1 /* 2 * Copyright (c) 2000, 2017, 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 metadata.iCCP_profileName = keyword; 432 433 metadata.iCCP_compressionMethod = stream.readUnsignedByte(); 434 435 byte[] compressedProfile = 436 new byte[chunkLength - keyword.length() - 2]; 437 stream.readFully(compressedProfile); 438 metadata.iCCP_compressedProfile = compressedProfile; 439 440 metadata.iCCP_present = true; 441 } 442 443 private void parse_iTXt_chunk(int chunkLength) throws IOException { 444 long chunkStart = stream.getStreamPosition(); 445 446 String keyword = readNullTerminatedString("ISO-8859-1", 80); 447 metadata.iTXt_keyword.add(keyword); 448 449 int compressionFlag = stream.readUnsignedByte(); 450 metadata.iTXt_compressionFlag.add(Boolean.valueOf(compressionFlag == 1)); 451 452 int compressionMethod = stream.readUnsignedByte(); 453 metadata.iTXt_compressionMethod.add(Integer.valueOf(compressionMethod)); 454 455 String languageTag = readNullTerminatedString("UTF8", 80); 456 metadata.iTXt_languageTag.add(languageTag); 457 458 long pos = stream.getStreamPosition(); 459 int maxLen = (int)(chunkStart + chunkLength - pos); 460 String translatedKeyword = 461 readNullTerminatedString("UTF8", maxLen); 462 metadata.iTXt_translatedKeyword.add(translatedKeyword); 463 464 String text; 465 pos = stream.getStreamPosition(); 466 byte[] b = new byte[(int)(chunkStart + chunkLength - pos)]; 467 stream.readFully(b); 468 469 if (compressionFlag == 1) { // Decompress the text 470 text = new String(inflate(b), "UTF8"); 471 } else { 472 text = new String(b, "UTF8"); 473 } 474 metadata.iTXt_text.add(text); 475 476 // Check if the text chunk contains image creation time 477 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) { 478 // Update Standard/Document/ImageCreationTime from text chunk 479 int index = metadata.iTXt_text.size() - 1; 480 metadata.decodeImageCreationTimeFromTextChunk( 481 metadata.iTXt_text.listIterator(index)); 482 } 483 } 484 485 private void parse_pHYs_chunk() throws IOException { 486 metadata.pHYs_pixelsPerUnitXAxis = stream.readInt(); 487 metadata.pHYs_pixelsPerUnitYAxis = stream.readInt(); 488 metadata.pHYs_unitSpecifier = stream.readUnsignedByte(); 489 490 metadata.pHYs_present = true; 491 } 492 493 private void parse_sBIT_chunk() throws IOException { 494 int colorType = metadata.IHDR_colorType; 495 if (colorType == PNG_COLOR_GRAY || 496 colorType == PNG_COLOR_GRAY_ALPHA) { 497 metadata.sBIT_grayBits = stream.readUnsignedByte(); 498 } else if (colorType == PNG_COLOR_RGB || 499 colorType == PNG_COLOR_PALETTE || 500 colorType == PNG_COLOR_RGB_ALPHA) { 501 metadata.sBIT_redBits = stream.readUnsignedByte(); 502 metadata.sBIT_greenBits = stream.readUnsignedByte(); 503 metadata.sBIT_blueBits = stream.readUnsignedByte(); 504 } 505 506 if (colorType == PNG_COLOR_GRAY_ALPHA || 507 colorType == PNG_COLOR_RGB_ALPHA) { 508 metadata.sBIT_alphaBits = stream.readUnsignedByte(); 509 } 510 511 metadata.sBIT_colorType = colorType; 512 metadata.sBIT_present = true; 513 } 514 515 private void parse_sPLT_chunk(int chunkLength) 516 throws IOException, IIOException { 517 metadata.sPLT_paletteName = readNullTerminatedString("ISO-8859-1", 80); 518 chunkLength -= metadata.sPLT_paletteName.length() + 1; 519 520 int sampleDepth = stream.readUnsignedByte(); 521 metadata.sPLT_sampleDepth = sampleDepth; 522 523 int numEntries = chunkLength/(4*(sampleDepth/8) + 2); 524 metadata.sPLT_red = new int[numEntries]; 525 metadata.sPLT_green = new int[numEntries]; 526 metadata.sPLT_blue = new int[numEntries]; 527 metadata.sPLT_alpha = new int[numEntries]; 528 metadata.sPLT_frequency = new int[numEntries]; 529 530 if (sampleDepth == 8) { 531 for (int i = 0; i < numEntries; i++) { 532 metadata.sPLT_red[i] = stream.readUnsignedByte(); 533 metadata.sPLT_green[i] = stream.readUnsignedByte(); 534 metadata.sPLT_blue[i] = stream.readUnsignedByte(); 535 metadata.sPLT_alpha[i] = stream.readUnsignedByte(); 536 metadata.sPLT_frequency[i] = stream.readUnsignedShort(); 537 } 538 } else if (sampleDepth == 16) { 539 for (int i = 0; i < numEntries; i++) { 540 metadata.sPLT_red[i] = stream.readUnsignedShort(); 541 metadata.sPLT_green[i] = stream.readUnsignedShort(); 542 metadata.sPLT_blue[i] = stream.readUnsignedShort(); 543 metadata.sPLT_alpha[i] = stream.readUnsignedShort(); 544 metadata.sPLT_frequency[i] = stream.readUnsignedShort(); 545 } 546 } else { 547 throw new IIOException("sPLT sample depth not 8 or 16!"); 548 } 549 550 metadata.sPLT_present = true; 551 } 552 553 private void parse_sRGB_chunk() throws IOException { 554 metadata.sRGB_renderingIntent = stream.readUnsignedByte(); 555 556 metadata.sRGB_present = true; 557 } 558 559 private void