2 * Copyright (C) 2006 Apple Computer, Inc.
4 * Portions are Copyright (C) 2001-6 mozilla.org
7 * Stuart Parmenter <stuart@mozilla.com>
9 * Copyright (C) 2007-2009 Torch Mobile, Inc.
11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2.1 of the License, or (at your option) any later version.
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this library; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * Alternatively, the contents of this file may be used under the terms
26 * of either the Mozilla Public License Version 1.1, found at
27 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
28 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
29 * (the "GPL"), in which case the provisions of the MPL or the GPL are
30 * applicable instead of those above. If you wish to allow use of your
31 * version of this file only under the terms of one of those two
32 * licenses (the MPL or the GPL) and not to allow others to use your
33 * version of this file under the LGPL, indicate your decision by
34 * deletingthe provisions above and replace them with the notice and
35 * other provisions required by the MPL or the GPL, as the case may be.
36 * If you do not delete the provisions above, a recipient may use your
37 * version of this file under any of the LGPL, the MPL or the GPL.
41 #include "platform/image-decoders/jpeg/JPEGImageDecoder.h"
43 #include "platform/PlatformInstrumentation.h"
44 #include "wtf/PassOwnPtr.h"
45 #include "wtf/dtoa/utils.h"
48 #include <stdio.h> // jpeglib.h needs stdio FILE.
59 #if CPU(BIG_ENDIAN) || CPU(MIDDLE_ENDIAN)
60 #error Blink assumes a little-endian target.
63 #if defined(JCS_ALPHA_EXTENSIONS)
64 #define TURBO_JPEG_RGB_SWIZZLE
65 #if SK_B32_SHIFT // Output little-endian RGBA pixels (Android).
66 inline J_COLOR_SPACE rgbOutputColorSpace() { return JCS_EXT_RGBA; }
67 #else // Output little-endian BGRA pixels.
68 inline J_COLOR_SPACE rgbOutputColorSpace() { return JCS_EXT_BGRA; }
70 inline bool turboSwizzled(J_COLOR_SPACE colorSpace) { return colorSpace == JCS_EXT_RGBA || colorSpace == JCS_EXT_BGRA; }
71 inline bool colorSpaceHasAlpha(J_COLOR_SPACE colorSpace) { return turboSwizzled(colorSpace); }
73 inline J_COLOR_SPACE rgbOutputColorSpace() { return JCS_RGB; }
74 inline bool colorSpaceHasAlpha(J_COLOR_SPACE) { return false; }
77 #if USE(LOW_QUALITY_IMAGE_NO_JPEG_DITHERING)
78 inline J_DCT_METHOD dctMethod() { return JDCT_IFAST; }
79 inline J_DITHER_MODE ditherMode() { return JDITHER_NONE; }
81 inline J_DCT_METHOD dctMethod() { return JDCT_ISLOW; }
82 inline J_DITHER_MODE ditherMode() { return JDITHER_FS; }
85 #if USE(LOW_QUALITY_IMAGE_NO_JPEG_FANCY_UPSAMPLING)
86 inline bool doFancyUpsampling() { return false; }
88 inline bool doFancyUpsampling() { return true; }
93 const int exifMarker = JPEG_APP0 + 1;
95 // JPEG only supports a denominator of 8.
96 const unsigned scaleDenominator = 8;
102 struct decoder_error_mgr {
103 struct jpeg_error_mgr pub; // "public" fields for IJG library
104 jmp_buf setjmp_buffer; // For handling catastropic errors
108 JPEG_HEADER, // Reading JFIF headers
109 JPEG_START_DECOMPRESS,
110 JPEG_DECOMPRESS_PROGRESSIVE, // Output progressive pixels
111 JPEG_DECOMPRESS_SEQUENTIAL, // Output sequential pixels
116 void init_source(j_decompress_ptr jd);
117 boolean fill_input_buffer(j_decompress_ptr jd);
118 void skip_input_data(j_decompress_ptr jd, long num_bytes);
119 void term_source(j_decompress_ptr jd);
120 void error_exit(j_common_ptr cinfo);
122 // Implementation of a JPEG src object that understands our state machine
123 struct decoder_source_mgr {
124 // public fields; must be first in this struct!
