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 the remaining metadata if the 702 * ignoreMetadata flag is set, and only if this is not a palette 703 * image (in that case, we need to read the metadata to get the 704 * tRNS chunk, which is needed for the getImageTypes() method). 705 */ 706 int colorType = metadata.IHDR_colorType; 707 if (ignoreMetadata && colorType != PNG_COLOR_PALETTE) { 708 try { 709 while (true) { 710 int chunkLength = stream.readInt(); 711 712 // verify the chunk length first 713 if (chunkLength < 0 || chunkLength + 4 < 0) { 714 throw new IIOException("Invalid chunk length " + chunkLength); 715 } 716 717 int chunkType = stream.readInt(); 718 719 if (chunkType == IDAT_TYPE) { 720 // We've reached the image data 721 stream.skipBytes(-8); 722 imageStartPosition = stream.getStreamPosition(); 723 break; 724 } else { 725 // Skip the chunk plus the 4 CRC bytes that follow 726 stream.skipBytes(chunkLength + 4); 727 } 728 } 729 } catch (IOException e) { 730 throw new IIOException("Error skipping PNG metadata", e); 731 } 732 733 gotMetadata = true; 734 return; 735 } 736 737 try { 738 loop: while (true) { 739 int chunkLength = stream.readInt(); 740 int chunkType = stream.readInt(); 741 int chunkCRC; 742 743 // verify the chunk length 744 if (chunkLength < 0) { 745 throw new IIOException("Invalid chunk length " + chunkLength); 746 }; 747 748 try { 749 stream.mark(); 750 stream.seek(stream.getStreamPosition() + chunkLength); 751 chunkCRC = stream.readInt(); 752 stream.reset(); 753 } catch (IOException e) { 754 throw new IIOException("Invalid chunk length " + chunkLength); 755 } 756 757 switch (chunkType) { 758 case IDAT_TYPE: 759 // If chunk type is 'IDAT', we've reached the image data. 760 if (imageStartPosition == -1L) { 761 /* 762 * The PNG specification mandates that if colorType is 763 * PNG_COLOR_PALETTE then the PLTE chunk should appear 764 * before the first IDAT chunk. 765 */ 766 if (colorType == PNG_COLOR_PALETTE && 767 !(metadata.PLTE_present)) 768 { 769 throw new IIOException("Required PLTE chunk" 770 + " missing"); 771 } 772 /* 773 * PNGs may contain multiple IDAT chunks containing 774 * a portion of image data. We store the position of 775 * the first IDAT chunk and continue with iteration 776 * of other chunks that follow image data. 777 */ 778 imageStartPosition = stream.getStreamPosition() - 8; 779 } 780 // Move to the CRC byte location. 781 stream.skipBytes(chunkLength); 782 break; 783 case IEND_TYPE: 784 /* 785 * If the chunk type is 'IEND', we've reached end of image. 786 * Seek to the first IDAT chunk for subsequent decoding. 787 */ 788 stream.seek(imageStartPosition); 789 790 /* 791 * flushBefore discards the portion of the stream before 792 * the indicated position. Hence this should be used after 793 * we complete iteration over available chunks including 794 * those that appear after the IDAT. 795 */ 796 stream.flushBefore(stream.getStreamPosition()); 797 break loop; 798 case PLTE_TYPE: 799 parse_PLTE_chunk(chunkLength); 800 break; 801 case bKGD_TYPE: 802 parse_bKGD_chunk(); 803 break; 804 case cHRM_TYPE: 805 parse_cHRM_chunk(); 806 break; 807 case gAMA_TYPE: 808 parse_gAMA_chunk(); 809 break; 810 case hIST_TYPE: 811 parse_hIST_chunk(chunkLength); 812 break; 813 case iCCP_TYPE: 814 parse_iCCP_chunk(chunkLength); 815 break; 816 case iTXt_TYPE: 817 if (ignoreMetadata) { 818 stream.skipBytes(chunkLength); 819 } else { 820 parse_iTXt_chunk(chunkLength); 821 } 822 break; 823 case pHYs_TYPE: 824 parse_pHYs_chunk(); 825 break; 826 case sBIT_TYPE: 827 parse_sBIT_chunk(); 828 break; 829 case sPLT_TYPE: 830 parse_sPLT_chunk(chunkLength); 831 break; 832 case sRGB_TYPE: 833 parse_sRGB_chunk(); 834 break; 835 