parse_tEXt_chunk(int chunkLength) throws IOException { 560 String keyword = readNullTerminatedString("ISO-8859-1", 80); 561 metadata.tEXt_keyword.add(keyword); 562 563 byte[] b = new byte[chunkLength - keyword.length() - 1]; 564 stream.readFully(b); 565 metadata.tEXt_text.add(new String(b, "ISO-8859-1")); 566 567 // Check if the text chunk contains image creation time 568 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) { 569 // Update Standard/Document/ImageCreationTime from text chunk 570 int index = metadata.tEXt_text.size() - 1; 571 metadata.decodeImageCreationTimeFromTextChunk( 572 metadata.tEXt_text.listIterator(index)); 573 } 574 } 575 576 private void parse_tIME_chunk() throws IOException { 577 metadata.tIME_year = stream.readUnsignedShort(); 578 metadata.tIME_month = stream.readUnsignedByte(); 579 metadata.tIME_day = stream.readUnsignedByte(); 580 metadata.tIME_hour = stream.readUnsignedByte(); 581 metadata.tIME_minute = stream.readUnsignedByte(); 582 metadata.tIME_second = stream.readUnsignedByte(); 583 584 metadata.tIME_present = true; 585 } 586 587 private void parse_tRNS_chunk(int chunkLength) throws IOException { 588 int colorType = metadata.IHDR_colorType; 589 if (colorType == PNG_COLOR_PALETTE) { 590 if (!metadata.PLTE_present) { 591 processWarningOccurred( 592 "tRNS chunk without prior PLTE chunk, ignoring it."); 593 return; 594 } 595 596 // Alpha table may have fewer entries than RGB palette 597 int maxEntries = metadata.PLTE_red.length; 598 int numEntries = chunkLength; 599 if (numEntries > maxEntries) { 600 processWarningOccurred( 601 "tRNS chunk has more entries than prior PLTE chunk, ignoring extras."); 602 numEntries = maxEntries; 603 } 604 metadata.tRNS_alpha = new byte[numEntries]; 605 metadata.tRNS_colorType = PNG_COLOR_PALETTE; 606 stream.read(metadata.tRNS_alpha, 0, numEntries); 607 stream.skipBytes(chunkLength - numEntries); 608 } else if (colorType == PNG_COLOR_GRAY) { 609 if (chunkLength != 2) { 610 processWarningOccurred( 611 "tRNS chunk for gray image must have length 2, ignoring chunk."); 612 stream.skipBytes(chunkLength); 613 return; 614 } 615 metadata.tRNS_gray = stream.readUnsignedShort(); 616 metadata.tRNS_colorType = PNG_COLOR_GRAY; 617 } else if (colorType == PNG_COLOR_RGB) { 618 if (chunkLength != 6) { 619 processWarningOccurred( 620 "tRNS chunk for RGB image must have length 6, ignoring chunk."); 621 stream.skipBytes(chunkLength); 622 return; 623 } 624 metadata.tRNS_red = stream.readUnsignedShort(); 625 metadata.tRNS_green = stream.readUnsignedShort(); 626 metadata.tRNS_blue = stream.readUnsignedShort(); 627 metadata.tRNS_colorType = PNG_COLOR_RGB; 628 } else { 629 processWarningOccurred( 630 "Gray+Alpha and RGBS images may not have a tRNS chunk, ignoring it."); 631 return; 632 } 633 634 metadata.tRNS_present = true; 635 } 636 637 private static byte[] inflate(byte[] b) throws IOException { 638 InputStream bais = new ByteArrayInputStream(b); 639 InputStream iis = new InflaterInputStream(bais); 640 ByteArrayOutputStream baos = new ByteArrayOutputStream(); 641 642 int c; 643 try { 644 while ((c = iis.read()) != -1) { 645 baos.write(c); 646 } 647 } finally { 648 iis.close(); 649 } 650 return baos.toByteArray(); 651 } 652 653 private void parse_zTXt_chunk(int chunkLength) throws IOException { 654 String keyword = readNullTerminatedString("ISO-8859-1", 80); 655 metadata.zTXt_keyword.add(keyword); 656 657 int method = stream.readUnsignedByte(); 658 metadata.zTXt_compressionMethod.add(method); 659 660 byte[] b = new byte[chunkLength - keyword.length() - 2]; 661 stream.readFully(b); 662 metadata.zTXt_text.add(new String(inflate(b), "ISO-8859-1")); 663 664 // Check if the text chunk contains image creation time 665 if (keyword.equals(PNGMetadata.tEXt_creationTimeKey)) { 666 // Update Standard/Document/ImageCreationTime from text chunk 667 int index = metadata.zTXt_text.size() - 1; 668 metadata.decodeImageCreationTimeFromTextChunk( 669 metadata.zTXt_text.listIterator(index)); 670 } 671 } 672 673 private void readMetadata() throws IIOException { 674 if (gotMetadata) { 675 return; 676 } 677 678 readHeader(); 679 680 /* 681 * Optimization: We can skip the remaining metadata if the 682 * ignoreMetadata flag is set, and only if this is not a palette 683 * image (in that case, we need to read the metadata to get the 684 * tRNS chunk, which is needed for the getImageTypes() method). 