125 struct jpeg_source_mgr pub;
127 JPEGImageReader* decoder;
130 static unsigned readUint16(JOCTET* data, bool isBigEndian)
133 return (GETJOCTET(data[0]) << 8) | GETJOCTET(data[1]);
134 return (GETJOCTET(data[1]) << 8) | GETJOCTET(data[0]);
137 static unsigned readUint32(JOCTET* data, bool isBigEndian)
140 return (GETJOCTET(data[0]) << 24) | (GETJOCTET(data[1]) << 16) | (GETJOCTET(data[2]) << 8) | GETJOCTET(data[3]);
141 return (GETJOCTET(data[3]) << 24) | (GETJOCTET(data[2]) << 16) | (GETJOCTET(data[1]) << 8) | GETJOCTET(data[0]);
144 static bool checkExifHeader(jpeg_saved_marker_ptr marker, bool& isBigEndian, unsigned& ifdOffset)
146 // For exif data, the APP1 block is followed by 'E', 'x', 'i', 'f', '\0',
147 // then a fill byte, and then a tiff file that contains the metadata.
148 // A tiff file starts with 'I', 'I' (intel / little endian byte order) or
149 // 'M', 'M' (motorola / big endian byte order), followed by (uint16_t)42,
150 // followed by an uint32_t with the offset to the tag block, relative to the
152 const unsigned exifHeaderSize = 14;
153 if (!(marker->marker == exifMarker
154 && marker->data_length >= exifHeaderSize
155 && marker->data[0] == 'E'
156 && marker->data[1] == 'x'
157 && marker->data[2] == 'i'
158 && marker->data[3] == 'f'
159 && marker->data[4] == '\0'
160 // data[5] is a fill byte
161 && ((marker->data[6] == 'I' && marker->data[7] == 'I')
162 || (marker->data[6] == 'M' && marker->data[7] == 'M'))))
165 isBigEndian = marker->data[6] == 'M';
166 if (readUint16(marker->data + 8, isBigEndian) != 42)
169 ifdOffset = readUint32(marker->data + 10, isBigEndian);
173 static ImageOrientation readImageOrientation(jpeg_decompress_struct* info)
175 // The JPEG decoder looks at EXIF metadata.
176 // FIXME: Possibly implement XMP and IPTC support.
177 const unsigned orientationTag = 0x112;
178 const unsigned shortType = 3;
179 for (jpeg_saved_marker_ptr marker = info->marker_list; marker; marker = marker->next) {
182 if (!checkExifHeader(marker, isBigEndian, ifdOffset))
184 const unsigned offsetToTiffData = 6; // Account for 'Exif\0<fill byte>' header.
185 if (marker->data_length < offsetToTiffData || ifdOffset >= marker->data_length - offsetToTiffData)
187 ifdOffset += offsetToTiffData;
189 // The jpeg exif container format contains a tiff block for metadata.
190 // A tiff image file directory (ifd) consists of a uint16_t describing
191 // the number of ifd entries, followed by that many entries.
192 // When touching this code, it's useful to look at the tiff spec:
193 // http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdf
194 JOCTET* ifd = marker->data + ifdOffset;
195 JOCTET* end = marker->data + marker->data_length;
198 unsigned tagCount = readUint16(ifd, isBigEndian);
199 ifd += 2; // Skip over the uint16 that was just read.
201 // Every ifd entry is 2 bytes of tag, 2 bytes of contents datatype,
202 // 4 bytes of number-of-elements, and 4 bytes of either offset to the
203 // tag data, or if the data is small enough, the inlined data itself.