case tEXt_TYPE: 836 parse_tEXt_chunk(chunkLength); 837 break; 838 case tIME_TYPE: 839 parse_tIME_chunk(); 840 break; 841 case tRNS_TYPE: 842 parse_tRNS_chunk(chunkLength); 843 break; 844 case zTXt_TYPE: 845 if (ignoreMetadata) { 846 stream.skipBytes(chunkLength); 847 } else { 848 parse_zTXt_chunk(chunkLength); 849 } 850 break; 851 default: 852 // Read an unknown chunk 853 byte[] b = new byte[chunkLength]; 854 stream.readFully(b); 855 856 StringBuilder chunkName = new StringBuilder(4); 857 chunkName.append((char)(chunkType >>> 24)); 858 chunkName.append((char)((chunkType >> 16) & 0xff)); 859 chunkName.append((char)((chunkType >> 8) & 0xff)); 860 chunkName.append((char)(chunkType & 0xff)); 861 862 int ancillaryBit = chunkType >>> 28; 863 if (ancillaryBit == 0) { 864 processWarningOccurred( 865 "Encountered unknown chunk with critical bit set!"); 866 } 867 868 metadata.unknownChunkType.add(chunkName.toString()); 869 metadata.unknownChunkData.add(b); 870 break; 871 } 872 873 // double check whether all chunk data were consumed 874 if (chunkCRC != stream.readInt()) { 875 throw new IIOException("Failed to read a chunk of type " + 876 chunkType); 877 } 878 } 879 } catch (IOException e) { 880 throw new IIOException("Error reading PNG metadata", e); 881 } 882 883 gotMetadata = true; 884 } 885 886 // Data filtering methods 887 888 private static void decodeSubFilter(byte[] curr, int coff, int count, 889 int bpp) { 890 for (int i = bpp; i < count; i++) { 891 int val; 892 893 val = curr[i + coff] & 0xff; 894 val += curr[i + coff - bpp] & 0xff; 895 896 curr[i + coff] = (byte)val; 897 } 898 } 899 900 private static void decodeUpFilter(byte[] curr, int coff, 901 byte[] prev, int poff, 902 int count) { 903 for (int i = 0; i < count; i++) { 904 int raw = curr[i + coff] & 0xff; 905 int prior = prev[i + poff] & 0xff; 906 907 curr[i + coff] = (byte)(raw + prior); 908 } 909 } 910 911 private static void decodeAverageFilter(byte[] curr, int coff, 912 byte[] prev, int poff, 913 int count, int bpp) { 914 int raw, priorPixel, priorRow; 915 916 for (int i = 0; i < bpp; i++) { 917 raw = curr[i + coff] & 0xff; 918 priorRow = prev[i + poff] & 0xff; 919 920 curr[i + coff] = (byte)(raw + priorRow/2); 921 } 922 923 for (int i = bpp; i < count; i++) { 924 raw = curr[i + coff] & 0xff; 925 priorPixel = curr[i + coff - bpp] & 0xff; 926 priorRow = prev[i + poff] & 0xff; 927 928 curr[i + coff] = (byte)(raw + (priorPixel + priorRow)/2); 929 } 930 } 931 932 private static int paethPredictor(int a, int b, int c) { 933 int p = a + b - c; 934 int pa = Math.abs(p - a); 935 int pb = Math.abs(p - b); 936 int pc = Math.abs(p - c); 937 938 if ((pa <= pb) && (pa <= pc)) { 939 return a; 940 } else if (pb <= pc) { 941 return b; 942 } else { 943 return c; 944 } 945 } 946 947 private static void decodePaethFilter(byte[] curr, int coff, 948 byte[] prev, int poff, 949 int count, int bpp) { 950 int raw, priorPixel, priorRow, priorRowPixel; 951 952 for (int i = 0; i < bpp; i++) { 953 raw = curr[i + coff] & 0xff; 954 priorRow = prev[i + poff] & 0xff; 955 956 curr[i + coff] = (byte)(raw + priorRow); 957 } 958 959 for (int i = bpp; i < count; i++) { 960 raw = curr[i + coff] & 0xff; 961 priorPixel = curr[i + coff - bpp] & 0xff; 962 priorRow = prev[i + poff] & 0xff; 963 priorRowPixel = prev[i + poff - bpp] & 0xff; 964 965 curr[i + coff] = (byte)(raw + paethPredictor(priorPixel, 966 priorRow, 967 priorRowPixel)); 968 } 969 } 970 971 private static final int[][] bandOffsets = { 972 null, 973 { 0 }, // G 974 { 0, 1 }, // GA in GA order 975 { 0, 1, 2 }, // RGB in RGB order 976 { 0, 1, 2, 3 } // RGBA in RGBA order 977 }; 978 979 private WritableRaster createRaster(int width, int height, int bands, 980 