685 */ 686 int colorType = metadata.IHDR_colorType; 687 if (ignoreMetadata && colorType != PNG_COLOR_PALETTE) { 688 try { 689 while (true) { 690 int chunkLength = stream.readInt(); 691 692 // verify the chunk length first 693 if (chunkLength < 0 || chunkLength + 4 < 0) { 694 throw new IIOException("Invalid chunk length " + chunkLength); 695 } 696 697 int chunkType = stream.readInt(); 698 699 if (chunkType == IDAT_TYPE) { 700 // We've reached the image data 701 stream.skipBytes(-8); 702 imageStartPosition = stream.getStreamPosition(); 703 break; 704 } else { 705 // Skip the chunk plus the 4 CRC bytes that follow 706 stream.skipBytes(chunkLength + 4); 707 } 708 } 709 } catch (IOException e) { 710 throw new IIOException("Error skipping PNG metadata", e); 711 } 712 713 gotMetadata = true; 714 return; 715 } 716 717 try { 718 loop: while (true) { 719 int chunkLength = stream.readInt(); 720 int chunkType = stream.readInt(); 721 int chunkCRC; 722 723 // verify the chunk length 724 if (chunkLength < 0) { 725 throw new IIOException("Invalid chunk length " + chunkLength); 726 }; 727 728 try { 729 stream.mark(); 730 stream.seek(stream.getStreamPosition() + chunkLength); 731 chunkCRC = stream.readInt(); 732 stream.reset(); 733 } catch (IOException e) { 734 throw new IIOException("Invalid chunk length " + chunkLength); 735 } 736 737 switch (chunkType) { 738 case IDAT_TYPE: 739 // If chunk type is 'IDAT', we've reached the image data. 740 if (imageStartPosition == -1L) { 741 /* 742 * PNGs may contain multiple IDAT chunks containing 743 * a portion of image data. We store the position of 744 * the first IDAT chunk and continue with iteration 745 * of other chunks that follow image data. 746 */ 747 imageStartPosition = stream.getStreamPosition() - 8; 748 } 749 // Move to the CRC byte location. 750 stream.skipBytes(chunkLength); 751 break; 752 case IEND_TYPE: 753 /* 754 * If the chunk type is 'IEND', we've reached end of image. 755 * Seek to the first IDAT chunk for subsequent decoding. 756 */ 757 stream.seek(imageStartPosition); 758 759 /* 760 * flushBefore discards the portion of the stream before 761 * the indicated position. Hence this should be used after 762 * we complete iteration over available chunks including 763 * those that appear after the IDAT. 764 */ 765 stream.flushBefore(stream.getStreamPosition()); 766 break loop; 767 case PLTE_TYPE: 768 parse_PLTE_chunk(chunkLength); 769 break; 770 case bKGD_TYPE: 771 parse_bKGD_chunk(); 772 break; 773 case cHRM_TYPE: 774 parse_cHRM_chunk(); 775 break; 776 case gAMA_TYPE: 777 parse_gAMA_chunk(); 778 break; 779 case hIST_TYPE: 780 parse_hIST_chunk(chunkLength); 781 break; 782 case iCCP_TYPE: 783 parse_iCCP_chunk(chunkLength); 784 break; 785 case iTXt_TYPE: 786 if (ignoreMetadata) { 787 stream.skipBytes(chunkLength); 788 } else { 789 parse_iTXt_chunk(chunkLength); 790 } 791 break; 792 case pHYs_TYPE: 793 parse_pHYs_chunk(); 794 break; 795 case sBIT_TYPE: 796 parse_sBIT_chunk(); 797 break; 798 case sPLT_TYPE: 799 parse_sPLT_chunk(chunkLength); 800 break; 801 case sRGB_TYPE: 802 parse_sRGB_chunk(); 803 break; 804 case tEXt_TYPE: 805 parse_tEXt_chunk(chunkLength); 806 break; 807 case tIME_TYPE: 808 parse_tIME_chunk(); 809 break; 810 case tRNS_TYPE: 811 parse_tRNS_chunk(chunkLength); 812 break; 813 case zTXt_TYPE: 814 if (ignoreMetadata) { 815 stream.skipBytes(chunkLength); 816 } else { 817 parse_zTXt_chunk(chunkLength); 818 } 819 break; 820 default: 821 // Read an unknown chunk 822 byte[] b = new byte[chunkLength]; 823 stream.readFully(b); 824 825 StringBuilder chunkName = new StringBuilder(4); 826 chunkName.append((char)(chunkType >>> 24)); 827 chunkName.append((char)((chunkType >> 16) & 0xff)); 828 chunkName.append((char)((chunkType >> 8) & 0xff)); 829 chunkName.append((char)(chunkType & 0xff)); 830 831 int ancillaryBit = chunkType >>> 28; 832 if (ancillaryBit == 0) { 833 processWarningOccurred( 834 "Encountered unknown chunk with critical bit set!"); 835 } 836 837 metadata.unknownChunkType.add(chunkName.toString()); 838 metadata.unknownChunkData.add(b); 839 break; 840 } 841 842 // double check whether all chunk data were consumed 843 if (chunkCRC != stream.readInt()) { 844 throw new IIOException("Failed to read a chunk of type " + 845 chunkType); 846 } 847 } 848 } catch (IOException e) { 849 throw new IIOException("Error reading PNG metadata", e); 850 } 851 852 gotMetadata = true; 853 } 854 855 // Data filtering methods 856 857 private static void decodeSubFilter(byte[] curr, int coff, int count, 858 int bpp) { 859 for (int i = bpp; i < count; i++) { 860 int val; 861 862 val = curr[i + coff] & 0xff; 863 val += curr[i + coff - bpp] & 0xff; 864 865 curr[i + coff] = (byte)val; 866 } 867 } 868 869 private static void decodeUpFilter(byte[] curr, int coff, 870 byte[] prev, int poff, 871 int count) { 872 for (int i = 0; i < count; i++) { 873 int raw = curr[i + coff] & 0xff; 874 int prior = prev[i + poff] & 0xff; 875 876 curr[i + coff] = (byte)(raw + prior); 877 } 878 } 879 