
538 }
539
540 int sampleDepth = stream.readUnsignedByte();
541 metadata.sPLT_sampleDepth = sampleDepth;
542
543 int numEntries = remainingChunkLength/(4*(sampleDepth/8) + 2);
544 metadata.sPLT_red = new int[numEntries];
545 metadata.sPLT_green = new int[numEntries];
546 metadata.sPLT_blue = new int[numEntries];
547 metadata.sPLT_alpha = new int[numEntries];
548 metadata.sPLT_frequency = new int[numEntries];
549
550 if (sampleDepth == 8) {
551 for (int i = 0; i < numEntries; i++) {
552 metadata.sPLT_red[i] = stream.readUnsignedByte();
553 metadata.sPLT_green[i] = stream.readUnsignedByte();
554 metadata.sPLT_blue[i] = stream.readUnsignedByte();
555 metadata.sPLT_alpha[i] = stream.readUnsignedByte();
556 metadata.sPLT_frequency[i] = stream.readUnsignedShort();
557 }
558 } else if (sampleDepth == 16) {
559 for (int i = 0; i < numEntries; i++) {
560 metadata.sPLT_red[i] = stream.readUnsignedShort();
561 metadata.sPLT_green[i] = stream.readUnsignedShort();
562 metadata.sPLT_blue[i] = stream.readUnsignedShort();
563 metadata.sPLT_alpha[i] = stream.readUnsignedShort();
564 metadata.sPLT_frequency[i] = stream.readUnsignedShort();
565 }
566 } else {
567 throw new IIOException("sPLT sample depth not 8 or 16!");
568 }
569
570 metadata.sPLT_present = true;
571 }
572
573 private void parse_sRGB_chunk() throws IOException {
574 metadata.sRGB_renderingIntent = stream.readUnsignedByte();
575
576 metadata.sRGB_present = true;
577 }
578
579 private void parse_tEXt_chunk(int chunkLength) throws IOException {
580 String keyword = readNullTerminatedString("ISO-8859-1", 80);
581 int textLength = chunkLength - keyword.length() - 1;
582 if (textLength < 0) {
583 throw new IIOException("tEXt chunk length is not proper");
584 }
585 metadata.tEXt_keyword.add(keyword);
586
587 byte[] b = new byte[textLength];
588 stream.readFully(b);
589 metadata.tEXt_text.add(new String(b, "ISO-8859-1"));
590
591 // Check if the text chunk contains image creation time
592 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) {
593 // Update Standard/Document/ImageCreationTime from text chunk
594 int index = metadata.tEXt_text.size() - 1;
595 metadata.decodeImageCreationTimeFromTextChunk(
596 metadata.tEXt_text.listIterator(index));
597 }
598 }
599
600 private void parse_tIME_chunk() throws IOException {
601 metadata.tIME_year = stream.readUnsignedShort();
602 metadata.tIME_month = stream.readUnsignedByte();
603 metadata.tIME_day = stream.readUnsignedByte();
604 metadata.tIME_hour = stream.readUnsignedByte();
605 metadata.tIME_minute = stream.readUnsignedByte();
606 metadata.tIME_second = stream.readUnsignedByte();
607
608 metadata.tIME_present = true;
609 }
610
611 private void parse_tRNS_chunk(int chunkLength) throws IOException {
612 int colorType = metadata.IHDR_colorType;
613 if (colorType == PNG_COLOR_PALETTE) {
614 if (!metadata.PLTE_present) {
615 processWarningOccurred(
616 "tRNS chunk without prior PLTE chunk, ignoring it.");
617 return;
618 }
619
620 // Alpha table may have fewer entries than RGB palette
621 int maxEntries = metadata.PLTE_red.length;
622 int numEntries = chunkLength;
623 if (numEntries > maxEntries && maxEntries > 0) {
624 processWarningOccurred(
625 "tRNS chunk has more entries than prior PLTE chunk, ignoring extras.");
626 numEntries = maxEntries;
627 }
628 metadata.tRNS_alpha = new byte[numEntries];
629 metadata.tRNS_colorType = PNG_COLOR_PALETTE;
630 stream.read(metadata.tRNS_alpha, 0, numEntries);
631 stream.skipBytes(chunkLength - numEntries);
632 } else if (colorType == PNG_COLOR_GRAY) {
633 if (chunkLength != 2) {
634 processWarningOccurred(
635 "tRNS chunk for gray image must have length 2, ignoring chunk.");
636 stream.skipBytes(chunkLength);
637 return;
638 }
639 metadata.tRNS_gray = stream.readUnsignedShort();
640 metadata.tRNS_colorType = PNG_COLOR_GRAY;
641 } else if (colorType == PNG_COLOR_RGB) {
642 if (chunkLength != 6) {
643 processWarningOccurred(
644 "tRNS chunk for RGB image must have length 6, ignoring chunk.");
645 stream.skipBytes(chunkLength);
646 return;
647 }
648 metadata.tRNS_red = stream.readUnsignedShort();
649 metadata.tRNS_green = stream.readUnsignedShort();
650 metadata.tRNS_blue = stream.readUnsignedShort();
651 metadata.tRNS_colorType = PNG_COLOR_RGB;
652 } else {
653 processWarningOccurred(
654 "Gray+Alpha and RGBS images may not have a tRNS chunk, ignoring it.");
655 return;
656 }
657
658 metadata.tRNS_present = true;
659 }
660
661 private static byte[] inflate(byte[] b) throws IOException {
662 InputStream bais = new ByteArrayInputStream(b);
663 InputStream iis = new InflaterInputStream(bais);
664 ByteArrayOutputStream baos = new ByteArrayOutputStream();
665
666 int c;
667 try {
668 while ((c = iis.read()) != -1) {
669 baos.write(c);
670 }
671 } finally {
672 iis.close();
673 }
674 return baos.toByteArray();
675 }
676
677 private void parse_zTXt_chunk(int chunkLength) throws IOException {
678 String keyword = readNullTerminatedString("ISO-8859-1", 80);
679 int textLength = chunkLength - keyword.length() - 2;
680 if (textLength < 0) {
681 throw new IIOException("zTXt chunk length is not proper");
682 }
683 metadata.zTXt_keyword.add(keyword);
684
685 int method = stream.readUnsignedByte();
686 metadata.zTXt_compressionMethod.add(method);
687
688 byte[] b = new byte[textLength];
689 stream.readFully(b);
690 metadata.zTXt_text.add(new String(inflate(b), "ISO-8859-1"));
691
692 // Check if the text chunk contains image creation time
693 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) {
694 // Update Standard/Document/ImageCreationTime from text chunk
695 int index = metadata.zTXt_text.size() - 1;
696 metadata.decodeImageCreationTimeFromTextChunk(
697 metadata.zTXt_text.listIterator(index));
698 }
699 }
700
701 private void readMetadata() throws IIOException {
702 if (gotMetadata) {
703 return;
704 }
705
706 readHeader();
707
708 /*
709 * Optimization: We can skip reading metadata if ignoreMetadata
710 * flag is set and colorType is not PNG_COLOR_PALETTE. However,
711 * we parse tRNS chunk to retrieve the transparent color from the
712 * metadata. Doing so, helps PNGImageReader to appropriately
713 * identify and set transparent pixels in the decoded image for
714 * colorType PNG_COLOR_RGB and PNG_COLOR_GRAY.
