1 /*
2 * Copyright (c) 2000, 2018, 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;
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 return new String(baos.toByteArray(), charset);
220 }
221
222 private void readHeader() throws IIOException {
223 if (gotHeader) {
224 return;
225 }
226 if (stream == null) {
227 throw new IllegalStateException("Input source not set!");
228 }
229
230 try {
231 byte[] signature = new byte[8];
232 stream.readFully(signature);
233
234 if (signature[0] != (byte)137 ||
235 signature[1] != (byte)80 ||
236 signature[2] != (byte)78 ||
237 signature[3] != (byte)71 ||
238 signature[4] != (byte)13 ||
239 signature[5] != (byte)10 ||
240 signature[6] != (byte)26 ||
241 signature[7] != (byte)10) {
242 throw new IIOException("Bad PNG signature!");
243 }
244
245 int IHDR_length = stream.readInt();
246 if (IHDR_length != 13) {
247 throw new IIOException("Bad length for IHDR chunk!");
248 }
249 int IHDR_type = stream.readInt();
250 if (IHDR_type != IHDR_TYPE) {
251 throw new IIOException("Bad type for IHDR chunk!");
252 }
253
254 this.metadata = new PNGMetadata();
255
256 int width = stream.readInt();
257 int height = stream.readInt();
258
259 // Re-use signature array to bulk-read these unsigned byte values
260 stream.readFully(signature, 0, 5);
261 int bitDepth = signature[0] & 0xff;
262 int colorType = signature[1] & 0xff;
263 int compressionMethod = signature[2] & 0xff;
264 int filterMethod = signature[3] & 0xff;
265 int interlaceMethod = signature[4] & 0xff;
266
267 // Skip IHDR CRC
268 stream.skipBytes(4);
269
270 stream.flushBefore(stream.getStreamPosition());
271
272 if (width <= 0) {
273 throw new IIOException("Image width <= 0!");
274 }
275 if (height <= 0) {
276 throw new IIOException("Image height <= 0!");
277 }
278 if (bitDepth != 1 && bitDepth != 2 && bitDepth != 4 &&
279 bitDepth != 8 && bitDepth != 16) {
280 throw new IIOException("Bit depth must be 1, 2, 4, 8, or 16!");
281 }
282 if (colorType != 0 && colorType != 2 && colorType != 3 &&
283 colorType != 4 && colorType != 6) {
284 throw new IIOException("Color type must be 0, 2, 3, 4, or 6!");
285 }
286 if (colorType == PNG_COLOR_PALETTE && bitDepth == 16) {
287 throw new IIOException("Bad color type/bit depth combination!");
288 }
289 if ((colorType == PNG_COLOR_RGB ||
290 colorType == PNG_COLOR_RGB_ALPHA ||
291 colorType == PNG_COLOR_GRAY_ALPHA) &&
292 (bitDepth != 8 && bitDepth != 16)) {
293 throw new IIOException("Bad color type/bit depth combination!");
294 }
295 if (compressionMethod != 0) {
296 throw new IIOException("Unknown compression method (not 0)!");
297 }
298 if (filterMethod != 0) {
299 throw new IIOException("Unknown filter method (not 0)!");
300 }
301 if (interlaceMethod != 0 && interlaceMethod != 1) {
302 throw new IIOException("Unknown interlace method (not 0 or 1)!");
303 }
304
305 metadata.IHDR_present = true;
306 metadata.IHDR_width = width;
307 metadata.IHDR_height = height;
308 metadata.IHDR_bitDepth = bitDepth;
309 metadata.IHDR_colorType = colorType;
310 metadata.IHDR_compressionMethod = compressionMethod;
311 metadata.IHDR_filterMethod = filterMethod;
312 metadata.IHDR_interlaceMethod = interlaceMethod;
313 gotHeader = true;
314 } catch (IOException e) {
315 throw new IIOException("I/O error reading PNG header!", e);
316 }
317 }
318
319 private void parse_PLTE_chunk(int chunkLength) throws IOException {
320 if (metadata.PLTE_present) {
321 processWarningOccurred(
322 "A PNG image may not contain more than one PLTE chunk.\n" +
323 "The chunk wil be ignored.");
324 return;
325 } else if (metadata.IHDR_colorType == PNG_COLOR_GRAY ||
326 metadata.IHDR_colorType == PNG_COLOR_GRAY_ALPHA) {
327 processWarningOccurred(
328 "A PNG gray or gray alpha image cannot have a PLTE chunk.\n" +
329 "The chunk wil be ignored.");
330 return;
331 }
332
333 byte[] palette = new byte[chunkLength];
334 stream.readFully(palette);
335
336 int numEntries = chunkLength/3;
337 if (metadata.IHDR_colorType == PNG_COLOR_PALETTE) {
338 int maxEntries = 1 << metadata.IHDR_bitDepth;
339 if (numEntries > maxEntries) {
340 processWarningOccurred(
341 "PLTE chunk contains too many entries for bit depth, ignoring extras.");
342 numEntries = maxEntries;
343 }
344 numEntries = Math.min(numEntries, maxEntries);
345 }
346
347 // Round array sizes up to 2^2^n
348 int paletteEntries;
349 if (numEntries > 16) {
350 paletteEntries = 256;
351 } else if (numEntries > 4) {
352 paletteEntries = 16;
353 } else if (numEntries > 2) {
354 paletteEntries = 4;
355 } else {
356 paletteEntries = 2;
357 }
358
359 metadata.PLTE_present = true;
360 metadata.PLTE_red = new byte[paletteEntries];
361 metadata.PLTE_green = new byte[paletteEntries];
362 metadata.PLTE_blue = new byte[paletteEntries];
363
364 int index = 0;
365 for (int i = 0; i < numEntries; i++) {
366 metadata.PLTE_red[i] = palette[index++];
367 metadata.PLTE_green[i] = palette[index++];
368 metadata.PLTE_blue[i] = palette[index++];
369 }
370 }
371
372 private void parse_bKGD_chunk() throws IOException {
373 if (metadata.IHDR_colorType == PNG_COLOR_PALETTE) {
374 metadata.bKGD_colorType = PNG_COLOR_PALETTE;
375 metadata.bKGD_index = stream.readUnsignedByte();
376 } else if (metadata.IHDR_colorType == PNG_COLOR_GRAY ||
377 metadata.IHDR_colorType == PNG_COLOR_GRAY_ALPHA) {
378 metadata.bKGD_colorType = PNG_COLOR_GRAY;
379 metadata.bKGD_gray = stream.readUnsignedShort();
380 } else { // RGB or RGB_ALPHA
381 metadata.bKGD_colorType = PNG_COLOR_RGB;
382 metadata.bKGD_red = stream.readUnsignedShort();
383 metadata.bKGD_green = stream.readUnsignedShort();
384 metadata.bKGD_blue = stream.readUnsignedShort();
385 }
386
387 metadata.bKGD_present = true;
388 }
389
390 private void parse_cHRM_chunk() throws IOException {
391 metadata.cHRM_whitePointX = stream.readInt();
392 metadata.cHRM_whitePointY = stream.readInt();
393 metadata.cHRM_redX = stream.readInt();
394 metadata.cHRM_redY = stream.readInt();
395 metadata.cHRM_greenX = stream.readInt();
396 metadata.cHRM_greenY = stream.readInt();
397 metadata.cHRM_blueX = stream.readInt();
398 metadata.cHRM_blueY = stream.readInt();
399
400 metadata.cHRM_present = true;
401 }
402
403 private void parse_gAMA_chunk() throws IOException {
404 int gamma = stream.readInt();
405 metadata.gAMA_gamma = gamma;
406
407 metadata.gAMA_present = true;
408 }
409
410 private void parse_hIST_chunk(int chunkLength) throws IOException,
411 IIOException
412 {
413 if (!metadata.PLTE_present) {
414 throw new IIOException("hIST chunk without prior PLTE chunk!");
415 }
416
417 /* According to PNG specification length of
418 * hIST chunk is specified in bytes and
419 * hIST chunk consists of 2 byte elements
420 * (so we expect length is even).
