examples/Multimedia/ICL/ICLCodec/PngScanlineEncoder.cpp

/*
Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
* Neither the name of Nokia Corporation nor the names of its contributors
  may be used to endorse or promote products derived from this software
  without specific prior written permission.

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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Description:  
*/



#include "PngScanlineEncoder.h"

//
// CPngWriteSubCodec: base class for writing PNG scanlines
//

// Factory function
CPngWriteSubCodec* CPngWriteSubCodec::NewL(const TPngImageInformation& aInfo, const CFbsBitmap* aSource)
        {
        CPngWriteSubCodec* self = NULL;

        switch (aInfo.iBitDepth)
                {
                case 1:
                        self = new(ELeave) CBitDepth1Encoder;
                        break;
                case 2:
                        self = new(ELeave) CBitDepth2Encoder;
                        break;
                case 4:
                        self = new(ELeave) CBitDepth4Encoder;
                        break;
                case 8:
                        switch (aInfo.iColorType)
                                {
                                case TPngImageInformation::EGrayscale:
                                case TPngImageInformation::EIndexedColor:
                                        self = new(ELeave) CBitDepth8Encoder;
                                        break;
                                case TPngImageInformation::EDirectColor:
                                        self = new(ELeave) CBitDepth8ColorType2Encoder;
                                        break;
                                default:
                                        User::Leave(KErrNotSupported);
                                        break;
                                }
                        break;
                default:
                        User::Leave(KErrNotSupported);
                        break;
                }
        ASSERT(self);
        CleanupStack::PushL(self);
        self->ConstructL(aInfo, aSource);
        CleanupStack::Pop(self);
        return self;
        }

CPngWriteSubCodec::CPngWriteSubCodec()
        : iScanlineDes(NULL, 0)
        {
        }

CPngWriteSubCodec::~CPngWriteSubCodec()
        {
        delete iScanlineBuffer;
        delete iPalette;
        }

void CPngWriteSubCodec::ConstructL(const TPngImageInformation& aInfo, const CFbsBitmap* aSource)
        {
        iInfo = aInfo;
        iSource = aSource;
        iScanlineBufferSize = ScanlineBufferSize(iInfo.iSize.iWidth);
        iScanlineBuffer = HBufC8::NewMaxL(iScanlineBufferSize);
        iScanlineDes.Set(&(iScanlineBuffer->Des())[0], iScanlineBufferSize, iScanlineBufferSize);

        // Init stuff specific to derived class
        DoConstructL();
        }

void CPngWriteSubCodec::DoConstructL()
        {
        }

TDes8& CPngWriteSubCodec::Buffer()
        {
        iScanlineDes.FillZ();
        return iScanlineDes;
        }

TDes8& CPngWriteSubCodec::EncodeL(const TInt aScanline)
        {
        if (aScanline < iInfo.iSize.iHeight)
                {
                TUint8* dataPtr = const_cast<TUint8*>(iScanlineDes.Ptr());
                const TUint8* dataPtrLimit = dataPtr + iScanlineBufferSize;

                DoEncode(iSource, aScanline, dataPtr, dataPtrLimit);
                }
        else
                {
                iScanlineDes.Set(NULL, 0, 0);
                }
        return iScanlineDes;
        }

TUint8 CPngWriteSubCodec::ReverseBits(const TUint8 aValue) const
        {
        TUint value = aValue;
        TUint reverseVal = 0;
        for (TInt i = 0; i < 8; i++)
                {
                reverseVal <<= 1;
                reverseVal |= value & 1;
                value >>= 1;
                }
        return TUint8(reverseVal);
        }

void CPngWriteSubCodec::EncodePalettedScanline(TUint8* aDataPtr, const CFbsBitmap* aSource, const TInt aScanline,
                                                                                           const TInt aPixelsPerByte, const TInt aShiftValue)
        {
        // Encode a single scanline with indexes into the current palette
        ASSERT(iInfo.iPalettePresent);
        TPoint pos(0, aScanline);
        const TInt scanLength = iInfo.iSize.iWidth;
        for (TInt i=0; i < scanLength; i += aPixelsPerByte)
                {
                // Pack each byte with 'aPixelsPerByte' index values
                TUint8 pixels = 0;
                for (TInt j=0; j < aPixelsPerByte; j++)
                        {
                        pixels <<= aShiftValue;
                        TRgb rgb;
                        aSource->GetPixel(rgb, pos);
                        pixels |= TUint8(iPalette->NearestIndex(rgb));
                        pos.iX++;
                        }
                *aDataPtr = pixels;
                aDataPtr++;
                }
        }