715 */
716 int colorType = metadata.IHDR_colorType;
717 if (ignoreMetadata && colorType != PNG_COLOR_PALETTE) {
718 try {
719 while (true) {
720 int chunkLength = stream.readInt();
721
722 // verify the chunk length first
723 if (chunkLength < 0 || chunkLength + 4 < 0) {
724 throw new IIOException("Invalid chunk length " + chunkLength);
725 }
726
727 int chunkType = stream.readInt();
728
729 if (chunkType == IDAT_TYPE) {
730 // We've reached the first IDAT chunk position
731 stream.skipBytes(-8);
732 imageStartPosition = stream.getStreamPosition();
733 /*
734 * According to PNG specification tRNS chunk must
735 * precede the first IDAT chunk. So we can stop
736 * reading metadata.
737 */
738 break;
739 } else if (chunkType == tRNS_TYPE) {
740 parse_tRNS_chunk(chunkLength);
741 // After parsing tRNS chunk we will skip 4 CRC bytes
742 stream.skipBytes(4);
743 } else {
744 // Skip the chunk plus the 4 CRC bytes that follow
745 stream.skipBytes(chunkLength + 4);
746 }
747 }
748 } catch (IOException e) {
749 throw new IIOException("Error skipping PNG metadata", e);
750 }
751
752 gotMetadata = true;
753 return;
754 }
755
756 try {
757 loop: while (true) {
758 int chunkLength = stream.readInt();
759 int chunkType = stream.readInt();
760 // Initialize chunkCRC, value assigned has no significance
761 int chunkCRC = -1;
762
763 // verify the chunk length
764 if (chunkLength < 0) {
765 throw new IIOException("Invalid chunk length " + chunkLength);
766 };
767
768 try {
769 /*
770 * As per PNG specification all chunks should have
771 * 4 byte CRC. But there are some images where
772 * CRC is not present/corrupt for IEND chunk.
773 * And these type of images are supported by other
774 * decoders. So as soon as we hit chunk type
775 * for IEND chunk stop reading metadata.
776 */
777 if (chunkType != IEND_TYPE) {
778 stream.mark();
779 stream.seek(stream.getStreamPosition() + chunkLength);
780 chunkCRC = stream.readInt();
781 stream.reset();
782 }
783 } catch (IOException e) {
784 throw new IIOException("Invalid chunk length " + chunkLength);
785 }
786
787 switch (chunkType) {
788 case IDAT_TYPE:
789 // If chunk type is 'IDAT', we've reached the image data.
790 if (imageStartPosition == -1L) {
791 /*
792 * The PNG specification mandates that if colorType is
793 * PNG_COLOR_PALETTE then the PLTE chunk should appear
794 * before the first IDAT chunk.
795 */
796 if (colorType == PNG_COLOR_PALETTE &&
797 !(metadata.PLTE_present))
798 {
799 throw new IIOException("Required PLTE chunk"
800 + " missing");
801 }
802 /*
803 * PNGs may contain multiple IDAT chunks containing
804 * a portion of image data. We store the position of
805 * the first IDAT chunk and continue with iteration
806 * of other chunks that follow image data.
807 */
808 imageStartPosition = stream.getStreamPosition() - 8;
809 }
810 // Move to the CRC byte location.
811 stream.skipBytes(chunkLength);
812 break;
813 case IEND_TYPE:
814 /*
815 * If the chunk type is 'IEND', we've reached end of image.
816 * Seek to the first IDAT chunk for subsequent decoding.
817 */
818 stream.seek(imageStartPosition);
819
820 /*
821 * flushBefore discards the portion of the stream before
822 * the indicated position. Hence this should be used after
823 * we complete iteration over available chunks including
824 * those that appear after the IDAT.