421 */
422 metadata.hIST_histogram = new char[chunkLength/2];
423 stream.readFully(metadata.hIST_histogram,
424 0, metadata.hIST_histogram.length);
425
426 metadata.hIST_present = true;
427 }
428
429 private void parse_iCCP_chunk(int chunkLength) throws IOException {
430 String keyword = readNullTerminatedString("ISO-8859-1", 80);
431 int compressedProfileLength = chunkLength - keyword.length() - 2;
432 if (compressedProfileLength <= 0) {
433 throw new IIOException("iCCP chunk length is not proper");
434 }
435 metadata.iCCP_profileName = keyword;
436
437 metadata.iCCP_compressionMethod = stream.readUnsignedByte();
438
439 byte[] compressedProfile =
440 new byte[compressedProfileLength];
441 stream.readFully(compressedProfile);
442 metadata.iCCP_compressedProfile = compressedProfile;
443
444 metadata.iCCP_present = true;
445 }
446
447 private void parse_iTXt_chunk(int chunkLength) throws IOException {
448 long chunkStart = stream.getStreamPosition();
449
450 String keyword = readNullTerminatedString("ISO-8859-1", 80);
451 metadata.iTXt_keyword.add(keyword);
452
453 int compressionFlag = stream.readUnsignedByte();
454 metadata.iTXt_compressionFlag.add(Boolean.valueOf(compressionFlag == 1));
455
456 int compressionMethod = stream.readUnsignedByte();
457 metadata.iTXt_compressionMethod.add(Integer.valueOf(compressionMethod));
458
459 String languageTag = readNullTerminatedString("UTF8", 80);
460 metadata.iTXt_languageTag.add(languageTag);
461
462 long pos = stream.getStreamPosition();
463 int maxLen = (int)(chunkStart + chunkLength - pos);
464 String translatedKeyword =
465 readNullTerminatedString("UTF8", maxLen);
466 metadata.iTXt_translatedKeyword.add(translatedKeyword);
467
468 String text;
469 pos = stream.getStreamPosition();
470 int textLength = (int)(chunkStart + chunkLength - pos);
471 if (textLength <= 0) {
472 throw new IIOException("iTXt chunk length is not proper");
473 }
474 byte[] b = new byte[textLength];
475 stream.readFully(b);
476
477 if (compressionFlag == 1) { // Decompress the text
478 text = new String(inflate(b), "UTF8");
479 } else {
480 text = new String(b, "UTF8");
481 }
482 metadata.iTXt_text.add(text);
483
484 // Check if the text chunk contains image creation time
485 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) {
486 // Update Standard/Document/ImageCreationTime from text chunk
487 int index = metadata.iTXt_text.size() - 1;
488 metadata.decodeImageCreationTimeFromTextChunk(
489 metadata.iTXt_text.listIterator(index));
490 }
491 }
492
493 private void parse_pHYs_chunk() throws IOException {
494 metadata.pHYs_pixelsPerUnitXAxis = stream.readInt();
495 metadata.pHYs_pixelsPerUnitYAxis = stream.readInt();
496 metadata.pHYs_unitSpecifier = stream.readUnsignedByte();
497
498 metadata.pHYs_present = true;
499 }
500
501 private void parse_sBIT_chunk() throws IOException {
502 int colorType = metadata.IHDR_colorType;
503 if (colorType == PNG_COLOR_GRAY ||
504 colorType == PNG_COLOR_GRAY_ALPHA) {
505 metadata.sBIT_grayBits = stream.readUnsignedByte();
506 } else if (colorType == PNG_COLOR_RGB ||
507 colorType == PNG_COLOR_PALETTE ||
508 colorType == PNG_COLOR_RGB_ALPHA) {
509 metadata.sBIT_redBits = stream.readUnsignedByte();
510 metadata.sBIT_greenBits = stream.readUnsignedByte();
511 metadata.sBIT_blueBits = stream.readUnsignedByte();
512 }
513
514 if (colorType == PNG_COLOR_GRAY_ALPHA ||
515 colorType == PNG_COLOR_RGB_ALPHA) {
516 metadata.sBIT_alphaBits = stream.readUnsignedByte();
517 }
518
519 metadata.sBIT_colorType = colorType;
520 metadata.sBIT_present = true;
521 }
522
523 private void parse_sPLT_chunk(int chunkLength)
524 throws IOException, IIOException {
525 metadata.sPLT_paletteName = readNullTerminatedString("ISO-8859-1", 80);
526 int remainingChunkLength = chunkLength -
527 (metadata.sPLT_paletteName.length() + 1);
528 if (remainingChunkLength <= 0) {
529 throw new IIOException("sPLT chunk length is not proper");
530 }
531
532 int sampleDepth = stream.readUnsignedByte();
533 metadata.sPLT_sampleDepth = sampleDepth;
534
535 int numEntries = remainingChunkLength/(4*(sampleDepth/8) + 2);
536 metadata.sPLT_red = new int[numEntries];
537 metadata.sPLT_green = new int[numEntries];
538 metadata.sPLT_blue = new int[numEntries];
539 metadata.sPLT_alpha = new int[numEntries];
540 metadata.sPLT_frequency = new int[numEntries];
541
542 if (sampleDepth == 8) {
543 for (int i = 0; i < numEntries; i++) {
544 metadata.sPLT_red[i] = stream.readUnsignedByte();
545 metadata.sPLT_green[i] = stream.readUnsignedByte();
546 metadata.sPLT_blue[i] = stream.readUnsignedByte();
547 metadata.sPLT_alpha[i] = stream.readUnsignedByte();
548 metadata.sPLT_frequency[i] = stream.readUnsignedShort();
549 }
550 } else if (sampleDepth == 16) {
551 for (int i = 0; i < numEntries; i++) {
552 metadata.sPLT_red[i] = stream.readUnsignedShort();
553 metadata.sPLT_green[i] = stream.readUnsignedShort();
554 metadata.sPLT_blue[i] = stream.readUnsignedShort();
555 metadata.sPLT_alpha[i] = stream.readUnsignedShort();
556 metadata.sPLT_frequency[i] = stream.readUnsignedShort();
557 }
558 } else {
559 throw new IIOException("sPLT sample depth not 8 or 16!");
560 }
561
562 metadata.sPLT_present = true;
563 }
564
565 private void parse_sRGB_chunk() throws IOException {
566 metadata.sRGB_renderingIntent = stream.readUnsignedByte();
567
568 metadata.sRGB_present = true;
569 }
570
571 private void parse_tEXt_chunk(int chunkLength) throws IOException {
572 String keyword = readNullTerminatedString("ISO-8859-1", 80);
573 int textLength = chunkLength - keyword.length() - 1;
574 if (textLength <= 0) {
575 throw new IIOException("tEXt chunk length is not proper");
576 }
577 metadata.tEXt_keyword.add(keyword);
578
579 byte[] b = new byte[textLength];
580 stream.readFully(b);
581 metadata.tEXt_text.add(new String(b, "ISO-8859-1"));
582
583 // Check if the text chunk contains image creation time
584 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) {
585 // Update Standard/Document/ImageCreationTime from text chunk
586 int index = metadata.tEXt_text.size() - 1;