880 private static void decodeAverageFilter(byte[] curr, int coff, 881 byte[] prev, int poff, 882 int count, int bpp) { 883 int raw, priorPixel, priorRow; 884 885 for (int i = 0; i < bpp; i++) { 886 raw = curr[i + coff] & 0xff; 887 priorRow = prev[i + poff] & 0xff; 888 889 curr[i + coff] = (byte)(raw + priorRow/2); 890 } 891 892 for (int i = bpp; i < count; i++) { 893 raw = curr[i + coff] & 0xff; 894 priorPixel = curr[i + coff - bpp] & 0xff; 895 priorRow = prev[i + poff] & 0xff; 896 897 curr[i + coff] = (byte)(raw + (priorPixel + priorRow)/2); 898 } 899 } 900 901 private static int paethPredictor(int a, int b, int c) { 902 int p = a + b - c; 903 int pa = Math.abs(p - a); 904 int pb = Math.abs(p - b); 905 int pc = Math.abs(p - c); 906 907 if ((pa <= pb) && (pa <= pc)) { 908 return a; 909 } else if (pb <= pc) { 910 return b; 911 } else { 912 return c; 913 } 914 } 915 916 private static void decodePaethFilter(byte[] curr, int coff, 917 byte[] prev, int poff, 918 int count, int bpp) { 919 int raw, priorPixel, priorRow, priorRowPixel; 920 921 for (int i = 0; i < bpp; i++) { 922 raw = curr[i + coff] & 0xff; 923 priorRow = prev[i + poff] & 0xff; 924 925 curr[i + coff] = (byte)(raw + priorRow); 926 } 927 928 for (int i = bpp; i < count; i++) { 929 raw = curr[i + coff] & 0xff; 930 priorPixel = curr[i + coff - bpp] & 0xff; 931 priorRow = prev[i + poff] & 0xff; 932 priorRowPixel = prev[i + poff - bpp] & 0xff; 933 934 curr[i + coff] = (byte)(raw + paethPredictor(priorPixel, 935 priorRow, 936 priorRowPixel)); 937 } 938 } 939 940 private static final int[][] bandOffsets = { 941 null, 942 { 0 }, // G 943 { 0, 1 }, // GA in GA order 944 { 0, 1, 2 }, // RGB in RGB order 945 { 0, 1, 2, 3 } // RGBA in RGBA order 946 }; 947 948 private WritableRaster createRaster(int width, int height, int bands, 949 int scanlineStride, 950 int bitDepth) { 951 952 DataBuffer dataBuffer; 953 WritableRaster ras = null; 954 Point origin = new Point(0, 0); 955 if ((bitDepth < 8) && (bands == 1)) { 956 dataBuffer = new DataBufferByte(height*scanlineStride); 957 ras = Raster.createPackedRaster(dataBuffer, 958 width, height, 959 bitDepth, 960 origin); 961 } else if (bitDepth <= 8) { 962 dataBuffer = new DataBufferByte(height*scanlineStride); 963 ras = Raster.createInterleavedRaster(dataBuffer, 964 width, height, 965 scanlineStride, 966 bands, 967 bandOffsets[bands], 968 origin); 969 } else { 970 dataBuffer = new DataBufferUShort(height*scanlineStride); 971 ras = Raster.createInterleavedRaster(dataBuffer, 972 width, height, 973 scanlineStride, 974 bands, 975 bandOffsets[bands], 976 origin); 977 } 978 979 return ras; 980 } 981 982 private void skipPass(int passWidth, int passHeight) 983 throws IOException, IIOException { 984 if ((passWidth == 0) || (passHeight == 0)) { 985 return; 986 } 987 988 int inputBands = inputBandsForColorType[metadata.IHDR_colorType]; 989 int bytesPerRow = (inputBands*passWidth*metadata.IHDR_bitDepth + 7)/8; 990 991 // Read the image row-by-row 992 for (int srcY = 0; srcY < passHeight; srcY++) { 993 // Skip filter byte and the remaining row bytes 994 pixelStream.skipBytes(1 + bytesPerRow); 995 } 996 } 997 998 private void updateImageProgress(int newPixels) { 999 pixelsDone += newPixels; 1000 processImageProgress(100.0F*pixelsDone/totalPixels); 1001 } 1002 1003 private void decodePass(int passNum, 1004 int xStart, int yStart, 1005 int xStep, int yStep, 1006 int passWidth, int passHeight) throws IOException { 1007 1008 if ((passWidth == 0) || (passHeight == 0)) { 1009 return; 1010 } 1011 1012 WritableRaster imRas = theImage.getWritableTile(0, 0); 1013 int dstMinX = imRas.getMinX(); 1014 int dstMaxX = dstMinX + imRas.getWidth() - 1; 1015 int dstMinY = imRas.getMinY(); 1016 int dstMaxY = dstMinY + imRas.getHeight() - 1; 1017 1018 // Determine which pixels will be updated in this pass 1019 int[] vals = 1020 ReaderUtil.computeUpdatedPixels(sourceRegion, 1021 destinationOffset, 1022 dstMinX, dstMinY, 1023 dstMaxX, dstMaxY, 1024 sourceXSubsampling, 1025 sourceYSubsampling, 1026 xStart, yStart, 1027 passWidth, passHeight, 1028 xStep, yStep); 1029 int updateMinX = vals[0]; 1030 int updateMinY = vals[1]; 1031 int updateWidth = vals[2]; 1032 int updateXStep = vals[4]; 1033 int updateYStep = vals[5]; 1034 1035 int bitDepth = metadata.IHDR_bitDepth; 1036 int inputBands = inputBandsForColorType[metadata.IHDR_colorType]; 1037 int bytesPerPixel = (bitDepth == 16) ? 