int scanlineStride, 981 int bitDepth) { 982 983 DataBuffer dataBuffer; 984 WritableRaster ras = null; 985 Point origin = new Point(0, 0); 986 if ((bitDepth < 8) && (bands == 1)) { 987 dataBuffer = new DataBufferByte(height*scanlineStride); 988 ras = Raster.createPackedRaster(dataBuffer, 989 width, height, 990 bitDepth, 991 origin); 992 } else if (bitDepth <= 8) { 993 dataBuffer = new DataBufferByte(height*scanlineStride); 994 ras = Raster.createInterleavedRaster(dataBuffer, 995 width, height, 996 scanlineStride, 997 bands, 998 bandOffsets[bands], 999 origin); 1000 } else { 1001 dataBuffer = new DataBufferUShort(height*scanlineStride); 1002 ras = Raster.createInterleavedRaster(dataBuffer, 1003 width, height, 1004 scanlineStride, 1005 bands, 1006 bandOffsets[bands], 1007 origin); 1008 } 1009 1010 return ras; 1011 } 1012 1013 private void skipPass(int passWidth, int passHeight) 1014 throws IOException, IIOException { 1015 if ((passWidth == 0) || (passHeight == 0)) { 1016 return; 1017 } 1018 1019 int inputBands = inputBandsForColorType[metadata.IHDR_colorType]; 1020 int bitsPerRow = Math. 1021 multiplyExact((inputBands * metadata.IHDR_bitDepth), passWidth); 1022 int bytesPerRow = (bitsPerRow + 7) / 8; 1023 1024 // Read the image row-by-row 1025 for (int srcY = 0; srcY < passHeight; srcY++) { 1026 // Skip filter byte and the remaining row bytes 1027 pixelStream.skipBytes(1 + bytesPerRow); 1028 } 1029 } 1030 1031 private void updateImageProgress(int newPixels) { 1032 pixelsDone += newPixels; 1033 processImageProgress(100.0F*pixelsDone/totalPixels); 1034 } 1035 1036 private void decodePass(int passNum, 1037 int xStart, int yStart, 1038 int xStep, int yStep, 1039 int passWidth, int passHeight) throws IOException { 1040 1041 if ((passWidth == 0) || (passHeight == 0)) { 1042 return; 1043 } 1044 1045 WritableRaster imRas = theImage.getWritableTile(0, 0); 1046 int dstMinX = imRas.getMinX(); 1047 int dstMaxX = dstMinX + imRas.getWidth() - 1; 1048 int dstMinY = imRas.getMinY(); 1049 int dstMaxY = dstMinY + imRas.getHeight() - 1; 1050 1051 // Determine which pixels will be updated in this pass 1052 int[] vals = 1053 ReaderUtil.computeUpdatedPixels(sourceRegion, 1054 destinationOffset, 1055 dstMinX, dstMinY, 1056 dstMaxX, dstMaxY, 1057 sourceXSubsampling, 1058 sourceYSubsampling, 1059 xStart, yStart, 1060 passWidth, passHeight, 1061 xStep, yStep); 1062 int updateMinX = vals[0]; 1063 int updateMinY = vals[1]; 1064 int updateWidth = vals[2]; 1065 int updateXStep = vals[4]; 1066 int updateYStep = vals[5]; 1067 1068 int bitDepth = metadata.IHDR_bitDepth; 1069 int inputBands = inputBandsForColorType[metadata.IHDR_colorType]; 1070 int bytesPerPixel = (bitDepth == 16) ? 2 : 1; 1071 bytesPerPixel *= inputBands; 1072 1073 int bitsPerRow = Math.multiplyExact((inputBands * bitDepth), passWidth); 1074 int bytesPerRow = (bitsPerRow + 7) / 8; 1075 int eltsPerRow = (bitDepth == 16) ? bytesPerRow/2 : bytesPerRow; 1076 1077 // If no pixels need updating, just skip the input data 1078 if (updateWidth == 0) { 1079 for (int srcY = 0; srcY < passHeight; srcY++) { 1080 // Update count of pixels read 1081 updateImageProgress(passWidth); 1082 /* 1083 * If read has been aborted, just return 1084 * processReadAborted will be called later 1085 */ 1086 if (abortRequested()) { 1087 return; 1088 } 1089 // Skip filter byte and the remaining row bytes 1090 pixelStream.skipBytes(1 + bytesPerRow); 1091 } 1092 return; 1093 } 1094 1095 // Backwards map from destination pixels 1096 // (dstX = updateMinX + k*updateXStep) 1097 // to source pixels (sourceX), and then 1098 // to offset and skip in passRow (srcX and srcXStep) 1099 int sourceX = 1100 (updateMinX - destinationOffset.x)*sourceXSubsampling + 1101 sourceRegion.x; 1102 int srcX = (sourceX - xStart)/xStep; 1103 1104 // Compute the step factor in the source 1105 int srcXStep = updateXStep*sourceXSubsampling/xStep; 1106 1107 byte[] byteData = null; 1108 short[] shortData = null; 1109 byte[] curr = new byte[bytesPerRow]; 1110 byte[] prior = new byte[bytesPerRow]; 1111 1112 // Create a 1-row tall Raster to hold the data 1113 WritableRaster passRow = createRaster(passWidth, 1, inputBands, 1114 eltsPerRow, 1115 bitDepth); 1116 1117 // Create an array suitable for holding one pixel 1118 int[] ps = passRow.getPixel(0, 0, (int[])null); 1119 1120 DataBuffer dataBuffer = passRow.getDataBuffer(); 1121 int type = dataBuffer.getDataType(); 1122 if (type == DataBuffer.TYPE_BYTE) { 1123 byteData = ((DataBufferByte)dataBuffer).getData(); 1124 } else { 1125 shortData = ((DataBufferUShort)dataBuffer).getData(); 1126 } 1127 1128 processPassStarted(theImage, 1129 passNum, 1130 sourceMinProgressivePass, 1131 sourceMaxProgressivePass, 1132 updateMinX, updateMinY, 1133 updateXStep, updateYStep, 1134 destinationBands); 1135 1136 // Handle source and destination bands 1137 if (sourceBands != null) { 1138 passRow = passRow.createWritableChild(0, 0, 1139 passRow.getWidth(), 1, 1140 0, 0, 1141 sourceBands); 1142 } 1143 if (destinationBands != null) { 1144 imRas = imRas.createWritableChild(0, 0, 1145 imRas.getWidth(), 1146 imRas.getHeight(), 1147 0, 0, 1148 destinationBands); 1149 } 1150 1151 // Determine if all of the relevant output bands have the 1152 // same bit depth as the source data 1153 boolean adjustBitDepths = false; 1154 int[] outputSampleSize = imRas.getSampleModel().getSampleSize(); 1155 int numBands = outputSampleSize.length; 1156 for (int b = 0; b < numBands; b++) { 1157 if (outputSampleSize[b] != bitDepth) { 1158 adjustBitDepths = true; 1159 break; 1160 } 1161 } 1162 1163 // If the bit depths differ, create a lookup table per band to perform 1164 // the conversion 1165 int[][] scale = null; 1166 if (adjustBitDepths) { 1167 int maxInSample = (1 << bitDepth) - 1; 1168 int halfMaxInSample = maxInSample/2; 1169 scale = new int[numBands][]; 1170 for (int b = 0; b < numBands; b++) { 1171 int maxOutSample = (1 << outputSampleSize[b]) - 1; 1172 scale[b] = new int[maxInSample + 1]; 1173 for (int s = 0; s <= maxInSample; s++) { 1174 scale[b][s] = 1175 (s*maxOutSample + halfMaxInSample)/maxInSample; 1176 } 1177 } 1178 } 1179 1180 // Limit passRow to relevant area for the case where we 1181 // will can setRect to copy a contiguous span 1182 boolean useSetRect = srcXStep == 1 && 1183 updateXStep == 1 && 1184 !adjustBitDepths && 1185 (imRas instanceof ByteInterleavedRaster); 1186 1187 if (useSetRect) { 1188 passRow = passRow.createWritableChild(srcX, 0, 1189 updateWidth, 1, 1190 0, 0, 1191 null); 1192 } 1193 1194 // Decode the (sub)image row-by-row 1195 for (int srcY = 0; srcY < passHeight; srcY++) { 1196 // Update count of pixels read 1197 updateImageProgress(passWidth); 1198 /* 1199 * If read has been aborted, just return 1200 * processReadAborted will be called later 1201 */ 1202 if (abortRequested()) { 1203 return; 1204 } 1205 // Read the filter type byte and a row of data 1206 int filter = pixelStream.read(); 1207 try { 1208 // Swap curr and prior 1209 byte[] tmp = prior; 1210 prior = curr; 1211 curr = tmp; 1212 1213 pixelStream.readFully(curr, 0, bytesPerRow); 1214 } catch (java.util.zip.ZipException ze) { 1215 // TODO - throw a more meaningful exception 1216 throw ze; 1217 } 1218 1219 switch (filter) { 1220 case PNG_FILTER_NONE: 1221 break; 1222 case PNG_FILTER_SUB: 1223 decodeSubFilter(curr, 0, bytesPerRow, bytesPerPixel); 1224 break; 1225 case PNG_FILTER_UP: 1226 decodeUpFilter(curr, 