204 const int ifdEntrySize = 12;
205 for (unsigned i = 0; i < tagCount && end - ifd >= ifdEntrySize; ++i, ifd += ifdEntrySize) {
206 unsigned tag = readUint16(ifd, isBigEndian);
207 unsigned type = readUint16(ifd + 2, isBigEndian);
208 unsigned count = readUint32(ifd + 4, isBigEndian);
209 if (tag == orientationTag && type == shortType && count == 1)
210 return ImageOrientation::fromEXIFValue(readUint16(ifd + 8, isBigEndian));
214 return ImageOrientation();
218 static void readColorProfile(jpeg_decompress_struct* info, ColorProfile& colorProfile)
222 unsigned int profileLength;
224 if (!read_icc_profile(info, &profile, &profileLength))
227 // Only accept RGB color profiles from input class devices.
228 bool ignoreProfile = false;
229 char* profileData = reinterpret_cast<char*>(profile);
230 if (profileLength < ImageDecoder::iccColorProfileHeaderLength)
231 ignoreProfile = true;
232 else if (!ImageDecoder::rgbColorProfile(profileData, profileLength))
233 ignoreProfile = true;
234 else if (!ImageDecoder::inputDeviceColorProfile(profileData, profileLength))
235 ignoreProfile = true;
237 ASSERT(colorProfile.isEmpty());
239 colorProfile.append(profileData, profileLength);
245 class JPEGImageReader {
246 WTF_MAKE_FAST_ALLOCATED;
248 JPEGImageReader(JPEGImageDecoder* decoder)
252 , m_state(JPEG_HEADER)
258 memset(&m_info, 0, sizeof(jpeg_decompress_struct));
260 // We set up the normal JPEG error routines, then override error_exit.
261 m_info.err = jpeg_std_error(&m_err.pub);
262 m_err.pub.error_exit = error_exit;
264 // Allocate and initialize JPEG decompression object.
265 jpeg_create_decompress(&m_info);
267 decoder_source_mgr* src = 0;
269 src = (decoder_source_mgr*)fastZeroedMalloc(sizeof(decoder_source_mgr));
271 m_state = JPEG_ERROR;
276 m_info.src = (jpeg_source_mgr*)src;
278 // Set up callback functions.
279 src->pub.init_source = init_source;
280 src->pub.fill_input_buffer = fill_input_buffer;
281 src->pub.skip_input_data = skip_input_data;
282 src->pub.resync_to_restart = jpeg_resync_to_restart;
283 src->pub.term_source = term_source;
287 // Retain ICC color profile markers for color management.
288 setup_read_icc_profile(&m_info);
291 // Keep APP1 blocks, for obtaining exif data.
292 jpeg_save_markers(&m_info, exifMarker, 0xFFFF);
302 decoder_source_mgr* src = (decoder_source_mgr*)m_info.src;
309 qcms_transform_release(m_transform);
312 jpeg_destroy_decompress(&m_info);
315 void skipBytes(long numBytes)
317 decoder_source_mgr* src = (decoder_source_mgr*)m_info.src;
318 long bytesToSkip = std::min(numBytes, (long)src->pub.bytes_in_buffer);
319 src->pub.bytes_in_buffer -= (size_t)bytesToSkip;
320 src->pub.next_input_byte += bytesToSkip;
322 m_bytesToSkip = std::max(numBytes - bytesToSkip, static_cast<long>(0));
325 bool decode(const SharedBuffer& data, bool onlySize)
327 unsigned newByteCount = data.size() - m_bufferLength;
328 unsigned readOffset = m_bufferLength - m_info.src->bytes_in_buffer;
330 m_info.src->bytes_in_buffer += newByteCount;
331 m_info.src->next_input_byte = (JOCTET*)(data.data()) + readOffset;
333 // If we still have bytes to skip, try to skip those now.
335 skipBytes(m_bytesToSkip);
337 m_bufferLength = data.size();
339 // We need to do the setjmp here. Otherwise bad things will happen
340 if (setjmp(m_err.setjmp_buffer))
341 return m_decoder->setFailed();
345 // Read file parameters with jpeg_read_header().
