// Copyright (c) 2008-2009 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 "directgdiadapter.h"

 #include "swdirectgdiengine.h"

 #include "swdirectgdiimagesourceimpl.h"

 #include "swdirectgdidriverimpl.h"

 #include <bitdrawinterfaceid.h>

 #include <e32cmn.h>

 #include <bitdraw.h>

 #include <bmalphablend.h>

 #include <graphics/directgdidrawablesource.h>

 #include <pixelformats.h>

 #include "pixelutil.h"

 /**

 Helper class to deal with the case of blending 32-bit MAP source into 16-bit target which is not 

 supported by screen driver CDrawSixteenBppBitmap implementation.

 @publishedPartner

 @prototype

 @deprecated

 */

 class TDrawDeviceWrapper

 	{

 public:

 	TDrawDeviceWrapper(CFbsDrawDevice* aDrawDevice, CGraphicsContext::TDrawMode aDrawMode);

 	inline void WriteLine(TInt aX, TInt aY, TInt aLength, TUint32* aBuffer, CGraphicsContext::TDrawMode aDrawMode);

 private:

 	inline TUint16 ConvertTo64K(TUint32 aColor);

 	inline TUint16 Blend16MapTo64K(TUint16 aDest, TUint32 aSrc);

 	void BlendLine16MapTo64K(TInt aX, TInt aY, TInt aLength, TUint32* aBuffer, CGraphicsContext::TDrawMode aDrawMode);

 	void OriginalWriteLine(TInt aX, TInt aY, TInt aLength, TUint32* aBuffer, CGraphicsContext::TDrawMode aDrawMode);

 private:

 	CFbsDrawDevice* iDrawDevice;

 	TUint32* iBits;

 	typedef void (TDrawDeviceWrapper::*TWriteLineFunc)(TInt,TInt,TInt,TUint32*,CGraphicsContext::TDrawMode);

 	TWriteLineFunc iWriteLineFunc;

 	};

 TDrawDeviceWrapper::TDrawDeviceWrapper(CFbsDrawDevice* aDrawDevice, CGraphicsContext::TDrawMode aDrawMode):

 	iDrawDevice(aDrawDevice)

 	{

 	TAny* interface = NULL;

 	TInt err = iDrawDevice->GetInterface(KFastBlit2InterfaceID, interface);

 	// interface is guaranted to exist for 16-bit and 32-bit draw device

 	GRAPHICS_ASSERT_DEBUG(err == KErrNone, EDirectGdiPanicUnexpectedError);

 	iBits = (TUint32*) reinterpret_cast<MFastBlit2*>(interface)->Bits();

 	// setup which funtion to call here rather tha making decision inside WriteLine which is usually called within

 	// a tight scanline loop

 	iWriteLineFunc = iDrawDevice->DisplayMode() == EColor64K && aDrawMode == CGraphicsContext::EDrawModePEN ? 

 			&TDrawDeviceWrapper::BlendLine16MapTo64K : &TDrawDeviceWrapper::OriginalWriteLine;

 	}

 inline void TDrawDeviceWrapper::WriteLine(TInt aX, TInt aY, TInt aLength, TUint32* aBuffer, CGraphicsContext::TDrawMode aDrawMode)

 	{

 	// calling member functions via pointer to member functions i.e.

 	// (object.*member_fn)(arg)

 	//

 	(this->*iWriteLineFunc)(aX, aY, aLength, aBuffer, aDrawMode);

 	}

 void TDrawDeviceWrapper::OriginalWriteLine(TInt aX, TInt aY, TInt aLength, TUint32* aBuffer, CGraphicsContext::TDrawMode aDrawMode)

 	{

 	iDrawDevice->WriteLine(aX, aY, aLength, aBuffer, aDrawMode);

 	}

 void TDrawDeviceWrapper::BlendLine16MapTo64K(TInt aX, TInt aY, TInt aLength, TUint32* aBuffer, CGraphicsContext::TDrawMode)

 	{

 	TUint16* pixelPtr = reinterpret_cast<TUint16*>(iBits);

 	pixelPtr += (aY * iDrawDevice->LongWidth()) + aX;

 	const TUint32* bufferPtr = aBuffer;

 	const TUint32* bufferPtrLimit = bufferPtr + aLength;

 	while (bufferPtr < bufferPtrLimit)

 		{

 		*pixelPtr = Blend16MapTo64K(*pixelPtr, *bufferPtr);

 		++bufferPtr;

 		++pixelPtr;

 		}

 	}

 inline TUint16 TDrawDeviceWrapper::ConvertTo64K(TUint32 aSrc)

 	{

 	TInt col = (aSrc & 0x0000f8) >> 3;

 	col |= (aSrc & 0x00fc00) >> 5;

 	col |= (aSrc & 0xf80000) >> 8;

 	return col;

 	}

 inline TUint16 TDrawDeviceWrapper::Blend16MapTo64K(TUint16 aDst, TUint32 aSrc)