//
// These classes specialise the PNG writer to write
// scanlines with different bitmap depths/colour types
//

//
// CBitDepth1Encoder
//

void CBitDepth1Encoder::DoConstructL()
        {
        if (iInfo.iColorType == TPngImageInformation::EIndexedColor)
                {
                // Setup palette
                iPalette = CPalette::NewL(2);
                iPalette->SetEntry(0, KRgbBlack);
                iPalette->SetEntry(1, KRgbWhite);
                iInfo.iPalettePresent = ETrue;
                }
        }

TInt CBitDepth1Encoder::ScanlineBufferSize(TInt aPixelLength)
        {
        // 8 pixels per byte
        return ((aPixelLength + KPngDepth1RoundUpValue) / KPngDepth1PixelsPerByte) + KPngScanlineFilterTypeLength;
        }

void CBitDepth1Encoder::DoEncode(const CFbsBitmap* aSource, const TInt aScanline,
                                                                 TUint8* aDataPtr, const TUint8* aDataPtrLimit)
        {
        // Filter method
        PtrWriteUtil::WriteInt8(aDataPtr, iInfo.iFilterMethod);
        aDataPtr++;

        // Pixel data
        const TInt scanLength = iInfo.iSize.iWidth;
        if (iInfo.iColorType == TPngImageInformation::EIndexedColor)
                {
                // Write palette indexes
                EncodePalettedScanline(aDataPtr, aSource, aScanline, KPngDepth1PixelsPerByte, KPngDepth1ShiftValue);
                }
        else
                {
                // Write RGB data
                TInt dataLength = (scanLength + KPngDepth1RoundUpValue) / KPngDepth1PixelsPerByte;
                TPtr8 dataPtr(aDataPtr, dataLength, dataLength);

                aSource->GetScanLine(dataPtr, TPoint(0, aScanline), scanLength, EGray2);

                // Reverse the order of the bits
                while (aDataPtr < aDataPtrLimit)
                        {
                        aDataPtr[0] = ReverseBits(aDataPtr[0]);
                        aDataPtr++;
                        }
                }
        }

//
// CBitDepth2Encoder
//

void CBitDepth2Encoder::DoConstructL()
        {
        if (iInfo.iColorType == TPngImageInformation::EIndexedColor)
                {
                // Setup palette entries
                iPalette = CPalette::NewL(4);
                iPalette->SetEntry(0, KRgbBlack);
                iPalette->SetEntry(1, KRgbDarkGray);
                iPalette->SetEntry(2, KRgbGray);
                iPalette->SetEntry(3, KRgbWhite);
                iInfo.iPalettePresent = ETrue;
                }
        }

TInt CBitDepth2Encoder::ScanlineBufferSize(TInt aPixelLength)
        {
        return ((aPixelLength + KPngDepth2RoundUpValue) / KPngDepth2PixelsPerByte) + KPngScanlineFilterTypeLength;
        }

void CBitDepth2Encoder::DoEncode(const CFbsBitmap* aSource, const TInt aScanline,
                                                                 TUint8* aDataPtr, const TUint8* aDataPtrLimit)
        {
        // Filter method
        PtrWriteUtil::WriteInt8(aDataPtr, iInfo.iFilterMethod);
        aDataPtr++;

        // Pixel data
        const TInt scanLength = iInfo.iSize.iWidth;
        if (iInfo.iColorType == TPngImageInformation::EIndexedColor)
                {
                // Write palette indexes
                EncodePalettedScanline(aDataPtr, aSource, aScanline, KPngDepth2PixelsPerByte, KPngDepth2ShiftValue);
                }
        else
                {
                // RGB values
                TPtr8 dataPtr(aDataPtr, (scanLength + KPngDepth2RoundUpValue) / KPngDepth2PixelsPerByte);
                aSource->GetScanLine(dataPtr, TPoint(0, aScanline), scanLength, EGray4);

                // Reverse the order of the bits
                while (aDataPtr < aDataPtrLimit)
                        {
                        TUint8 value = aDataPtr[0];
                        TUint8 reverse = 0;
                        for (TInt i=0; i < KPngDepth2PixelsPerByte; i++)
                                {
                                reverse <<= 2;  // advance the bits for the reverse value
                                reverse |= value & 0x3; // mask off the 2 bits, then OR with existing reverse value
                                value >>= 2;    // advance the bits for the actual value
                                }
                        aDataPtr[0] = reverse;
                        aDataPtr++;
                        }
                }
        }