587 metadata.decodeImageCreationTimeFromTextChunk(
588 metadata.tEXt_text.listIterator(index));
589 }
590 }
591
592 private void parse_tIME_chunk() throws IOException {
593 metadata.tIME_year = stream.readUnsignedShort();
594 metadata.tIME_month = stream.readUnsignedByte();
595 metadata.tIME_day = stream.readUnsignedByte();
596 metadata.tIME_hour = stream.readUnsignedByte();
597 metadata.tIME_minute = stream.readUnsignedByte();
598 metadata.tIME_second = stream.readUnsignedByte();
599
600 metadata.tIME_present = true;
601 }
602
603 private void parse_tRNS_chunk(int chunkLength) throws IOException {
604 int colorType = metadata.IHDR_colorType;
605 if (colorType == PNG_COLOR_PALETTE) {
606 if (!metadata.PLTE_present) {
607 processWarningOccurred(
608 "tRNS chunk without prior PLTE chunk, ignoring it.");
609 return;
610 }
611
612 // Alpha table may have fewer entries than RGB palette
613 int maxEntries = metadata.PLTE_red.length;
614 int numEntries = chunkLength;
615 if (numEntries > maxEntries && maxEntries > 0) {
616 processWarningOccurred(
617 "tRNS chunk has more entries than prior PLTE chunk, ignoring extras.");
618 numEntries = maxEntries;
619 }
620 metadata.tRNS_alpha = new byte[numEntries];
621 metadata.tRNS_colorType = PNG_COLOR_PALETTE;
622 stream.read(metadata.tRNS_alpha, 0, numEntries);
623 stream.skipBytes(chunkLength - numEntries);
624 } else if (colorType == PNG_COLOR_GRAY) {
625 if (chunkLength != 2) {
626 processWarningOccurred(
627 "tRNS chunk for gray image must have length 2, ignoring chunk.");
628 stream.skipBytes(chunkLength);
629 return;
630 }
631 metadata.tRNS_gray = stream.readUnsignedShort();
632 metadata.tRNS_colorType = PNG_COLOR_GRAY;
633 } else if (colorType == PNG_COLOR_RGB) {
634 if (chunkLength != 6) {
635 processWarningOccurred(
636 "tRNS chunk for RGB image must have length 6, ignoring chunk.");
637 stream.skipBytes(chunkLength);
638 return;
639 }
640 metadata.tRNS_red = stream.readUnsignedShort();
641 metadata.tRNS_green = stream.readUnsignedShort();
642 metadata.tRNS_blue = stream.readUnsignedShort();
643 metadata.tRNS_colorType = PNG_COLOR_RGB;
644 } else {
645 processWarningOccurred(
646 "Gray+Alpha and RGBS images may not have a tRNS chunk, ignoring it.");
647 return;
648 }
649
650 metadata.tRNS_present = true;
651 }
652
653 private static byte[] inflate(byte[] b) throws IOException {
654 InputStream bais = new ByteArrayInputStream(b);
655 InputStream iis = new InflaterInputStream(bais);
656 ByteArrayOutputStream baos = new ByteArrayOutputStream();
657
658 int c;
659 try {
660 while ((c = iis.read()) != -1) {
661 baos.write(c);
662 }
663 } finally {
664 iis.close();
665 }
666 return baos.toByteArray();
667 }
668
669 private void parse_zTXt_chunk(int chunkLength) throws IOException {
670 String keyword = readNullTerminatedString("ISO-8859-1", 80);
671 int textLength = chunkLength - keyword.length() - 2;
672 if (textLength <= 0) {
673 throw new IIOException("zTXt chunk length is not proper");
674 }
675 metadata.zTXt_keyword.add(keyword);
676
677 int method = stream.readUnsignedByte();
678 metadata.zTXt_compressionMethod.add(method);
679
680 byte[] b = new byte[textLength];
681 stream.readFully(b);
682 metadata.zTXt_text.add(new String(inflate(b), "ISO-8859-1"));
683
684 // Check if the text chunk contains image creation time
685 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) {
686 // Update Standard/Document/ImageCreationTime from text chunk
687 int index = metadata.zTXt_text.size() - 1;
688 metadata.decodeImageCreationTimeFromTextChunk(
689 metadata.zTXt_text.listIterator(index));
690 }
691 }
692
693 private void readMetadata() throws IIOException {
694 if (gotMetadata) {
695 return;
696 }
697
698 readHeader();
699
700 /*
701 * Optimization: We can skip reading metadata if ignoreMetadata
702 * flag is set and colorType is not PNG_COLOR_PALETTE. However,
703 * we parse tRNS chunk to retrieve the transparent color from the
704 * metadata. Doing so, helps PNGImageReader to appropriately
705 * identify and set transparent pixels in the decoded image for
706 * colorType PNG_COLOR_RGB and PNG_COLOR_GRAY.
707 */
708 int colorType = metadata.IHDR_colorType;
709 if (ignoreMetadata && colorType != PNG_COLOR_PALETTE) {
710 try {
711 while (true) {
712 int chunkLength = stream.readInt();
713
714 // verify the chunk length first
715 if (chunkLength < 0 || chunkLength + 4 < 0) {
716 throw new IIOException("Invalid chunk length " + chunkLength);
717 }
718
719 int chunkType = stream.readInt();
720
721 if (chunkType == IDAT_TYPE) {
722 // We've reached the first IDAT chunk position
723 stream.skipBytes(-8);
724 imageStartPosition = stream.getStreamPosition();
725 /*
726 * According to PNG specification tRNS chunk must
727 * precede the first IDAT chunk. So we can stop
728 * reading metadata.
729 */
730 break;
731 } else if (chunkType == tRNS_TYPE) {
732 parse_tRNS_chunk(chunkLength);
733 // After parsing tRNS chunk we will skip 4 CRC bytes
734 stream.skipBytes(4);
735 } else {
736 // Skip the chunk plus the 4 CRC bytes that follow
737 stream.skipBytes(chunkLength + 4);
738 }
739 }
740 } catch (IOException e) {
741 throw new IIOException("Error skipping PNG metadata", e);
742 }
743
744 gotMetadata = true;
745 return;
746 }
747
748 try {
749 loop: while (true) {
750 int chunkLength = stream.readInt();
751 int chunkType = stream.readInt();
752 int chunkCRC;
753
754 // verify the chunk length
755 if (chunkLength < 0) {
756 throw new IIOException("Invalid chunk length " + chunkLength);
757 };
758
759 try {
760 stream.mark();
761 stream.seek(stream.getStreamPosition() + chunkLength);
762 chunkCRC = stream.readInt();
763 stream.reset();
764 } catch (IOException e) {
765 throw new IIOException("Invalid chunk length " + chunkLength);
766 }
767
768 switch (chunkType) {
769 case IDAT_TYPE:
770 // If chunk type is 'IDAT', we've reached the image data.
771 if (imageStartPosition == -1L) {
772 /*
773 * The PNG specification mandates that if colorType is
774 * PNG_COLOR_PALETTE then the PLTE chunk should appear
775 * before the first IDAT chunk.