825 */
826 stream.flushBefore(stream.getStreamPosition());
827 break loop;
828 case PLTE_TYPE:
829 parse_PLTE_chunk(chunkLength);
830 break;
831 case bKGD_TYPE:
832 parse_bKGD_chunk();
833 break;
834 case cHRM_TYPE:
835 parse_cHRM_chunk();
836 break;
837 case gAMA_TYPE:
838 parse_gAMA_chunk();
839 break;
840 case hIST_TYPE:
841 parse_hIST_chunk(chunkLength);
842 break;
843 case iCCP_TYPE:
844 parse_iCCP_chunk(chunkLength);
845 break;
846 case iTXt_TYPE:
847 if (ignoreMetadata) {
848 stream.skipBytes(chunkLength);
849 } else {
850 parse_iTXt_chunk(chunkLength);
851 }
852 break;
853 case pHYs_TYPE:
854 parse_pHYs_chunk();
855 break;
856 case sBIT_TYPE:
857 parse_sBIT_chunk();
858 break;
859 case sPLT_TYPE:
860 parse_sPLT_chunk(chunkLength);
861 break;
862 case sRGB_TYPE:
863 parse_sRGB_chunk();
864 break;
865 case tEXt_TYPE:
866 parse_tEXt_chunk(chunkLength);
867 break;
868 case tIME_TYPE:
869 parse_tIME_chunk();
870 break;
871 case tRNS_TYPE:
872 parse_tRNS_chunk(chunkLength);
873 break;
874 case zTXt_TYPE:
875 if (ignoreMetadata) {
876 stream.skipBytes(chunkLength);
877 } else {
878 parse_zTXt_chunk(chunkLength);
879 }
880 break;
881 default:
882 // Read an unknown chunk
883 byte[] b = new byte[chunkLength];
884 stream.readFully(b);
885
886 StringBuilder chunkName = new StringBuilder(4);
887 chunkName.append((char)(chunkType >>> 24));
888 chunkName.append((char)((chunkType >> 16) & 0xff));
889 chunkName.append((char)((chunkType >> 8) & 0xff));
890 chunkName.append((char)(chunkType & 0xff));
891
892 int ancillaryBit = chunkType >>> 28;
893 if (ancillaryBit == 0) {
894 processWarningOccurred(
895 "Encountered unknown chunk with critical bit set!");
896 }
897
898 metadata.unknownChunkType.add(chunkName.toString());
899 metadata.unknownChunkData.add(b);
900 break;
901 }
902
903 // double check whether all chunk data were consumed
904 if (chunkCRC != stream.readInt()) {
905 throw new IIOException("Failed to read a chunk of type " +
906 chunkType);
907 }
908 }
909 } catch (IOException e) {
910 throw new IIOException("Error reading PNG metadata", e);
911 }
912
913 gotMetadata = true;
914 }
915
916 // Data filtering methods
917
918 private static void decodeSubFilter(byte[] curr, int coff, int count,
919 int bpp) {
920 for (int i = bpp; i < count; i++) {
921 int val;
922
923 val = curr[i + coff] & 0xff;
924 val += curr[i + coff - bpp] & 0xff;
925
926 curr[i + coff] = (byte)val;
927 }
928 }
929
930 private static void decodeUpFilter(byte[] curr, int coff,
931 byte[] prev, int poff,
932 int count) {
933 for (int i = 0; i < count; i++) {
934 int raw = curr[i + coff] & 0xff;
935 int prior = prev[i + poff] & 0xff;
936
937 curr[i + coff] = (byte)(raw + prior);
938 }
939 }
940
941 private static void decodeAverageFilter(byte[] curr, int coff,
942 byte[] prev, int poff,
943 int count, int bpp) {
944 int raw, priorPixel, priorRow;
945
946 for (int i = 0; i < bpp; i++) {
947 raw = curr[i + coff] & 0xff;
948 priorRow = prev[i + poff] & 0xff;
949
950 curr[i + coff] = (byte)(raw + priorRow/2);
951 }
952
953 for (int i = bpp; i < count; i++) {
954 raw = curr[i + coff] & 0xff;
955 priorPixel = curr[i + coff - bpp] & 0xff;
956 priorRow = prev[i + poff] & 0xff;
957
958 curr[i + coff] = (byte)(raw + (priorPixel + priorRow)/2);
959 }
960 }
961
962 private static int paethPredictor(int a, int b, int c) {
963 int p = a + b - c;
964 int pa = Math.abs(p - a);
965 int pb = Math.abs(p - b);
966 int pc = Math.abs(p - c);
967
968 if ((pa <= pb) && (pa <= pc)) {
969 return a;
970 } else if (pb <= pc) {
971 return b;
972 } else {
973 return c;
974 }
975 }
976
977 private static void decodePaethFilter(byte[] curr, int coff,
978 byte[] prev, int poff,
979 int count, int bpp) {
980 int raw, priorPixel, priorRow, priorRowPixel;
981
982 for (int i = 0; i < bpp; i++) {
983 raw = curr[i + coff] & 0xff;
984 priorRow = prev[i + poff] & 0xff;
985
986 curr[i + coff] = (byte)(raw + priorRow);
987 }
988
989 for (int i = bpp; i < count; i++) {
990 raw = curr[i + coff] & 0xff;
991 priorPixel = curr[i + coff - bpp] & 0xff;
992 priorRow = prev[i + poff] & 0xff;
993 priorRowPixel = prev[i + poff - bpp] & 0xff;
994
995 curr[i + coff] = (byte)(raw + paethPredictor(priorPixel,
996 priorRow,
997 priorRowPixel));
998 }
999 }
1000
1001 private static final int[][] bandOffsets = {
1002 null,
1003 { 0 }, // G
1004 { 0, 1 }, // GA in GA order
1005 { 0, 1, 2 }, // RGB in RGB order
1006 { 0, 1, 2, 3 } // RGBA in RGBA order
1007 };
1008
1009 private WritableRaster createRaster(int width, int height, int bands,
1010 int scanlineStride,
1011 int bitDepth) {
1012
1013 DataBuffer dataBuffer;
1014 WritableRaster ras = null;
1015 Point origin = new Point(0, 0);
1016 if ((bitDepth < 8) && (bands == 1)) {
1017 dataBuffer = new DataBufferByte(height*scanlineStride);
1018 ras = Raster.createPackedRaster(dataBuffer,
1019 width, height,
1020 bitDepth,
1021 origin);
1022 } else if (bitDepth <= 8) {
1023 dataBuffer = new DataBufferByte(height*scanlineStride);
1024 ras = Raster.createInterleavedRaster(dataBuffer,
1025 width, height,
1026 scanlineStride,
1027 bands,
1028 bandOffsets[bands],
1029 origin);
1030 } else {
1031 dataBuffer = new DataBufferUShort(height*scanlineStride);
1032 ras = Raster.createInterleavedRaster(dataBuffer,
1033 width, height,
1034 scanlineStride,
1035 bands,
1036 bandOffsets[bands],
1037 origin);
1038 }
1039
1040 return ras;
1041 }
1042
1043 private void skipPass(int passWidth, int passHeight)
1044 throws IOException, IIOException {
1045 if ((passWidth == 0) || (passHeight == 0)) {
1046 return;
1047 }
1048
1049 int inputBands = inputBandsForColorType[metadata.IHDR_colorType];
1050 int bitsPerRow = Math.
