--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mmplugins/imagingplugins/codecs/ImageProcessor.cpp	Tue Feb 02 01:56:55 2010 +0200
@@ -0,0 +1,2532 @@
+// Copyright (c) 1999-2009 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:
+//
+
+#include <icl/imageprocessor.h>
+#include "ImageProcessorPriv.h"
+#include "ImageUtils.h"
+#include "ImageClientMain.h"
+
+//Size of dynamically allocated buffers used by CPixelWriter & CMonochromePixelWriter
+const TInt KPixelWriterBufferSize = 1024;
+const TInt KPixelWriterBufferThreeQuarter = 768;
+
+/**
+Constructor for this class.
+*/
+EXPORT_C CImageProcessorExtension::CImageProcessorExtension()
+:iOperation(EDecodeNormal)
+	{
+	}
+
+/**
+Destructor for this class.
+*/
+EXPORT_C CImageProcessorExtension::~CImageProcessorExtension()
+	{
+	}
+
+/**
+Sets the area of interest of the image to be decoded.
+
+@param aRect
+	   A reference to a TRect that specifies the location and size of the region to be decoded.
+
+*/
+EXPORT_C void CImageProcessorExtension::SetClippingRect(const TRect& aRect)
+	{
+	iClippingRect = aRect;
+	}
+
+/**
+Sets the scaling coefficient for the decode.
+
+@param aScalingCoeff
+	   The scaling coefficient.
+
+@see TImageConvScaler::SetScalingL
+*/
+EXPORT_C void CImageProcessorExtension::SetScaling(TInt aScalingCoeff)
+	{
+	iScalingCoeff = aScalingCoeff;
+	}
+
+/**
+Sets the desired size of the destination image for the decode.
+
+@param aDesiredSize
+	   The desired size of the destination image.
+
+@see TImageConvScaler::SetScalingL
+*/
+EXPORT_C void CImageProcessorExtension::SetScaling(const TSize& aDesiredSize)
+	{
+	iDesiredSize = aDesiredSize;
+	}
+
+/**
+Sets the operation to be applied to the image.
+
+@param aOperation
+	   The operation to apply to the image.
+
+@see TImageConvScaler::SetScalingL
+*/
+EXPORT_C void CImageProcessorExtension::SetOperation(TTransformOptions aOperation)
+	{
+	iOperation = aOperation;
+	}
+
+/**
+Sets an initial one-off number of scanlines to be skipped.
+This must be called prior to calling SetYPosIncrement(),
+if it is to be used.
+
+@param  aNumberOfScanlines
+        The number of scanlines to skip.
+        
+@see CImageProcessor::SetYPosIncrement()
+*/
+EXPORT_C void CImageProcessorExtension::SetInitialScanlineSkipPadding(TInt aNumberOfScanlines)
+	{
+	iNumberOfScanlinesToSkip = aNumberOfScanlines;
+	}
+
+//
+// ImageProcessorUtility
+//
+
+//
+//	CColorImageProcessor
+//
+
+/**
+ * @see CImageProcessor.
+ * @internalComponent
+ */
+void CColorImageProcessor::CreateBlockBufferL(TInt aBlockArea)
+	{
+	delete[] iBlockBuffer;
+	iBlockBuffer = NULL;
+
+	if(aBlockArea)
+		iBlockBuffer = new (ELeave) TRgb[aBlockArea];
+
+	iBlockArea = aBlockArea;
+	}
+
+/**
+ * Destructor.
+ * @see CImageProcessor.
+ * @internalComponent
+ */
+CColorImageProcessor::~CColorImageProcessor()
+	{
+	delete[] iBlockBuffer;
+	}
+
+/**
+ * @see CImageProcessor.
+ * @internalComponent
+ */
+TBool CColorImageProcessor::SetPixelRun(TRgb aColor,TInt aCount)
+	{
+	TBool returnValue = EFalse;
+
+	while(aCount--)
+		returnValue |= SetPixel(aColor);
+
+	return returnValue;
+	}
+
+/**
+ * @see CImageProcessor.
+ * @internalComponent
+ */
+TBool CColorImageProcessor::SetPixels(TRgb* aColorBuffer,TInt aBufferLength)
+	{
+	TBool returnValue = EFalse;
+
+	while(aBufferLength--)
+		returnValue |= SetPixel(*aColorBuffer++);
+
+	return returnValue;
+	}
+
+/**
+ * @see CImageProcessor.
+ * @internalComponent
+ */
+TBool CColorImageProcessor::SetMonoPixel(TInt aGray256)
+	{
+	return SetPixel(TRgb(aGray256,aGray256,aGray256));
+	}
+
+/**
+ * @see CImageProcessor.
+ * @internalComponent
+ */
+TBool CColorImageProcessor::SetMonoPixelRun(TInt aGray256,TInt aCount)
+	{
+	return SetPixelRun(TRgb(aGray256,aGray256,aGray256),aCount);
+	}
+
+/**
+ * @see CImageProcessor.
+ * @internalComponent
+ */
+TBool CColorImageProcessor::SetMonoPixels(TUint32* aGray256Buffer,TInt aBufferLength)
+	{
+	TBool returnValue = EFalse;
+
+	while(aBufferLength--)
+		{
+		TUint32 gray256 = *aGray256Buffer++;
+		returnValue = SetPixel(TRgb(gray256,gray256,gray256));
+		}
+	return returnValue;
+	}
+
+/**
+ * @see CImageProcessor.
+ * @internalComponent
+ */
+TBool CColorImageProcessor::SetMonoPixelBlock(TUint32* aGray256Buffer)
+	{
+	ASSERT(iBlockBuffer);
+
+	TRgb* blockBufferPtr = iBlockBuffer;
+	TRgb* blockBufferPtrLimit = blockBufferPtr+iBlockArea;
+
+	while(blockBufferPtr<blockBufferPtrLimit)
+		{
+		TUint32 gray256 = *aGray256Buffer++;
+		*blockBufferPtr++ = TRgb(gray256,gray256,gray256);
+		}
+
+	return SetPixelBlock(iBlockBuffer);
+	}
+
+//
+//	CMonochromeImageProcessor
+//
+
+/**
+ * @see CImageProcessor.
+ */
+void CMonochromeImageProcessor::CreateBlockBufferL(TInt aBlockArea)
+	{
+	delete[] iBlockBuffer;
+	iBlockBuffer = NULL;
+
+	iBlockBuffer = new (ELeave) TUint32[aBlockArea];
+	iBlockArea = aBlockArea;
+	}
+
+/**
+ * Destructor.
+ * @see CImageProcessor.
+ */
+CMonochromeImageProcessor::~CMonochromeImageProcessor()
+	{
+	delete []iBlockBuffer;
+	}
+
+/**
+ * @see CImageProcessor.
+ */
+TBool CMonochromeImageProcessor::SetMonoPixelRun(TInt aGray256,TInt aCount)
+	{
+	TBool returnValue = EFalse;
+
+	while(aCount--)
+		returnValue = SetMonoPixel(aGray256);
+
+	return returnValue;
+	}
+
+/**
+ * @see CImageProcessor.
+ */
+TBool CMonochromeImageProcessor::SetMonoPixels(TUint32* aGray256Buffer,TInt aBufferLength)
+	{
+	TBool returnValue = EFalse;
+
+	while(aBufferLength--)
+		returnValue = SetMonoPixel(*aGray256Buffer++);
+
+	return returnValue;
+	}
+
+/**
+ * @see CImageProcessor.
+ */
+TBool CMonochromeImageProcessor::SetPixel(TRgb aColor)
+	{
+	return SetMonoPixel(TColorConvertor::RgbToMonochrome(aColor));
+	}
+
+/**
+ * @see CImageProcessor.
+ */
+TBool CMonochromeImageProcessor::SetPixelRun(TRgb aColor,TInt aCount)
+	{
+	return SetMonoPixelRun(TColorConvertor::RgbToMonochrome(aColor),aCount);
+	}
+
+/**
+ * @see CImageProcessor.
+ */
+TBool CMonochromeImageProcessor::SetPixels(TRgb* aColorBuffer,TInt aBufferLength)
+	{
+	TBool returnValue = EFalse;
+
+	while(aBufferLength--)
+		returnValue = SetMonoPixel(TColorConvertor::RgbToMonochrome(*aColorBuffer++));
+
+	return returnValue;
+	}
+
+/**
+ * @see CImageProcessor.
+ */
+TBool CMonochromeImageProcessor::SetPixelBlock(TRgb* aColorBuffer)
+	{
+	ASSERT(iBlockBuffer);
+
+	TUint32* blockBufferPtr = iBlockBuffer;
+	TUint32* blockBufferPtrLimit = blockBufferPtr+iBlockArea;
+
+	while(blockBufferPtr<blockBufferPtrLimit)
+		*blockBufferPtr++ = TColorConvertor::RgbToMonochrome(*aColorBuffer++);
+
+	return SetMonoPixelBlock(iBlockBuffer);
+	}
+
+//
+// CPixelWriter
+//
+
+/**
+ *
+ * Static factory function to create CPixelWriter objects.
+ *
+ * @return  Pointer to a fully constructed CPixelWriter object. 
+ */
+CPixelWriter* CPixelWriter::NewL()
+	{
+	return new(ELeave) CPixelWriter;
+	}
+
+/**
+ *
+ * Default constructor for this class.
+ */
+CPixelWriter::CPixelWriter():
+	iYInc(1)
+	{}	
+	
+/**
+ *
+ * Destructor.