346 if (jpeg_read_header(&m_info, true) == JPEG_SUSPENDED)
347 return false; // I/O suspension.
349 switch (m_info.jpeg_color_space) {
353 // libjpeg can convert GRAYSCALE and YCbCr image pixels to RGB.
354 m_info.out_color_space = rgbOutputColorSpace();
355 #if defined(TURBO_JPEG_RGB_SWIZZLE)
356 if (m_info.saw_JFIF_marker)
358 // FIXME: Swizzle decoding does not support Adobe transform=0
359 // images (yet), so revert to using JSC_RGB in that case.
360 if (m_info.saw_Adobe_marker && !m_info.Adobe_transform)
361 m_info.out_color_space = JCS_RGB;
366 // libjpeg can convert YCCK to CMYK, but neither to RGB, so we
367 // manually convert CMKY to RGB.
368 m_info.out_color_space = JCS_CMYK;
371 return m_decoder->setFailed();
374 m_state = JPEG_START_DECOMPRESS;
376 // We can fill in the size now that the header is available.
377 if (!m_decoder->setSize(m_info.image_width, m_info.image_height))
380 // Calculate and set decoded size.
381 m_info.scale_num = m_decoder->desiredScaleNumerator();
382 m_info.scale_denom = scaleDenominator;
383 jpeg_calc_output_dimensions(&m_info);
384 m_decoder->setDecodedSize(m_info.output_width, m_info.output_height);
386 m_decoder->setOrientation(readImageOrientation(info()));
389 // Allow color management of the decoded RGBA pixels if possible.
390 if (!m_decoder->ignoresGammaAndColorProfile()) {
391 ColorProfile colorProfile;
392 readColorProfile(info(), colorProfile);
393 createColorTransform(colorProfile, colorSpaceHasAlpha(m_info.out_color_space));
394 #if defined(TURBO_JPEG_RGB_SWIZZLE)
395 // Input RGBA data to qcms. Note: restored to BGRA on output.
396 if (m_transform && m_info.out_color_space == JCS_EXT_BGRA)
397 m_info.out_color_space = JCS_EXT_RGBA;
401 // Don't allocate a giant and superfluous memory buffer when the
402 // image is a sequential JPEG.
403 m_info.buffered_image = jpeg_has_multiple_scans(&m_info);
406 // We can stop here. Reduce our buffer length and available data.
407 m_bufferLength -= m_info.src->bytes_in_buffer;
408 m_info.src->bytes_in_buffer = 0;
413 case JPEG_START_DECOMPRESS:
414 // Set parameters for decompression.
415 // FIXME -- Should reset dct_method and dither mode for final pass
416 // of progressive JPEG.
417 m_info.dct_method = dctMethod();
418 m_info.dither_mode = ditherMode();
419 m_info.do_fancy_upsampling = doFancyUpsampling();
420 m_info.enable_2pass_quant = false;
421 m_info.do_block_smoothing = true;
423 // Make a one-row-high sample array that will go away when done with
424 // image. Always make it big enough to hold an RGB row. Since this
425 // uses the IJG memory manager, it must be allocated before the call
426 // to jpeg_start_compress().
427 // FIXME: note that some output color spaces do not need the samples
428 // buffer. Remove this allocation for those color spaces.
429 m_samples = (*m_info.mem->alloc_sarray)(reinterpret_cast<j_common_ptr>(&m_info), JPOOL_IMAGE, m_info.output_width * 4, 1);
431 // Start decompressor.
432 if (!jpeg_start_decompress(&m_info))
433 return false; // I/O suspension.
435 // If this is a progressive JPEG ...