1051 multiplyExact((inputBands * metadata.IHDR_bitDepth), passWidth);
1052 int bytesPerRow = (bitsPerRow + 7) / 8;
1053
1054 // Read the image row-by-row
1055 for (int srcY = 0; srcY < passHeight; srcY++) {
1056 // Skip filter byte and the remaining row bytes
1057 pixelStream.skipBytes(1 + bytesPerRow);
1058 }
1059 }
1060
1061 private void updateImageProgress(int newPixels) {
1062 pixelsDone += newPixels;
1063 processImageProgress(100.0F*pixelsDone/totalPixels);
1064 }
1065
1066 private void decodePass(int passNum,
1067 int xStart, int yStart,
1068 int xStep, int yStep,
1069 int passWidth, int passHeight) throws IOException {
1070
1071 if ((passWidth == 0) || (passHeight == 0)) {
1072 return;
1073 }
1074
1075 WritableRaster imRas = theImage.getWritableTile(0, 0);
1076 int dstMinX = imRas.getMinX();
1077 int dstMaxX = dstMinX + imRas.getWidth() - 1;
1078 int dstMinY = imRas.getMinY();
1079 int dstMaxY = dstMinY + imRas.getHeight() - 1;
1080
1081 // Determine which pixels will be updated in this pass
1082 int[] vals =
1083 ReaderUtil.computeUpdatedPixels(sourceRegion,
1084 destinationOffset,
1085 dstMinX, dstMinY,
1086 dstMaxX, dstMaxY,
1087 sourceXSubsampling,
1088 sourceYSubsampling,
1089 xStart, yStart,
1090 passWidth, passHeight,
1091 xStep, yStep);
1092 int updateMinX = vals[0];
1093 int updateMinY = vals[1];
1094 int updateWidth = vals[2];
1095 int updateXStep = vals[4];
1096 int updateYStep = vals[5];
1097
1098 int bitDepth = metadata.IHDR_bitDepth;
1099 int inputBands = inputBandsForColorType[metadata.IHDR_colorType];
1100 int bytesPerPixel = (bitDepth == 16) ? 2 : 1;
1101 bytesPerPixel *= inputBands;
1102
1103 int bitsPerRow = Math.multiplyExact((inputBands * bitDepth), passWidth);
1104 int bytesPerRow = (bitsPerRow + 7) / 8;
1105 int eltsPerRow = (bitDepth == 16) ? bytesPerRow/2 : bytesPerRow;
1106
1107 // If no pixels need updating, just skip the input data
1108 if (updateWidth == 0) {
1109 for (int srcY = 0; srcY < passHeight; srcY++) {
1110 // Update count of pixels read
1111 updateImageProgress(passWidth);
1112 /*
1113 * If read has been aborted, just return
1114 * processReadAborted will be called later
1115 */
1116 if (abortRequested()) {
1117 return;
1118 }
1119 // Skip filter byte and the remaining row bytes
1120 pixelStream.skipBytes(1 + bytesPerRow);
1121 }
1122 return;
1123 }
1124
1125 // Backwards map from destination pixels
1126 // (dstX = updateMinX + k*updateXStep)
1127 // to source pixels (sourceX), and then
1128 // to offset and skip in passRow (srcX and srcXStep)
1129 int sourceX =
1130 (updateMinX - destinationOffset.x)*sourceXSubsampling +
1131 sourceRegion.x;
1132 int srcX = (sourceX - xStart)/xStep;
1133
1134 // Compute the step factor in the source
1135 int srcXStep = updateXStep*sourceXSubsampling/xStep;
1136
1137 byte[] byteData = null;
1138 short[] shortData = null;
1139 byte[] curr = new byte[bytesPerRow];
1140 byte[] prior = new byte[bytesPerRow];
1141
1142 // Create a 1-row tall Raster to hold the data
1143 WritableRaster passRow = createRaster(passWidth, 1, inputBands,
1144 eltsPerRow,
1145 bitDepth);
1146
1147 // Create an array suitable for holding one pixel
1148 int[] ps = passRow.getPixel(0, 0, (int[])null);
1149
1150 DataBuffer dataBuffer = passRow.getDataBuffer();
1151 int type = dataBuffer.getDataType();
1152 if (type == DataBuffer.TYPE_BYTE) {
1153 byteData = ((DataBufferByte)dataBuffer).getData();
1154 } else {
1155 shortData = ((DataBufferUShort)dataBuffer).getData();
1156 }
1157
1158 processPassStarted(theImage,
1159 passNum,
1160 sourceMinProgressivePass,
1161 sourceMaxProgressivePass,
1162 updateMinX, updateMinY,
1163 updateXStep, updateYStep,
1164 destinationBands);
1165
1166 // Handle source and destination bands
1167 if (sourceBands != null) {
1168 passRow = passRow.createWritableChild(0, 0,
1169 passRow.getWidth(), 1,
1170 0, 0,
1171 sourceBands);
1172 }
1173 if (destinationBands != null) {
1174 imRas = imRas.createWritableChild(0, 0,
1175 imRas.getWidth(),
1176 imRas.getHeight(),
1177 0, 0,
1178 destinationBands);
1179 }