+ */
+CPixelWriter::~CPixelWriter()
+	{
+	Reset();
+	ASSERT(iColorConv==NULL);
+	ASSERT(iRgbBuffer==NULL);
+	ASSERT(iIndexBuffer==NULL);
+	}
+
+/**
+ *
+ * @see CImageProcessor
+ */
+void CPixelWriter::PrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect)
+	{
+	DoPrepareL(aBitmap,aImageRect,NULL);
+	}
+
+/**
+ *
+ * @see CImageProcessor
+ */
+void CPixelWriter::PrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect,const TSize& aRgbBlockSize)
+	{
+	DoPrepareL(aBitmap,aImageRect,&aRgbBlockSize);
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+void CPixelWriter::SetYPosIncrement(TInt aYInc)
+	{
+	iYInc = aYInc - iNumberOfScanlinesToSkip;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+void CPixelWriter::SetLineRepeat(TInt aLineRepeat)
+	{
+	ASSERT(aLineRepeat>=0);
+	iLineRepeat = aLineRepeat;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+void CPixelWriter::SetPixelPadding(TInt aNumberOfPixels)
+	{
+	iPixelPadding = aNumberOfPixels;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CPixelWriter::SetPixel(TRgb aColor)
+	{
+	*iRgbBufferPtr++ = aColor;
+
+	if (iRgbBufferPtr == iRgbBufferPtrLimit)
+		return FlushPixels();
+
+	return EFalse;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CPixelWriter::SetPixelRun(TRgb aColor,TInt aCount)
+	{
+	while(aCount)
+		{
+		TRgb* ptr = iRgbBufferPtr;
+		TRgb* limit = ptr+aCount;
+		if(limit>iRgbBufferPtrLimit)
+			limit = iRgbBufferPtrLimit;
+
+		TInt n = limit-ptr;
+		aCount -= n;
+
+		if(n&1)
+			*ptr++ = aColor;
+		if(n&2)
+			{
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			}
+		if(n&4)
+			{
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			}
+		while(ptr<limit)
+			{
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			*ptr++ = aColor;
+			}
+
+		iRgbBufferPtr = ptr;
+
+		if(ptr!=iRgbBufferPtrLimit)
+			break;
+
+		if(FlushPixels())
+			return ETrue;
+		}
+
+	return EFalse;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CPixelWriter::SetPixels(TRgb* aColorBuffer, TInt aBufferLength)
+	{
+	if (aBufferLength >= KPixelWriterBufferThreeQuarter)
+		{
+		TRgb* rgbBuffer = iRgbBuffer;
+
+		if (iRgbBufferPtr != rgbBuffer) 
+			{
+			// flush rest of the pixels 
+			if(FlushPixels())
+				{
+				return ETrue;
+				}
+			}
+
+		// use external buffer without copying data
+		TBool rValue = EFalse;
+
+		while (aBufferLength && !rValue)
+			{
+			TInt bufferLength = (aBufferLength>KPixelWriterBufferSize)?KPixelWriterBufferSize:aBufferLength;
+			iRgbBuffer = aColorBuffer;
+			iRgbBufferPtr = aColorBuffer+bufferLength;
+			iRgbBufferPtrLimit = aColorBuffer+bufferLength;
+
+			rValue = FlushPixels();
+			aBufferLength -= bufferLength;
+			aColorBuffer += bufferLength;
+			}
+		
+		// restore pointers to inner buffer
+		iRgbBuffer = rgbBuffer;
+		iRgbBufferPtr = rgbBuffer;
+		iRgbBufferPtrLimit = rgbBuffer+KPixelWriterBufferSize;
+		
+		return rValue;
+		}
+
+	while(aBufferLength)
+		{
+		TRgb* ptr = iRgbBufferPtr;
+		TRgb* limit = ptr+aBufferLength;
+		if(limit>iRgbBufferPtrLimit)
+			limit = iRgbBufferPtrLimit;
+
+		TInt n = limit-ptr;
+		aBufferLength -= n;
+
+		if(n&1)
+			*ptr++ = *aColorBuffer++;
+		if(n&2)
+			{
+			*ptr++ = *aColorBuffer++;
+			*ptr++ = *aColorBuffer++;
+			}
+		while(ptr<limit)
+			{
+			*ptr++ = *aColorBuffer++;
+			*ptr++ = *aColorBuffer++;
+			*ptr++ = *aColorBuffer++;
+			*ptr++ = *aColorBuffer++;
+			}
+
+		iRgbBufferPtr = ptr;
+
+		if(ptr!=iRgbBufferPtrLimit)
+			break;
+
+		if(FlushPixels())
+			return ETrue;
+		}
+
+	return EFalse;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CPixelWriter::SetPixelBlock(TRgb* aColorBuffer)
+	{
+	ASSERT(aColorBuffer);
+
+	TUint32* indexBufferPtr = iIndexBuffer;
+	if (iDisplayMode==EColor16M || iDisplayMode == EColor16MU || iDisplayMode == EColor16MA)
+		{
+		indexBufferPtr = reinterpret_cast<TUint32*>(aColorBuffer);
+		}
+	else
+		{
+		SetPixelBlockIndex(aColorBuffer);
+		}
+
+	TInt ySkip = 0;
+	if(iNumberOfScanlinesToSkip > 0)
+		{
+		ySkip = iNumberOfScanlinesToSkip * iBlockSize.iWidth;
+		indexBufferPtr += ySkip;
+		ySkip = iNumberOfScanlinesToSkip;
+		iNumberOfScanlinesToSkip = 0; // Only call this conditional once.
+		}
+	
+	TInt imageWidth = iImageRegion.iBr.iX;
+	TInt imageHeight = iImageRegion.iBr.iY;
+	TInt endOfImage = iDrawBottomUp ? -1 : imageHeight;
+	
+	// The minimum number of pixels to render horizontally
+	TInt minWidth = Min(iBlockSize.iWidth, imageWidth - iPos.iX);
+	
+	// The next vertical position.  Note that this is usually the height of the block, but 
+	// in the case of the first block when clipping is required, this will be reduced by ySkip.
+	TInt nextYPos = iDrawBottomUp ?	(iPos.iY - iBlockSize.iHeight) + ySkip :
+									(iPos.iY + iBlockSize.iHeight) - ySkip;
+	
+	TInt endPosition = iDrawBottomUp ? Max(nextYPos, endOfImage) : Min(nextYPos, endOfImage);
+	
+	// Once the first block has been processed, iYInc is set to block height
+	iYInc = iDrawBottomUp ? -iBlockSize.iHeight + ySkip : iBlockSize.iHeight - ySkip;
+				
+	// Skip unnecessary pixels (for cropping, or padding when rotated)
+	indexBufferPtr += iPixelPadding;
+	
+	TPoint pos(iPos);
+	iUtil.Begin();
+	for(;iDrawBottomUp ? pos.iY > endPosition : pos.iY < endPosition; iDrawBottomUp ? pos.iY-- : pos.iY++)
+		{
+		iUtil.SetPos(pos);
+		iUtil.SetPixels(indexBufferPtr, minWidth);
+		indexBufferPtr += iBlockSize.iWidth; // next line in block
+		}
+	iUtil.End();
+
+	iPos.iX += iBlockSize.iWidth;
+	
+	if (iPos.iX >= imageWidth)
+		{
+		return NewLine();
+		}
+
+	return EFalse;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CPixelWriter::FlushPixels()
+	{
+	TRgb* rgbBufferPtrLimit = iRgbBufferPtr;
+	iRgbBufferPtr = iRgbBuffer;
+
+	if(iPos.iY < iImageRegion.iTl.iY || iPos.iY >= iImageRegion.iBr.iY)
+		return ETrue;
+
+	iUtil.Begin();
+
+	TBool finished = EFalse;
+	for (TRgb* rgbBufferPtr = iRgbBuffer; rgbBufferPtr < rgbBufferPtrLimit; )
+		{
+		TInt pixelsToSkip = Min(rgbBufferPtrLimit - rgbBufferPtr,iPixelsToSkip);
+		rgbBufferPtr += pixelsToSkip;
+		iPixelsToSkip -= pixelsToSkip;
+
+		if(iPixelsToSkip)
+			break;
+
+		TInt pixelsToFlush = Min(rgbBufferPtrLimit - rgbBufferPtr,iImageRegion.iBr.iX - iPos.iX);
+
+		if(!pixelsToFlush)
+			break;
+
+		SetPixelBufferIndex(rgbBufferPtr,pixelsToFlush);
+		rgbBufferPtr += pixelsToFlush;
+
+		TBool fillDown = iYInc > 0;
+		TPoint pos(iPos);
+		TInt posYLimit;
+		if(fillDown)
+			posYLimit = Min(pos.iY + iLineRepeat + 1 ,iImageRegion.iBr.iY);
+		else
+			posYLimit = Max(pos.iY - iLineRepeat - 1 ,iImageRegion.iTl.iY-1);
+
+		for(;fillDown ? pos.iY < posYLimit : pos.iY > posYLimit; fillDown ? pos.iY++ : pos.iY--)
+			{
+			if(!iUtil.SetPos(pos-iImageRegion.iTl))
+				{
+				iUtil.End();
+				return ETrue;
+				}
+			iUtil.SetPixels(iIndexBuffer,pixelsToFlush);
+			}
+
+		iPos.iX += pixelsToFlush;
+		if (iPos.iX >= iImageRegion.iBr.iX)
+			{
+			finished = NewLine();
+			if(finished)
+				break;
+			}
+		}
+
+	iUtil.End();
+
+	return finished;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CPixelWriter::SetPos(const TPoint& aPosition)
+	{
+	if(iImageRegion.Contains(aPosition))
+		{
+		FlushPixels();
+		iPixelsToSkip = 0;
+		iPos = aPosition;
+		return ETrue;
+		}
+
+	return EFalse;
+	}
+
+void CPixelWriter::Reset()
+	{
+	delete iColorConv;
+	iColorConv = NULL;
+
+	delete[] iRgbBuffer;
+	iRgbBuffer = NULL;
+
+	delete[] iIndexBuffer;
+	iIndexBuffer = NULL;
+
+	iPos.SetXY(0,0);
+	iPixelsToSkip = 0;
+	iImageRegion.SetRect(0,0,0,0);
+	iBlockSize.SetSize(0,0);
+	
+	iDrawBottomUp = EFalse;
+	}
+
+void CPixelWriter::DoPrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect,const TSize* aBlockSize)
+	{
+	if( (aImageRect.iTl.iX<0) || (aImageRect.iTl.iY<0) || (aImageRect.Size().iWidth>aBitmap.SizeInPixels().iWidth) || (aImageRect.Size().iHeight>aBitmap.SizeInPixels().iHeight) )
+		{
+		User::Leave(KErrArgument);
+		}
+
+	Reset();
+	
+	iDisplayMode = aBitmap.DisplayMode();
+
+	iImageRegion = aImageRect;
+
+	ASSERT(iColorConv==NULL);
+	iColorConv = TColorConvertor::NewL(aBitmap.DisplayMode());
+	iUtil.SetBitmapL(&aBitmap);
+
+	if (aBlockSize)
+		{
+		if (aBlockSize->iWidth <= 0 || aBlockSize->iHeight <= 0)
+			{
+			User::Leave(KErrArgument);
+			}
+
+		iBlockSize = *aBlockSize;
+		iBlockArea = iBlockSize.iWidth * iBlockSize.iHeight;
+		
+		ASSERT(iIndexBuffer == NULL);
+		iIndexBuffer = new(ELeave) TUint32[iBlockArea];
+
+		iIndexBufferPtrLimit = iIndexBuffer + iBlockArea;
+		CreateBlockBufferL(iBlockArea);
+		
+		switch(iOperation)
+			{
+			case EDecodeRotate180:
+			case EDecodeRotate270:
+			case EDecodeHorizontalFlip:
+			case EDecodeVerticalFlipRotate90:
+				iDrawBottomUp = ETrue;
+				break;
+			default:
+				iDrawBottomUp = EFalse;
+			}
+		
+		iYInc = iDrawBottomUp ? -iBlockSize.iHeight : iBlockSize.iHeight;
+		iStartPosition.SetXY(iImageRegion.iTl.iX, iDrawBottomUp ? iImageRegion.iBr.iY - 1 : 0);
+		iEndPosition.SetXY(iImageRegion.iBr.iX, iDrawBottomUp ?