2 : 1; 1038 bytesPerPixel *= inputBands; 1039 1040 int bytesPerRow = (inputBands*passWidth*bitDepth + 7)/8; 1041 int eltsPerRow = (bitDepth == 16) ? bytesPerRow/2 : bytesPerRow; 1042 1043 // If no pixels need updating, just skip the input data 1044 if (updateWidth == 0) { 1045 for (int srcY = 0; srcY < passHeight; srcY++) { 1046 // Update count of pixels read 1047 updateImageProgress(passWidth); 1048 /* 1049 * If read has been aborted, just return 1050 * processReadAborted will be called later 1051 */ 1052 if (abortRequested()) { 1053 return; 1054 } 1055 // Skip filter byte and the remaining row bytes 1056 pixelStream.skipBytes(1 + bytesPerRow); 1057 } 1058 return; 1059 } 1060 1061 // Backwards map from destination pixels 1062 // (dstX = updateMinX + k*updateXStep) 1063 // to source pixels (sourceX), and then 1064 // to offset and skip in passRow (srcX and srcXStep) 1065 int sourceX = 1066 (updateMinX - destinationOffset.x)*sourceXSubsampling + 1067 sourceRegion.x; 1068 int srcX = (sourceX - xStart)/xStep; 1069 1070 // Compute the step factor in the source 1071 int srcXStep = updateXStep*sourceXSubsampling/xStep; 1072 1073 byte[] byteData = null; 1074 short[] shortData = null; 1075 byte[] curr = new byte[bytesPerRow]; 1076 byte[] prior = new byte[bytesPerRow]; 1077 1078 // Create a 1-row tall Raster to hold the data 1079 WritableRaster passRow = createRaster(passWidth, 1, inputBands, 1080 eltsPerRow, 1081 bitDepth); 1082 1083 // Create an array suitable for holding one pixel 1084 int[] ps = passRow.getPixel(0, 0, (int[])null); 1085 1086 DataBuffer dataBuffer = passRow.getDataBuffer(); 1087 int type = dataBuffer.getDataType(); 1088 if (type == DataBuffer.TYPE_BYTE) { 1089 byteData = ((DataBufferByte)dataBuffer).getData(); 1090 } else { 1091 shortData = ((DataBufferUShort)dataBuffer).getData(); 1092 } 1093 1094 processPassStarted(theImage, 1095 passNum, 1096 sourceMinProgressivePass, 1097 sourceMaxProgressivePass, 1098 updateMinX, updateMinY, 1099 updateXStep, updateYStep, 1100 destinationBands); 1101 1102 // Handle source and destination bands 1103 if (sourceBands != null) { 1104 passRow = passRow.createWritableChild(0, 0, 1105 passRow.getWidth(), 1, 1106 0, 0, 1107 sourceBands); 1108 } 1109 if (destinationBands != null) { 1110 imRas = imRas.createWritableChild(0, 0, 1111 imRas.getWidth(), 1112 imRas.getHeight(), 1113 0, 0, 1114 destinationBands); 1115 } 1116 1117 // Determine if all of the relevant output bands have the 1118 // same bit depth as the source data 1119 boolean adjustBitDepths = false; 1120 int[] outputSampleSize = imRas.getSampleModel().getSampleSize(); 1121 int numBands = outputSampleSize.length; 1122 for (int b = 0; b < numBands; b++) { 1123 if (outputSampleSize[b] != bitDepth) { 1124 adjustBitDepths = true; 1125 break; 1126 } 1127 } 1128 1129 // If the bit depths differ, create a lookup table per band to perform 1130 // the conversion 1131 int[][] scale = null; 1132 if (adjustBitDepths) { 1133 int maxInSample = (1 << bitDepth) - 1; 1134 int halfMaxInSample = maxInSample/2; 1135 scale = new int[numBands][]; 1136 for (int b = 0; b < numBands; b++) { 1137 int maxOutSample = (1 << outputSampleSize[b]) - 1; 1138 scale[b] = new int[maxInSample + 1]; 1139 for (int s = 0; s <= maxInSample; s++) { 1140 scale[b][s] = 1141 (s*maxOutSample + halfMaxInSample)/maxInSample; 1142 } 1143 } 1144 } 1145 1146 // Limit passRow to relevant area for the case where we 1147 // will can setRect to copy a contiguous span 1148 boolean useSetRect = srcXStep == 1 && 1149 updateXStep == 1 && 1150 !adjustBitDepths && 1151 (imRas instanceof ByteInterleavedRaster); 1152 1153 if (useSetRect) { 1154 passRow = passRow.createWritableChild(srcX, 0, 1155 updateWidth, 1, 1156 0, 0, 1157 null); 1158 } 1159 1160 // Decode the (sub)image row-by-row 1161 for (int srcY = 0; srcY < passHeight; srcY++) { 1162 // Update count of pixels read 1163 updateImageProgress(passWidth); 1164 /* 1165 * If read has been aborted, just return 1166 * processReadAborted will be called later 1167 */ 1168 if (abortRequested()) { 1169 return; 1170 } 1171 // Read the filter type byte and a row of data 1172 int filter = pixelStream.read(); 1173 try { 1174 // Swap curr and prior 1175 byte[] tmp = prior; 1176 prior = curr; 1177 curr = tmp; 1178 1179 pixelStream.readFully(curr, 0, bytesPerRow); 1180 } catch (java.util.zip.ZipException ze) { 1181 // TODO - throw a more meaningful exception 1182 throw ze; 1183 } 1184 1185 switch (filter) { 1186 case PNG_FILTER_NONE: 1187 break; 1188 case PNG_FILTER_SUB: 1189 decodeSubFilter(curr, 0, bytesPerRow, bytesPerPixel); 1190 break; 1191 case PNG_FILTER_UP: 1192 decodeUpFilter(curr, 0, prior, 0, bytesPerRow); 1193 break; 1194 case PNG_FILTER_AVERAGE: 1195 decodeAverageFilter(curr, 0, prior, 0, bytesPerRow, 1196 bytesPerPixel); 1197 break; 1198 case PNG_FILTER_PAETH: 1199 decodePaethFilter(curr, 0, prior, 0, bytesPerRow, 1200 bytesPerPixel); 1201 break; 1202 default: 1203 throw new IIOException("Unknown row