gecko/image/decoders/nsJPEGDecoder.h
Jeff Muizelaar a30ad6a153 Bug 812602. Don't decode jpegs progressively when we have all the data. r=joe
Decoding progressively is slower because we duplicate work like color
conversion and color correction for each outputted scan. We already suppress
paints when have all of the data, so we shouldn't do this extra work.

--HG--
extra : rebase_source : e6dd733546e1bb9e6e3279d9ceea0b4c0a88e049
2012-11-18 20:18:52 -05:00

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2.7 KiB
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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsJPEGDecoder_h__
#define nsJPEGDecoder_h__
#include "RasterImage.h"
/* On Windows systems, RasterImage.h brings in 'windows.h', which defines INT32.
* But the jpeg decoder has its own definition of INT32. To avoid build issues,
* we need to undefine the version from 'windows.h'. */
#undef INT32
#include "Decoder.h"
#include "nsAutoPtr.h"
#include "imgIDecoderObserver.h"
#include "nsIInputStream.h"
#include "nsIPipe.h"
#include "qcms.h"
extern "C" {
#include "jpeglib.h"
}
#include <setjmp.h>
namespace mozilla {
namespace image {
typedef struct {
struct jpeg_error_mgr pub; /* "public" fields for IJG library*/
jmp_buf setjmp_buffer; /* For handling catastropic errors */
} decoder_error_mgr;
typedef enum {
JPEG_HEADER, /* Reading JFIF headers */
JPEG_START_DECOMPRESS,
JPEG_DECOMPRESS_PROGRESSIVE, /* Output progressive pixels */
JPEG_DECOMPRESS_SEQUENTIAL, /* Output sequential pixels */
JPEG_DONE,
JPEG_SINK_NON_JPEG_TRAILER, /* Some image files have a */
/* non-JPEG trailer */
JPEG_ERROR
} jstate;
class RasterImage;
class nsJPEGDecoder : public Decoder
{
public:
nsJPEGDecoder(RasterImage &aImage, imgIDecoderObserver* aObserver, Decoder::DecodeStyle aDecodeStyle);
virtual ~nsJPEGDecoder();
virtual void InitInternal();
virtual void WriteInternal(const char* aBuffer, uint32_t aCount);
virtual void FinishInternal();
virtual Telemetry::ID SpeedHistogram();
void NotifyDone();
protected:
void OutputScanlines(bool* suspend);
public:
uint8_t *mImageData;
struct jpeg_decompress_struct mInfo;
struct jpeg_source_mgr mSourceMgr;
decoder_error_mgr mErr;
jstate mState;
uint32_t mBytesToSkip;
const JOCTET *mSegment; // The current segment we are decoding from
uint32_t mSegmentLen; // amount of data in mSegment
JOCTET *mBackBuffer;
uint32_t mBackBufferLen; // Offset of end of active backtrack data
uint32_t mBackBufferSize; // size in bytes what mBackBuffer was created with
uint32_t mBackBufferUnreadLen; // amount of data currently in mBackBuffer
JOCTET *mProfile;
uint32_t mProfileLength;
qcms_profile *mInProfile;
qcms_transform *mTransform;
bool mReading;
const Decoder::DecodeStyle mDecodeStyle;
uint32_t mCMSMode;
};
} // namespace image
} // namespace mozilla
#endif // nsJPEGDecoder_h__