+							iImageRegion.iTl.iY - 1 : iImageRegion.iBr.iY);
+		iPos = iStartPosition;
+		}
+	else
+		{
+		iPos = iImageRegion.iTl;
+		iStartPosition = iPos;
+		iEndPosition = aImageRect.iBr;
+		
+		ASSERT(iRgbBuffer == NULL);
+		iRgbBuffer = new(ELeave) TRgb[KPixelWriterBufferSize];
+
+		iRgbBufferPtr = iRgbBuffer;
+		iRgbBufferPtrLimit = iRgbBuffer + KPixelWriterBufferSize;
+
+		ASSERT(iIndexBuffer == NULL);
+		iIndexBuffer = new(ELeave) TUint32[KPixelWriterBufferSize];
+
+		iIndexBufferPtrLimit = iIndexBuffer + KPixelWriterBufferSize;
+		}
+	}
+
+TBool CPixelWriter::NewLine()
+	{
+	iPos.iX = iStartPosition.iX;
+	iPos.iY += iYInc;
+
+	if(iPos.iY < iStartPosition.iY || iPos.iY >= iEndPosition.iY)
+		{
+		return ETrue;
+		}
+	
+	iPixelsToSkip = iPixelPadding;
+	return EFalse;
+	}
+
+void CPixelWriter::SetPixelBufferIndex(TRgb* aColorBuffer,TInt aCount)
+	{
+	iColorConv->ColorToIndex(REINTERPRET_CAST(TInt*,iIndexBuffer),aColorBuffer,aCount);
+	}
+
+void CPixelWriter::SetPixelBlockIndex(TRgb* aColorBuffer)
+	{
+	iColorConv->ColorToIndex(REINTERPRET_CAST(TInt*,iIndexBuffer),aColorBuffer,iIndexBufferPtrLimit-iIndexBuffer);
+	}
+
+//
+//	CMonochromePixelWriter
+//
+
+/**
+ *
+ * Static factory function to create CMonochromePixelWriter objects.
+ *
+ * @return  Pointer to a fully constructed CMonochromePixelWriter object. 
+ */
+CMonochromePixelWriter* CMonochromePixelWriter::NewL()
+	{
+	return new(ELeave) CMonochromePixelWriter;
+	}
+
+/**
+ *
+ * Default constructor for this class.
+ */
+CMonochromePixelWriter::CMonochromePixelWriter():
+	iYInc(1)
+	{}
+
+/**
+ *
+ * Destructor
+ */
+CMonochromePixelWriter::~CMonochromePixelWriter()
+	{
+	Reset();
+	}
+
+/**
+ *
+ * @see CImageProcessor
+ */
+void CMonochromePixelWriter::PrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect)
+	{
+	DoPrepareL(aBitmap,aImageRect,NULL);
+	}
+
+/**
+ *
+ * @see CImageProcessor
+ */
+void CMonochromePixelWriter::PrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect,const TSize& aRgbBlockSize)
+	{
+	DoPrepareL(aBitmap,aImageRect,&aRgbBlockSize);
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+void CMonochromePixelWriter::SetYPosIncrement(TInt aYInc)
+	{
+	iYInc = aYInc - iNumberOfScanlinesToSkip;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+void CMonochromePixelWriter::SetPixelPadding(TInt aNumberOfPixels)
+	{
+	iPixelPadding = aNumberOfPixels;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+void CMonochromePixelWriter::SetLineRepeat(TInt aLineRepeat)
+	{
+	ASSERT(aLineRepeat>=0);
+	iLineRepeat = aLineRepeat;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CMonochromePixelWriter::SetMonoPixel(TInt aGray256)
+	{
+	*iGray256BufferPtr++ = aGray256;
+
+	if (iGray256BufferPtr != iGray256BufferPtrLimit)
+		return EFalse;
+
+	return FlushPixels();
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CMonochromePixelWriter::SetMonoPixelRun(TInt aGray256,TInt aCount)
+	{
+	while(aCount)
+		{
+		TUint32* ptr = iGray256BufferPtr;
+		TUint32* limit = ptr+aCount;
+		if(limit>iGray256BufferPtrLimit)
+			limit = iGray256BufferPtrLimit;
+
+		TInt n = limit-ptr;
+		aCount -= n;
+
+		if(n&1)
+			*ptr++ = aGray256;
+		if(n&2)
+			{
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			}
+		if(n&4)
+			{
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			}
+		while(ptr<limit)
+			{
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			*ptr++ = aGray256;
+			}
+
+		iGray256BufferPtr = ptr;
+
+		if(ptr!=iGray256BufferPtrLimit)
+			break;
+
+		if(FlushPixels())
+			return ETrue;
+		}
+
+	return EFalse;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CMonochromePixelWriter::SetMonoPixels(TUint32* aGray256Buffer,TInt aBufferLength)
+	{
+
+	if (aBufferLength >= KPixelWriterBufferThreeQuarter)
+		{
+		TUint32* gray256Buffer = iGray256Buffer;
+
+		if (iGray256BufferPtr != gray256Buffer) 
+			{
+			// flush rest of the pixels 
+			if(FlushPixels())
+				{
+				return ETrue;
+				}
+			}
+
+		// use external buffer without copying data
+		TBool rValue = EFalse;
+		
+		while (aBufferLength && !rValue)
+			{
+			TInt bufferLength = (aBufferLength>KPixelWriterBufferSize)?KPixelWriterBufferSize:aBufferLength;
+			iGray256Buffer = aGray256Buffer;
+			iGray256BufferPtr = aGray256Buffer+bufferLength;
+			iGray256BufferPtrLimit = aGray256Buffer+bufferLength;
+
+			rValue = FlushPixels();
+			aBufferLength -= bufferLength;
+			aGray256Buffer += bufferLength;
+			}
+		
+		// restore pointers to inner buffer
+		iGray256Buffer = gray256Buffer;
+		iGray256BufferPtr = gray256Buffer;
+		iGray256BufferPtrLimit = gray256Buffer+KPixelWriterBufferSize;
+		
+		return rValue;
+		}
+
+	while(aBufferLength)
+		{
+		TUint32* ptr = iGray256BufferPtr;
+		TUint32* limit = ptr+aBufferLength;
+		if(limit>iGray256BufferPtrLimit)
+			limit = iGray256BufferPtrLimit;
+
+		TInt n = limit-ptr;
+		aBufferLength -= n;
+
+		if(n&1)
+			*ptr++ = *aGray256Buffer++;
+		if(n&2)
+			{
+			*ptr++ = *aGray256Buffer++;
+			*ptr++ = *aGray256Buffer++;
+			}
+		while(ptr<limit)
+			{
+			*ptr++ = *aGray256Buffer++;
+			*ptr++ = *aGray256Buffer++;
+			*ptr++ = *aGray256Buffer++;
+			*ptr++ = *aGray256Buffer++;
+			}
+
+		iGray256BufferPtr = ptr;
+
+		if(ptr!=iGray256BufferPtrLimit)
+			break;
+
+		if(FlushPixels())
+			return ETrue;
+		}
+
+	return EFalse;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CMonochromePixelWriter::SetMonoPixelBlock(TUint32* aGray256Buffer)
+	{
+	SetPixelBlockIndex(aGray256Buffer);
+	
+	TUint32* indexBufferPtr = iIndexBuffer;
+
+	TInt ySkip = 0;
+	if(iNumberOfScanlinesToSkip > 0)
+		{
+		ySkip = iNumberOfScanlinesToSkip * iBlockSize.iWidth;
+		indexBufferPtr += ySkip;
+		ySkip = iNumberOfScanlinesToSkip;
+		iNumberOfScanlinesToSkip = 0; // Only call this conditional once.
+		}
+	
+	TInt imageWidth = iImageRegion.iBr.iX;
+	TInt imageHeight = iImageRegion.iBr.iY;
+	TInt endOfImage = iDrawBottomUp ? -1 : imageHeight;
+	
+	// The minimum number of pixels to render horizontally
+	TInt minWidth = Min(iBlockSize.iWidth, imageWidth - iPos.iX);
+	
+	// The next vertical position.  Note that this is usually the height of the block, but 
+	// in the case of the first block when clipping is required, this will be reduced by ySkip.
+	TInt nextYPos = iDrawBottomUp ?	(iPos.iY - iBlockSize.iHeight) + ySkip :
+										(iPos.iY + iBlockSize.iHeight) - ySkip;
+	
+	TInt endPosition = iDrawBottomUp ? Max(nextYPos, endOfImage) : Min(nextYPos, endOfImage);
+	
+	// Once the first block has been processed, iYInc is set to block height
+	iYInc = iDrawBottomUp ? -iBlockSize.iHeight + ySkip : iBlockSize.iHeight - ySkip;
+				
+	// Skip unnecessary pixels (for cropping, or padding when rotated)
+	indexBufferPtr += iPixelPadding;
+	
+	TPoint pos(iPos);
+	iUtil.Begin();
+	for(;iDrawBottomUp ? pos.iY > endPosition : pos.iY < endPosition; iDrawBottomUp ? pos.iY-- : pos.iY++)
+		{
+		iUtil.SetPos(pos);
+		iUtil.SetPixels(indexBufferPtr, minWidth);
+		indexBufferPtr += iBlockSize.iWidth; // next line in block
+		}
+	iUtil.End();
+
+	iPos.iX += iBlockSize.iWidth;
+	
+	if (iPos.iX >= imageWidth)
+		{
+		return NewLine();
+		}
+
+	return EFalse;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CMonochromePixelWriter::FlushPixels()
+	{
+	TUint32* gray256BufferPtrLimit = iGray256BufferPtr;
+	iGray256BufferPtr = iGray256Buffer;
+
+	if(iPos.iY < iImageRegion.iTl.iY || iPos.iY >= iImageRegion.iBr.iY)
+		return ETrue;
+
+	iUtil.Begin();
+
+	TBool finished = EFalse;
+	for (TUint32* gray256BufferPtr = iGray256Buffer; gray256BufferPtr < gray256BufferPtrLimit; )
+		{
+		TInt pixelsToSkip = Min(gray256BufferPtrLimit - gray256BufferPtr,iPixelsToSkip);
+		gray256BufferPtr += pixelsToSkip;
+		iPixelsToSkip -= pixelsToSkip;
+
+		if(iPixelsToSkip)
+			break;
+
+		TInt pixelsToFlush = Min(gray256BufferPtrLimit - gray256BufferPtr,iImageRegion.iBr.iX - iPos.iX);
+
+		if(!pixelsToFlush)
+			break;
+
+		SetPixelBufferIndex(gray256BufferPtr,pixelsToFlush);
+		gray256BufferPtr += pixelsToFlush;
+
+		TBool fillDown = iYInc > 0;
+		TPoint pos(iPos);
+		TInt posYLimit;
+		if(fillDown)
+			posYLimit = Min(pos.iY + iLineRepeat + 1 ,iImageRegion.iBr.iY);
+		else
+			posYLimit = Max(pos.iY - iLineRepeat - 1 ,iImageRegion.iTl.iY-1);
+
+		for(;fillDown ? pos.iY < posYLimit : pos.iY > posYLimit; fillDown ? pos.iY++ : pos.iY--)
+			{
+			if(!iUtil.SetPos(pos-iImageRegion.iTl))
+				{
+				iUtil.End();
+				return ETrue;
+				}
+			iUtil.SetPixels(iIndexBuffer,pixelsToFlush);
+			}
+
+		iPos.iX += pixelsToFlush;
+		if (iPos.iX >= iImageRegion.iBr.iX)
+			{
+			finished = NewLine();
+			if(finished)
+				break;
+			}
+		}
+
+	iUtil.End();
+
+	return finished;
+	}
+
+/**
+ *
+ * @see CImageProcessor.