1180
1181 // Determine if all of the relevant output bands have the
1182 // same bit depth as the source data
1183 boolean adjustBitDepths = false;
1184 int[] outputSampleSize = imRas.getSampleModel().getSampleSize();
1185 for (int b = 0; b < inputBands; b++) {
1186 if (outputSampleSize[b] != bitDepth) {
1187 adjustBitDepths = true;
1188 break;
1189 }
1190 }
1191
1192 // If the bit depths differ, create a lookup table per band to perform
1193 // the conversion
1194 int[][] scale = null;
1195 if (adjustBitDepths) {
1196 int maxInSample = (1 << bitDepth) - 1;
1197 int halfMaxInSample = maxInSample/2;
1198 scale = new int[inputBands][];
1199 for (int b = 0; b < inputBands; b++) {
1200 int maxOutSample = (1 << outputSampleSize[b]) - 1;
1201 scale[b] = new int[maxInSample + 1];
1202 for (int s = 0; s <= maxInSample; s++) {
1203 scale[b][s] =
1204 (s*maxOutSample + halfMaxInSample)/maxInSample;
1205 }
1206 }
1207 }
1208
1209 // Limit passRow to relevant area for the case where we
1210 // will can setRect to copy a contiguous span
1211 boolean useSetRect = srcXStep == 1 &&
1212 updateXStep == 1 &&
1213 !adjustBitDepths &&
1214 (imRas instanceof ByteInterleavedRaster);
1215
1216 if (useSetRect) {
1217 passRow = passRow.createWritableChild(srcX, 0,
1218 updateWidth, 1,
1219 0, 0,
1220 null);
1221 }
1222
1223 // Decode the (sub)image row-by-row
1224 for (int srcY = 0; srcY < passHeight; srcY++) {
1225 // Update count of pixels read
1226 updateImageProgress(passWidth);
1227 /*
1228 * If read has been aborted, just return
1229 * processReadAborted will be called later
1230 */
1231 if (abortRequested()) {
1232 return;
1233 }
1234 // Read the filter type byte and a row of data
1235 int filter = pixelStream.read();
1236 try {
1237 // Swap curr and prior
1238 byte[] tmp = prior;
1239 prior = curr;
1240 curr = tmp;
1241
1242 pixelStream.readFully(curr, 0, bytesPerRow);
1243 } catch (java.util.zip.ZipException ze) {
1244 // TODO - throw a more meaningful exception
1245 throw ze;
1246 }
1247
1248 switch (filter) {
1249 case PNG_FILTER_NONE:
1250 break;
1251 case PNG_FILTER_SUB:
1252 decodeSubFilter(curr, 0, bytesPerRow, bytesPerPixel);
1253 break;
1254 case PNG_FILTER_UP:
1255 decodeUpFilter(curr, 0, prior, 0, bytesPerRow);
1256 break;
1257 case PNG_FILTER_AVERAGE:
1258 decodeAverageFilter(curr, 0, prior, 0, bytesPerRow,
1259 bytesPerPixel);
1260 break;
1261 case PNG_FILTER_PAETH:
1262 decodePaethFilter(curr, 0, prior, 0, bytesPerRow,
1263 bytesPerPixel);
1264 break;
1265 default:
1266 throw new IIOException("Unknown row filter type (= " +
1267 filter + ")!");
1268 }
1269
1270 // Copy data into passRow byte by byte
1271 if (bitDepth < 16) {
1272 System.arraycopy(curr, 0, byteData, 0, bytesPerRow);
1273 } else {
1274 int idx = 0;
1275 for (int j = 0; j < eltsPerRow; j++) {
1276 shortData[j] =
1277 (short)((curr[idx] << 8) | (curr[idx + 1] & 0xff));
1278 idx += 2;
1279 }
1280 }
1281
1282 // True Y position in source
1283 int sourceY = srcY*yStep + yStart;
1284 if ((sourceY >= sourceRegion.y) &&
1285 (sourceY < sourceRegion.y + sourceRegion.height) &&
1286 (((sourceY - sourceRegion.y) %
1287 sourceYSubsampling) == 0)) {
1288
1289 int dstY = destinationOffset.y +
1290 (sourceY - sourceRegion.y)/sourceYSubsampling;
1291 if (dstY < dstMinY) {
1292 continue;
1293 }
1294 if (dstY > dstMaxY) {
1295 break;
1296 }
1297
1298 /*
1299 * For PNG images of color type PNG_COLOR_RGB or PNG_COLOR_GRAY
1300 * that contain a specific transparent color (given by tRNS
1301 * chunk), we compare the decoded pixel color with the color
1302 * given by tRNS chunk to set the alpha on the destination.
1303 */
1304 boolean tRNSTransparentPixelPresent =
1305 theImage.getSampleModel().getNumBands() == inputBands + 1 &&
1306 metadata.hasTransparentColor();
1307 if (useSetRect &&
1308 !tRNSTransparentPixelPresent) {
1309 imRas.setRect(updateMinX, dstY, passRow);
1310 } else {
1311 int newSrcX = srcX;
1312
1313 /*
1314 * Create intermediate array to fill the extra alpha
1315 * channel when tRNSTransparentPixelPresent is true.