436 m_state = (m_info.buffered_image) ? JPEG_DECOMPRESS_PROGRESSIVE : JPEG_DECOMPRESS_SEQUENTIAL;
439 case JPEG_DECOMPRESS_SEQUENTIAL:
440 if (m_state == JPEG_DECOMPRESS_SEQUENTIAL) {
442 if (!m_decoder->outputScanlines())
443 return false; // I/O suspension.
445 // If we've completed image output...
446 ASSERT(m_info.output_scanline == m_info.output_height);
451 case JPEG_DECOMPRESS_PROGRESSIVE:
452 if (m_state == JPEG_DECOMPRESS_PROGRESSIVE) {
455 status = jpeg_consume_input(&m_info);
456 } while ((status != JPEG_SUSPENDED) && (status != JPEG_REACHED_EOI));
459 if (!m_info.output_scanline) {
460 int scan = m_info.input_scan_number;
462 // If we haven't displayed anything yet
463 // (output_scan_number == 0) and we have enough data for
464 // a complete scan, force output of the last full scan.
465 if (!m_info.output_scan_number && (scan > 1) && (status != JPEG_REACHED_EOI))
468 if (!jpeg_start_output(&m_info, scan))
469 return false; // I/O suspension.
472 if (m_info.output_scanline == 0xffffff)
473 m_info.output_scanline = 0;
475 // If outputScanlines() fails, it deletes |this|. Therefore,
476 // copy the decoder pointer and use it to check for failure
477 // to avoid member access in the failure case.
478 JPEGImageDecoder* decoder = m_decoder;
479 if (!decoder->outputScanlines()) {
480 if (decoder->failed()) // Careful; |this| is deleted.
482 if (!m_info.output_scanline)
483 // Didn't manage to read any lines - flag so we
484 // don't call jpeg_start_output() multiple times for
486 m_info.output_scanline = 0xffffff;
487 return false; // I/O suspension.
490 if (m_info.output_scanline == m_info.output_height) {
491 if (!jpeg_finish_output(&m_info))
492 return false; // I/O suspension.
494 if (jpeg_input_complete(&m_info) && (m_info.input_scan_number == m_info.output_scan_number))
497 m_info.output_scanline = 0;
506 // Finish decompression.
507 return jpeg_finish_decompress(&m_info);
510 // We can get here if the constructor failed.
511 return m_decoder->setFailed();
517 jpeg_decompress_struct* info() { return &m_info; }
518 JSAMPARRAY samples() const { return m_samples; }
519 JPEGImageDecoder* decoder() { return m_decoder; }
521 qcms_transform* colorTransform() const { return m_transform; }
523 void createColorTransform(const ColorProfile& colorProfile, bool hasAlpha)
526 qcms_transform_release(m_transform);
529 if (colorProfile.isEmpty())
531 qcms_profile* deviceProfile = ImageDecoder::qcmsOutputDeviceProfile();
534 qcms_profile* inputProfile = qcms_profile_from_memory(colorProfile.data(), colorProfile.size());
537 // We currently only support color profiles for RGB profiled images.
538 ASSERT(icSigRgbData == qcms_profile_get_color_space(inputProfile));
539 qcms_data_type dataFormat = hasAlpha ? QCMS_DATA_RGBA_8 : QCMS_DATA_RGB_8;
540 // FIXME: Don't force perceptual intent if the image profile contains an intent.
541 m_transform = qcms_transform_create(inputProfile, dataFormat, deviceProfile, dataFormat, QCMS_INTENT_PERCEPTUAL);
542 qcms_profile_release(inputProfile);
547 JPEGImageDecoder* m_decoder;
548 unsigned m_bufferLength;
551 jpeg_decompress_struct m_info;
552 decoder_error_mgr m_err;
555 JSAMPARRAY m_samples;
558 qcms_transform* m_transform;
562 // Override the standard error method in the IJG JPEG decoder code.
563 void error_exit(j_common_ptr cinfo)
565 // Return control to the setjmp point.