 	{

 	const TInt alpha = aSrc >> 24;

 	if(alpha == 0x00)

 		{

 		return aDst;

 		}

 	if (alpha == 0xff)

 		{

 		return ConvertTo64K(aSrc);

 		}

 	// extract source components from 16MAP

 	const TInt src_rb = aSrc & 0x00ff00ff;

 	const TInt src_g = aSrc & 0x0000ff00;

 	const TInt oneMinusAlpha = 0x0100 - alpha;

 	// extract destination components from 64K format

     TInt dr = (aDst & 0xf800) >> 8;

     dr += dr >> 5;

     TInt dg = (aDst & 0x07e0) >> 3;

     dg += dg >> 6;

     TInt db = (aDst & 0x001f) << 3;

     db += db >> 5;

 	// combine red and blue components into a word to combine mult in one go

 	TInt dst_rb = (dr << 16) | db;

 	TInt dst_g = dg << 8;

 	// dst and src are in pre-multiplied format (64K can be treated both as pre or non-pre)

 	// dst = src + (1-alpha) * dst

 	//

 	dst_rb = (src_rb + ((oneMinusAlpha * dst_rb) >> 8)) & 0x00ff00ff;

 	dst_g = (src_g + ((oneMinusAlpha * dst_g) >> 8)) & 0x0000ff00;

 	const TUint32 argb = 0xff000000 | dst_rb | dst_g;

 	return ConvertTo64K(argb);

 	}

 //

 // implements MDirectGdiEngine interfaces

 //

 /**

 @see MDirectGdiEngine::DrawResource(const TRect&,const RDirectGdiDrawableSource&,const TDesC8&)

 */

 void CSwDirectGdiEngine::DrawResource(

 		const TRect& aDestRect,

 		const RDirectGdiDrawableSource& aSource,

 		const TDesC8& /*aParam*/)

 	{

 	// DirectGDI reference implementation only support pixel based resource

 	// see CSwDirectGdiDriverImpl::CreateDrawableSource()

 	//

 	CSwDirectGdiImageSourceImpl* imgSrc = NULL;

 	TSize imgSize;

 	if (CheckImageSource(aSource.Handle(), imgSrc, &imgSize) != KErrNone)

 		{

 		return;

 		}

 	// drawing resource unscaled with no rotation

 	//

 	DrawResourceCommon(aDestRect, imgSrc, TRect(TPoint(0,0), imgSize), DirectGdi::EGraphicsRotationNone);

 	}

 /**

 @see MDirectGdiEngine::DrawResource(const TPoint&,const RDirectGdiDrawableSource&,DirectGdi::TGraphicsRotation)

 */

 void CSwDirectGdiEngine::DrawResource(const TPoint& aPos,

 		const RDirectGdiDrawableSource& aSource,

 		DirectGdi::TGraphicsRotation aRotation)

 	{

 	CSwDirectGdiImageSourceImpl* imgSrc = NULL;

 	TSize imgSize;

 	if (CheckImageSource(aSource.Handle(), imgSrc, &imgSize) != KErrNone)

 		{

 		return;

 		}

 	// drawing resource unscaled

 	//

 	// rotation will be applied before scaling, we must create destination rectangle 

 	// that match the size of rotated image

 	TRect destRect(aPos, imgSize);

 	if (aRotation==DirectGdi::EGraphicsRotation90 || aRotation==DirectGdi::EGraphicsRotation270)

 		{

 		// keep the top left corner in the same position but swap width and height

 		destRect.SetWidth(imgSize.iHeight);

 		destRect.SetHeight(imgSize.iWidth);

 		}

 	DrawResourceCommon(destRect, imgSrc, TRect(TPoint(0,0), imgSize), aRotation);

 	}

 /**

 @see MDirectGdiEngine::DrawResource(const TRect&,const RDirectGdiDrawableSource&,DirectGdi::TGraphicsRotation)

 */

 void CSwDirectGdiEngine::DrawResource(const TRect& aDestRect,

 		const RDirectGdiDrawableSource& aSource,

 		DirectGdi::TGraphicsRotation aRotation)

 	{

 	// aDestRect is not empty when we reach here

 	//

 	CSwDirectGdiImageSourceImpl* imgSrc = NULL;

 	TSize imgSize;

 	if (CheckImageSource(aSource.Handle(), imgSrc, &imgSize) != KErrNone)

 		{

 		return;

 		}

 	DrawResourceCommon(aDestRect, imgSrc, TRect(TPoint(0,0), imgSize), aRotation);

 	}

 /**

 @see MDirectGdiEngine::DrawResource(const TRect&,const RDirectGdiDrawableSource&,const TRect&,DirectGdi::TGraphicsRotation)

 */

 void CSwDirectGdiEngine::DrawResource(

 		const TRect& aDestRect,				

 		const RDirectGdiDrawableSource& aSource, 

 		const TRect& aSrcRect,

 		DirectGdi::TGraphicsRotation aRotation)