776 */
777 if (colorType == PNG_COLOR_PALETTE &&
778 !(metadata.PLTE_present))
779 {
780 throw new IIOException("Required PLTE chunk"
781 + " missing");
782 }
783 /*
784 * PNGs may contain multiple IDAT chunks containing
785 * a portion of image data. We store the position of
786 * the first IDAT chunk and continue with iteration
787 * of other chunks that follow image data.
788 */
789 imageStartPosition = stream.getStreamPosition() - 8;
790 }
791 // Move to the CRC byte location.
792 stream.skipBytes(chunkLength);
793 break;
794 case IEND_TYPE:
795 /*
796 * If the chunk type is 'IEND', we've reached end of image.
797 * Seek to the first IDAT chunk for subsequent decoding.
798 */
799 stream.seek(imageStartPosition);
800
801 /*
802 * flushBefore discards the portion of the stream before
803 * the indicated position. Hence this should be used after
804 * we complete iteration over available chunks including
805 * those that appear after the IDAT.
806 */
807 stream.flushBefore(stream.getStreamPosition());
808 break loop;
809 case PLTE_TYPE:
810 parse_PLTE_chunk(chunkLength);
811 break;
812 case bKGD_TYPE:
813 parse_bKGD_chunk();
814 break;
815 case cHRM_TYPE:
816 parse_cHRM_chunk();
817 break;
818 case gAMA_TYPE:
819 parse_gAMA_chunk();
820 break;
821 case hIST_TYPE:
822 parse_hIST_chunk(chunkLength);
823 break;
824 case iCCP_TYPE:
825 parse_iCCP_chunk(chunkLength);
826 break;
827 case iTXt_TYPE:
828 if (ignoreMetadata) {
829 stream.skipBytes(chunkLength);
830 } else {
831 parse_iTXt_chunk(chunkLength);
832 }
833 break;
834 case pHYs_TYPE:
835 parse_pHYs_chunk();
836 break;
837 case sBIT_TYPE:
838 parse_sBIT_chunk();
839 break;
840 case sPLT_TYPE:
841 parse_sPLT_chunk(chunkLength);
842 break;
843 case sRGB_TYPE:
844 parse_sRGB_chunk();
845 break;
846 case tEXt_TYPE:
847 parse_tEXt_chunk(chunkLength);
848 break;
849 case tIME_TYPE:
850 parse_tIME_chunk();
851 break;
852 case tRNS_TYPE:
853 parse_tRNS_chunk(chunkLength);
854 break;
855 case zTXt_TYPE:
856 if (ignoreMetadata) {
857 stream.skipBytes(chunkLength);
858 } else {
859 parse_zTXt_chunk(chunkLength);
860 }
861 break;
862 default:
863 // Read an unknown chunk
864 byte[] b = new byte[chunkLength];
865 stream.readFully(b);
866
867 StringBuilder chunkName = new StringBuilder(4);
868 chunkName.append((char)(chunkType >>> 24));
869 chunkName.append((char)((chunkType >> 16) & 0xff));
870 chunkName.append((char)((chunkType >> 8) & 0xff));
871 chunkName.append((char)(chunkType & 0xff));
872
873 int ancillaryBit = chunkType >>> 28;
874 if (ancillaryBit == 0) {
875 processWarningOccurred(
876 "Encountered unknown chunk with critical bit set!");
877 }
878
879 metadata.unknownChunkType.add(chunkName.toString());
880 metadata.unknownChunkData.add(b);
881 break;
882 }
883
884 // double check whether all chunk data were consumed
885 if (chunkCRC != stream.readInt()) {
886 throw new IIOException("Failed to read a chunk of type " +
887 chunkType);
888 }
889 }
890 } catch (IOException e) {
891 throw new IIOException("Error reading PNG metadata", e);
892 }
893
894 gotMetadata = true;
895 }
896
897 // Data filtering methods
898
899 private static void decodeSubFilter(byte[] curr, int coff, int count,
900 int bpp) {
901 for (int i = bpp; i < count; i++) {
902 int val;
903
904 val = curr[i + coff] & 0xff;
905 val += curr[i + coff - bpp] & 0xff;
906
907 curr[i + coff] = (byte)val;
908 }
909 }
910
911 private static void decodeUpFilter(byte[] curr, int coff,
912 byte[] prev, int poff,
913 int count) {
914 for (int i = 0; i < count; i++) {
915 int raw = curr[i + coff] & 0xff;
916 int prior = prev[i + poff] & 0xff;
917
918 curr[i + coff] = (byte)(raw + prior);
919 }
920 }
921
922 private static void decodeAverageFilter(byte[] curr, int coff,
923 byte[] prev, int poff,
924 int count, int bpp) {
925 int raw, priorPixel, priorRow;
926
927 for (int i = 0; i < bpp; i++) {
928 raw = curr[i + coff] & 0xff;
929 priorRow = prev[i + poff] & 0xff;
930
931 curr[i + coff] = (byte)(raw + priorRow/2);
932 }
933
934 for (int i = bpp; i < count; i++) {
935 raw = curr[i + coff] & 0xff;
936 priorPixel = curr[i + coff - bpp] & 0xff;
937 priorRow = prev[i + poff] & 0xff;
938
939 curr[i + coff] = (byte)(raw + (priorPixel + priorRow)/2);
940 }
941 }
942
943 private static int paethPredictor(int a, int b, int c) {
944 int p = a + b - c;
945 int pa = Math.abs(p - a);
946 int pb = Math.abs(p - b);
947 int pc = Math.abs(p - c);
948
949 if ((pa <= pb) && (pa <= pc)) {
950 return a;
951 } else if (pb <= pc) {
952 return b;
953 } else {
954 return c;
955 }
956 }
957
958 private static void decodePaethFilter(byte[] curr, int coff,
959 byte[] prev, int poff,
960 int count, int bpp) {
961 int raw, priorPixel, priorRow, priorRowPixel;
962
963 for (int i = 0; i < bpp; i++) {
964 raw = curr[i + coff] & 0xff;
965 priorRow = prev[i + poff] & 0xff;
966
967 curr[i + coff] = (byte)(raw + priorRow);
968 }
969
970 for (int i = bpp; i < count; i++) {
971 raw = curr[i + coff] & 0xff;
972 priorPixel = curr[i + coff - bpp] & 0xff;
973 priorRow = prev[i + poff] & 0xff;
974 priorRowPixel = prev[i + poff - bpp] & 0xff;
975
976 curr[i + coff] = (byte)(raw + paethPredictor(priorPixel,
977 priorRow,
978 priorRowPixel));
979 }
980 }
981
982 private static final int[][] bandOffsets = {
983 null,
984 { 0 }, // G
985 { 0, 1 }, // GA in GA order
986 { 0, 1, 2 }, // RGB in RGB order
987 { 0, 1, 2, 3 } // RGBA in RGBA order
988 };
989
990 private WritableRaster createRaster(int width, int height, int bands,
991 int scanlineStride,
992 int bitDepth) {
993
994 DataBuffer dataBuffer;
995 WritableRaster ras = null;
996 Point origin = new Point(0, 0);
997 if ((bitDepth < 8) && (bands == 1)) {
998 dataBuffer = new DataBufferByte(height*scanlineStride);
999 ras = Raster.createPackedRaster(dataBuffer,
1000 width, height,
1001 bitDepth,
1002 origin);
1003 } else if (bitDepth <= 8) {
1004 dataBuffer = new DataBufferByte(height*scanlineStride);
1005 ras = Raster.createInterleavedRaster(dataBuffer,
1006 width, height,
1007 scanlineStride,
1008 bands,
1009 bandOffsets[bands],
1010 origin);
1011 } else {
1012 dataBuffer = new DataBufferUShort(height*scanlineStride);
1013 ras = Raster.createInterleavedRaster(dataBuffer,
1014 width, height,
1015 scanlineStride,
1016 bands,
1017 bandOffsets[bands],
1018 origin);
1019 }
1020
1021 return ras;
1022 }
1023
1024 private void skipPass(int passWidth, int passHeight)
1025 throws IOException, IIOException {
1026 if ((passWidth == 0) || (passHeight == 0)) {
1027 return;
1028 }
1029
1030 int inputBands = inputBandsForColorType[metadata.IHDR_colorType];
1031 int bitsPerRow = Math.
