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examples/Multimedia/ICL/ICLCodec/PNGCodec.h

// PngCodec.H
//
// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
//
//

#ifndef __PNGCODEC_H__
#define __PNGCODEC_H__

#include <bitdev.h>
#include <ezcompressor.h>
#include <ezdecompressor.h>
#include <icl/imageprocessor.h>
#include <icl/imagecodec.h>

#include "PNGConvert.h"

//.
// Constants.relating to PNG standard 
//
const TInt KPngFileSignatureLength = 8;
const TUint8 KPngSignature[KPngFileSignatureLength] = { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };

const TInt KPngChunkIdSize = 4;
const TInt KPngMaxPLTESize = 256;
const TInt KPngNumInterlacedPasses = 8; // 7 passes plus a safety entry

const TInt KPngChunkLengthSize = 4;
const TInt KPngChunkCRCSize = 4;

const TInt KPngIHDRChunkSize = 13;
const TInt KPngIENDChunkSize = 0;
const TInt KPngcHRMChunkSize = 32;
const TInt KPnggAMAChunkSize = 4;
const TInt KPngpHYsChunkSize = 9;
const TInt KPngtIMEChunkSize = 7;

// KPngMaxImageSize is the maximum size for width and height, as defined in the PNG Specification v1.0 page 14
const TUint KPngMaxImageSize = ((TUint)2 << 30) - 1;
const TInt KPngCrcTableLength = 256;
const TUint KPngCrcMask = 0xffffffff;

_LIT8(KPngIHDRChunkId,"IHDR");
_LIT8(KPngPLTEChunkId,"PLTE");
_LIT8(KPngIDATChunkId,"IDAT");
_LIT8(KPngIENDChunkId,"IEND");
_LIT8(KPngbKGDChunkId,"bKGD");
_LIT8(KPngpHYsChunkId,"pHYs");
_LIT8(KPngtRNSChunkId,"tRNS");


// .
// Encapsulates information about a PNG image
// See PNG standard for details.
// 
class TPngImageInformation : public TFrameInfo
        {
public:
        TPngImageInformation();
public:
        enum TColorElements
                {
                EMonochrome = 0x0,
                EPaletteUsed = 0x1,
                EColorUsed = 0x2,
                EAlphaChannelUsed = 0x4
                };
        enum TColorType
                {
                EGrayscale = EMonochrome, // 0
                EDirectColor = EColorUsed, // 2
                EIndexedColor = EColorUsed | EPaletteUsed, // 3
                EAlphaGrayscale = EMonochrome | EAlphaChannelUsed, // 4
                EAlphaDirectColor = EColorUsed | EAlphaChannelUsed // 6
                };
        enum TCompressionMethod
                {
                EDeflateInflate32K = 0
                };
        enum TFilterMethod
                {
                EAdaptiveFiltering = 0
                };
        enum TInterlaceMethod
                {
                ENoInterlace = 0,
                EAdam7Interlace = 1
                };
        enum TPhysicalUnits
                {
                EUnknownUnits = 0,
                EMeters = 1
                };
public:
        // IHDR chunk
        TSize iSize; // iWidth/iHeight = 1 ... (2^31)-1
        TInt iBitDepth; // 1,2,4,8,16 subject to color type restrictions
        TColorType iColorType; // 0,2,3,4,6
        TCompressionMethod iCompressionMethod; // 0
        TFilterMethod iFilterMethod; // 0
        TInterlaceMethod iInterlaceMethod; // 0 or 1

        // PLTE chunk
        TBool iPalettePresent;
        TRgb iPalette[KPngMaxPLTESize];

        // bKGD chunk
        TBool iBackgroundPresent;

        // pHYs chunk
        TBool iPhysicalPresent;
        TPhysicalUnits iPhysicalUnits;
        TSize iPhysicalSize;

        // tRNS chunk
        TBool iTransparencyPresent;
        TUint16 iTransparentGray;
        TUint16 iTransparentRed;
        TUint16 iTransparentGreen;
        TUint16 iTransparentBlue;
        TUint8 iTransparencyValue[KPngMaxPLTESize];
        };