1316 */
1317 final int[] temp = new int[inputBands + 1];
1318 final int opaque = (bitDepth < 16) ? 255 : 65535;
1319 for (int dstX = updateMinX;
1320 dstX < updateMinX + updateWidth;
1321 dstX += updateXStep) {
1322
1323 passRow.getPixel(newSrcX, 0, ps);
1324 if (adjustBitDepths) {
1325 for (int b = 0; b < inputBands; b++) {
1326 ps[b] = scale[b][ps[b]];
1327 }
1328 }
1329 if (tRNSTransparentPixelPresent) {
1330 if (metadata.tRNS_colorType == PNG_COLOR_RGB) {
1331 temp[0] = ps[0];
1332 temp[1] = ps[1];
1333 temp[2] = ps[2];
1334 if (ps[0] == metadata.tRNS_red &&
1335 ps[1] == metadata.tRNS_green &&
1336 ps[2] == metadata.tRNS_blue) {
1337 temp[3] = 0;
1338 } else {
1339 temp[3] = opaque;
1340 }
1341 } else {
1342 // when tRNS_colorType is PNG_COLOR_GRAY
1343 temp[0] = ps[0];
1344 if (ps[0] == metadata.tRNS_gray) {
1345 temp[1] = 0;
1346 } else {
1347 temp[1] = opaque;
1348 }
1349 }
1350 imRas.setPixel(dstX, dstY, temp);
1351 } else {
1352 imRas.setPixel(dstX, dstY, ps);
1353 }
1354 newSrcX += srcXStep;
1355 }
1356 }
1357
1358 processImageUpdate(theImage,
1359 updateMinX, dstY,
1360 updateWidth, 1,
1361 updateXStep, updateYStep,
1362 destinationBands);
1363 }
1364 }
1365
1366 processPassComplete(theImage);
1367 }
1368
1369 private void decodeImage()
1370 throws IOException, IIOException {
1371 int width = metadata.IHDR_width;
1372 int height = metadata.IHDR_height;
1373
1374 this.pixelsDone = 0;
1375 this.totalPixels = width*height;
1376
1377 if (metadata.IHDR_interlaceMethod == 0) {
1378 decodePass(0, 0, 0, 1, 1, width, height);
1379 } else {
1380 for (int i = 0; i <= sourceMaxProgressivePass; i++) {
1381 int XOffset = adam7XOffset[i];
1382 int YOffset = adam7YOffset[i];
1383 int XSubsampling = adam7XSubsampling[i];
1384 int YSubsampling = adam7YSubsampling[i];
1385 int xbump = adam7XSubsampling[i + 1] - 1;
1386 int ybump = adam7YSubsampling[i + 1] - 1;
1387
1388 if (i >= sourceMinProgressivePass) {
1389 decodePass(i,
1390 XOffset,
1391 YOffset,
1392 XSubsampling,
1393 YSubsampling,
1394 (width + xbump)/XSubsampling,
1395 (height + ybump)/YSubsampling);
1396 } else {
1397 skipPass((width + xbump)/XSubsampling,
1398 (height + ybump)/YSubsampling);
1399 }
1400
1401 /*
1402 * If read has been aborted, just return
1403 * processReadAborted will be called later
1404 */
1405 if (abortRequested()) {
1406 return;
1407 }
1408 }
1409 }
1410 }
1411
1412 private void readImage(ImageReadParam param) throws IIOException {
1413 readMetadata();
1414
1415 int width = metadata.IHDR_width;
1416 int height = metadata.IHDR_height;
1417
1418 // Init default values
1419 sourceXSubsampling = 1;
1420 sourceYSubsampling = 1;
1421 sourceMinProgressivePass = 0;
1422 sourceMaxProgressivePass = 6;
1423 sourceBands = null;
1424 destinationBands = null;
1425 destinationOffset = new Point(0, 0);
1426
1427 // If an ImageReadParam is available, get values from it
1428 if (param != null) {
1429 sourceXSubsampling = param.getSourceXSubsampling();
1430 sourceYSubsampling = param.getSourceYSubsampling();
1431
1432 sourceMinProgressivePass =
1433 Math.max(param.getSourceMinProgressivePass(), 0);
1434 sourceMaxProgressivePass =
1435 Math.min(param.getSourceMaxProgressivePass(), 6);
1436
1437 sourceBands = param.getSourceBands();
1438 destinationBands = param.getDestinationBands();
1439 destinationOffset = param.getDestinationOffset();
1440 }
1441 Inflater inf = null;
1442 try {
1443 stream.seek(imageStartPosition);
1444
1445 Enumeration<InputStream> e = new PNGImageDataEnumeration(stream);
1446 InputStream is = new SequenceInputStream(e);
1447
1448 /* InflaterInputStream uses an Inflater instance which consumes
1449 * native (non-GC visible) resources. This is normally implicitly
1450 * freed when the stream is closed. However since the
1451 * InflaterInputStream wraps a client-supplied input stream,
1452 * we cannot close it.
1453 * But the app may depend on GC finalization to close the stream.
1454 * Therefore to ensure timely freeing of native resources we
1455 * explicitly create the Inflater instance and free its resources
1456 * when we are done with the InflaterInputStream by calling
1457 * inf.end();
1458 */
1459 inf = new Inflater();
1460 is = new InflaterInputStream(is, inf);
1461 is = new BufferedInputStream(is);
1462 this.pixelStream = new DataInputStream(is);
1463
1464 /*
1465 * PNG spec declares that valid range for width
1466 * and height is [1, 2^31-1], so here we may fail to allocate
1467 * a buffer for destination image due to memory limitation.
1468 *
1469 * If the read operation triggers OutOfMemoryError, the same
1470 * will be wrapped in an IIOException at PNGImageReader.read
1471 * method.
1472 *
1473 * The recovery strategy for this case should be defined at
1474 * the level of application, so we will not try to estimate
1475 * the required amount of the memory and/or handle OOM in
1476 * any way.
1477 */
1478 theImage = getDestination(param,
1479 getImageTypes(0),
1480 width,
1481 height);
1482
1483 Rectangle destRegion = new Rectangle(0, 0, 0, 0);
1484 sourceRegion = new Rectangle(0, 0, 0, 0);
1485 computeRegions(param, width, height,
1486 theImage,
1487 sourceRegion, destRegion);
1488 destinationOffset.setLocation(destRegion.getLocation());
1489
1490 // At this point the header has been read and we know
1491 // how many bands are in the image, so perform checking
1492 // of the read param.