filter type (= " + 1204 filter + ")!"); 1205 } 1206 1207 // Copy data into passRow byte by byte 1208 if (bitDepth < 16) { 1209 System.arraycopy(curr, 0, byteData, 0, bytesPerRow); 1210 } else { 1211 int idx = 0; 1212 for (int j = 0; j < eltsPerRow; j++) { 1213 shortData[j] = 1214 (short)((curr[idx] << 8) | (curr[idx + 1] & 0xff)); 1215 idx += 2; 1216 } 1217 } 1218 1219 // True Y position in source 1220 int sourceY = srcY*yStep + yStart; 1221 if ((sourceY >= sourceRegion.y) && 1222 (sourceY < sourceRegion.y + sourceRegion.height) && 1223 (((sourceY - sourceRegion.y) % 1224 sourceYSubsampling) == 0)) { 1225 1226 int dstY = destinationOffset.y + 1227 (sourceY - sourceRegion.y)/sourceYSubsampling; 1228 if (dstY < dstMinY) { 1229 continue; 1230 } 1231 if (dstY > dstMaxY) { 1232 break; 1233 } 1234 1235 if (useSetRect) { 1236 imRas.setRect(updateMinX, dstY, passRow); 1237 } else { 1238 int newSrcX = srcX; 1239 1240 for (int dstX = updateMinX; 1241 dstX < updateMinX + updateWidth; 1242 dstX += updateXStep) { 1243 1244 passRow.getPixel(newSrcX, 0, ps); 1245 if (adjustBitDepths) { 1246 for (int b = 0; b < numBands; b++) { 1247 ps[b] = scale[b][ps[b]]; 1248 } 1249 } 1250 imRas.setPixel(dstX, dstY, ps); 1251 newSrcX += srcXStep; 1252 } 1253 } 1254 1255 processImageUpdate(theImage, 1256 updateMinX, dstY, 1257 updateWidth, 1, 1258 updateXStep, updateYStep, 1259 destinationBands); 1260 } 1261 } 1262 1263 processPassComplete(theImage); 1264 } 1265 1266 private void decodeImage() 1267 throws IOException, IIOException { 1268 int width = metadata.IHDR_width; 1269 int height = metadata.IHDR_height; 1270 1271 this.pixelsDone = 0; 1272 this.totalPixels = width*height; 1273 1274 if (metadata.IHDR_interlaceMethod == 0) { 1275 decodePass(0, 0, 0, 1, 1, width, height); 1276 } else { 1277 for (int i = 0; i <= sourceMaxProgressivePass; i++) { 1278 int XOffset = adam7XOffset[i]; 1279 int YOffset = adam7YOffset[i]; 1280 int XSubsampling = adam7XSubsampling[i]; 1281 int YSubsampling = adam7YSubsampling[i]; 1282 int xbump = adam7XSubsampling[i + 1] - 1; 1283 int ybump = adam7YSubsampling[i + 1] - 1; 1284 1285 if (i >= sourceMinProgressivePass) { 1286 decodePass(i, 1287 XOffset, 1288 YOffset, 1289 XSubsampling, 1290 YSubsampling, 1291 (width + xbump)/XSubsampling, 1292 (height + ybump)/YSubsampling); 1293 } else { 1294 skipPass((width + xbump)/XSubsampling, 1295 (height + ybump)/YSubsampling); 1296 } 1297 1298 /* 1299 * If read has been aborted, just return 1300 * processReadAborted will be called later 1301 */ 1302 if (abortRequested()) { 1303 return; 1304 } 1305 } 1306 } 1307 } 1308 1309 private void readImage(ImageReadParam param) throws IIOException { 1310 readMetadata(); 1311 1312 int width = metadata.IHDR_width; 1313 int height = metadata.IHDR_height; 1314 1315 // Init default values 1316 sourceXSubsampling = 1; 1317 sourceYSubsampling = 1; 1318 sourceMinProgressivePass = 0; 1319 sourceMaxProgressivePass = 6; 1320 sourceBands = null; 1321 destinationBands = null; 1322 destinationOffset = new Point(0, 0); 1323 1324 // If an ImageReadParam is available, get values from it 1325 if (param != null) { 1326 sourceXSubsampling = param.getSourceXSubsampling(); 1327 sourceYSubsampling = param.getSourceYSubsampling(); 1328 1329 sourceMinProgressivePass = 1330 Math.max(param.getSourceMinProgressivePass(), 0); 1331 sourceMaxProgressivePass = 1332 Math.min(param.getSourceMaxProgressivePass(), 6); 1333 1334 sourceBands = param.getSourceBands(); 1335 destinationBands = param.getDestinationBands(); 1336 destinationOffset = param.getDestinationOffset(); 1337 } 1338 Inflater inf = null; 1339 try { 1340 stream.seek(imageStartPosition); 1341 1342 Enumeration<InputStream> e = new PNGImageDataEnumeration(stream); 1343 InputStream is = new SequenceInputStream(e); 1344 1345 /* InflaterInputStream uses an Inflater instance which consumes 1346 * native (non-GC visible) resources. This is normally implicitly 1347 * freed when the stream is closed. However since the 1348 * InflaterInputStream wraps a client-supplied input stream, 1349 * we cannot close it. 1350 * But the app may depend on GC finalization to close the stream. 1351 * Therefore to ensure timely freeing of native resources we 1352 * explicitly create the Inflater instance and free its resources 1353 * when we are done with the InflaterInputStream by calling 1354 * inf.end(); 1355 */ 1356 inf = new Inflater(); 1357 is = new InflaterInputStream(is, inf); 1358 is = new BufferedInputStream(is); 1359 this.pixelStream = new DataInputStream(is); 1360 1361 /* 1362 * NB: the PNG spec declares that valid range for width 1363 * and height is [1, 2^31-1], so here we may fail to allocate 1364 * a buffer for destination image due to memory limitation. 