0, prior, 0, bytesPerRow); 1227 break; 1228 case PNG_FILTER_AVERAGE: 1229 decodeAverageFilter(curr, 0, prior, 0, bytesPerRow, 1230 bytesPerPixel); 1231 break; 1232 case PNG_FILTER_PAETH: 1233 decodePaethFilter(curr, 0, prior, 0, bytesPerRow, 1234 bytesPerPixel); 1235 break; 1236 default: 1237 throw new IIOException("Unknown row filter type (= " + 1238 filter + ")!"); 1239 } 1240 1241 // Copy data into passRow byte by byte 1242 if (bitDepth < 16) { 1243 System.arraycopy(curr, 0, byteData, 0, bytesPerRow); 1244 } else { 1245 int idx = 0; 1246 for (int j = 0; j < eltsPerRow; j++) { 1247 shortData[j] = 1248 (short)((curr[idx] << 8) | (curr[idx + 1] & 0xff)); 1249 idx += 2; 1250 } 1251 } 1252 1253 // True Y position in source 1254 int sourceY = srcY*yStep + yStart; 1255 if ((sourceY >= sourceRegion.y) && 1256 (sourceY < sourceRegion.y + sourceRegion.height) && 1257 (((sourceY - sourceRegion.y) % 1258 sourceYSubsampling) == 0)) { 1259 1260 int dstY = destinationOffset.y + 1261 (sourceY - sourceRegion.y)/sourceYSubsampling; 1262 if (dstY < dstMinY) { 1263 continue; 1264 } 1265 if (dstY > dstMaxY) { 1266 break; 1267 } 1268 1269 if (useSetRect) { 1270 imRas.setRect(updateMinX, dstY, passRow); 1271 } else { 1272 int newSrcX = srcX; 1273 1274 for (int dstX = updateMinX; 1275 dstX < updateMinX + updateWidth; 1276 dstX += updateXStep) { 1277 1278 passRow.getPixel(newSrcX, 0, ps); 1279 if (adjustBitDepths) { 1280 for (int b = 0; b < numBands; b++) { 1281 ps[b] = scale[b][ps[b]]; 1282 } 1283 } 1284 imRas.setPixel(dstX, dstY, ps); 1285 newSrcX += srcXStep; 1286 } 1287 } 1288 1289 processImageUpdate(theImage, 1290 updateMinX, dstY, 1291 updateWidth, 1, 1292 updateXStep, updateYStep, 1293 destinationBands); 1294 } 1295 } 1296 1297 processPassComplete(theImage); 1298 } 1299 1300 private void decodeImage() 1301 throws IOException, IIOException { 1302 int width = metadata.IHDR_width; 1303 int height = metadata.IHDR_height; 1304 1305 this.pixelsDone = 0; 1306 this.totalPixels = width*height; 1307 1308 if (metadata.IHDR_interlaceMethod == 0) { 1309 decodePass(0, 0, 0, 1, 1, width, height); 1310 } else { 1311 for (int i = 0; i <= sourceMaxProgressivePass; i++) { 1312 int XOffset = adam7XOffset[i]; 1313 int YOffset = adam7YOffset[i]; 1314 int XSubsampling = adam7XSubsampling[i]; 1315 int YSubsampling = adam7YSubsampling[i]; 1316 int xbump = adam7XSubsampling[i + 1] - 1; 1317 int ybump = adam7YSubsampling[i + 1] - 1; 1318 1319 if (i >= sourceMinProgressivePass) { 1320 decodePass(i, 1321 XOffset, 1322 YOffset, 1323 XSubsampling, 1324 YSubsampling, 1325 (width + xbump)/XSubsampling, 1326 (height + ybump)/YSubsampling); 1327 } else { 1328 skipPass((width + xbump)/XSubsampling, 1329 (height + ybump)/YSubsampling); 1330 } 1331 1332 /* 1333 * If read has been aborted, just return 1334 * processReadAborted will be called later 1335 */ 1336 if (abortRequested()) { 1337 return; 1338 } 1339 } 1340 } 1341 } 1342 1343 private void readImage(ImageReadParam param) throws IIOException { 1344 readMetadata(); 1345 1346 int width = metadata.IHDR_width; 1347 int height = metadata.IHDR_height; 1348 1349 // Init default values 1350 sourceXSubsampling = 1; 1351 sourceYSubsampling = 1; 1352 sourceMinProgressivePass = 0; 1353 sourceMaxProgressivePass = 6; 1354 sourceBands = null; 1355 destinationBands = null; 1356 destinationOffset = new Point(0, 0); 1357 1358 // If an ImageReadParam is available, get values from it 1359 if (param != null) { 1360 sourceXSubsampling = param.getSourceXSubsampling(); 1361 sourceYSubsampling = param.getSourceYSubsampling(); 1362 1363 sourceMinProgressivePass = 1364 Math.max(param.getSourceMinProgressivePass(), 0); 1365 sourceMaxProgressivePass = 