+ */
+TBool CMonochromePixelWriter::SetPos(const TPoint& aPosition)
+	{
+	if(iImageRegion.Contains(aPosition))
+		{
+		FlushPixels();
+		iPixelsToSkip = 0;
+		iPos = aPosition;
+		return ETrue;
+		}
+
+	return EFalse;
+	}
+
+void CMonochromePixelWriter::Reset()
+	{
+	delete iColorConv;
+	iColorConv = NULL;
+
+	delete[] iGray256Buffer;
+	iGray256Buffer = NULL;
+
+	delete[] iIndexBuffer;
+	iIndexBuffer = NULL;
+
+	iPos.SetXY(0,0);
+	iPixelsToSkip = 0;
+	iImageRegion.SetRect(0,0,0,0);
+	iBlockSize.SetSize(0,0);
+	
+	iDrawBottomUp = EFalse;
+	}
+
+void CMonochromePixelWriter::DoPrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect,const TSize* aBlockSize)
+	{
+	if( (aImageRect.iTl.iX<0) || (aImageRect.iTl.iY<0) || (aImageRect.Size().iWidth>aBitmap.SizeInPixels().iWidth) || (aImageRect.Size().iHeight>aBitmap.SizeInPixels().iHeight) )
+		{
+		User::Leave(KErrArgument);
+		}
+
+	Reset();
+
+	iImageRegion = aImageRect;
+
+	iColorConv = TColorConvertor::NewL(aBitmap.DisplayMode());
+	iUtil.SetBitmapL(&aBitmap);
+
+	if (aBlockSize)
+		{
+		if (aBlockSize->iWidth <= 0 || aBlockSize->iHeight <= 0)
+			{
+			User::Leave(KErrArgument);
+			}
+
+		iBlockSize = *aBlockSize;
+		iBlockArea = iBlockSize.iWidth * iBlockSize.iHeight;
+		
+		ASSERT(iIndexBuffer == NULL);
+		iIndexBuffer = new(ELeave) TUint32[iBlockArea];
+
+		iIndexBufferPtrLimit = iIndexBuffer + iBlockArea;
+		CreateBlockBufferL(iBlockArea);
+		
+		switch(iOperation)
+			{
+			case EDecodeRotate180:
+			case EDecodeRotate270:
+			case EDecodeHorizontalFlip:
+			case EDecodeVerticalFlipRotate90:
+				iDrawBottomUp = ETrue;
+				break;
+			default:
+				iDrawBottomUp = EFalse;		
+			}
+		
+		iYInc = iDrawBottomUp ? -iBlockSize.iHeight : iBlockSize.iHeight;
+		iStartPosition.SetXY(iImageRegion.iTl.iX, iDrawBottomUp ? iImageRegion.iBr.iY - 1 : 0);
+		iEndPosition.SetXY(iImageRegion.iBr.iX, iDrawBottomUp ?
+							iImageRegion.iTl.iY - 1 : iImageRegion.iBr.iY);
+		iPos = iStartPosition;
+		}
+	else
+		{
+		iPos = iImageRegion.iTl;
+		iStartPosition = iPos;
+		iEndPosition = aImageRect.iBr;
+
+		ASSERT(iGray256Buffer == NULL);
+		iGray256Buffer = new(ELeave) TUint32[KPixelWriterBufferSize];
+
+		iGray256BufferPtr = iGray256Buffer;
+		iGray256BufferPtrLimit = iGray256Buffer + KPixelWriterBufferSize;
+
+		ASSERT(iIndexBuffer == NULL);
+		iIndexBuffer = new(ELeave) TUint32[KPixelWriterBufferSize];
+
+		iIndexBufferPtrLimit = iIndexBuffer + KPixelWriterBufferSize;
+		}
+	
+	for(TInt i=0; i<256; i++)
+		{
+		iIndexLookup[i] = iColorConv->ColorIndex(TRgb(i,i,i));	
+		}
+	}
+
+TBool CMonochromePixelWriter::NewLine()
+	{
+	iPos.iX = iStartPosition.iX;
+	iPos.iY += iYInc;
+
+	if(iPos.iY < iStartPosition.iY || iPos.iY >= iEndPosition.iY)
+		{
+		return ETrue;
+		}
+	
+	iPixelsToSkip = iPixelPadding;
+	return EFalse;
+	}
+
+void CMonochromePixelWriter::SetPixelBlockIndex(TUint32* aGray256Buffer)
+	{
+	CMonochromePixelWriter::SetPixelBufferIndex(aGray256Buffer,iBlockArea);
+	}
+
+void CMonochromePixelWriter::SetPixelBufferIndex(TUint32* aGray256Buffer,TInt aCount)
+	{
+	TUint32* indexBufferPtr = iIndexBuffer;
+	TUint32* indexBufferPtrLimit = indexBufferPtr+aCount;
+	TUint32* indexLookup = iIndexLookup;
+
+	if(aCount&1)
+		*indexBufferPtr++ = indexLookup[*aGray256Buffer++];
+	if(aCount&2)
+		{
+		*indexBufferPtr++ = indexLookup[*aGray256Buffer++];
+		*indexBufferPtr++ = indexLookup[*aGray256Buffer++];
+		}
+	while (indexBufferPtr < indexBufferPtrLimit)
+		{
+		*indexBufferPtr++ = indexLookup[*aGray256Buffer++];
+		*indexBufferPtr++ = indexLookup[*aGray256Buffer++];
+		*indexBufferPtr++ = indexLookup[*aGray256Buffer++];
+		*indexBufferPtr++ = indexLookup[*aGray256Buffer++];
+		}
+	}
+
+//
+// CErrorDiffuser::TColorError
+//
+
+inline CErrorDiffuser::TColorError::TColorError():
+	iRedError(0),
+	iGreenError(0),
+	iBlueError(0)
+	{}
+
+inline CErrorDiffuser::TColorError::TColorError(TInt aRedError,TInt aGreenError,TInt aBlueError):
+	iRedError(aRedError),
+	iGreenError(aGreenError),
+	iBlueError(aBlueError)
+	{}
+
+inline void CErrorDiffuser::TColorError::AdjustColor(TRgb& aColor) const
+	{
+	TInt red = ColorCcomponent::ClampColorComponent((iRedError >> 4) + aColor.Red());
+	TInt green = ColorCcomponent::ClampColorComponent((iGreenError >> 4) + aColor.Green());
+	TInt blue = ColorCcomponent::ClampColorComponent((iBlueError >> 4) + aColor.Blue());
+	aColor = TRgb(red,green,blue);
+	}
+
+inline void CErrorDiffuser::TColorError::SetError(TRgb aIdealColor,TRgb aActualColor)
+	{
+	iRedError = aIdealColor.Red() - aActualColor.Red();
+	iGreenError = aIdealColor.Green() - aActualColor.Green();
+	iBlueError = aIdealColor.Blue() - aActualColor.Blue();
+	}
+
+inline CErrorDiffuser::TColorError CErrorDiffuser::TColorError::operator+(const TColorError& aColorError) const
+	{
+	TInt redError = iRedError + aColorError.iRedError;
+	TInt greenError = iGreenError + aColorError.iGreenError;
+	TInt blueError = iBlueError + aColorError.iBlueError;
+	return TColorError(redError,greenError,blueError);
+	}
+
+inline CErrorDiffuser::TColorError CErrorDiffuser::TColorError::operator-(const TColorError& aColorError) const
+	{
+	TInt redError = iRedError - aColorError.iRedError;
+	TInt greenError = iGreenError - aColorError.iGreenError;
+	TInt blueError = iBlueError - aColorError.iBlueError;
+	return TColorError(redError,greenError,blueError);
+	}
+
+inline CErrorDiffuser::TColorError CErrorDiffuser::TColorError::operator<<(TInt aShift) const
+	{
+	TInt redError = iRedError << aShift;
+	TInt greenError = iGreenError << aShift;
+	TInt blueError = iBlueError << aShift;
+	return TColorError(redError,greenError,blueError);
+	}
+
+inline CErrorDiffuser::TColorError& CErrorDiffuser::TColorError::operator+=(const TColorError& aColorError)
+	{
+	iRedError += aColorError.iRedError;
+	iGreenError += aColorError.iGreenError;
+	iBlueError += aColorError.iBlueError;
+	return *this;
+	}
+
+CErrorDiffuser::CErrorDiffuser()
+	{
+	}
+
+CErrorDiffuser::~CErrorDiffuser()
+	{
+	Reset();
+	}
+
+void CErrorDiffuser::DoPrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect,const TSize* aBlockSize)
+	{
+	CPixelWriter::DoPrepareL(aBitmap,aImageRect,aBlockSize);
+
+	TInt scanlineErrorBufferLength = iImageRegion.iBr.iX+2;
+
+	if (iBlockArea > 0)
+		{
+		ASSERT(iEdgeErrorBuffer == NULL);
+		iEdgeErrorBuffer = new(ELeave) TColorError[iBlockSize.iHeight];
+
+		scanlineErrorBufferLength += iBlockSize.iWidth;
+		}
+
+	ASSERT(iScanlineErrorBuffer == NULL);
+	iScanlineErrorBuffer = new(ELeave) TColorError[scanlineErrorBufferLength];
+
+	if (iDisplayMode == EColor64K) 
+		{
+			ASSERT(iRedErrorLookupTable == NULL);
+			iRedErrorLookupTable = new(ELeave) TInt8[256];
+			ASSERT(iGreenErrorLookupTable == NULL);
+			iGreenErrorLookupTable = new(ELeave) TInt8[256];
+			
+			for (TInt i=0;i<256;i++) 
+				{
+					TInt tmp = i & 0xf8;
+					iRedErrorLookupTable[i] = i - (tmp | (tmp >> 5));
+					tmp = i & 0xfc;
+					iGreenErrorLookupTable[i] = i - (tmp | (tmp >> 6));
+				}
+		}
+	}
+
+void CErrorDiffuser::SetPixelBufferIndex(TRgb* aColorBuffer,TInt aCount)
+	{
+	// use optimized function for EColor64K mode
+	if (iDisplayMode == EColor64K) 
+		{
+		SetPixelBufferColor64KIndex(aColorBuffer, aCount);
+		return;
+		}
+
+	TInt clearX = iPos.iX;
+
+	TInt yDiff = iPos.iY - iLastPos.iY;
+	if(yDiff != 0)									// On a new line?