 	{

 	// pre:

 	// aDestRect and aSrcRect are not empty

 	//

 	CSwDirectGdiImageSourceImpl* imgSrc = NULL;

 	TSize imgSize;

 	if (CheckImageSource(aSource.Handle(), imgSrc, &imgSize) != KErrNone)

 		{

 		return;

 		}

 	// check source rectangle is fully contained within the image resource extent

 	if (aSrcRect.iTl.iX < 0 ||

 		aSrcRect.iTl.iY < 0 ||

 		aSrcRect.iBr.iX > imgSize.iWidth ||

 		aSrcRect.iBr.iY > imgSize.iHeight)

 		{

 		iDriver->SetError(KErrArgument);

 		return;

 		}   	

 	DrawResourceCommon(aDestRect, imgSrc, aSrcRect, aRotation);

 	}

 //

 // internal functions

 //

 /**

 Checks image resource is fully constructed and registered with the driver.

 @param  aHandle A valid handle to an image source.

 @param  aImg On return, contains the image source.

 @param  aSize If not NULL, will contain the dimensions of the image source.

 @return KErrNone if successful, KErrBadHandle if aHandle is not a valid handle to an image source.

 */

 TInt CSwDirectGdiEngine::CheckImageSource(TInt aHandle, CSwDirectGdiImageSourceImpl*& aImg, TSize* aSize)

 	{

 	// check image exist

 	if (!iDriver->ValidImageSource(aHandle))

 		{

 		// replace KErrNotFound

 		const TInt err = KErrBadHandle;

 		iDriver->SetError(err);

 		return err;

 		}

 	aImg = reinterpret_cast<CSwDirectGdiImageSourceImpl*>(aHandle);

 	// RSgImage cannot be created with zero size, so there is no point in validating its size and

 	// simply return image size if requested

 	if (aSize)

 		{		

 		*aSize = aImg->Size();

 		}

 	return KErrNone;

 	}

 /**

 Implements common DrawResource() functionality used by all DrawResource() variants.

 */

 void CSwDirectGdiEngine::DrawResourceCommon(

 		const TRect& aDestRect,

 		const CSwDirectGdiImageSourceImpl* aImg,

 		const TRect& aSrcRect,

 		DirectGdi::TGraphicsRotation aRotation)

 	{

 	// pre:

 	// aDestRect and aSrcRect are not empty

 	// aSrcRect is within the image extent

 	//

 	// translate relative coord to target absolute coord system

 	TRect destRectAbs(aDestRect);

 	destRectAbs.Move(iOrigin);

 	// check whether we need to blend or write

 	const TBool opaqueSource = (!PixelFormatUtil::HasAlpha(aImg->PixelFormat())) && (iDrawMode == DirectGdi::EDrawModePEN);

 	if (opaqueSource)

 		{

 		iDrawMode = DirectGdi::EDrawModeWriteAlpha;

 		}

 	// repeat drawing op for each rectangle in the clipping region

 	const TInt numOfRects = iDefaultRegionPtr->Count();	

 	for (TInt idx = 0; idx < numOfRects; ++idx)

 		{

 		TRect clipRectAbs = (*iDefaultRegionPtr)[idx];

 		if (!clipRectAbs.Intersects(destRectAbs))

 			{

 			continue;

 			}

 		// intersect current clip rect with dest rect to get actual draw area

 		clipRectAbs.Intersection(destRectAbs);

 		DoDrawResource(destRectAbs, aImg, aSrcRect, aRotation, clipRectAbs);

 		iDrawDevice->UpdateRegion(clipRectAbs);

 		}

 	if (opaqueSource)

 		{

 		iDrawMode = DirectGdi::EDrawModePEN;

 		}	

 	}

 /**

 Rotate a given rectangle 90 degree clockwise around the specified origin.

 */

 void CSwDirectGdiEngine::Rotate90(TRect& aRect, const TPoint& aOrigin)

 	{

 	// rotated bottom-left become top-left of rotated rect

 	//

 	TPoint bl(aRect.iTl.iX, aRect.iBr.iY);

 	const TInt w = aRect.Width();

 	const TInt h = aRect.Height();

 	const TPoint dbl = bl - aOrigin;

 	bl.iX = aOrigin.iX - dbl.iY;

 	bl.iY = aOrigin.iY + dbl.iX;

 	aRect = TRect(bl, TSize(h,w));

 	}

 /**

 Rotate a given rectangle 180 degree clockwise around the specified origin.

 */

 void CSwDirectGdiEngine::Rotate180(TRect& aRect, const TPoint& aOrigin)

 	{

 	// rotated bottom-right become top-left of rotated rect

 	//

 	TPoint br(aRect.iBr);

 	const TSize sz = aRect.Size();

 	const TPoint dbr = br - aOrigin;

 	br.iX = aOrigin.iX - dbr.iX;

 	br.iY = aOrigin.iY - dbr.iY;

 	aRect = TRect(br, sz);

 	}

 /**

 Rotate a given rectangle 270 degree clockwise around the specified origin.