1366 Math.min(param.getSourceMaxProgressivePass(), 6); 1367 1368 sourceBands = param.getSourceBands(); 1369 destinationBands = param.getDestinationBands(); 1370 destinationOffset = param.getDestinationOffset(); 1371 } 1372 Inflater inf = null; 1373 try { 1374 stream.seek(imageStartPosition); 1375 1376 Enumeration<InputStream> e = new PNGImageDataEnumeration(stream); 1377 InputStream is = new SequenceInputStream(e); 1378 1379 /* InflaterInputStream uses an Inflater instance which consumes 1380 * native (non-GC visible) resources. This is normally implicitly 1381 * freed when the stream is closed. However since the 1382 * InflaterInputStream wraps a client-supplied input stream, 1383 * we cannot close it. 1384 * But the app may depend on GC finalization to close the stream. 1385 * Therefore to ensure timely freeing of native resources we 1386 * explicitly create the Inflater instance and free its resources 1387 * when we are done with the InflaterInputStream by calling 1388 * inf.end(); 1389 */ 1390 inf = new Inflater(); 1391 is = new InflaterInputStream(is, inf); 1392 is = new BufferedInputStream(is); 1393 this.pixelStream = new DataInputStream(is); 1394 1395 /* 1396 * PNG spec declares that valid range for width 1397 * and height is [1, 2^31-1], so here we may fail to allocate 1398 * a buffer for destination image due to memory limitation. 1399 * 1400 * If the read operation triggers OutOfMemoryError, the same 1401 * will be wrapped in an IIOException at PNGImageReader.read 1402 * method. 1403 * 1404 * The recovery strategy for this case should be defined at 1405 * the level of application, so we will not try to estimate 1406 * the required amount of the memory and/or handle OOM in 1407 * any way. 1408 */ 1409 theImage = getDestination(param, 1410 getImageTypes(0), 1411 width, 1412 height); 1413 1414 Rectangle destRegion = new Rectangle(0, 0, 0, 0); 1415 sourceRegion = new Rectangle(0, 0, 0, 0); 1416 computeRegions(param, width, height, 1417 theImage, 1418 sourceRegion, destRegion); 1419 destinationOffset.setLocation(destRegion.getLocation()); 1420 1421 // At this point the header has been read and we know 1422 // how many bands are in the image, so perform checking 1423 // of the read param. 1424 int colorType = metadata.IHDR_colorType; 1425 checkReadParamBandSettings(param, 1426 inputBandsForColorType[colorType], 1427 theImage.getSampleModel().getNumBands()); 1428 1429 clearAbortRequest(); 1430 processImageStarted(0); 1431 if (abortRequested()) { 1432 processReadAborted(); 1433 } else { 1434 decodeImage(); 1435 if (abortRequested()) { 1436 processReadAborted(); 1437 } else { 1438 processImageComplete(); 1439 } 1440 } 1441 1442 } catch (IOException e) { 1443 throw new IIOException("Error reading PNG image data", e); 1444 } finally { 1445 if (inf != null) { 1446 inf.end(); 1447 } 1448 } 1449 } 1450 1451 public int getNumImages(boolean allowSearch) throws IIOException { 1452 if (stream == null) { 1453 throw new IllegalStateException("No input source set!"); 1454 } 1455 if (seekForwardOnly && allowSearch) { 1456 throw new IllegalStateException 1457 ("seekForwardOnly and allowSearch can't both be true!"); 1458 } 1459 return 1; 1460 } 1461 1462 public int getWidth(int imageIndex) throws IIOException { 1463 if (imageIndex != 0) { 1464 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1465 } 1466 1467 readHeader(); 1468 1469 return metadata.IHDR_width; 1470 } 1471 1472 public int getHeight(int imageIndex) throws IIOException { 1473 if (imageIndex != 0) { 1474 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1475 } 1476 1477 readHeader(); 1478 1479 return metadata.IHDR_height; 1480 } 1481 1482 public Iterator<ImageTypeSpecifier> getImageTypes(int