+		{
+		new(&iNextError) TColorError;
+		clearX = iImageRegion.iBr.iX;				// To clear to end of line
+
+		if(yDiff == -1 || yDiff == 1)				// Now on ajacent line?
+			{
+			clearX -= iLastPos.iX;					// Clear end of previous line
+			if(clearX)
+				{
+				Mem::FillZ(iScanlineErrorBuffer + iLastPos.iX + 2, clearX * sizeof(TColorError));
+				}
+			clearX = iPos.iX;						// To clear up to current position
+			}
+		iLastPos.iX = iImageRegion.iTl.iX;			// Start of this line
+		}
+
+	clearX -= iLastPos.iX;
+	if(clearX > 0)									// Treat any skipped pixels as if they produced no error
+		{
+		new(&iNextError) TColorError;
+		Mem::FillZ(iScanlineErrorBuffer + iLastPos.iX + 2, clearX * sizeof(TColorError));
+		}
+
+	iLastPos.iY = iPos.iY;
+	iLastPos.iX = iPos.iX+aCount;
+
+	TUint32* indexBufferPtr = iIndexBuffer;
+	TUint32* indexBufferPtrLimit = indexBufferPtr+aCount;
+	TColorError* scanlineErrorBufferPtr = iScanlineErrorBuffer + iPos.iX;
+	TColorError error;
+	TRgb color;
+
+	while(indexBufferPtr<indexBufferPtrLimit)
+		{
+		color = *aColorBuffer++;
+
+		iNextError.AdjustColor(color);
+		TUint32 index = iColorConv->ColorIndex(color);
+		*indexBufferPtr++ = index;
+
+		error.SetError(color, iColorConv->Color(index));
+
+		iNextError = (error << 3) - error; // Set right error for this pixel
+
+		*scanlineErrorBufferPtr++ += error + (error << 1); // Set left-down error for this pixel
+
+		*scanlineErrorBufferPtr += error + (error << 2); // Set down error for this pixel
+
+		iNextError += *(scanlineErrorBufferPtr+1);
+
+		*(scanlineErrorBufferPtr+1) = error; // Set right-down error for this pixel
+		}
+	}
+
+// faster function (see listing) then Bitmap Util ClampColorComponent
+inline TInt CErrorDiffuser::ClipColorComponent(TInt value)
+    {
+    if (TUint(value) > 0xFF)
+        {
+        value = value < 0 ? 0 : 0xFF;
+        }
+    return value;
+    }
+
+void CErrorDiffuser::SetPixelBufferColor64KIndex(TRgb* aColorBuffer,TInt aCount)
+	{
+	TInt clearX = iPos.iX;
+
+	TInt yDiff = iPos.iY - iLastPos.iY;
+	if(yDiff != 0)									// On a new line?
+		{
+		iNextRedError = 0;
+		iNextGreenError = 0;
+		iNextBlueError = 0;
+		clearX = iImageRegion.iBr.iX;				// To clear to end of line
+
+		if(yDiff == -1 || yDiff == 1)				// Now on ajacent line?
+			{
+			clearX -= iLastPos.iX;					// Clear end of previous line
+			if(clearX > 0) 
+				{
+				Mem::FillZ(iScanlineErrorBuffer + iLastPos.iX + 2, clearX * sizeof(TColorError));
+				}
+			clearX = iPos.iX;						// To clear up to current position
+			}
+		iLastPos.iX = iImageRegion.iTl.iX;			// Start of this line
+		}
+
+	clearX -= iLastPos.iX;
+	if(clearX > 0)									// Treat any skipped pixels as if they produced no error
+		{
+		iNextRedError = 0;
+		iNextGreenError = 0;
+		iNextBlueError = 0;
+		Mem::FillZ(iScanlineErrorBuffer + iLastPos.iX + 2, clearX * sizeof(TColorError));
+		}
+
+	iLastPos.iY = iPos.iY;
+	iLastPos.iX = iPos.iX+aCount;
+
+	TUint32* indexBufferPtr = iIndexBuffer;
+	TUint32* indexBufferPtrLimit = indexBufferPtr+aCount;
+
+	TColorError* scanlineErrorBufferPtr = iScanlineErrorBuffer + iPos.iX;
+
+	TInt redError = iNextRedError;
+	TInt greenError = iNextGreenError;
+	TInt blueError = iNextBlueError;
+	
+	while(indexBufferPtr<indexBufferPtrLimit)
+		{
+		// red			
+		register TInt red = aColorBuffer->Red();
+		red = ClipColorComponent(red + (redError >> 4));
+
+		register TInt error = iRedErrorLookupTable[red];
+		
+		// Set right error for red component
+		scanlineErrorBufferPtr->iRedError += error + (error << 1); // Set left-down error for this pixel
+		(scanlineErrorBufferPtr+1)->iRedError += error + (error << 2); // Set down error for this pixel
+		redError = (scanlineErrorBufferPtr+2)->iRedError + (error << 3) - error; // Set right error for this pixel
+		(scanlineErrorBufferPtr+2)->iRedError = error; // Set right-down error for this pixel
+
+		// green			
+		register TInt green = aColorBuffer->Green();
+			
+		green = ClipColorComponent(green + (greenError >> 4));
+
+		error = iGreenErrorLookupTable[green];
+		
+		// Set right error for green component
+		scanlineErrorBufferPtr->iGreenError += error + (error << 1); // Set left-down error for this pixel
+		(scanlineErrorBufferPtr+1)->iGreenError += error + (error << 2); // Set down error for this pixel
+		greenError = (scanlineErrorBufferPtr+2)->iGreenError + (error << 3) - error; // Set right error for this pixel
+		(scanlineErrorBufferPtr+2)->iGreenError = error; // Set right-down error for this pixel
+
+		// blue			
+		register TInt blue = aColorBuffer->Blue();
+			
+		blue = ClipColorComponent(blue + (blueError >> 4));
+		
+		*indexBufferPtr++ = ((red & 0xf8) << 8) | ((green & 0xfc) << 3) | ((blue & 0xf8) >> 3);
+		
+		error = iRedErrorLookupTable[blue];// use the same lookup table for blue color
+
+		// Set right error for blue component
+		scanlineErrorBufferPtr->iBlueError += error + (error << 1); // Set left-down error for this pixel
+		(scanlineErrorBufferPtr+1)->iBlueError += error + (error << 2); // Set down error for this pixel
+		blueError = (scanlineErrorBufferPtr+2)->iBlueError + (error << 3) - error; // Set right error for this pixel
+		(scanlineErrorBufferPtr+2)->iBlueError = error; // Set right-down error for this pixel
+
+		scanlineErrorBufferPtr++;
+		aColorBuffer++;
+		}
+
+		iNextRedError = redError;
+		iNextGreenError = greenError;
+		iNextBlueError = blueError;
+
+
+	}
+
+void CErrorDiffuser::SetPixelBlockIndex(TRgb* aColorBuffer)
+	{
+	if(iPos.iY!=iLastPos.iY)
+		{
+		Mem::FillZ(iEdgeErrorBuffer,sizeof(TColorError) * iBlockSize.iHeight);
+		}
+
+	TUint32* indexBufferPtr = iIndexBuffer;
+
+	TColorError error;
+	TColorError* edgeErrorBuffer = iEdgeErrorBuffer;
+
+	for (TInt row = 0; row < iBlockSize.iHeight; row++)
+		{
+		TColorError* errorValue = iScanlineErrorBuffer + iPos.iX;
+		TColorError nextError = *edgeErrorBuffer + *errorValue;
+		*edgeErrorBuffer = error;
+
+		for (TInt col = 0; col < iBlockSize.iWidth; col++)
+			{
+			TRgb bufferColor = *aColorBuffer++;
+			nextError.AdjustColor(bufferColor);
+
+			TUint32 index = iColorConv->ColorIndex(bufferColor);
+			*indexBufferPtr++ = index;
+
+			error.SetError(bufferColor,iColorConv->Color(index));
+
+			if (col > 0)
+				*(errorValue - 1) += error + (error << 1); // Set left-down error for this pixel
+			else
+				*errorValue = error + (error << 1);
+
+			*errorValue += error + (error << 2); // Set down error for this pixel
+			errorValue++;
+
+			nextError = (error << 3) - error; // Set right error for this pixel
+
+			if (col < iBlockSize.iWidth)
+				{
+				nextError += *errorValue;
+				*errorValue = error; // Set right-down error for this pixel
+				}
+
+			}
+
+		*edgeErrorBuffer++ += nextError;
+		}
+
+	iLastPos.iY = iPos.iY;
+	iLastPos.iX = iPos.iX+iBlockSize.iWidth;
+	}
+
+void CErrorDiffuser::Reset()
+	{
+	CPixelWriter::Reset();
+
+	delete[] iScanlineErrorBuffer;
+	iScanlineErrorBuffer = NULL;
+
+	delete[] iEdgeErrorBuffer;
+	iEdgeErrorBuffer = NULL;
+	
+	delete iRedErrorLookupTable;
+	iRedErrorLookupTable = NULL;
+	
+	delete iGreenErrorLookupTable;
+	iGreenErrorLookupTable = NULL;
+
+	}
+
+//
+// CMonochromeErrorDiffuser
+//
+
+
+/**
+ *
+ * Static factory function to create CMonochromeErrorDiffuser objects.
+ *
+ * @return  Pointer to a fully constructed CMonochromeErrorDiffuser object. 