566 decoder_error_mgr *err = reinterpret_cast_ptr<decoder_error_mgr *>(cinfo->err);
567 longjmp(err->setjmp_buffer, -1);
570 void init_source(j_decompress_ptr)
574 void skip_input_data(j_decompress_ptr jd, long num_bytes)
576 decoder_source_mgr *src = (decoder_source_mgr *)jd->src;
577 src->decoder->skipBytes(num_bytes);
580 boolean fill_input_buffer(j_decompress_ptr)
582 // Our decode step always sets things up properly, so if this method is ever
583 // called, then we have hit the end of the buffer. A return value of false
584 // indicates that we have no data to supply yet.
588 void term_source(j_decompress_ptr jd)
590 decoder_source_mgr *src = (decoder_source_mgr *)jd->src;
591 src->decoder->decoder()->jpegComplete();
594 JPEGImageDecoder::JPEGImageDecoder(ImageSource::AlphaOption alphaOption,
595 ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption,
596 size_t maxDecodedBytes)
597 : ImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes)
601 JPEGImageDecoder::~JPEGImageDecoder()
605 bool JPEGImageDecoder::isSizeAvailable()
607 if (!ImageDecoder::isSizeAvailable())
610 return ImageDecoder::isSizeAvailable();
613 bool JPEGImageDecoder::setSize(unsigned width, unsigned height)
615 if (!ImageDecoder::setSize(width, height))
618 if (!desiredScaleNumerator())
621 setDecodedSize(width, height);
625 void JPEGImageDecoder::setDecodedSize(unsigned width, unsigned height)
627 m_decodedSize = IntSize(width, height);
630 unsigned JPEGImageDecoder::desiredScaleNumerator() const
632 size_t originalBytes = size().width() * size().height() * 4;
633 if (originalBytes <= m_maxDecodedBytes) {
634 return scaleDenominator;
637 // Downsample according to the maximum decoded size.
638 unsigned scaleNumerator = static_cast<unsigned>(floor(sqrt(
639 // MSVC needs explicit parameter type for sqrt().
640 static_cast<float>(m_maxDecodedBytes * scaleDenominator * scaleDenominator / originalBytes))));
642 return scaleNumerator;
645 ImageFrame* JPEGImageDecoder::frameBufferAtIndex(size_t index)
650 if (m_frameBufferCache.isEmpty()) {
651 m_frameBufferCache.resize(1);
652 m_frameBufferCache[0].setPremultiplyAlpha(m_premultiplyAlpha);
655 ImageFrame& frame = m_frameBufferCache[0];
656 if (frame.status() != ImageFrame::FrameComplete) {
657 PlatformInstrumentation::willDecodeImage("JPEG");
659 PlatformInstrumentation::didDecodeImage();
662 frame.notifyBitmapIfPixelsChanged();
666 bool JPEGImageDecoder::setFailed()
669 return ImageDecoder::setFailed();
672 template <J_COLOR_SPACE colorSpace> void setPixel(ImageFrame& buffer, ImageFrame::PixelData* pixel, JSAMPARRAY samples, int column)
674 JSAMPLE* jsample = *samples + column * (colorSpace == JCS_RGB ? 3 : 4);
676 switch (colorSpace) {
678 buffer.setRGBARaw(pixel, jsample[0], jsample[1], jsample[2], 255);
681 // Source is 'Inverted CMYK', output is RGB.
682 // See: http://www.easyrgb.com/math.php?MATH=M12#text12
683 // Or: http://www.ilkeratalay.com/colorspacesfaq.php#rgb
685 // X = X * (1 - K ) + K [for X = C, M, or Y]
686 // Thus, from Inverted CMYK to CMY is:
687 // X = (1-iX) * (1 - (1-iK)) + (1-iK) => 1 - iX*iK
688 // From CMY (0..1) to RGB (0..1):
689 // R = 1 - C => 1 - (1 - iC*iK) => iC*iK [G and B similar]
690 unsigned k = jsample[3];
691 buffer.setRGBARaw(pixel, jsample[0] * k / 255, jsample[1] * k / 255, jsample[2] * k / 255, 255);
696 template <J_COLOR_SPACE colorSpace> bool outputRows(JPEGImageReader* reader, ImageFrame& buffer)
698 JSAMPARRAY samples = reader->samples();
699 jpeg_decompress_struct* info = reader->info();
700 int width = info->output_width;
702 while (info->output_scanline < info->output_height) {
703 // jpeg_read_scanlines will increase the scanline counter, so we
704 // save the scanline before calling it.