1493 int colorType = metadata.IHDR_colorType;
1494 if (theImage.getSampleModel().getNumBands()
1495 == inputBandsForColorType[colorType] + 1
1496 && metadata.hasTransparentColor()) {
1497 checkReadParamBandSettings(param,
1498 inputBandsForColorType[colorType] + 1,
1499 theImage.getSampleModel().getNumBands());
1500 } else {
1501 checkReadParamBandSettings(param,
1502 inputBandsForColorType[colorType],
1503 theImage.getSampleModel().getNumBands());
1504 }
1505
1506 clearAbortRequest();
1507 processImageStarted(0);
1508 if (abortRequested()) {
1509 processReadAborted();
1510 } else {
1511 decodeImage();
1512 if (abortRequested()) {
1513 processReadAborted();
1514 } else {
1515 processImageComplete();
1516 }
1517 }
1518
1519 } catch (IOException e) {
1520 throw new IIOException("Error reading PNG image data", e);
1521 } finally {
1522 if (inf != null) {
1523 inf.end();
1524 }
1525 }
1526 }
1527
1528 public int getNumImages(boolean allowSearch) throws IIOException {
1529 if (stream == null) {
1530 throw new IllegalStateException("No input source set!");
1531 }
1532 if (seekForwardOnly && allowSearch) {
1533 throw new IllegalStateException
1534 ("seekForwardOnly and allowSearch can't both be true!");
1535 }
1536 return 1;
1537 }
1538
1539 public int getWidth(int imageIndex) throws IIOException {
1540 if (imageIndex != 0) {
1541 throw new IndexOutOfBoundsException("imageIndex != 0!");
1542 }
1543
1544 readHeader();
1545
1546 return metadata.IHDR_width;
1547 }
1548
1549 public int getHeight(int imageIndex) throws IIOException {
1550 if (imageIndex != 0) {
1551 throw new IndexOutOfBoundsException("imageIndex != 0!");
1552 }
1553
1554 readHeader();
1555
1556 return metadata.IHDR_height;
1557 }
1558
1559 public Iterator<ImageTypeSpecifier> getImageTypes(int imageIndex)
1560 throws IIOException
1561 {
1562 if (imageIndex != 0) {
1563 throw new IndexOutOfBoundsException("imageIndex != 0!");
1564 }
1565
1566 readHeader();
1567
1568 ArrayList<ImageTypeSpecifier> l =
1569 new ArrayList<ImageTypeSpecifier>(1);
1570
1571 ColorSpace rgb;
1572 ColorSpace gray;
1573 int[] bandOffsets;
1574
1575 int bitDepth = metadata.IHDR_bitDepth;
1576 int colorType = metadata.IHDR_colorType;
1577
1578 int dataType;
1579 if (bitDepth <= 8) {
1580 dataType = DataBuffer.TYPE_BYTE;
1581 } else {
1582 dataType = DataBuffer.TYPE_USHORT;
1583 }
1584
1585 switch (colorType) {
1586 /*
1587 * For PNG images of color type PNG_COLOR_RGB or PNG_COLOR_GRAY that
1588 * contain a specific transparent color (given by tRNS chunk), we add
1589 * ImageTypeSpecifier(s) that support transparency to the list of
1590 * supported image types.
1591 */
1592 case PNG_COLOR_GRAY:
1593 readMetadata(); // Need tRNS chunk
1594
1595 if (metadata.hasTransparentColor()) {
1596 gray = ColorSpace.getInstance(ColorSpace.CS_GRAY);
1597 bandOffsets = new int[2];
1598 bandOffsets[0] = 0;
1599 bandOffsets[1] = 1;
1600 l.add(ImageTypeSpecifier.createInterleaved(gray,
1601 bandOffsets,
1602 dataType,
1603 true,
1604 false));
1605 }
1606 // Packed grayscale
1607 l.add(ImageTypeSpecifier.createGrayscale(bitDepth,
1608 dataType,
1609 false));
1610 break;
1611
1612 case PNG_COLOR_RGB:
1613 readMetadata(); // Need tRNS chunk
1614
1615 if (bitDepth == 8) {
1616 if (metadata.hasTransparentColor()) {
1617 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1618 BufferedImage.TYPE_4BYTE_ABGR));
1619 }
1620 // some standard types of buffered images
1621 // which can be used as destination
1622 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1623 BufferedImage.TYPE_3BYTE_BGR));
1624
1625 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1626 BufferedImage.TYPE_INT_RGB));
1627
1628 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1629 BufferedImage.TYPE_INT_BGR));
1630
1631 }
1632
1633 if (metadata.hasTransparentColor()) {
1634 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB);
1635 bandOffsets = new int[4];
1636 bandOffsets[0] = 0;
1637 bandOffsets[1] = 1;
1638 bandOffsets[2] = 2;
1639 bandOffsets[3] = 3;
1640
1641 l.add(ImageTypeSpecifier.
1642 createInterleaved(rgb, bandOffsets,
1643 dataType, true, false));
1644 }
1645 // Component R, G, B
1646 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB);
1647 bandOffsets = new int[3];
1648 bandOffsets[0] = 0;
1649 bandOffsets[1] = 1;
1650 bandOffsets[2] = 2;
1651 l.add(ImageTypeSpecifier.createInterleaved(rgb,
1652 bandOffsets,
1653 dataType,
1654 false,
1655 false));
1656 break;
1657
1658 case PNG_COLOR_PALETTE:
1659 readMetadata(); // Need tRNS chunk
1660
1661 /*
1662 * The PLTE chunk spec says:
1663 *
1664 * The number of palette entries must not exceed the range that
1665 * can be represented in the image bit depth (for example, 2^4 = 16
1666 * for a bit depth of 4). It is permissible to have fewer entries
1667 * than the bit depth would allow. In that case, any out-of-range
1668 * pixel value found in the image data is an error.
1669 *
1670 * http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html#C.PLTE
1671 *
1672 * Consequently, the case when the palette length is smaller than
1673 * 2^bitDepth is legal in the view of PNG spec.
1674 *
1675 * However the spec of createIndexed() method demands the exact
1676 * equality of the palette lengh and number of possible palette
1677 * entries (2^bitDepth).