 */

 void CSwDirectGdiEngine::Rotate270(TRect& aRect, const TPoint& aOrigin)

 	{

 	// rotated top-right become top-left of rotated rect

 	//

 	TPoint tr(aRect.iBr.iX, aRect.iTl.iY);

 	const TInt w = aRect.Width();

 	const TInt h = aRect.Height();

 	const TPoint dtr = tr - aOrigin;

 	tr.iX = aOrigin.iX + dtr.iY;

 	tr.iY = aOrigin.iY - dtr.iX;

 	aRect = TRect(tr, TSize(h,w));

 	}

 /**

 Tests that the size of a given rotated rectangle match the image source extent.

 */

 TBool CSwDirectGdiEngine::RotatedSizeMatch(const TRect& aDst, const TRect& aSrc, DirectGdi::TGraphicsRotation aRot)

 	{

 	if (aRot==DirectGdi::EGraphicsRotationNone || aRot==DirectGdi::EGraphicsRotation180)

 		{

 		return aDst.Size()==aSrc.Size();

 		}

 	else

 		{

 		return aDst.Width()==aSrc.Height() && aDst.Height()==aSrc.Width();

 		}

 	}

 /**

 Draws a rectangular area of resource and apply rotation and/or scaling if requested.

 */

 void CSwDirectGdiEngine::DoDrawResource(

 		const TRect& aDestRectAbs,

 		const CSwDirectGdiImageSourceImpl* aImg,

 		const TRect& aSrcRect,

 		DirectGdi::TGraphicsRotation aRotation,

 		const TRect& aClipRectAbs)

 	{

 	// pre:

 	// SetClippingRegion() already check that clipping region is always contained

 	// within device full extent.

 	// check src rect match the size of rotated dest rect

 	if (RotatedSizeMatch(aDestRectAbs, aSrcRect, aRotation))

 		{

 		// aClipRect is the effective drawing clipped area, it has been intersected with dest rect by the

 		// calling function/DoDrawResourceCommon() and it is not empty when we reach here

 		// image size has been checked at the top level DrawResource() no need to check it again

 		// use aClipRect to determine how much area should be read from the image and transform

 		// the effective read area into source rect depending on rotation parameter

 		// start with aClipRect

 		TRect xformSrcRect(aClipRectAbs);

 		switch (aRotation)

 			{

 			case DirectGdi::EGraphicsRotationNone:

 				// align top-left corner of dest rect with top-left corner of src rect

 				xformSrcRect.Move(aSrcRect.iTl - aDestRectAbs.iTl);

 				break;

 			case DirectGdi::EGraphicsRotation90:

 				{

 				// align top-right corner of dest rect with top-left corner of src rect

 				xformSrcRect.Move(aSrcRect.iTl - TPoint(aDestRectAbs.iBr.iX, aDestRectAbs.iTl.iY));

 				// rotate 270 (-90) degree using top-left corner of src rect as pivot point

 				Rotate270(xformSrcRect, aSrcRect.iTl);

 				}

 				break;

 			case DirectGdi::EGraphicsRotation180:

 				{

 				// align bottom-right corner of dest rect with top-left corner of src rect

 				xformSrcRect.Move(aSrcRect.iTl - aDestRectAbs.iBr);

 				// rotate 180 (-180) degree using top-left corner of src rect as pivot point

 				Rotate180(xformSrcRect, aSrcRect.iTl);

 				}

 				break;

 			case DirectGdi::EGraphicsRotation270:

 				{

 				// align bottom-left corner of dest rect with top-left corner of src rect

 				xformSrcRect.Move(aSrcRect.iTl - TPoint(aDestRectAbs.iTl.iX, aDestRectAbs.iBr.iY));

 				// rotate 90 (-270) degree using top-left corner of src rect as pivot point

 				Rotate90(xformSrcRect, aSrcRect.iTl);

 				}

 				break;

 			// no need for extra check, aRotation has been checked at generic layer

 			}

 		DoBlitResource(aClipRectAbs.iTl, aImg, xformSrcRect, aRotation);

 		return;

 		}

 	DoScaledBlitResource(aDestRectAbs, aImg, aSrcRect, aRotation, aClipRectAbs);

 	}

 /**

 Draws a rectangular area of resource rotated with no scaling.

 @panic DGDIAdapter 1009, if the pixel format of the draw device is unknown (debug only). 

 */

 void CSwDirectGdiEngine::DoBlitResource(

 		const TPoint& aDest,

 		const CSwDirectGdiImageSourceImpl* aImg,

 		const TRect& aSrcRect,

 		DirectGdi::TGraphicsRotation aRotation)

 	{		

 	// pre:

 	// aDest is the top-left of clipped destination rectangle i.e. intersection of user destination

 	// rectangle with current clipping rect

 	// aSrcRect is rotated clipped read area i.e. effective read area with respect to original 

 	// image orientation i.e.it no longer represents user specified source rect.