+ */
+CMonochromeErrorDiffuser* CMonochromeErrorDiffuser::NewL()
+	{
+	return new(ELeave) CMonochromeErrorDiffuser;
+	}
+
+CMonochromeErrorDiffuser::CMonochromeErrorDiffuser()
+	{}
+
+CMonochromeErrorDiffuser::~CMonochromeErrorDiffuser()
+	{
+	Reset();
+	}
+
+void CMonochromeErrorDiffuser::DoPrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect,const TSize* aBlockSize)
+	{
+	CMonochromePixelWriter::DoPrepareL(aBitmap,aImageRect,aBlockSize);
+
+	TInt scanlineErrorBufferLength = iImageRegion.iBr.iX+2;
+
+	if (iBlockArea > 0)
+		{
+		ASSERT(iEdgeErrorBuffer == NULL);
+		iEdgeErrorBuffer = new(ELeave) TInt[iBlockSize.iHeight];
+
+		Mem::FillZ(iEdgeErrorBuffer,sizeof(TInt) * iBlockSize.iHeight);
+		scanlineErrorBufferLength += iBlockSize.iWidth;
+		}
+
+	ASSERT(iScanlineErrorBuffer == NULL);
+	iScanlineErrorBuffer = new(ELeave) TInt[scanlineErrorBufferLength];
+
+	Mem::FillZ(iScanlineErrorBuffer,sizeof(TInt) * scanlineErrorBufferLength);
+	}
+
+void CMonochromeErrorDiffuser::SetPixelBufferIndex(TUint32* aGray256Buffer,TInt aCount)
+	{
+	TInt clearX = iPos.iX;
+
+	TInt yDiff = iPos.iY - iLastPos.iY;
+	if(yDiff != 0)									// On a new line?
+		{
+		iNextError = 0;
+		clearX = iImageRegion.iBr.iX;				// To clear to end of line
+
+		if(yDiff == -1 || yDiff == 1)				// Now on ajacent line?
+			{
+			clearX -= iLastPos.iX;					// Clear end of previous line
+			if(clearX)
+				Mem::FillZ(iScanlineErrorBuffer + iLastPos.iX + 2, clearX * sizeof(TInt));
+			clearX = iPos.iX;						// To clear up to current position
+			}
+		iLastPos.iX = iImageRegion.iTl.iX;			// Start of this line
+		}
+
+	clearX -= iLastPos.iX;
+	if(clearX > 0)									// Treat any skipped pixels as if they produced no error
+		{
+		iNextError = 0;
+		Mem::FillZ(iScanlineErrorBuffer + iLastPos.iX + 2, clearX * sizeof(TInt));
+		}
+
+	iLastPos.iY = iPos.iY;
+	iLastPos.iX = iPos.iX+aCount;
+
+	TUint32* indexBufferPtr = iIndexBuffer;
+	TUint32* indexBufferPtrLimit = indexBufferPtr+aCount;
+
+	TInt* scanlineErrorBufferPtr = iScanlineErrorBuffer + iPos.iX;
+	TInt nextError = iNextError;
+
+	while(indexBufferPtr<indexBufferPtrLimit)
+		{
+		TInt gray256 = *aGray256Buffer++;
+
+		TInt error = gray256 + (nextError >> 4);
+		TUint32 index = iIndexLookup[ColorCcomponent::ClampColorComponent(error)];
+		*indexBufferPtr++ = index;
+
+		error -= TColorConvertor::RgbToMonochrome(iColorConv->Color(index));
+
+		nextError = (error << 3) - error; // Set right error for this pixel
+
+		*scanlineErrorBufferPtr++ += error + (error << 1); // Set left-down error for this pixel
+
+		*scanlineErrorBufferPtr += error + (error << 2); // Set down error for this pixel
+
+		nextError += *(scanlineErrorBufferPtr+1);
+
+		*(scanlineErrorBufferPtr+1) = error; // Set right-down error for this pixel
+		}
+
+	iNextError = nextError;
+	}
+
+void CMonochromeErrorDiffuser::SetPixelBlockIndex(TUint32* aGray256Buffer)
+	{
+	if(iPos.iY!=iLastPos.iY)
+		{
+		Mem::FillZ(iEdgeErrorBuffer,sizeof(TInt) * iBlockSize.iHeight);
+		}
+
+	TUint32* indexBufferPtr = iIndexBuffer;
+
+	TInt error = 0;
+	TInt* edgeErrorBuffer = iEdgeErrorBuffer;
+
+	for (TInt row = 0; row < iBlockSize.iHeight; row++)
+		{
+		TInt* errorValue = iScanlineErrorBuffer + iPos.iX;
+		TInt nextError = *edgeErrorBuffer + *errorValue;
+		*edgeErrorBuffer = error;
+
+		for (TInt col = 0; col < iBlockSize.iWidth; col++)
+			{
+			TInt gray256 = *aGray256Buffer++;
+
+			error = gray256 + (nextError >> 4); // Same as /16
+			
+			TUint32 index = iIndexLookup[ColorCcomponent::ClampColorComponent(error)];
+			*indexBufferPtr++ = index;
+
+			error -= TColorConvertor::RgbToMonochrome(iColorConv->Color(index));
+
+			if (col > 0)
+				*(errorValue - 1) += error + (error << 1); // Set left-down error for this pixel
+			else
+				*errorValue = error + (error << 1);
+
+			*errorValue += error + (error << 2); // Set down error for this pixel
+			errorValue++;
+
+			nextError = (error << 3) - error; // Set right error for this pixel
+
+			if (col < iBlockSize.iWidth)
+				{
+				nextError += *errorValue;
+				*errorValue = error; // Set right-down error for this pixel
+				}
+			}
+
+		*edgeErrorBuffer++ += nextError;
+		}
+
+	iLastPos.iY = iPos.iY;
+	iLastPos.iX = iPos.iX+iBlockSize.iWidth;
+	}
+
+void CMonochromeErrorDiffuser::Reset()
+	{
+	CMonochromePixelWriter::Reset();
+
+	delete[] iScanlineErrorBuffer;
+	iScanlineErrorBuffer = NULL;
+
+	delete[] iEdgeErrorBuffer;
+	iEdgeErrorBuffer = NULL;
+	}
+
+//
+// CThumbnailProcessor
+//
+
+/**
+ *
+ * Static factory function to create CThumbnailProcessor objects.
+ *
+ * @param	"aImageProc"
+ *          A pointer to an externally constructed CImageProcessorExtension object.
+ *          This will be deleted when the CThumbnailProcessor object is deleted.
+ * @param	"aReductionFactor"
+ *          The reduction factor to use.
+ * @return  Pointer to a fully constructed CThumbnailProcessor object. 
+ */
+CThumbnailProcessor* CThumbnailProcessor::NewL(CImageProcessorExtension* aImageProc,TInt aReductionFactor)
+	{
+	return new(ELeave) CThumbnailProcessor(aImageProc,aReductionFactor);
+	}
+
+CThumbnailProcessor::CThumbnailProcessor(CImageProcessorExtension* aImageProc,TInt aReductionFactor):
+	iImageProc(aImageProc),
+	iYInc(1),
+	iReductionFactor(aReductionFactor)
+		{}
+
+CThumbnailProcessor::~CThumbnailProcessor()
+	{
+	delete iImageProc;
+	delete[] iReducedPixelBuffer;
+	delete[] iReducedSumBuffer;
+	}
+
+void CThumbnailProcessor::PrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect)
+	{
+	PrepareCommonL(aImageRect);
+	iYInc = 1;
+
+	TInt bufferSize = (iImageRegion.iBr.iX + (1<<iReductionFactor) -1 ) >> iReductionFactor;
+
+	ASSERT(iReducedSumBuffer == NULL);
+	iReducedSumBuffer = new(ELeave) TColorSum[bufferSize];
+	Mem::FillZ(iReducedSumBuffer,bufferSize * sizeof(TColorSum));
+
+	iImageProc->PrepareL(aBitmap,iReducedImageRegion);
+
+	ASSERT(iReducedPixelBuffer == NULL);
+	iReducedPixelBuffer = new(ELeave) TRgb[iReducedImageRegion.iBr.iX];
+	}
+
+void CThumbnailProcessor::PrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect,const TSize& aRgbBlockSize)
+	{
+	PrepareCommonL(aImageRect);
+
+	CreateBlockBufferL(aRgbBlockSize.iWidth*aRgbBlockSize.iHeight);
+
+	iOriginalBlockSize = aRgbBlockSize;
+	iYInc = iDrawBottomUp ? -iOriginalBlockSize.iHeight : iOriginalBlockSize.iHeight;
+
+	iReducedBlockSize = aRgbBlockSize;
+	iReducedBlockSize.iWidth >>= iReductionFactor;
+	iReducedBlockSize.iHeight >>= iReductionFactor;
+
+	iImageProc->SetInitialScanlineSkipPadding(iNumberOfScanlinesToSkip >> iReductionFactor);
+	iImageProc->SetPixelPadding(iPixelPadding >> iReductionFactor);
+	iImageProc->PrepareL(aBitmap,iReducedImageRegion,iReducedBlockSize);
+
+	ASSERT(iReducedPixelBuffer == NULL);
+	iReducedPixelBuffer = new(ELeave) TRgb[iReducedBlockSize.iWidth * iReducedBlockSize.iHeight];
+	}
+
+void CThumbnailProcessor::PrepareCommonL(const TRect& aImageRect)