//
// Handles reading raw PNG scanlines and preparing the data
// to be decompressed. A helper to CPngReadCodec.
// It is abstract, and subclassed to implement readers for 
// scanlines of different bitmap depths
//
class CPngReadSubCodec : public CBase
        {
public:
        static CPngReadSubCodec* NewL(CImageProcessor* aImageProc,CImageProcessor* aMaskProc,const TPngImageInformation& aInfo);
        virtual ~CPngReadSubCodec();
        TDes8& FirstBuffer();
        TDes8& DecodeL();
protected:
        CPngReadSubCodec();
        void WritePixel(TRgb aPixelColor);
        void WritePixel(TRgb aPixelColor,TUint8 aAlphaValue);
private:
        void ConstructL(CImageProcessor* aImageProc,CImageProcessor* aMaskProc,const TPngImageInformation& aInfo);
        void FilterScanlineDataL(TUint8* aDataPtr,const TUint8* aDataPtrLimit);
        TInt PaethPredictor(TInt aLeft,TInt aAbove,TInt aAboveLeft);
        virtual void DoConstructL() = 0;
        virtual TInt ScanlineBufferSize(TInt aPixelLength) = 0;
        virtual void DoDecode(TUint8* aDataPtr,const TUint8* aDataPtrLimit) = 0;
        void UpdatePos();
protected:
        CImageProcessor* iImageProc;
        CImageProcessor* iMaskProc;
        TPngImageInformation iInfo;
        TInt iScanlineBufferSize;
        TInt iBytesPerPixel;
        HBufC8* iScanlineBuffer1;
        HBufC8* iScanlineBuffer2;
        TPtr8 iScanlineDes1;
        TPtr8 iScanlineDes2;
        TInt iCurrentScanlineBuffer;
        TInt iInterlacedScanlineBufferSize[KPngNumInterlacedPasses];
        TInt iPass;
        TPoint iPos;
        };

class CPngDecoder;

//
// Codec class that does the real work of reading a PNG image.
// Inherits base classes that provide image mask processing
// and interface to unzip functionality
//
class CPngReadCodec : public CImageMaskProcessorReadCodec, public MEZBufferManager
        {
public:
        // Construction
        ~CPngReadCodec();
        void ConstructL () { CImageMaskProcessorReadCodec::ConstructL(); } // make public, since we don't have NewL

private:
        // From CImageReadCodec
        // Initialise frame to read
        void InitFrameL(TFrameInfo& aFrameInfo, CFrameImageData& aFrameImageData, 
                TBool aDisableErrorDiffusion, CFbsBitmap& aDestination, CFbsBitmap* aDestinationMask);
        // Initialise from header
        void InitFrameHeader(TFrameInfo& aFrameSettings, CFrameImageData& /* aFrameImageData */);
        // Process header
        TFrameState ProcessFrameHeaderL(TBufPtr8& aData);
        // Process frame
        TFrameState ProcessFrameL(TBufPtr8& aSrc);

private:
        // Helper functions to process PNG chunk types
        void DoNewFrameL(CPngDecoder* aPngDecoder);
        void DoProcessInfoL(const TUint8*& aDataPtr,const TUint8* aDataPtrLimit);
        void DoProcessIHDRL(const TUint8* aDataPtr,TInt aChunkLength);
        void DoProcessPLTEL(const TUint8* aDataPtr,TInt aChunkLength);
        void DoProcessbKGDL(const TUint8* aDataPtr,TInt aChunkLength);
        void DoProcesspHYsL(const TUint8* aDataPtr,TInt aChunkLength);
        void DoProcesstRNSL(const TUint8* aDataPtr,TInt aChunkLength);
        void DoProcessDataL(const TUint8*& aDataPtr,const TUint8* aDataPtrLimit);

        // From MEZBufferManager: feed data to unzip
        void InitializeL(CEZZStream &aZStream);
        void NeedInputL(CEZZStream &aZStream);
        void NeedOutputL(CEZZStream &aZStream);
        void FinalizeL(CEZZStream &aZStream);

private:
        TFrameInfo* iFrameInfo;
        TPngImageInformation iImageInfo;
        TBuf8<KPngChunkIdSize> iChunkId;
        TInt iChunkBytesRemaining;
        CPngReadSubCodec* iDecoder;
        CEZDecompressor* iDecompressor;
        TPtrC8 iDataDes;
        };