 	// no need to do extra check on parameters here because:

 	// aDest is guaranteed to be within device drawing area

 	// aSrcRect is guaranteed to be within image source area

 	const TUidPixelFormat devFormat = PixelFormatUtil::ConvertToPixelFormat(iDrawDevice->DisplayMode());

 	GRAPHICS_ASSERT_DEBUG(devFormat != EUidPixelFormatUnknown, EDirectGdiPanicInvalidDisplayMode);

 	const TUidPixelFormat imgFormat = aImg->PixelFormat();

 	const TUint32* imgAddr = reinterpret_cast<TUint32*>(aImg->DataBuffer());

 	const TInt imgStride = aImg->Stride();

 	const TSize imgSize = aImg->Size();

 	const CGraphicsContext::TDrawMode drawMode = GcDrawMode(iDrawMode);

 	const TInt width = aSrcRect.Width();

 	const TInt height = aSrcRect.Height();

 	// write scanline starting from top dest row

 	TInt destY = aDest.iY;

 	// setup pixel reader toolkit

 	TPixelBufferReader reader(imgAddr, imgSize, imgStride, imgFormat);

 	TDrawDeviceWrapper writer(iDrawDevice, GcDrawMode(iDrawMode));

 	//

 	// special case when rotation is none

 	//

 	if (aRotation == DirectGdi::EGraphicsRotationNone)

 		{

 		TAny* interface = NULL;

 		// source and destination format match and using write alpha mode i.e. reduce blit to memcpy

 		if (iDrawMode == DirectGdi::EDrawModeWriteAlpha && devFormat == imgFormat)

 			{

 			TInt err = iDrawDevice->GetInterface(KFastBlit2InterfaceID, interface);

 			if (err == KErrNone)

 				{

 				GRAPHICS_ASSERT_DEBUG(interface, EDirectGdiPanicInvalidPointer);

 				MFastBlit2* fblit = static_cast<MFastBlit2*>(interface);

 				err = fblit->WriteBitmapBlock(aDest, imgAddr, imgStride, imgSize, aSrcRect);

 				if (err == KErrNone)

 					{

 					return;

 					}

 				}

 			}

 		// fallback from MFastBlit2  when source and destination format match. 

 		// Note that there was previously an optimization added here that used MFlastBlend if 

 		// available, however it did not work correctly for some cases using DrawResource so has been 

 		// removed from this code. (A source drawn with OpenGLES on to a target in XRGB_8888 format

 		// actually had alpha in the unused channel which was being drawn by MFastBlend)

 		if (devFormat == imgFormat)

 			{

 			for (TInt row=aSrcRect.iTl.iY; row<aSrcRect.iBr.iY; ++row,++destY)

 				{

 				const TPoint pos(aSrcRect.iTl.iX, row);

 				const TUint32* slptr = reader.GetPixelAddr(pos);

 				writer.WriteLine(aDest.iX, destY, width, const_cast<TUint32*>(slptr), drawMode);

 				}

 			return;

 			}

 		// there is one additional case that can be optimised by eleminating copy when:

 		// rotation : none

 		// scaling 	: none

 		// dst		: opaque

 		// src		: has alpha and premultiplied

 		// mode 	: PEN

 		}

 	//

 	// generic cases

 	//

 	// copying is necessary either to convert pixel format or to read back buffer in reverse order 

 	// to achieve rotation

 	//

 	const TInt scanLineBytes = iDrawDevice->ScanLineBytes();

 	TUint32* scanLineBuffer = iDrawDevice->ScanLineBuffer();

 	TPtr8 scanLineDes(reinterpret_cast<TUint8*>(scanLineBuffer),scanLineBytes,scanLineBytes);

 	// if destination is opaque e.g. RGB_565, XRGB_8888 and the source has alpha, it shall blend

 	// (because iDrawMode is set to WritePEN)

 	// we treat opaque destination as in pre-multiplied format (with alpha value 1), and read the 

 	// source in pre-multiplied format too, to enable optimum blending computation i.e.

 	// "src + (1-alpha) * dst"

 	const TUidPixelFormat readFormat = !PixelFormatUtil::HasAlpha(devFormat) &&

 							iDrawMode == DirectGdi::EDrawModePEN ?