1678 *
1679 * {@link javax.imageio.ImageTypeSpecifier.html#createIndexed}
1680 *
1681 * In order to avoid this contradiction we need to extend the
1682 * palette arrays to the limit defined by the bitDepth.
1683 */
1684
1685 int plength = 1 << bitDepth;
1686
1687 byte[] red = metadata.PLTE_red;
1688 byte[] green = metadata.PLTE_green;
1689 byte[] blue = metadata.PLTE_blue;
1690
1691 if (metadata.PLTE_red.length < plength) {
1692 red = Arrays.copyOf(metadata.PLTE_red, plength);
1693 Arrays.fill(red, metadata.PLTE_red.length, plength,
1694 metadata.PLTE_red[metadata.PLTE_red.length - 1]);
1695
1696 green = Arrays.copyOf(metadata.PLTE_green, plength);
1697 Arrays.fill(green, metadata.PLTE_green.length, plength,
1698 metadata.PLTE_green[metadata.PLTE_green.length - 1]);
1699
1700 blue = Arrays.copyOf(metadata.PLTE_blue, plength);
1701 Arrays.fill(blue, metadata.PLTE_blue.length, plength,
1702 metadata.PLTE_blue[metadata.PLTE_blue.length - 1]);
1703
1704 }
1705
1706 // Alpha from tRNS chunk may have fewer entries than
1707 // the RGB LUTs from the PLTE chunk; if so, pad with
1708 // 255.
1709 byte[] alpha = null;
1710 if (metadata.tRNS_present && (metadata.tRNS_alpha != null)) {
1711 if (metadata.tRNS_alpha.length == red.length) {
1712 alpha = metadata.tRNS_alpha;
1713 } else {
1714 alpha = Arrays.copyOf(metadata.tRNS_alpha, red.length);
1715 Arrays.fill(alpha,
1716 metadata.tRNS_alpha.length,
1717 red.length, (byte)255);
1718 }
1719 }
1720
1721 l.add(ImageTypeSpecifier.createIndexed(red, green,
1722 blue, alpha,
1723 bitDepth,
1724 DataBuffer.TYPE_BYTE));
1725 break;
1726
1727 case PNG_COLOR_GRAY_ALPHA:
1728 // Component G, A
1729 gray = ColorSpace.getInstance(ColorSpace.CS_GRAY);
1730 bandOffsets = new int[2];
1731 bandOffsets[0] = 0;
1732 bandOffsets[1] = 1;
1733 l.add(ImageTypeSpecifier.createInterleaved(gray,
1734 bandOffsets,
1735 dataType,
1736 true,
1737 false));
1738 break;
1739
1740 case PNG_COLOR_RGB_ALPHA:
1741 if (bitDepth == 8) {
1742 // some standard types of buffered images
1743 // wich can be used as destination
1744 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1745 BufferedImage.TYPE_4BYTE_ABGR));
1746
1747 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1748 BufferedImage.TYPE_INT_ARGB));
1749 }
1750
1751 // Component R, G, B, A (non-premultiplied)
1752 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB);
1753 bandOffsets = new int[4];
1754 bandOffsets[0] = 0;
1755 bandOffsets[1] = 1;
1756 bandOffsets[2] = 2;
1757 bandOffsets[3] = 3;
1758
1759 l.add(ImageTypeSpecifier.createInterleaved(rgb,
1760 bandOffsets,
1761 dataType,
1762 true,
1763 false));
1764 break;
1765
1766 default:
1767 break;
1768 }
1769
1770 return l.iterator();
1771 }
1772
1773 /*
1774 * Super class implementation uses first element
1775 * of image types list as raw image type.
1776 *
1777 * Also, super implementation uses first element of this list
1778 * as default destination type image read param does not specify
1779 * anything other.
1780 *
1781 * However, in case of RGB and RGBA color types, raw image type
1782 * produces buffered image of custom type. It causes some
1783 * performance degradation of subsequent rendering operations.
1784 *
1785 * To resolve this contradiction we put standard image types
1786 * at the first positions of image types list (to produce standard
1787 * images by default) and put raw image type (which is custom)
1788 * at the last position of this list.
1789 *
1790 * After this changes we should override getRawImageType()
1791 * to return last element of image types list.
1792 */
1793 public ImageTypeSpecifier getRawImageType(int imageIndex)
1794 throws IOException {
1795
1796 Iterator<ImageTypeSpecifier> types = getImageTypes(imageIndex);
1797 ImageTypeSpecifier raw = null;
1798 do {
1799 raw = types.next();
1800 } while (types.hasNext());
1801 return raw;
1802 }
1803
1804 public ImageReadParam getDefaultReadParam() {
1805 return new ImageReadParam();
1806 }
1807
1808 public IIOMetadata getStreamMetadata()
1809 throws IIOException {
1810 return null;
1811 }
1812
1813 public IIOMetadata getImageMetadata(int imageIndex) throws IIOException {
1814 if (imageIndex != 0) {
1815 throw new IndexOutOfBoundsException("imageIndex != 0!");
1816 }
1817 readMetadata();
1818 return metadata;
1819 }
1820
1821 public BufferedImage read(int imageIndex, ImageReadParam param)
1822 throws IIOException {
1823 if (imageIndex != 0) {
1824 throw new IndexOutOfBoundsException("imageIndex != 0!");
1825 }
1826
1827 try {
1828 readImage(param);
1829 } catch (IOException |
1830 IllegalStateException |
1831 IllegalArgumentException e)
1832 {
1833 throw e;
1834 } catch (Throwable e) {
1835 throw new IIOException("Caught exception during read: ", e);
1836 }
1837 return theImage;
1838 }
1839
1840 public void reset() {
1841 super.reset();
1842 resetStreamSettings();
1843 }
1844
1845 private void resetStreamSettings() {
1846 gotHeader = false;
1847 gotMetadata = false;
1848 metadata = null;
1849 pixelStream = null;
1850 imageStartPosition = -1L;
1851 }
1852 }