+	{
+	ASSERT(iReductionFactor > 0);
+	iImageRegion = aImageRect;
+
+	TInt roundUp = (1<<iReductionFactor)-1;
+	iReducedImageRegion.iTl.iX = aImageRect.iTl.iX >> iReductionFactor;
+	iReducedImageRegion.iTl.iY = aImageRect.iTl.iY >> iReductionFactor;
+	
+	TSize size = aImageRect.Size();
+	size.iWidth = (size.iWidth + roundUp) >> iReductionFactor;
+	size.iHeight = (size.iHeight + roundUp) >> iReductionFactor;
+	iReducedImageRegion.iBr = iReducedImageRegion.iTl + size;
+
+	switch(iOperation)
+		{
+		case EDecodeRotate180:
+		case EDecodeRotate270:
+		case EDecodeHorizontalFlip:
+		case EDecodeVerticalFlipRotate90:
+			iDrawBottomUp = ETrue;
+			iImageProc->SetOperation(iOperation);
+			break;
+		default:
+			iDrawBottomUp = EFalse;
+		}
+	iStartPosition.SetXY(iImageRegion.iTl.iX, iDrawBottomUp ? aImageRect.iBr.iY - 1 : 0);
+	iEndPosition.SetXY(aImageRect.iBr.iX, iDrawBottomUp ? aImageRect.iTl.iY - 1 : aImageRect.iBr.iY);
+	iPos = iStartPosition;
+
+	iPositionChanged = ETrue;
+
+	iEndOfLineX = iEndPosition.iX + iPixelPadding;
+
+	delete[] iReducedPixelBuffer;
+	iReducedPixelBuffer = NULL;
+
+	delete[] iReducedSumBuffer;
+	iReducedSumBuffer = NULL;
+	}
+
+TBool CThumbnailProcessor::SetPixel(TRgb aColor)
+	{
+	TInt x = iPos.iX;
+
+	if (x < iImageRegion.iBr.iX)
+		{
+		TColorSum* sumPtr = iReducedSumBuffer + (x >> iReductionFactor);
+		sumPtr->iRed += aColor.Red();
+		sumPtr->iGreen += aColor.Green();
+		sumPtr->iBlue += aColor.Blue();
+		sumPtr->iCount++;
+		}
+
+	x++;
+	iPos.iX = x;
+
+	if (x == iEndOfLineX)
+		return NewLine();
+
+	return EFalse;
+	}
+
+TBool CThumbnailProcessor::NewLine()
+	{
+	TInt newY = iPos.iY + iYInc;
+
+	TBool finished = (newY < iStartPosition.iY || newY >= iEndPosition.iY);
+	TBool outsideOfBuffer = ((newY ^ iPos.iY) >> iReductionFactor) != 0;
+
+	if(finished || outsideOfBuffer)
+		{
+		DoFlushPixels();
+		}
+
+	iPos.iX = iStartPosition.iX;
+	iPos.iY = newY;
+
+	if(iPositionChanged && outsideOfBuffer)
+		{
+		iImageProc->SetPos(TPoint(iPos.iX >> iReductionFactor,iPos.iY >> iReductionFactor));
+		iPositionChanged = EFalse;
+		}
+
+	return finished;
+	}
+
+TBool CThumbnailProcessor::SetPixelBlock(TRgb* aColorBuffer)
+	{
+	if ((iPos.iX >> iReductionFactor) < iReducedImageRegion.iBr.iX)
+		{
+		ASSERT(aColorBuffer);
+
+		if(iPositionChanged)
+			{
+			iImageProc->SetPos(TPoint(iPos.iX >> iReductionFactor,iPos.iY >> iReductionFactor));
+			iPositionChanged = EFalse;
+			}
+
+		TInt xOuterStop = iReducedBlockSize.iWidth<<iReductionFactor;
+		TInt yOuterStop = iReducedBlockSize.iHeight<<iReductionFactor;
+
+		TInt outerStep = 1<<iReductionFactor;
+		TInt divisionFactor = 2*iReductionFactor;
+
+		TRgb* reducedPixelBuffer = iReducedPixelBuffer;
+
+		for (TInt yOuter = 0; yOuter < yOuterStop; yOuter += outerStep)
+			{
+			for (TInt xOuter = 0; xOuter < xOuterStop; xOuter += outerStep)
+				{
+				TRgb* colorBuffer = &aColorBuffer[yOuter * iOriginalBlockSize.iWidth + xOuter];
+				TInt red = 0;
+				TInt green = 0;
+				TInt blue = 0;
+
+				for (TInt yInner = 0; yInner < outerStep; yInner++)
+					{
+					for (TInt xInner = 0; xInner < outerStep; xInner++)
+						{
+						red += colorBuffer[xInner].Red();
+						green += colorBuffer[xInner].Green();
+						blue += colorBuffer[xInner].Blue();
+						}
+					colorBuffer += iOriginalBlockSize.iWidth;
+					}
+
+				red >>= divisionFactor;
+				green >>= divisionFactor;
+				blue >>= divisionFactor;
+
+				*reducedPixelBuffer++ = TRgb(red,green,blue);
+				}
+			}
+
+		iImageProc->SetPixelBlock(iReducedPixelBuffer);
+		}
+
+	iPos.iX += iOriginalBlockSize.iWidth;
+	if (iPos.iX >= iEndOfLineX)
+		{
+		iPos.iX = iStartPosition.iX;
+		iPos.iY += iYInc;
+		if(iPos.iY < iStartPosition.iY || iPos.iY >= iEndPosition.iY)
+			{
+			return ETrue;
+			}
+		}
+
+	return EFalse;
+
+	}
+
+TBool CThumbnailProcessor::FlushPixels()
+	{
+	DoFlushPixels();
+	iImageProc->FlushPixels();
+
+	iPositionChanged = ETrue;
+
+	if(iPos.iY < iStartPosition.iY || iPos.iY >= iEndPosition.iY)
+		{
+		return ETrue;
+		}
+
+	return EFalse;
+	}
+
+void CThumbnailProcessor::DoFlushPixels()
+	{
+	if(!iReducedSumBuffer)
+		return;
+
+	TColorSum* reducedSumPtr = iReducedSumBuffer + iReducedImageRegion.iTl.iX;
+	TColorSum* reducedSumPtrLimit = iReducedSumBuffer + iReducedImageRegion.iBr.iX;
+
+	while(reducedSumPtr < reducedSumPtrLimit)
+		{
+
+		while(reducedSumPtr->iCount==0)
+			{
+			reducedSumPtr++;
+			if(reducedSumPtr==reducedSumPtrLimit)
+				return;
+			}
+
+		if(iPositionChanged)
+			iImageProc->SetPos(TPoint(reducedSumPtr - iReducedSumBuffer,iPos.iY >> iReductionFactor));
+
+		TRgb* reducedPixelBufferPtr = iReducedPixelBuffer;
+		TInt fullCountFactor = 2*iReductionFactor;
+
+		while(reducedSumPtr < reducedSumPtrLimit)
+			{
+			TInt count = reducedSumPtr->iCount;
+			TUint32 red;
+			TUint32 green;
+			TUint32 blue;
+
+			if(count == (1<<fullCountFactor))
+				{
+				red = reducedSumPtr->iRed >> fullCountFactor;
+				green = reducedSumPtr->iGreen >> fullCountFactor;
+				blue = reducedSumPtr->iBlue >> fullCountFactor;
+				}
+			else if(count!=0)
+				{
+				red = reducedSumPtr->iRed / count;
+				green = reducedSumPtr->iGreen / count;
+				blue = reducedSumPtr->iBlue / count;
+				}
+			else
+				break;
+
+			*reducedPixelBufferPtr++ = TRgb(red,green,blue);
+
+			reducedSumPtr++;
+			}
+
+		TInt numPixels = reducedPixelBufferPtr-iReducedPixelBuffer;
+		iImageProc->SetPixels(iReducedPixelBuffer,numPixels);
+
+		Mem::FillZ(reducedSumPtr-numPixels,numPixels * sizeof(TColorSum));
+		}
+
+	}
+
+TBool CThumbnailProcessor::SetPos(const TPoint& aPosition)
+	{
+	if(iImageRegion.Contains(aPosition)==EFalse)
+		return EFalse;
+
+	if((aPosition.iY ^ iPos.iY) >> iReductionFactor)
+		DoFlushPixels();
+
+	iPositionChanged = ETrue;
+	iPos = aPosition;
+
+	return ETrue;
+	}
+
+void CThumbnailProcessor::SetYPosIncrement(TInt aYInc)
+	{
+	iYInc = aYInc;
+
+	TInt reducedYInc = aYInc >> iReductionFactor;
+	if(reducedYInc==0)
+		reducedYInc = 1;
+
+	iImageProc->SetYPosIncrement(reducedYInc);
+	}
+
+void CThumbnailProcessor::SetLineRepeat(TInt aLineRepeat)
+	{
+	TInt reducedLineRepeat = aLineRepeat >> iReductionFactor;
+	iImageProc->SetLineRepeat(reducedLineRepeat);
+	}
+
+void CThumbnailProcessor::SetPixelPadding(TInt aNumberOfPixels)
+	{
+	iPixelPadding = aNumberOfPixels;
+	iEndOfLineX = iEndPosition.iX + iPixelPadding;
+	}
+
+//
+// CMonochromeThumbnailProcessor
+//
+
+/**
+ *
+ * Static factory function to create CMonochromeThumbnailProcessor objects.
+ *
+ * @param	"aImageProc"
+ *          A pointer to an externally constructed CImageProcessorExtension object.
+ *          This will be deleted when the CMonochromeThumbnailProcessor object is deleted.
+ * @param	aReductionFactor"
+ *          The reduction factor to use.
+ * @return  Pointer to a fully constructed CMonochromeThumbnailProcessor object. 