 							EUidPixelFormatARGB_8888_PRE : devFormat;

 	if (aRotation == DirectGdi::EGraphicsRotationNone)

 		{

 		// general fallback from FastBlendBitmap

 		//

 		const TInt readLen = width;

 		// normal read scanline, left to right

 		//

 		for (TInt row=aSrcRect.iTl.iY; row<aSrcRect.iBr.iY; ++row,++destY)

 			{

 			const TPoint pos(aSrcRect.iTl.iX, row);

 			reader.GetScanLine(scanLineDes,pos, readLen, readFormat, TPixelBufferReader::EReadHorizontal);

 			writer.WriteLine(aDest.iX, destY, readLen, scanLineBuffer, drawMode);

 			}

 		}

 	else if (aRotation == DirectGdi::EGraphicsRotation90)

 		{

 		const TInt readLen = height;

 		// read scanline vertically from bottom to up, and from the lef-most column

 		//

 		for (TInt col=aSrcRect.iTl.iX; col<aSrcRect.iBr.iX; ++col,++destY)

 			{

 			const TPoint pos(col, aSrcRect.iBr.iY-1);

 			reader.GetScanLine(scanLineDes, pos, readLen, readFormat, TPixelBufferReader::EReadVerticalReverse);

 			writer.WriteLine(aDest.iX, destY, readLen, scanLineBuffer, drawMode);

 			}

 		}

 	else if (aRotation == DirectGdi::EGraphicsRotation180)

 		{

 		const TInt readLen = width;

 		// read scanline from right to left, starting from the most bottom scanline

 		//

 		for (TInt row=aSrcRect.iBr.iY-1; row>=aSrcRect.iTl.iY; --row,++destY)

 			{

 			const TPoint pos(aSrcRect.iBr.iX-1, row);

 			reader.GetScanLine(scanLineDes, pos, readLen, readFormat, TPixelBufferReader::EReadHorizontalReverse);

 			writer.WriteLine(aDest.iX, destY, readLen, scanLineBuffer, drawMode);

 			}

 		}

 	else if (aRotation == DirectGdi::EGraphicsRotation270)

 		{

 		const TInt readLen = height;

 		// read scanline vertically top to bottom, and from the right-most column

 		//

 		for (TInt col=aSrcRect.iBr.iX-1; col>=aSrcRect.iTl.iX; --col,++destY)

 			{

 			const TPoint pos(col, aSrcRect.iTl.iY);

 			reader.GetScanLine(scanLineDes, pos, readLen, readFormat, TPixelBufferReader::EReadVertical);

 			writer.WriteLine(aDest.iX, destY, readLen, scanLineBuffer, drawMode);

 			}

 		}

 	}

 /**

 Draws a rectangular area of resource rotated and/or scaled up/down.

 @panic DGDIAdapter 1009, if the pixel format of the draw device is unknown (debug only).

 */

 void CSwDirectGdiEngine::DoScaledBlitResource(

 		const TRect& aDestRectAbs,

 		const CSwDirectGdiImageSourceImpl* aImg,

 		const TRect& aSrcRect,

 		DirectGdi::TGraphicsRotation aRotation,

 		const TRect& aClipRectAbs)

 	{

 	// pre:

 	// aDestRectAbs is the user specified dest rect that has been translated to target coord system. It may

 	// be larger/outside the target drawing area. We must not modify this rect as it will be used to

 	// determine the scaling factor.

 	// aSrcRect is the user specified src rect, it is within the image extent.

 	// aClipRectAbs is the intersection of current clipping rect and aDestRectAbs and is within the

 	// target drawing area.

 	const TUidPixelFormat devFormat = PixelFormatUtil::ConvertToPixelFormat(iDrawDevice->DisplayMode());

 	GRAPHICS_ASSERT_DEBUG(devFormat != EUidPixelFormatUnknown, EDirectGdiPanicInvalidDisplayMode);

 	const TUint32* imgAddr = reinterpret_cast<TUint32*>(aImg->DataBuffer());

 	const TInt imgStride = aImg->Stride();

 	const TSize imgSize = aImg->Size();

 	const TUidPixelFormat imgFormat = aImg->PixelFormat();

 	const CGraphicsContext::TDrawMode drawMode = GcDrawMode(iDrawMode);

 	// if destination is opaque e.g. RGB_565, XRGB_8888 and the source has alpha, it shall blend

 	// (because iDrawMode is set to WritePEN)

 	// we treat opaque destination as in pre-multiplied format (with alpha value 1), and read the 

 	// source in pre-multiplied format too, to enable optimum blending computation i.e.

 	// "src + (1-alpha) * dst"

 	const TUidPixelFormat readFormat = !PixelFormatUtil::HasAlpha(devFormat) &&

 							iDrawMode == DirectGdi::EDrawModePEN ?