imageIndex) 1483 throws IIOException 1484 { 1485 if (imageIndex != 0) { 1486 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1487 } 1488 1489 readHeader(); 1490 1491 ArrayList<ImageTypeSpecifier> l = 1492 new ArrayList<ImageTypeSpecifier>(1); 1493 1494 ColorSpace rgb; 1495 ColorSpace gray; 1496 int[] bandOffsets; 1497 1498 int bitDepth = metadata.IHDR_bitDepth; 1499 int colorType = metadata.IHDR_colorType; 1500 1501 int dataType; 1502 if (bitDepth <= 8) { 1503 dataType = DataBuffer.TYPE_BYTE; 1504 } else { 1505 dataType = DataBuffer.TYPE_USHORT; 1506 } 1507 1508 switch (colorType) { 1509 case PNG_COLOR_GRAY: 1510 // Packed grayscale 1511 l.add(ImageTypeSpecifier.createGrayscale(bitDepth, 1512 dataType, 1513 false)); 1514 break; 1515 1516 case PNG_COLOR_RGB: 1517 if (bitDepth == 8) { 1518 // some standard types of buffered images 1519 // which can be used as destination 1520 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1521 BufferedImage.TYPE_3BYTE_BGR)); 1522 1523 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1524 BufferedImage.TYPE_INT_RGB)); 1525 1526 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1527 BufferedImage.TYPE_INT_BGR)); 1528 1529 } 1530 // Component R, G, B 1531 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB); 1532 bandOffsets = new int[3]; 1533 bandOffsets[0] = 0; 1534 bandOffsets[1] = 1; 1535 bandOffsets[2] = 2; 1536 l.add(ImageTypeSpecifier.createInterleaved(rgb, 1537 bandOffsets, 1538 dataType, 1539 false, 1540 false)); 1541 break; 1542 1543 case PNG_COLOR_PALETTE: 1544 readMetadata(); // Need tRNS chunk 1545 1546 /* 1547 * The PLTE chunk spec says: 1548 * 1549 * The number of palette entries must not exceed the range that 1550 * can be represented in the image bit depth (for example, 2^4 = 16 1551 * for a bit depth of 4). It is permissible to have fewer entries 1552 * than the bit depth would allow. In that case, any out-of-range 1553 * pixel value found in the image data is an error. 1554 * 1555 * http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html#C.PLTE 1556 * 1557 * Consequently, the case when the palette length is smaller than 1558 * 2^bitDepth is legal in the view of PNG spec. 1559 * 1560 * However the spec of createIndexed() method demands the exact 1561 * equality of the palette lengh and number of possible palette 1562 * entries (2^bitDepth). 1563 * 1564 * {@link javax.imageio.ImageTypeSpecifier.html#createIndexed} 1565 * 1566 * In order to avoid this contradiction we need to extend the 1567 * palette arrays to the limit defined by the bitDepth. 1568 */ 1569 1570 int plength = 1 << bitDepth; 1571 1572 byte[] red = metadata.PLTE_red; 1573 byte[] green = metadata.PLTE_green; 1574 byte[] blue = metadata.PLTE_blue; 1575 1576 if (metadata.PLTE_red.length < plength) { 1577 red = Arrays.copyOf(metadata.PLTE_red, plength); 1578 Arrays.fill(red, metadata.PLTE_red.length, plength, 1579 metadata.PLTE_red[metadata.PLTE_red.length - 1]); 1580 1581 green = Arrays.copyOf(metadata.PLTE_green, plength); 1582 Arrays.fill(green, metadata.PLTE_green.length, plength, 1583 metadata.PLTE_green[metadata.PLTE_green.length - 1]); 1584 1585 blue = Arrays.copyOf(metadata.PLTE_blue, plength); 1586 Arrays.fill(blue, metadata.PLTE_blue.length, plength, 1587 metadata.PLTE_blue[metadata.PLTE_blue.length - 1]); 1588 1589 } 1590 1591 // Alpha from tRNS chunk may have fewer entries than 1592 // the RGB LUTs from the PLTE chunk; if so, pad with 1593 // 255. 