705 int y = info->output_scanline;
706 // Request one scanline: returns 0 or 1 scanlines.
707 if (jpeg_read_scanlines(info, samples, 1) != 1)
710 if (reader->colorTransform() && colorSpace == JCS_RGB)
711 qcms_transform_data(reader->colorTransform(), *samples, *samples, width);
713 ImageFrame::PixelData* pixel = buffer.getAddr(0, y);
714 for (int x = 0; x < width; ++pixel, ++x)
715 setPixel<colorSpace>(buffer, pixel, samples, x);
718 buffer.setPixelsChanged(true);
722 bool JPEGImageDecoder::outputScanlines()
724 if (m_frameBufferCache.isEmpty())
727 jpeg_decompress_struct* info = m_reader->info();
729 // Initialize the framebuffer if needed.
730 ImageFrame& buffer = m_frameBufferCache[0];
731 if (buffer.status() == ImageFrame::FrameEmpty) {
732 ASSERT(info->output_width == static_cast<JDIMENSION>(m_decodedSize.width()));
733 ASSERT(info->output_height == static_cast<JDIMENSION>(m_decodedSize.height()));
735 if (!buffer.setSize(info->output_width, info->output_height))
737 buffer.setStatus(ImageFrame::FramePartial);
738 // The buffer is transparent outside the decoded area while the image is
739 // loading. The completed image will be marked fully opaque in jpegComplete().
740 buffer.setHasAlpha(true);
742 // For JPEGs, the frame always fills the entire image.
743 buffer.setOriginalFrameRect(IntRect(IntPoint(), size()));
746 #if defined(TURBO_JPEG_RGB_SWIZZLE)
747 if (turboSwizzled(info->out_color_space)) {
748 while (info->output_scanline < info->output_height) {
749 unsigned char* row = reinterpret_cast<unsigned char*>(buffer.getAddr(0, info->output_scanline));
750 if (jpeg_read_scanlines(info, &row, 1) != 1)
753 if (qcms_transform* transform = m_reader->colorTransform())
754 qcms_transform_data_type(transform, row, row, info->output_width, rgbOutputColorSpace() == JCS_EXT_BGRA ? QCMS_OUTPUT_BGRX : QCMS_OUTPUT_RGBX);
757 buffer.setPixelsChanged(true);
762 switch (info->out_color_space) {
764 return outputRows<JCS_RGB>(m_reader.get(), buffer);
766 return outputRows<JCS_CMYK>(m_reader.get(), buffer);
768 ASSERT_NOT_REACHED();
774 void JPEGImageDecoder::jpegComplete()
776 if (m_frameBufferCache.isEmpty())
779 // Hand back an appropriately sized buffer, even if the image ended up being
781 ImageFrame& buffer = m_frameBufferCache[0];
782 buffer.setHasAlpha(false);
783 buffer.setStatus(ImageFrame::FrameComplete);
786 void JPEGImageDecoder::decode(bool onlySize)
792 m_reader = adoptPtr(new JPEGImageReader(this));
795 // If we couldn't decode the image but we've received all the data, decoding
797 if (!m_reader->decode(*m_data, onlySize) && isAllDataReceived())
799 // If we're done decoding the image, we don't need the JPEGImageReader
800 // anymore. (If we failed, |m_reader| has already been cleared.)
801 else if (!m_frameBufferCache.isEmpty() && (m_frameBufferCache[0].status() == ImageFrame::FrameComplete))