 							EUidPixelFormatARGB_8888_PRE : devFormat;

 	TUint32* scanLineBuffer = iDrawDevice->ScanLineBuffer();

 	const TInt scanLineBytes = iDrawDevice->ScanLineBytes();

 	TPtr8 scanLineDes(reinterpret_cast<TUint8*>(scanLineBuffer), scanLineBytes, scanLineBytes);

 	// setup pixel reader toolkit

 	//

 	TPixelBufferReader reader(imgAddr, imgSize, imgStride, imgFormat);

 	TDrawDeviceWrapper writer(iDrawDevice, GcDrawMode(iDrawMode));

 	if (aRotation == DirectGdi::EGraphicsRotationNone)

 		{		

 		// Note that there was previously an optimization added here that used MFlastBlend if 

 		// available, however it did not work correctly for some cases using DrawResource so has been 

 		// removed from this code. (A source drawn with OpenGLES on to a target in XRGB_8888 format

 		// actually had alpha in the unused channel which was being drawn by MFastBlend)

 		//

 		const TInt srcLen = aSrcRect.Width();

 		const TInt destLen = aDestRectAbs.Width();

 		const TInt clipLen = aClipRectAbs.Width();

 		const TInt clipPos = aClipRectAbs.iTl.iX - aDestRectAbs.iTl.iX;

 		// setup DDA for scaling in Y direction based on src rect and dst rect size

 		// scaling in X direction will be done by GetScaledScanLine()

 		//

 		// setup Y scaler and start from top-left of src/dest to bottom-right of src/dest

 		TLinearDDA yScaler;

 		yScaler.Construct(

 				TPoint(aSrcRect.iTl.iY, aDestRectAbs.iTl.iY),

 				TPoint(aSrcRect.iBr.iY, aDestRectAbs.iBr.iY),

 				TLinearDDA::ELeft);

 		// move to position of current clip rect top row as the start of dest Y

 		TInt srcY;	

 		yScaler.JumpToYCoord2(srcY, aClipRectAbs.iTl.iY);

 		// yPos contains mapping between src Y (TPoint.iX) and dest Y (TPoint.iY)

 		TPoint yPos(srcY, aClipRectAbs.iTl.iY);

 		// write to target from top to bottom

 		//

 		while (yPos.iY < aClipRectAbs.iBr.iY)

 			{

 			reader.GetScaledScanLine(scanLineDes,

 									TPoint(aSrcRect.iTl.iX, yPos.iX),	// src X and Y

 									clipPos,							// clipped dest X

 									clipLen,

 									destLen,

 									srcLen,

 									readFormat,

 									TPixelBufferReader::EReadHorizontal);

 			// use dest Y here

 			writer.WriteLine(aClipRectAbs.iTl.iX, yPos.iY, clipLen, scanLineBuffer, drawMode);

 			// move scaler one position

 			yScaler.NextStep(yPos);

 			};

 		}

 	else if (aRotation == DirectGdi::EGraphicsRotation90)

 		{

 		// we're going to read source vertically from bottom to up, swap relevant bits and pieces

 		// dst-width corresponds to src-height

 		// dst-height corresponds to src-width

 		//

 		const TInt srcLen = aSrcRect.Height();

 		const TInt destLen = aDestRectAbs.Width();

 		// the following doesn't change, the amount of pixel read (vertically) will be based on

 		// the drawing area witdh i.e. clip width

 		//

 		const TInt clipLen = aClipRectAbs.Width();

 		// offset into read area doesn't change either, it will be translated into some Y position

 		// from bottom row of source image

 		const TInt clipPos = aClipRectAbs.iTl.iX - aDestRectAbs.iTl.iX;

 		// setup DDA for scaling in src X direction based on src rect and dst rect size

 		// scaling in src Y direction will be done by GetScaledScanLine(EReadVerticalReverse)

 		//

 		// scaler map dest Y to src X because of 90 degre rotation

 		// start from  top row dest, left-most column src to bottom row dest, right-most column src

 		//

 		TLinearDDA xScaler;

 		xScaler.Construct(

 				TPoint(aSrcRect.iTl.iX, aDestRectAbs.iTl.iY),

 				TPoint(aSrcRect.iBr.iX, aDestRectAbs.iBr.iY),

 				TLinearDDA::ELeft);

 		// move to position of current clip rect top row as the start of src X

 		TInt srcX;	

 		xScaler.JumpToYCoord2(srcX, aClipRectAbs.iTl.iY);

 		// xPos contains mapping between src X (TPoint.iX) and dest Y (TPoint.iY)

 		TPoint xPos(srcX, aClipRectAbs.iTl.iY);

 		// write to target from top to bottom

 		//

 		while (xPos.iY < aClipRectAbs.iBr.iY)

 			{

 			// read pixel vertically from left column to right

 			reader.GetScaledScanLine(scanLineDes,

 									TPoint(xPos.iX, aSrcRect.iBr.iY - 1),	// src X, src Y

 									clipPos,								// distance from bottom source

 									clipLen,

 									destLen,

 									srcLen,

 									readFormat,

 									TPixelBufferReader::EReadVerticalReverse);

 			// use dest Y here

 			writer.WriteLine(aClipRectAbs.iTl.iX, xPos.iY, clipLen, scanLineBuffer, drawMode);

 			// move scaler one position

 			xScaler.NextStep(xPos);

 			}

 		}

 	else if (aRotation == DirectGdi::EGraphicsRotation180)