1594 byte[] alpha = null; 1595 if (metadata.tRNS_present && (metadata.tRNS_alpha != null)) { 1596 if (metadata.tRNS_alpha.length == red.length) { 1597 alpha = metadata.tRNS_alpha; 1598 } else { 1599 alpha = Arrays.copyOf(metadata.tRNS_alpha, red.length); 1600 Arrays.fill(alpha, 1601 metadata.tRNS_alpha.length, 1602 red.length, (byte)255); 1603 } 1604 } 1605 1606 l.add(ImageTypeSpecifier.createIndexed(red, green, 1607 blue, alpha, 1608 bitDepth, 1609 DataBuffer.TYPE_BYTE)); 1610 break; 1611 1612 case PNG_COLOR_GRAY_ALPHA: 1613 // Component G, A 1614 gray = ColorSpace.getInstance(ColorSpace.CS_GRAY); 1615 bandOffsets = new int[2]; 1616 bandOffsets[0] = 0; 1617 bandOffsets[1] = 1; 1618 l.add(ImageTypeSpecifier.createInterleaved(gray, 1619 bandOffsets, 1620 dataType, 1621 true, 1622 false)); 1623 break; 1624 1625 case PNG_COLOR_RGB_ALPHA: 1626 if (bitDepth == 8) { 1627 // some standard types of buffered images 1628 // wich can be used as destination 1629 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1630 BufferedImage.TYPE_4BYTE_ABGR)); 1631 1632 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1633 BufferedImage.TYPE_INT_ARGB)); 1634 } 1635 1636 // Component R, G, B, A (non-premultiplied) 1637 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB); 1638 bandOffsets = new int[4]; 1639 bandOffsets[0] = 0; 1640 bandOffsets[1] = 1; 1641 bandOffsets[2] = 2; 1642 bandOffsets[3] = 3; 1643 1644 l.add(ImageTypeSpecifier.createInterleaved(rgb, 1645 bandOffsets, 1646 dataType, 1647 true, 1648 false)); 1649 break; 1650 1651 default: 1652 break; 1653 } 1654 1655 return l.iterator(); 1656 } 1657 1658 /* 1659 * Super class implementation uses first element 1660 * of image types list as raw image type. 1661 * 1662 * Also, super implementation uses first element of this list 1663 * as default destination type image read param does not specify 1664 * anything other. 1665 * 1666 * However, in case of RGB and RGBA color types, raw image type 1667 * produces buffered image of custom type. It causes some 1668 * performance degradation of subsequent rendering operations. 1669 * 1670 * To resolve this contradiction we put standard image types 1671 * at the first positions of image types list (to produce standard 1672 * images by default) and put raw image type (which is custom) 1673 * at the last position of this list. 1674 * 1675 * After this changes we should override getRawImageType() 1676 * to return last element of image types list. 1677 */ 1678 public ImageTypeSpecifier getRawImageType(int imageIndex) 1679 throws IOException { 1680 1681 Iterator<ImageTypeSpecifier> types = getImageTypes(imageIndex); 1682 ImageTypeSpecifier raw = null; 1683 do { 1684 raw = types.next(); 1685 } while (types.hasNext()); 1686 return raw; 1687 } 1688 1689 public ImageReadParam getDefaultReadParam() { 1690 return new ImageReadParam(); 1691 } 1692 1693 public IIOMetadata getStreamMetadata() 1694 throws IIOException { 1695 return null; 1696 } 1697 1698 public IIOMetadata getImageMetadata(int imageIndex) throws IIOException { 1699 if (imageIndex != 0) { 1700 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1701 } 1702 readMetadata(); 1703 return metadata; 1704 } 1705 1706 public BufferedImage read(int imageIndex, ImageReadParam param) 1707 throws IIOException { 1708 if (imageIndex != 0) { 1709 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1710 } 1711 1712 try { 1713 readImage(param); 1714 } catch (IOException | 1715 IllegalStateException | 1716 IllegalArgumentException e) 1717 { 1718 throw e; 1719 } catch (Throwable e) { 1720 throw new IIOException("Caught exception during read: ", e); 1721 } 1722 return theImage; 1723 } 1724 1725 public void reset() { 1726 super.reset(); 1727 resetStreamSettings(); 1728 } 1729 1730 private void resetStreamSettings() { 1731 gotHeader = false; 1732 gotMetadata = false; 1733 metadata = null; 1734 pixelStream = null; 1735 imageStartPosition = -1L; 1736 } 1737 }