+ */
+CMonochromeThumbnailProcessor* CMonochromeThumbnailProcessor::NewL(CImageProcessorExtension* aImageProc,TInt aReductionFactor)
+	{
+	return new(ELeave) CMonochromeThumbnailProcessor(aImageProc,aReductionFactor);
+	}
+
+CMonochromeThumbnailProcessor::CMonochromeThumbnailProcessor(CImageProcessorExtension* aImageProc,TInt aReductionFactor):
+	iImageProc(aImageProc),
+	iYInc(1),
+	iReductionFactor(aReductionFactor)
+		{}
+
+CMonochromeThumbnailProcessor::~CMonochromeThumbnailProcessor()
+	{
+	delete iImageProc;
+	delete[] iReducedPixelBuffer;
+	delete[] iReducedSumBuffer;
+	}
+
+void CMonochromeThumbnailProcessor::PrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect)
+	{
+	PrepareCommonL(aImageRect);
+	iYInc = 1;
+	
+	TInt bufferSize = (iImageRegion.iBr.iX + (1<<iReductionFactor) -1 ) >> iReductionFactor;
+
+	ASSERT(iReducedSumBuffer == NULL);
+	iReducedSumBuffer = new(ELeave) TMonochromeSum[bufferSize];
+	Mem::FillZ(iReducedSumBuffer,bufferSize * sizeof(TMonochromeSum));
+
+	iImageProc->PrepareL(aBitmap,iReducedImageRegion);
+
+	ASSERT(iReducedPixelBuffer == NULL);
+	iReducedPixelBuffer = new(ELeave) TUint32[iReducedImageRegion.iBr.iX];
+	}
+
+void CMonochromeThumbnailProcessor::PrepareL(CFbsBitmap& aBitmap,const TRect& aImageRect,const TSize& aRgbBlockSize)
+	{
+	PrepareCommonL(aImageRect);
+
+	CreateBlockBufferL(aRgbBlockSize.iWidth*aRgbBlockSize.iHeight);
+
+	iOriginalBlockSize = aRgbBlockSize;
+	iYInc = iDrawBottomUp ? -iOriginalBlockSize.iHeight : iOriginalBlockSize.iHeight;
+
+
+	iReducedBlockSize = aRgbBlockSize;
+	iReducedBlockSize.iWidth >>= iReductionFactor;
+	iReducedBlockSize.iHeight >>= iReductionFactor;
+
+	iImageProc->SetInitialScanlineSkipPadding(iNumberOfScanlinesToSkip >> iReductionFactor);
+	iImageProc->SetPixelPadding(iPixelPadding >> iReductionFactor);
+	iImageProc->PrepareL(aBitmap,iReducedImageRegion,iReducedBlockSize);
+
+	ASSERT(iReducedPixelBuffer == NULL);
+	iReducedPixelBuffer = new(ELeave) TUint32[iReducedBlockSize.iWidth * iReducedBlockSize.iHeight];
+	}
+
+void CMonochromeThumbnailProcessor::PrepareCommonL(const TRect& aImageRect)
+	{
+	ASSERT(iReductionFactor > 0);
+	iImageRegion = aImageRect;
+
+	TInt roundUp = (1<<iReductionFactor)-1;
+	iReducedImageRegion.iTl.iX = aImageRect.iTl.iX >> iReductionFactor;
+	iReducedImageRegion.iTl.iY = aImageRect.iTl.iY >> iReductionFactor;
+
+	TSize size = aImageRect.Size();
+	size.iWidth = (size.iWidth + roundUp) >> iReductionFactor;
+	size.iHeight = (size.iHeight + roundUp) >> iReductionFactor;
+	iReducedImageRegion.iBr = iReducedImageRegion.iTl + size;
+	
+	switch(iOperation)
+		{
+		case EDecodeRotate180:
+		case EDecodeRotate270:
+		case EDecodeHorizontalFlip:
+		case EDecodeVerticalFlipRotate90:
+			iDrawBottomUp = ETrue;
+			iImageProc->SetOperation(iOperation);
+			break;
+		default:
+			iDrawBottomUp = EFalse;
+		}
+	iStartPosition.SetXY(iImageRegion.iTl.iX, iDrawBottomUp ? aImageRect.iBr.iY - 1 : 0);
+	iEndPosition.SetXY(aImageRect.iBr.iX, iDrawBottomUp ? aImageRect.iTl.iY - 1 : aImageRect.iBr.iY);
+	iPos = iStartPosition;
+	
+	iPositionChanged = ETrue;
+
+	iEndOfLineX = iEndPosition.iX + iPixelPadding;
+
+	delete[] iReducedPixelBuffer;
+	iReducedPixelBuffer = NULL;
+
+	delete iReducedSumBuffer;
+	iReducedSumBuffer = NULL;
+	}
+
+TBool CMonochromeThumbnailProcessor::SetMonoPixel(TInt aGray256)
+	{
+	TInt x = iPos.iX;
+
+	if (x < iImageRegion.iBr.iX)
+		{
+		TMonochromeSum* sumPtr = iReducedSumBuffer + (x >> iReductionFactor);
+		sumPtr->iLevel += aGray256;
+		sumPtr->iCount++;
+		}
+
+	x++;
+	iPos.iX = x;
+
+	if (x == iEndOfLineX)
+		return NewLine();
+
+	return EFalse;
+	}
+
+TBool CMonochromeThumbnailProcessor::SetMonoPixelRun(TInt aGray256,TInt aCount)
+	{
+	while (aCount != 0)
+		{
+		TInt x		= iPos.iX;
+		TInt xLimit = x+aCount;
+
+		iPos.iX = xLimit;
+
+		if (xLimit > iImageRegion.iBr.iX)
+			xLimit = iImageRegion.iBr.iX;
+
+		if (xLimit > x)
+			{
+			TInt numPixels = xLimit-x;
+
+			TInt reductionFactor = iReductionFactor;
+			TInt reductionCount = 1<<reductionFactor;	//number of horizontal pixel in a TMonochromeSum
+
+			TMonochromeSum* sumPtr = iReducedSumBuffer + (x >> reductionFactor);
+
+			TInt n = reductionCount-(x&(reductionCount-1));	//number of pixels to complete current TMonochromeSum
+
+			if(numPixels > n)
+				{
+				sumPtr->iCount += n;					//Complete first TMonochromeSum in run
+				sumPtr->iLevel += n * aGray256;
+				sumPtr++;
+				numPixels -= n;
+
+				while(numPixels > reductionCount)			//Complete middle TMonochromeSum(s) in run
+					{
+					sumPtr->iCount += reductionCount;
+					sumPtr->iLevel += aGray256 << reductionFactor;
+					sumPtr++;
+					numPixels -= reductionCount;
+					}
+				}
+
+			sumPtr->iCount += numPixels;				//Update last/only TMonochromeSum in run
+			sumPtr->iLevel += numPixels * aGray256;
+			}
+
+		if (iPos.iX < iEndOfLineX)
+			break;
+
+		aCount = iPos.iX - iEndOfLineX;
+
+		if(NewLine())
+			return ETrue;
+		}
+
+	return EFalse;
+	}
+
+TBool CMonochromeThumbnailProcessor::NewLine()
+	{
+	TInt newY = iPos.iY + iYInc;
+
+	TBool finished = (newY < iStartPosition.iY || newY >= iEndPosition.iY);
+	TBool outsideOfBuffer = ((newY ^ iPos.iY) >> iReductionFactor) != 0;
+
+	if(finished || outsideOfBuffer)
+		{
+		DoFlushPixels();
+		}
+
+	iPos.iX = iStartPosition.iX;
+	iPos.iY = newY;
+
+	if(iPositionChanged && outsideOfBuffer)
+		{
+		iImageProc->SetPos(TPoint(iPos.iX >> iReductionFactor,iPos.iY >> iReductionFactor));
+		iPositionChanged = EFalse;
+		}
+
+	return finished;
+	}
+
+TBool CMonochromeThumbnailProcessor::SetMonoPixelBlock(TUint32* aGray256Buffer)
+	{
+	if ((iPos.iX >> iReductionFactor) < iReducedImageRegion.iBr.iX)
+		{
+		ASSERT(aGray256Buffer);
+
+		if(iPositionChanged)
+			{
+			iImageProc->SetPos(TPoint(iPos.iX >> iReductionFactor,iPos.iY >> iReductionFactor));
+			iPositionChanged = EFalse;
+			}
+
+		TInt xOuterStop = iReducedBlockSize.iWidth<<iReductionFactor;
+		TInt yOuterStop = iReducedBlockSize.iHeight<<iReductionFactor;
+
+		TInt outerStep = 1<<iReductionFactor;
+		TInt divisionFactor = 2*iReductionFactor;
+
+		TUint32* reducedPixelBuffer = iReducedPixelBuffer;
+
+		for (TInt yOuter = 0; yOuter < yOuterStop; yOuter += outerStep)
+			{
+			for (TInt xOuter = 0; xOuter < xOuterStop; xOuter += outerStep)
+				{
+				TUint32* gray256Buffer = &aGray256Buffer[yOuter * iOriginalBlockSize.iWidth + xOuter];
+				TInt level = 0;
+
+				for (TInt yInner = 0; yInner < outerStep; yInner++)
+					{
+					for (TInt xInner = 0; xInner < outerStep; xInner++)
+						level += gray256Buffer[xInner];
+
+					gray256Buffer += iOriginalBlockSize.iWidth;
+					}
+
+				level >>= divisionFactor;
+				*reducedPixelBuffer++ = level;
+				}
+			}
+
+		iImageProc->SetMonoPixelBlock(iReducedPixelBuffer);
+		}
+
+	iPos.iX += iOriginalBlockSize.iWidth;
+	if (iPos.iX >= iEndOfLineX)
+		{
+		iPos.iX = iStartPosition.iX;
+		iPos.iY += iYInc;
+		if(iPos.iY < iStartPosition.iY || iPos.iY >= iEndPosition.iY)
+			{
+			return ETrue;
+			}
+		}
+
+	return EFalse;
+
+	}
+
+TBool CMonochromeThumbnailProcessor::FlushPixels()
+	{
+	DoFlushPixels();
+	iImageProc->FlushPixels();
+
+	iPositionChanged = ETrue;
+
+		if(iPos.iY < iStartPosition.iY || iPos.iY >= iEndPosition.iY)
+			{
+			return ETrue;
+			}
+
+	return EFalse;
+	}
+
+void CMonochromeThumbnailProcessor::DoFlushPixels()
+	{
+	if(!iReducedSumBuffer)
+		return;
+
+	TMonochromeSum* reducedSumPtr = iReducedSumBuffer + iReducedImageRegion.iTl.iX;
+	TMonochromeSum* reducedSumPtrLimit = iReducedSumBuffer + iReducedImageRegion.iBr.iX;
+
+	while(reducedSumPtr < reducedSumPtrLimit)
+		{
+
+		while(reducedSumPtr->iCount==0)
+			{
+			reducedSumPtr++;
+			if(reducedSumPtr==reducedSumPtrLimit)
+				return;
+			}
+
+		if(iPositionChanged)
+			iImageProc->SetPos(TPoint(reducedSumPtr - iReducedSumBuffer,iPos.iY >> iReductionFactor));
+
+		TUint32* reducedPixelBufferPtr = iReducedPixelBuffer;
+		TInt fullCountFactor = 2*iReductionFactor;
+		TInt fullCount = 1<<fullCountFactor;
+
+		do
+			{
+			TInt level = reducedSumPtr->iLevel;
+			TInt count = reducedSumPtr->iCount;
+
+			if(count==fullCount)
+				level >>= fullCountFactor;
+			else if(count!=0)
+				level /= count;
+			else
+				break;
+
+			*reducedPixelBufferPtr++ = level;
+
+			reducedSumPtr++;
+			}
+		while(reducedSumPtr < reducedSumPtrLimit);
+
+		TInt numPixels = reducedPixelBufferPtr-iReducedPixelBuffer;
+		iImageProc->SetMonoPixels(iReducedPixelBuffer,numPixels);
+
+		Mem::FillZ(reducedSumPtr-numPixels,numPixels * sizeof(TMonochromeSum));
+		}
+
+	}
+
+TBool CMonochromeThumbnailProcessor::SetPos(const TPoint& aPosition)
+	{
+	if(iImageRegion.Contains(aPosition)==EFalse)
+		return EFalse;
+
+	if((aPosition.iY ^ iPos.iY) >> iReductionFactor)
+		DoFlushPixels();
+
+	iPositionChanged = ETrue;
+	iPos = aPosition;
+
+	return ETrue;
+	}
+
+void CMonochromeThumbnailProcessor::SetYPosIncrement(TInt aYInc)
+	{
+	iYInc = aYInc;
+
+	TInt reducedYInc = aYInc >> iReductionFactor;
+	if(reducedYInc==0)
+		reducedYInc = 1;
+
+	iImageProc->SetYPosIncrement(reducedYInc);
+	}
+
+void CMonochromeThumbnailProcessor::SetLineRepeat(TInt aLineRepeat)
+	{
+	TInt reducedLineRepeat = aLineRepeat >> iReductionFactor;
+	iImageProc->SetLineRepeat(reducedLineRepeat);
+	}
+
+void CMonochromeThumbnailProcessor::SetPixelPadding(TInt aNumberOfPixels)
+	{
+	iPixelPadding = aNumberOfPixels;
+	iEndOfLineX = iEndPosition.iX + iPixelPadding;
+	}
+