 		{

 		const TInt srcLen = aSrcRect.Width();

 		const TInt destLen = aDestRectAbs.Width();

 		const TInt clipLen = aClipRectAbs.Width();

 		// clipPos doesn't need to be inverted (using iBr.iX) because the yScaler below

 		// will do that for us (by stepping backward)

 		//

 		const TInt clipPos = aClipRectAbs.iTl.iX - aDestRectAbs.iTl.iX;

 		// setup DDA for scaling in Y direction based on src rect and dst rect size

 		// scaling in X direction will be done by GetScaledScanLine()

 		//

 		// setup Y scaler and start from bottom-right of src/dest to top-left of src/dest

 		// to do backward stepping (src Y inversion)

 		TLinearDDA yScaler;

 		yScaler.Construct(

 				// we starting from 1st pixel from bottom of source image, we need to

 				// step back 1 position as bottom-row coord is beyond the last pixel in the source rect

 				TPoint(aSrcRect.iBr.iY - 1, aDestRectAbs.iTl.iY),

 				TPoint(aSrcRect.iTl.iY - 1, aDestRectAbs.iBr.iY),

 				TLinearDDA::ELeft);

 		// move to position of current clip rect top row as the start of dest Y

 		// which will calculate inverted src Y distance from bottom of source rectangle

 		TInt invSrcY;	

 		yScaler.JumpToYCoord2(invSrcY, aClipRectAbs.iTl.iY);

 		// yPos contains mapping between inverted src Y (TPoint.iX) and dest Y (TPoint.iY)

 		TPoint yPos(invSrcY, aClipRectAbs.iTl.iY);

 		// write to target from top to bottom

 		//

 		while (yPos.iY < aClipRectAbs.iBr.iY)

 			{

 			// read scanline from righ to left i.e. use aSrcRect.iBr.iX-1 (last column)

 			// as starting src X value

 			reader.GetScaledScanLine(scanLineDes,

 									TPoint(aSrcRect.iBr.iX - 1, yPos.iX),	// src X and inverted src Y

 									clipPos,								// clipped dest X

 									clipLen,

 									destLen,

 									srcLen,

 									readFormat,

 									TPixelBufferReader::EReadHorizontalReverse);

 			// use dest Y here

 			writer.WriteLine(aClipRectAbs.iTl.iX, yPos.iY, clipLen, scanLineBuffer, drawMode);

 			// move scaler one position

 			yScaler.NextStep(yPos);

 			}

 		}

 	else if(aRotation == DirectGdi::EGraphicsRotation270)

 		{

 		// we're going to read source vertically from top to bottom, swap relevant bits and pieces

 		// dst-width corresponds to src-height

 		// dst-height corresponds to src-width

 		const TInt srcLen = aSrcRect.Height();

 		const TInt destLen = aDestRectAbs.Width();

 		// the following doesn't change, the amount of pixel read (vertically) will be based on

 		// the drawing area witdh i.e. clip width

 		const TInt clipLen = aClipRectAbs.Width();

 		// offset into read area doesn't change either, it will be translated into some Y position

 		// from top row of source image

 		const TInt clipPos = aClipRectAbs.iTl.iX - aDestRectAbs.iTl.iX;

 		// setup DDA for scaling in src X direction based on src rect and dst rect size

 		// scaling in src Y direction will be done by GetScaledScanLine(EReadVertical)

 		//

 		// scaler map dest Y to src X because of 270 degre rotation

 		// start from top row dest, right-most column src to bottom row dest, left-most column src

 		TLinearDDA xScaler;

 		xScaler.Construct(

 				// decrement 1 pixel to get into last pixel within source

 				TPoint(aSrcRect.iBr.iX - 1, aDestRectAbs.iTl.iY),

 				TPoint(aSrcRect.iTl.iX - 1, aDestRectAbs.iBr.iY),

 				TLinearDDA::ELeft);

 		// move to position of current clip rect top row as the start of src X

 		TInt srcX;	

 		xScaler.JumpToYCoord2(srcX, aClipRectAbs.iTl.iY);

 		// xPos contains mapping between src X (TPoint.iX) and dest Y (TPoint.iY)

 		TPoint xPos(srcX, aClipRectAbs.iTl.iY);

 		// write to target from top to bottom

 		//

 		while (xPos.iY < aClipRectAbs.iBr.iY)

 			{

 			// read pixel vertically from left column to right

 			reader.GetScaledScanLine(scanLineDes,

 									TPoint(xPos.iX, aSrcRect.iTl.iY),		// src X, src Y

 									clipPos,								// distance from bottom source

 									clipLen,

 									destLen,

 									srcLen,

 									readFormat,

 									TPixelBufferReader::EReadVertical);

 			// use dest Y here

 			writer.WriteLine(aClipRectAbs.iTl.iX, xPos.iY, clipLen, scanLineBuffer, drawMode);

 			// move scaler one position

 			xScaler.NextStep(xPos);

 			}

 		}

 	}