1032 multiplyExact((inputBands * metadata.IHDR_bitDepth), passWidth);
1033 int bytesPerRow = (bitsPerRow + 7) / 8;
1034
1035 // Read the image row-by-row
1036 for (int srcY = 0; srcY < passHeight; srcY++) {
1037 // Skip filter byte and the remaining row bytes
1038 pixelStream.skipBytes(1 + bytesPerRow);
1039 }
1040 }
1041
1042 private void updateImageProgress(int newPixels) {
1043 pixelsDone += newPixels;
1044 processImageProgress(100.0F*pixelsDone/totalPixels);
1045 }
1046
1047 private void decodePass(int passNum,
1048 int xStart, int yStart,
1049 int xStep, int yStep,
1050 int passWidth, int passHeight) throws IOException {
1051
1052 if ((passWidth == 0) || (passHeight == 0)) {
1053 return;
1054 }
1055
1056 WritableRaster imRas = theImage.getWritableTile(0, 0);
1057 int dstMinX = imRas.getMinX();
1058 int dstMaxX = dstMinX + imRas.getWidth() - 1;
1059 int dstMinY = imRas.getMinY();
1060 int dstMaxY = dstMinY + imRas.getHeight() - 1;
1061
1062 // Determine which pixels will be updated in this pass
1063 int[] vals =
1064 ReaderUtil.computeUpdatedPixels(sourceRegion,
1065 destinationOffset,
1066 dstMinX, dstMinY,
1067 dstMaxX, dstMaxY,
1068 sourceXSubsampling,
1069 sourceYSubsampling,
1070 xStart, yStart,
1071 passWidth, passHeight,
1072 xStep, yStep);
1073 int updateMinX = vals[0];
1074 int updateMinY = vals[1];
1075 int updateWidth = vals[2];
1076 int updateXStep = vals[4];
1077 int updateYStep = vals[5];
1078
1079 int bitDepth = metadata.IHDR_bitDepth;
1080 int inputBands = inputBandsForColorType[metadata.IHDR_colorType];
1081 int bytesPerPixel = (bitDepth == 16) ? 2 : 1;
1082 bytesPerPixel *= inputBands;
1083
1084 int bitsPerRow = Math.multiplyExact((inputBands * bitDepth), passWidth);
1085 int bytesPerRow = (bitsPerRow + 7) / 8;
1086 int eltsPerRow = (bitDepth == 16) ? bytesPerRow/2 : bytesPerRow;
1087
1088 // If no pixels need updating, just skip the input data
1089 if (updateWidth == 0) {
1090 for (int srcY = 0; srcY < passHeight; srcY++) {
1091 // Update count of pixels read
1092 updateImageProgress(passWidth);
1093 /*
1094 * If read has been aborted, just return
1095 * processReadAborted will be called later
1096 */
1097 if (abortRequested()) {
1098 return;
1099 }
1100 // Skip filter byte and the remaining row bytes
1101 pixelStream.skipBytes(1 + bytesPerRow);
1102 }
1103 return;
1104 }
1105
1106 // Backwards map from destination pixels
1107 // (dstX = updateMinX + k*updateXStep)
1108 // to source pixels (sourceX), and then
1109 // to offset and skip in passRow (srcX and srcXStep)
1110 int sourceX =
1111 (updateMinX - destinationOffset.x)*sourceXSubsampling +
1112 sourceRegion.x;
1113 int srcX = (sourceX - xStart)/xStep;
1114
1115 // Compute the step factor in the source
1116 int srcXStep = updateXStep*sourceXSubsampling/xStep;
1117
1118 byte[] byteData = null;
1119 short[] shortData = null;
1120 byte[] curr = new byte[bytesPerRow];
1121 byte[] prior = new byte[bytesPerRow];
1122
1123 // Create a 1-row tall Raster to hold the data
1124 WritableRaster passRow = createRaster(passWidth, 1, inputBands,
1125 eltsPerRow,
1126 bitDepth);
1127
1128 // Create an array suitable for holding one pixel
1129 int[] ps = passRow.getPixel(0, 0, (int[])null);
1130
1131 DataBuffer dataBuffer = passRow.getDataBuffer();
1132 int type = dataBuffer.getDataType();
1133 if (type == DataBuffer.TYPE_BYTE) {
1134 byteData = ((DataBufferByte)dataBuffer).getData();
1135 } else {
1136 shortData = ((DataBufferUShort)dataBuffer).getData();
1137 }
1138
1139 processPassStarted(theImage,
1140 passNum,
1141 sourceMinProgressivePass,
1142 sourceMaxProgressivePass,
1143 updateMinX, updateMinY,
1144 updateXStep, updateYStep,
1145 destinationBands);
1146
1147 // Handle source and destination bands
1148 if (sourceBands != null) {
1149 passRow = passRow.createWritableChild(0, 0,
1150 passRow.getWidth(), 1,
1151 0, 0,
1152 sourceBands);
1153 }
1154 if (destinationBands != null) {
1155 imRas = imRas.createWritableChild(0, 0,
1156 imRas.getWidth(),
1157 imRas.getHeight(),
1158 0, 0,
1159 destinationBands);
1160 }
1161
1162 // Determine if all of the relevant output bands have the
1163 // same bit depth as the source data
1164 boolean adjustBitDepths = false;
1165 int[] outputSampleSize = imRas.getSampleModel().getSampleSize();
1166 int numBands = outputSampleSize.length;
1167 for (int b = 0; b < numBands; b++) {
1168 if (outputSampleSize[b] != bitDepth) {
1169 adjustBitDepths = true;
1170 break;
1171 }
1172 }
1173
1174 // If the bit depths differ, create a lookup table per band to perform
1175 // the conversion
1176 int[][] scale = null;
1177 if (adjustBitDepths) {
1178 int maxInSample = (1 << bitDepth) - 1;
1179 int halfMaxInSample = maxInSample/2;
1180 scale = new int[numBands][];
1181 for (int b = 0; b < numBands; b++) {
1182 int maxOutSample = (1 << outputSampleSize[b]) - 1;
1183 scale[b] = new int[maxInSample + 1];
1184 for (int s = 0; s <= maxInSample; s++) {
1185 scale[b][s] =
1186 (s*maxOutSample + halfMaxInSample)/maxInSample;
1187 }
1188 }
1189 }
1190
1191 // Limit passRow to relevant area for the case where we
1192 // will can setRect to copy a contiguous span
1193 boolean useSetRect = srcXStep == 1 &&
1194 updateXStep == 1 &&
1195 !adjustBitDepths &&
1196 (imRas instanceof ByteInterleavedRaster);
1197
1198 if (useSetRect) {
1199 passRow = passRow.createWritableChild(srcX, 0,
1200 updateWidth, 1,
1201 0, 0,
1202 null);
1203 }
1204
1205 // Decode the (sub)image row-by-row
1206 for (int srcY = 0; srcY < passHeight; srcY++) {
1207 // Update count of pixels read
1208 updateImageProgress(passWidth);
1209 /*
1210 * If read has been aborted, just return
1211 * processReadAborted will be called later
1212 */
1213 if (abortRequested()) {
1214 return;
1215 }
1216 // Read the filter type byte and a row of data
1217 int filter = pixelStream.read();
1218 try {
1219 // Swap curr and prior
1220 byte[] tmp = prior;
1221 prior = curr;
1222 curr = tmp;
1223
1224 pixelStream.readFully(curr, 0, bytesPerRow);