//
// CBitDepth4Encoder
//

void CBitDepth4Encoder::DoConstructL()
        {
        if (iInfo.iColorType == TPngImageInformation::EIndexedColor)
                {
                // Calculate palette for image
                iPalette = CPalette::NewDefaultL(EColor16);
                iInfo.iPalettePresent = ETrue;
                }
        }

TInt CBitDepth4Encoder::ScanlineBufferSize(TInt aPixelLength)
        {
        return ((aPixelLength + KPngDepth4RoundUpValue) / KPngDepth4PixelsPerByte) + KPngScanlineFilterTypeLength;
        }

void CBitDepth4Encoder::DoEncode(const CFbsBitmap* aSource, const TInt aScanline,
                                                                 TUint8* aDataPtr, const TUint8* aDataPtrLimit)
        {
        // Filter method
        PtrWriteUtil::WriteInt8(aDataPtr, iInfo.iFilterMethod);
        aDataPtr++;

        // Pixel data
        const TInt scanLength = iInfo.iSize.iWidth;
        if (iInfo.iColorType == TPngImageInformation::EIndexedColor)
                {
                // Write palette indexes
                EncodePalettedScanline(aDataPtr, aSource, aScanline, KPngDepth4PixelsPerByte, KPngDepth4ShiftValue);
                }
        else
                {
                TPtr8 dataPtr(aDataPtr, (scanLength + KPngDepth4RoundUpValue) / KPngDepth4PixelsPerByte);
                aSource->GetScanLine(dataPtr, TPoint(0, aScanline), scanLength,
                        (iInfo.iColorType == TPngImageInformation::EDirectColor) ? EColor16 : EGray16);

                // Swap order of the low/high bits
                while (aDataPtr < aDataPtrLimit)
                        {
                        TUint value = aDataPtr[0];
                        TUint low = value << KPngDepth4ShiftValue;
                        TUint high = value >> KPngDepth4ShiftValue;
                        aDataPtr[0] = TUint8(low | high);
                        aDataPtr++;
                        }
                }
        }

//
// CBitDepth8ColorType2Encoder
//

TInt CBitDepth8ColorType2Encoder::ScanlineBufferSize(TInt aPixelLength)
        {
        return (aPixelLength * KPngDepth8RgbBytesPerPixel) + KPngScanlineFilterTypeLength;
        }

void CBitDepth8ColorType2Encoder::DoEncode(const CFbsBitmap* aSource, const TInt aScanline,
                                                                                   TUint8* aDataPtr, const TUint8* aDataPtrLimit)
        {
        // Filter method
        PtrWriteUtil::WriteInt8(aDataPtr, iInfo.iFilterMethod);
        aDataPtr++;

        // Pixel data
        TPtr8 dataPtr(aDataPtr, iInfo.iSize.iWidth * KPngDepth8RgbBytesPerPixel);
        aSource->GetScanLine(dataPtr, TPoint(0, aScanline), iInfo.iSize.iWidth, EColor16M);

        while (aDataPtr < aDataPtrLimit)
                {
                // Swap the red and blue components of the image data
                TUint8 temp = aDataPtr[0];      // temp = Red
                aDataPtr[0] = aDataPtr[2];      // Red = Blue
                aDataPtr[2] = temp;                     // Blue = temp
                aDataPtr += KPngDepth8RgbBytesPerPixel;
                }
        }

//
// CBitDepth8Encoder
//

void CBitDepth8Encoder::DoConstructL()
        {
        if (iInfo.iColorType == TPngImageInformation::EIndexedColor)
                {
                // Calculate palette for image
                iPalette = CPalette::NewDefaultL(EColor256);
                iInfo.iPalettePresent = ETrue;
                }
        }

TInt CBitDepth8Encoder::ScanlineBufferSize(TInt aPixelLength)
        {
        return aPixelLength + KPngScanlineFilterTypeLength;
        }

void CBitDepth8Encoder::DoEncode(const CFbsBitmap* aSource, const TInt aScanline,
                                                                 TUint8* aDataPtr, const TUint8* /*aDataPtrLimit*/)
        {
        // Filter method
        PtrWriteUtil::WriteInt8(aDataPtr, iInfo.iFilterMethod);
        aDataPtr++;

        const TInt scanLength = iInfo.iSize.iWidth;
        if (iInfo.iColorType == TPngImageInformation::EIndexedColor)
                {
                // Write palette indexes
                EncodePalettedScanline(aDataPtr, aSource, aScanline, KPngDepth8PixelsPerByte, KPngDepth8ShiftValue);
                }
        else
                {
                // Pixel data
                TPtr8 dataPtr(aDataPtr, scanLength);
                aSource->GetScanLine(dataPtr, TPoint(0, aScanline), scanLength, EGray256);
                }
        }

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