//
// Handles preparing image data
// for compression and writing raw scanlines 
// A helper to CPngWriteCodec
// 
class CPngWriteSubCodec : public CBase
        {
public:
        static CPngWriteSubCodec* NewL(const TPngImageInformation& aInfo, const CFbsBitmap* aSource);
        virtual ~CPngWriteSubCodec();
protected:
        CPngWriteSubCodec();
private:
        void ConstructL(const TPngImageInformation& aInfo, const CFbsBitmap* aSource);
public:
        TDes8& Buffer();
        inline TInt BufferSize() const;
        TDes8& EncodeL(const TInt aScanline);
        inline CPalette* Palette() const;
protected:
        TUint8 ReverseBits(const TUint8 aValue) const;
        void EncodePalettedScanline(TUint8* aDataPtr, const CFbsBitmap* aSource, const TInt aScanline,
                                                                const TInt aPixelsPerByte, const TInt aShiftValue);
private:
        virtual void DoConstructL();
        virtual TInt ScanlineBufferSize(TInt aPixelLength) = 0;
        virtual void DoEncode(const CFbsBitmap* aSource, const TInt aScanline,
                                        TUint8* aDataPtr, const TUint8* aDataPtrLimit) = 0;
protected:
        TPngImageInformation iInfo;
        const CFbsBitmap* iSource;
        TInt iScanlineBufferSize;
        HBufC8* iScanlineBuffer;
        TPtr8 iScanlineDes;
        CPalette* iPalette;
        };

//
// Codec class that does the real work of writing a PNG image.
// Inherits base classes to interface to zip functionality
//
class CPngWriteCodec : public CImageWriteCodec, public MEZBufferManager
        {
public:
        // Construction
        CPngWriteCodec(TInt aBpp, TBool aColor, TBool aPaletted, TInt aCompressionLevel);
        void ConstructL () { CImageWriteCodec::ConstructL(); } // make public, since we don't have NewL
        ~CPngWriteCodec();

private:
        // from CImageWriteCodec
        void InitFrameL(TBufPtr8& aDst, const CFbsBitmap& aSource);
        TFrameState ProcessFrameL(TBufPtr8& aDst);

private:
        // Helper functions to write PNG chunks
        void WritePngChunk(TUint8*& aDestPtr, const TDesC8& aChunkId, const TDesC8& aData, TInt& aLength);
        void DeflateEncodedDataL(TBufPtr8& aDst, TFrameState& aState);
        void FlushCompressedDataL(TBufPtr8& aDst, TFrameState& aState);
        void WritePLTEChunk(TBufPtr8& aDst);
        void WriteIDATChunk(TBufPtr8& aDst);
        void WriteEndChunk(TBufPtr8& aDst);
        TInt WriteHeaderChunk(TBufPtr8& aDst);
        void GetImageDataL(TInt& aBytesToProcess);
        void GetPngScanLine(TDes8& aBuf, const TPoint& aPixel, TInt& aLength);
        void CalcCrcTable();
        void GetCrc(TUint32& aCrc, const TUint8* aPtr, const TInt aLength);

private:
        // from MEZBufferManager
        // feeds data to zip
        void InitializeL(CEZZStream &aZStream);
        void NeedInputL(CEZZStream &aZStream);
        void NeedOutputL(CEZZStream &aZStream);
        void FinalizeL(CEZZStream &aZStream);

private:
        enum TPngEncoderState
                {
                EPngDeflate,    // Deflate encoded image data
                EPngFlush,              // Flush encoded image data
                EPngWritePLTE,  // Write PLTE chunk
                EPngWriteIDAT,  // Write IDAT chunk
                EPngEndChunk    // Write end chunk
                };
        
private:
        TUint32 iCrcTable[KPngCrcTableLength];
        TBool iCrcTableCalculated;
        CPngWriteSubCodec* iEncoder;
        TPngEncoderState iEncoderState;
        TInt iCompressionLevel;
        CEZCompressor* iCompressor;
        TInt iScanline;
        TUint8* iDestStartPtr;
        TUint8* iDestPtr;
        TUint8* iDestPtrLimit;
        TPngImageInformation iImageInfo;
        TPtr8 iCompressorPtr;   // data area for compressor to write to
        TBool iCallAgain;
        };


// Global panic function
void Panic(TInt aError);

//
// inline definitions
//
inline TInt CPngWriteSubCodec::BufferSize() const
        { return iScanlineBufferSize; }

inline CPalette* CPngWriteSubCodec::Palette() const
        { return iPalette; }


#endif // __PNGCODEC_H__

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Copyright ©2010 Nokia Corporation and/or its subsidiary(-ies).
All rights reserved. Unless otherwise stated, these materials are provided under the terms of the Eclipse Public License v1.0.