1225 } catch (java.util.zip.ZipException ze) {
1226 // TODO - throw a more meaningful exception
1227 throw ze;
1228 }
1229
1230 switch (filter) {
1231 case PNG_FILTER_NONE:
1232 break;
1233 case PNG_FILTER_SUB:
1234 decodeSubFilter(curr, 0, bytesPerRow, bytesPerPixel);
1235 break;
1236 case PNG_FILTER_UP:
1237 decodeUpFilter(curr, 0, prior, 0, bytesPerRow);
1238 break;
1239 case PNG_FILTER_AVERAGE:
1240 decodeAverageFilter(curr, 0, prior, 0, bytesPerRow,
1241 bytesPerPixel);
1242 break;
1243 case PNG_FILTER_PAETH:
1244 decodePaethFilter(curr, 0, prior, 0, bytesPerRow,
1245 bytesPerPixel);
1246 break;
1247 default:
1248 throw new IIOException("Unknown row filter type (= " +
1249 filter + ")!");
1250 }
1251
1252 // Copy data into passRow byte by byte
1253 if (bitDepth < 16) {
1254 System.arraycopy(curr, 0, byteData, 0, bytesPerRow);
1255 } else {
1256 int idx = 0;
1257 for (int j = 0; j < eltsPerRow; j++) {
1258 shortData[j] =
1259 (short)((curr[idx] << 8) | (curr[idx + 1] & 0xff));
1260 idx += 2;
1261 }
1262 }
1263
1264 // True Y position in source
1265 int sourceY = srcY*yStep + yStart;
1266 if ((sourceY >= sourceRegion.y) &&
1267 (sourceY < sourceRegion.y + sourceRegion.height) &&
1268 (((sourceY - sourceRegion.y) %
1269 sourceYSubsampling) == 0)) {
1270
1271 int dstY = destinationOffset.y +
1272 (sourceY - sourceRegion.y)/sourceYSubsampling;
1273 if (dstY < dstMinY) {
1274 continue;
1275 }
1276 if (dstY > dstMaxY) {
1277 break;
1278 }
1279
1280 /*
1281 * For PNG images of color type PNG_COLOR_RGB or PNG_COLOR_GRAY
1282 * that contain a specific transparent color (given by tRNS
1283 * chunk), we compare the decoded pixel color with the color
1284 * given by tRNS chunk to set the alpha on the destination.
1285 */
1286 boolean tRNSTransparentPixelPresent =
1287 theImage.getSampleModel().getNumBands() == inputBands + 1 &&
1288 metadata.hasTransparentColor();
1289 if (useSetRect &&
1290 !tRNSTransparentPixelPresent) {
1291 imRas.setRect(updateMinX, dstY, passRow);
1292 } else {
1293 int newSrcX = srcX;
1294
1295 /*
1296 * Create intermediate array to fill the extra alpha
1297 * channel when tRNSTransparentPixelPresent is true.
1298 */
1299 final int[] temp = new int[inputBands + 1];
1300 final int opaque = (bitDepth < 16) ? 255 : 65535;
1301 for (int dstX = updateMinX;
1302 dstX < updateMinX + updateWidth;
1303 dstX += updateXStep) {
1304
1305 passRow.getPixel(newSrcX, 0, ps);
1306 if (adjustBitDepths) {
1307 for (int b = 0; b < numBands; b++) {
1308 ps[b] = scale[b][ps[b]];
1309 }
1310 }
1311 if (tRNSTransparentPixelPresent) {
1312 if (metadata.tRNS_colorType == PNG_COLOR_RGB) {
1313 temp[0] = ps[0];
1314 temp[1] = ps[1];
1315 temp[2] = ps[2];
1316 if (ps[0] == metadata.tRNS_red &&
1317 ps[1] == metadata.tRNS_green &&
1318 ps[2] == metadata.tRNS_blue) {
1319 temp[3] = 0;
1320 } else {
1321 temp[3] = opaque;
1322 }
1323 } else {
1324 // when tRNS_colorType is PNG_COLOR_GRAY
1325 temp[0] = ps[0];
1326 if (ps[0] == metadata.tRNS_gray) {
1327 temp[1] = 0;
1328 } else {
1329 temp[1] = opaque;
1330 }
1331 }
1332 imRas.setPixel(dstX, dstY, temp);
1333 } else {
1334 imRas.setPixel(dstX, dstY, ps);
1335 }
1336 newSrcX += srcXStep;
1337 }
1338 }
1339
1340 processImageUpdate(theImage,
1341 updateMinX, dstY,
1342 updateWidth, 1,
1343 updateXStep, updateYStep,
1344 destinationBands);
1345 }
1346 }
1347
1348 processPassComplete(theImage);
1349 }
1350
1351 private void decodeImage()
1352 throws IOException, IIOException {
1353 int width = metadata.IHDR_width;
1354 int height = metadata.IHDR_height;
1355
1356 this.pixelsDone = 0;
1357 this.totalPixels = width*height;
1358
1359 if (metadata.IHDR_interlaceMethod == 0) {
1360 decodePass(0, 0, 0, 1, 1, width, height);
1361 } else {
1362 for (int i = 0; i <= sourceMaxProgressivePass; i++) {
1363 int XOffset = adam7XOffset[i];
1364 int YOffset = adam7YOffset[i];
1365 int XSubsampling = adam7XSubsampling[i];
1366 int YSubsampling = adam7YSubsampling[i];
1367 int xbump = adam7XSubsampling[i + 1] - 1;
1368 int ybump = adam7YSubsampling[i + 1] - 1;
1369
1370 if (i >= sourceMinProgressivePass) {
1371 decodePass(i,
1372 XOffset,
1373 YOffset,
1374 XSubsampling,
1375 YSubsampling,
1376 (width + xbump)/XSubsampling,
1377 (height + ybump)/YSubsampling);
1378 } else {
1379 skipPass((width + xbump)/XSubsampling,
1380 (height + ybump)/YSubsampling);
1381 }
1382
1383 /*
1384 * If read has been aborted, just return
1385 * processReadAborted will be called later
1386 */
1387 if (abortRequested()) {
1388 return;
1389 }
1390 }
1391 }
1392 }
1393
1394 private void readImage(ImageReadParam param) throws IIOException {
1395 readMetadata();
1396
1397 int width = metadata.IHDR_width;
1398 int height = metadata.IHDR_height;
1399
1400 // Init default values
1401 sourceXSubsampling = 1;
1402 sourceYSubsampling = 1;
1403 sourceMinProgressivePass = 0;
1404 sourceMaxProgressivePass = 6;
1405 sourceBands = null;
1406 destinationBands = null;
1407 destinationOffset = new Point(0, 0);
1408
1409 // If an ImageReadParam is available, get values from it
1410 if (param != null) {
1411 sourceXSubsampling = param.getSourceXSubsampling();
1412 sourceYSubsampling = param.getSourceYSubsampling();
1413
1414 sourceMinProgressivePass =
1415 Math.max(param.getSourceMinProgressivePass(), 0);
1416 sourceMaxProgressivePass =
1417 Math.min(param.getSourceMaxProgressivePass(), 6);
1418
1419 sourceBands = param.getSourceBands();
1420 destinationBands = param.getDestinationBands();
1421 destinationOffset = param.getDestinationOffset();
1422 }
1423 Inflater inf = null;
1424 try {
1425 stream.seek(imageStartPosition);
1426
1427 Enumeration<InputStream> e = new PNGImageDataEnumeration(stream);
1428 InputStream is = new SequenceInputStream(e);
1429
1430 /* InflaterInputStream uses an Inflater instance which consumes
1431 * native (non-GC visible) resources. This is normally implicitly
1432 * freed when the stream is closed. However since the
1433 * InflaterInputStream wraps a client-supplied input stream,
1434 * we cannot close it.