1365 * 1366 * However, the recovery strategy for this case should be 1367 * defined on the level of application, so we will not 1368 * try to estimate the required amount of the memory and/or 1369 * handle OOM in any way. 1370 */ 1371 theImage = getDestination(param, 1372 getImageTypes(0), 1373 width, 1374 height); 1375 1376 Rectangle destRegion = new Rectangle(0, 0, 0, 0); 1377 sourceRegion = new Rectangle(0, 0, 0, 0); 1378 computeRegions(param, width, height, 1379 theImage, 1380 sourceRegion, destRegion); 1381 destinationOffset.setLocation(destRegion.getLocation()); 1382 1383 // At this point the header has been read and we know 1384 // how many bands are in the image, so perform checking 1385 // of the read param. 1386 int colorType = metadata.IHDR_colorType; 1387 checkReadParamBandSettings(param, 1388 inputBandsForColorType[colorType], 1389 theImage.getSampleModel().getNumBands()); 1390 1391 clearAbortRequest(); 1392 processImageStarted(0); 1393 if (abortRequested()) { 1394 processReadAborted(); 1395 } else { 1396 decodeImage(); 1397 if (abortRequested()) { 1398 processReadAborted(); 1399 } else { 1400 processImageComplete(); 1401 } 1402 } 1403 1404 } catch (IOException e) { 1405 throw new IIOException("Error reading PNG image data", e); 1406 } finally { 1407 if (inf != null) { 1408 inf.end(); 1409 } 1410 } 1411 } 1412 1413 public int getNumImages(boolean allowSearch) throws IIOException { 1414 if (stream == null) { 1415 throw new IllegalStateException("No input source set!"); 1416 } 1417 if (seekForwardOnly && allowSearch) { 1418 throw new IllegalStateException 1419 ("seekForwardOnly and allowSearch can't both be true!"); 1420 } 1421 return 1; 1422 } 1423 1424 public int getWidth(int imageIndex) throws IIOException { 1425 if (imageIndex != 0) { 1426 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1427 } 1428 1429 readHeader(); 1430 1431 return metadata.IHDR_width; 1432 } 1433 1434 public int getHeight(int imageIndex) throws IIOException { 1435 if (imageIndex != 0) { 1436 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1437 } 1438 1439 readHeader(); 1440 1441 return metadata.IHDR_height; 1442 } 1443 1444 public Iterator<ImageTypeSpecifier> getImageTypes(int imageIndex) 1445 throws IIOException 1446 { 1447 if (imageIndex != 0) { 1448 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1449 } 1450 1451 readHeader(); 1452 1453 ArrayList<ImageTypeSpecifier> l = 1454 new ArrayList<ImageTypeSpecifier>(1); 1455 1456 ColorSpace rgb; 1457 ColorSpace gray; 1458 int[] bandOffsets; 1459 1460 int bitDepth = metadata.IHDR_bitDepth; 1461 int colorType = metadata.IHDR_colorType; 1462 1463 int dataType; 1464 if (bitDepth <= 8) { 1465 dataType = DataBuffer.TYPE_BYTE; 1466 } else { 1467 dataType = DataBuffer.TYPE_USHORT; 1468 } 1469 1470 switch (colorType) { 1471 case PNG_COLOR_GRAY: 1472 // Packed grayscale 1473 l.add(ImageTypeSpecifier.createGrayscale(bitDepth, 1474 dataType, 1475 false)); 1476 break; 1477 1478 case PNG_COLOR_RGB: 1479 if (bitDepth == 8) { 1480 // some standard types of buffered images 1481 // which can be used as destination 1482 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1483 BufferedImage.TYPE_3BYTE_BGR)); 1484 1485 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1486 BufferedImage.TYPE_INT_RGB)); 1487 1488 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1489 BufferedImage.TYPE_INT_BGR)); 1490 1491 } 1492 // Component R, G, B 1493 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB); 1494 bandOffsets = new int[3]; 1495 bandOffsets[0] = 0; 1496 bandOffsets[1] = 1; 1497 bandOffsets[2] = 2; 1498 l.add(ImageTypeSpecifier.createInterleaved(rgb, 1499 bandOffsets, 1500 dataType, 1501 false, 1502 false)); 1503 break; 1504 1505 case PNG_COLOR_PALETTE: 1506 readMetadata(); // Need tRNS chunk 1507 1508 /* 1509 * The PLTE chunk spec says: 1510 * 1511 * The number of palette entries must not exceed the range that 1512 * can be represented in the image bit depth (for example, 2^4 = 16 1513 * for a bit depth of 4). It is permissible to have fewer entries 1514 * than the bit depth would allow. In that case, any out-of-range 1515 * pixel value found in the image data is an error. 1516 * 1517 * http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html#C.PLTE 1518 * 1519 * Consequently, the case when the palette length is smaller than 1520 * 2^bitDepth is legal in the view of PNG spec. 1521 * 1522 * However the spec of createIndexed() method demands the exact 1523 * equality of the palette lengh and number of possible palette 1524 * entries (2^bitDepth). 