1435 * But the app may depend on GC finalization to close the stream.
1436 * Therefore to ensure timely freeing of native resources we
1437 * explicitly create the Inflater instance and free its resources
1438 * when we are done with the InflaterInputStream by calling
1439 * inf.end();
1440 */
1441 inf = new Inflater();
1442 is = new InflaterInputStream(is, inf);
1443 is = new BufferedInputStream(is);
1444 this.pixelStream = new DataInputStream(is);
1445
1446 /*
1447 * PNG spec declares that valid range for width
1448 * and height is [1, 2^31-1], so here we may fail to allocate
1449 * a buffer for destination image due to memory limitation.
1450 *
1451 * If the read operation triggers OutOfMemoryError, the same
1452 * will be wrapped in an IIOException at PNGImageReader.read
1453 * method.
1454 *
1455 * The recovery strategy for this case should be defined at
1456 * the level of application, so we will not try to estimate
1457 * the required amount of the memory and/or handle OOM in
1458 * any way.
1459 */
1460 theImage = getDestination(param,
1461 getImageTypes(0),
1462 width,
1463 height);
1464
1465 Rectangle destRegion = new Rectangle(0, 0, 0, 0);
1466 sourceRegion = new Rectangle(0, 0, 0, 0);
1467 computeRegions(param, width, height,
1468 theImage,
1469 sourceRegion, destRegion);
1470 destinationOffset.setLocation(destRegion.getLocation());
1471
1472 // At this point the header has been read and we know
1473 // how many bands are in the image, so perform checking
1474 // of the read param.
1475 int colorType = metadata.IHDR_colorType;
1476 if (theImage.getSampleModel().getNumBands()
1477 == inputBandsForColorType[colorType] + 1
1478 && metadata.hasTransparentColor()) {
1479 checkReadParamBandSettings(param,
1480 inputBandsForColorType[colorType] + 1,
1481 theImage.getSampleModel().getNumBands());
1482 } else {
1483 checkReadParamBandSettings(param,
1484 inputBandsForColorType[colorType],
1485 theImage.getSampleModel().getNumBands());
1486 }
1487
1488 clearAbortRequest();
1489 processImageStarted(0);
1490 if (abortRequested()) {
1491 processReadAborted();
1492 } else {
1493 decodeImage();
1494 if (abortRequested()) {
1495 processReadAborted();
1496 } else {
1497 processImageComplete();
1498 }
1499 }
1500
1501 } catch (IOException e) {
1502 throw new IIOException("Error reading PNG image data", e);
1503 } finally {
1504 if (inf != null) {
1505 inf.end();
1506 }
1507 }
1508 }
1509
1510 public int getNumImages(boolean allowSearch) throws IIOException {
1511 if (stream == null) {
1512 throw new IllegalStateException("No input source set!");
1513 }
1514 if (seekForwardOnly && allowSearch) {
1515 throw new IllegalStateException
1516 ("seekForwardOnly and allowSearch can't both be true!");
1517 }
1518 return 1;
1519 }
1520
1521 public int getWidth(int imageIndex) throws IIOException {
1522 if (imageIndex != 0) {
1523 throw new IndexOutOfBoundsException("imageIndex != 0!");
1524 }
1525
1526 readHeader();
1527
1528 return metadata.IHDR_width;
1529 }
1530
1531 public int getHeight(int imageIndex) throws IIOException {
1532 if (imageIndex != 0) {
1533 throw new IndexOutOfBoundsException("imageIndex != 0!");
1534 }
1535
1536 readHeader();
1537
1538 return metadata.IHDR_height;
1539 }
1540
1541 public Iterator<ImageTypeSpecifier> getImageTypes(int imageIndex)
1542 throws IIOException
1543 {
1544 if (imageIndex != 0) {
1545 throw new IndexOutOfBoundsException("imageIndex != 0!");
1546 }
1547
1548 readHeader();
1549
1550 ArrayList<ImageTypeSpecifier> l =
1551 new ArrayList<ImageTypeSpecifier>(1);
1552
1553 ColorSpace rgb;
1554 ColorSpace gray;
1555 int[] bandOffsets;
1556
1557 int bitDepth = metadata.IHDR_bitDepth;
1558 int colorType = metadata.IHDR_colorType;
1559
1560 int dataType;
1561 if (bitDepth <= 8) {
1562 dataType = DataBuffer.TYPE_BYTE;
1563 } else {
1564 dataType = DataBuffer.TYPE_USHORT;
1565 }
1566
1567 switch (colorType) {
1568 /*
1569 * For PNG images of color type PNG_COLOR_RGB or PNG_COLOR_GRAY that
1570 * contain a specific transparent color (given by tRNS chunk), we add
1571 * ImageTypeSpecifier(s) that support transparency to the list of
1572 * supported image types.
1573 */
1574 case PNG_COLOR_GRAY:
1575 readMetadata(); // Need tRNS chunk
1576
1577 if (metadata.hasTransparentColor()) {
1578 gray = ColorSpace.getInstance(ColorSpace.CS_GRAY);
1579 bandOffsets = new int[2];
1580 bandOffsets[0] = 0;
1581 bandOffsets[1] = 1;
1582 l.add(ImageTypeSpecifier.createInterleaved(gray,
1583 bandOffsets,
1584 dataType,
1585 true,
1586 false));
1587 }
1588 // Packed grayscale
1589 l.add(ImageTypeSpecifier.createGrayscale(bitDepth,
1590 dataType,
1591 false));
1592 break;
1593
1594 case PNG_COLOR_RGB:
1595 readMetadata(); // Need tRNS chunk
1596
1597 if (bitDepth == 8) {
1598 if (metadata.hasTransparentColor()) {
1599 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1600 BufferedImage.TYPE_4BYTE_ABGR));
1601 }
1602 // some standard types of buffered images
1603 // which can be used as destination
1604 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1605 BufferedImage.TYPE_3BYTE_BGR));
1606
1607 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1608 BufferedImage.TYPE_INT_RGB));
1609
1610 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1611 BufferedImage.TYPE_INT_BGR));
1612
1613 }
1614
1615 if (metadata.hasTransparentColor()) {
1616 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB);
1617 bandOffsets = new int[4];
1618 bandOffsets[0] = 0;
1619 bandOffsets[1] = 1;
1620 bandOffsets[2] = 2;
1621 bandOffsets[3] = 3;
1622
1623 l.add(ImageTypeSpecifier.
1624 createInterleaved(rgb, bandOffsets,
1625 dataType, true, false));
1626 }
1627 // Component R, G, B
1628 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB);
1629 bandOffsets = new int[3];
1630 bandOffsets[0] = 0;
1631 bandOffsets[1] = 1;
1632 bandOffsets[2] = 2;
1633 l.add(ImageTypeSpecifier.createInterleaved(rgb,
1634 bandOffsets,
1635 dataType,
1636 false,
1637 false));
1638 break;
1639
1640 case PNG_COLOR_PALETTE:
1641 readMetadata(); // Need tRNS chunk
1642
1643 /*
1644 * The PLTE chunk spec says:
1645 *
1646 * The number of palette entries must not exceed the range that
1647 * can be represented in the image bit depth (for example, 2^4 = 16
1648 * for a bit depth of 4). It is permissible to have fewer entries
1649 * than the bit depth would allow. In that case, any out-of-range
1650 * pixel value found in the image data is an error.
1651 *
1652 * http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html#C.PLTE
1653 *
1654 * Consequently, the case when the palette length is smaller than
1655 * 2^bitDepth is legal in the view of PNG spec.
1656 *
1657 * However the spec of createIndexed() method demands the exact
1658 * equality of the palette lengh and number of possible palette
1659 * entries (2^bitDepth).
1660 *
1661 * {@link javax.imageio.ImageTypeSpecifier.html#createIndexed}
1662 *
1663 * In order to avoid this contradiction we need to extend the
1664 * palette arrays to the limit defined by the bitDepth.
1665 */
1666
1667 int plength = 1 << bitDepth;
1668
1669 byte[] red = metadata.PLTE_red;
1670 byte[] green = metadata.PLTE_green;
1671 byte[] blue = metadata.PLTE_blue;
1672
1673 if (metadata.PLTE_red.length < plength) {
1674 red = Arrays.copyOf(metadata.PLTE_red, plength);
1675 Arrays.fill(red, metadata.PLTE_red.length, plength,
1676 metadata.PLTE_red[metadata.PLTE_red.length - 1]);
1677
1678 green = Arrays.copyOf(metadata.PLTE_green, plength);
1679 Arrays.fill(green, metadata.PLTE_green.length, plength,
1680 metadata.PLTE_green[metadata.PLTE_green.length - 1]);
1681
1682 blue = Arrays.copyOf(metadata.PLTE_blue, plength);
1683 Arrays.fill(blue, metadata.PLTE_blue.length, plength,
1684 metadata.PLTE_blue[metadata.PLTE_blue.length - 1]);
1685
1686 }
1687
1688 // Alpha from tRNS chunk may have fewer entries than
1689 // the RGB LUTs from the PLTE chunk; if so, pad with
1690 // 255.
1691 byte[] alpha = null;
1692 if (metadata.tRNS_present && (metadata.tRNS_alpha != null)) {
1693 if (metadata.tRNS_alpha.length == red.length) {
1694 alpha = metadata.tRNS_alpha;
1695 } else {
1696 alpha = Arrays.copyOf(metadata.tRNS_alpha, red.length);
1697 Arrays.fill(alpha,
1698 metadata.tRNS_alpha.length,
1699 red.length, (byte)255);
1700 }
1701 }
1702
1703 l.add(ImageTypeSpecifier.createIndexed(red, green,
1704 blue, alpha,
1705 bitDepth,
1706 DataBuffer.TYPE_BYTE));
1707 break;
1708
1709 case PNG_COLOR_GRAY_ALPHA:
1710 // Component G, A
1711 gray = ColorSpace.getInstance(ColorSpace.CS_GRAY);
1712 bandOffsets = new int[2];
1713 bandOffsets[0] = 0;
1714 bandOffsets[1] = 1;
1715 l.add(ImageTypeSpecifier.createInterleaved(gray,
1716 bandOffsets,
1717 dataType,
1718 true,
1719 false));
1720 break;
1721
1722 case PNG_COLOR_RGB_ALPHA:
1723 if (bitDepth == 8) {
1724 // some standard types of buffered images
1725 // wich can be used as destination
1726 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1727 BufferedImage.TYPE_4BYTE_ABGR));
1728
1729 l.add(ImageTypeSpecifier.createFromBufferedImageType(
1730 BufferedImage.TYPE_INT_ARGB));
1731 }
1732
1733 // Component R, G, B, A (non-premultiplied)
1734 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB);
1735 bandOffsets = new int[4];
1736 bandOffsets[0] = 0;
1737 bandOffsets[1] = 1;
1738 bandOffsets[2] = 2;
1739 bandOffsets[3] = 3;
1740
1741 l.add(ImageTypeSpecifier.createInterleaved(rgb,
1742 bandOffsets,
1743 dataType,
1744 true,
1745 false));
1746 break;
1747
1748 default:
1749 break;
1750 }
1751
1752 return l.iterator();
1753 }
1754
1755 /*
1756 * Super class implementation uses first element
1757 * of image types list as raw image type.
1758 *
1759 * Also, super implementation uses first element of this list
1760 * as default destination type image read param does not specify
1761 * anything other.
1762 *
1763 * However, in case of RGB and RGBA color types, raw image type
1764 * produces buffered image of custom type. It causes some
1765 * performance degradation of subsequent rendering operations.
1766 *
1767 * To resolve this contradiction we put standard image types
1768 * at the first positions of image types list (to produce standard
1769 * images by default) and put raw image type (which is custom)
1770 * at the last position of this list.
1771 *
1772 * After this changes we should override getRawImageType()
1773 * to return last element of image types list.
1774 */
1775 public ImageTypeSpecifier getRawImageType(int imageIndex)
1776 throws IOException {
1777
1778 Iterator<ImageTypeSpecifier> types = getImageTypes(imageIndex);
1779 ImageTypeSpecifier raw = null;
1780 do {
1781 raw = types.next();
1782 } while (types.hasNext());
1783 return raw;
1784 }
1785
1786 public ImageReadParam getDefaultReadParam() {
1787 return new ImageReadParam();
1788 }
1789
1790 public IIOMetadata getStreamMetadata()
1791 throws IIOException {
1792 return null;
1793 }
1794
1795 public IIOMetadata getImageMetadata(int imageIndex) throws IIOException {
1796 if (imageIndex != 0) {
1797 throw new IndexOutOfBoundsException("imageIndex != 0!");
1798 }
1799 readMetadata();
1800 return metadata;
1801 }
1802
1803 public BufferedImage read(int imageIndex, ImageReadParam param)
1804 throws IIOException {
1805 if (imageIndex != 0) {
1806 throw new IndexOutOfBoundsException("imageIndex != 0!");
1807 }
1808
1809 try {
1810 readImage(param);
1811 } catch (IOException |
1812 IllegalStateException |
1813 IllegalArgumentException e)
1814 {
1815 throw e;
1816 } catch (Throwable e) {
1817 throw new IIOException("Caught exception during read: ", e);
1818 }
1819 return theImage;
1820 }
1821
1822 public void reset() {
1823 super.reset();
1824 resetStreamSettings();
1825 }
1826
1827 private void resetStreamSettings() {
1828 gotHeader = false;
1829 gotMetadata = false;
1830 metadata = null;
1831 pixelStream = null;
1832 imageStartPosition = -1L;
1833 }
1834 }