1525 * 1526 * {@link javax.imageio.ImageTypeSpecifier.html#createIndexed} 1527 * 1528 * In order to avoid this contradiction we need to extend the 1529 * palette arrays to the limit defined by the bitDepth. 1530 */ 1531 1532 int plength = 1 << bitDepth; 1533 1534 byte[] red = metadata.PLTE_red; 1535 byte[] green = metadata.PLTE_green; 1536 byte[] blue = metadata.PLTE_blue; 1537 1538 if (metadata.PLTE_red.length < plength) { 1539 red = Arrays.copyOf(metadata.PLTE_red, plength); 1540 Arrays.fill(red, metadata.PLTE_red.length, plength, 1541 metadata.PLTE_red[metadata.PLTE_red.length - 1]); 1542 1543 green = Arrays.copyOf(metadata.PLTE_green, plength); 1544 Arrays.fill(green, metadata.PLTE_green.length, plength, 1545 metadata.PLTE_green[metadata.PLTE_green.length - 1]); 1546 1547 blue = Arrays.copyOf(metadata.PLTE_blue, plength); 1548 Arrays.fill(blue, metadata.PLTE_blue.length, plength, 1549 metadata.PLTE_blue[metadata.PLTE_blue.length - 1]); 1550 1551 } 1552 1553 // Alpha from tRNS chunk may have fewer entries than 1554 // the RGB LUTs from the PLTE chunk; if so, pad with 1555 // 255. 1556 byte[] alpha = null; 1557 if (metadata.tRNS_present && (metadata.tRNS_alpha != null)) { 1558 if (metadata.tRNS_alpha.length == red.length) { 1559 alpha = metadata.tRNS_alpha; 1560 } else { 1561 alpha = Arrays.copyOf(metadata.tRNS_alpha, red.length); 1562 Arrays.fill(alpha, 1563 metadata.tRNS_alpha.length, 1564 red.length, (byte)255); 1565 } 1566 } 1567 1568 l.add(ImageTypeSpecifier.createIndexed(red, green, 1569 blue, alpha, 1570 bitDepth, 1571 DataBuffer.TYPE_BYTE)); 1572 break; 1573 1574 case PNG_COLOR_GRAY_ALPHA: 1575 // Component G, A 1576 gray = ColorSpace.getInstance(ColorSpace.CS_GRAY); 1577 bandOffsets = new int[2]; 1578 bandOffsets[0] = 0; 1579 bandOffsets[1] = 1; 1580 l.add(ImageTypeSpecifier.createInterleaved(gray, 1581 bandOffsets, 1582 dataType, 1583 true, 1584 false)); 1585 break; 1586 1587 case PNG_COLOR_RGB_ALPHA: 1588 if (bitDepth == 8) { 1589 // some standard types of buffered images 1590 // wich can be used as destination 1591 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1592 BufferedImage.TYPE_4BYTE_ABGR)); 1593 1594 l.add(ImageTypeSpecifier.createFromBufferedImageType( 1595 BufferedImage.TYPE_INT_ARGB)); 1596 } 1597 1598 // Component R, G, B, A (non-premultiplied) 1599 rgb = ColorSpace.getInstance(ColorSpace.CS_sRGB); 1600 bandOffsets = new int[4]; 1601 bandOffsets[0] = 0; 1602 bandOffsets[1] = 1; 1603 bandOffsets[2] = 2; 1604 bandOffsets[3] = 3; 1605 1606 l.add(ImageTypeSpecifier.createInterleaved(rgb, 1607 bandOffsets, 1608 dataType, 1609 true, 1610 false)); 1611 break; 1612 1613 default: 1614 break; 1615 } 1616 1617 return l.iterator(); 1618 } 1619 1620 /* 1621 * Super class implementation uses first element 1622 * of image types list as raw image type. 1623 * 1624 * Also, super implementation uses first element of this list 1625 * as default destination type image read param does not specify 1626 * anything other. 1627 * 1628 * However, in case of RGB and RGBA color types, raw image type 1629 * produces buffered image of custom type. It causes some 1630 * performance degradation of subsequent rendering operations. 1631 * 1632 * To resolve this contradiction we put standard image types 1633 * at the first positions of image types list (to produce standard 1634 * images by default) and put raw image type (which is custom) 1635 * at the last position of this list. 1636 * 1637 * After this changes we should override getRawImageType() 1638 * to return last element of image types list. 1639 */ 1640 public ImageTypeSpecifier getRawImageType(int imageIndex) 1641 throws IOException { 1642 1643 Iterator<ImageTypeSpecifier> types = getImageTypes(imageIndex); 1644 ImageTypeSpecifier raw = null; 1645 do { 1646 raw = types.next(); 1647 } while (types.hasNext()); 1648 return raw; 1649 } 1650 1651 public ImageReadParam getDefaultReadParam() { 1652 return new ImageReadParam(); 1653 } 1654 1655 public IIOMetadata getStreamMetadata() 1656 throws IIOException { 1657 return null; 1658 } 1659 1660 public IIOMetadata getImageMetadata(int imageIndex) throws IIOException { 1661 if (imageIndex != 0) { 1662 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1663 } 1664 readMetadata(); 1665 return metadata; 1666 } 1667 1668 public BufferedImage read(int imageIndex, ImageReadParam param) 1669 throws IIOException { 1670 if (imageIndex != 0) { 1671 throw new IndexOutOfBoundsException("imageIndex != 0!"); 1672 } 1673 1674 readImage(param); 1675 return theImage; 1676 } 1677 1678 public void reset() { 1679 super.reset(); 1680 resetStreamSettings(); 1681 } 1682 1683 private void resetStreamSettings() { 1684 gotHeader = false; 1685 gotMetadata = false; 1686 metadata = null; 1687 pixelStream = null; 1688 } 1689 }