// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

// which accompanies this distribution, and is available

// at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

const TUint32 KRBMask = 0x00ff00ff;

const TUint32 KAGMask = 0xff00ff00;

const TUint32 KGMask  = 0x0000ff00;

//Algoriths for Premultiplied alpha screenmode/pixel format.

inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMask)

	{

	if(aMask)

		{

		if(aMask == 0xff) // opaque, so unchanged

			{

			return aSrcPixel;

			}

		else

			{

			return PMABlend_noChecks(aDestPixel, aSrcPixel, aMask);

			}

		}

	 else // completely transparent

		{

		return aDestPixel;

 		}

	}

inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel)

	{

	TUint8 mask = (TUint8)(aSrcPixel >> 24);

	return PMAPixelBlend(aDestPixel, aSrcPixel, mask);

	}

inline TUint32 PMABlend_noChecks(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMaskingFactor)

	{

	TUint32 src_c = aSrcPixel & KRBMask;

	TUint32 dst_c = aDestPixel  & KRBMask;

	const TUint32 mask = 0x0100 - aMaskingFactor;

	dst_c = (src_c +  ((mask * dst_c)>>8)) & KRBMask;

	src_c = (aSrcPixel & KAGMask)>>8;

	TUint32 dst_ag = (aDestPixel & KAGMask)>>8;

	dst_c |= ((src_c +  ((mask * dst_ag)>>8)) & KRBMask)<<8;

	return dst_c;

	}

inline void PMABlend_noChecksInplace(TUint32& aDest_io, TUint32& aSrcPixel,TUint8& aMaskingFactor)

	{

	TUint32 src_c = aSrcPixel & KRBMask;

	TUint32 dst_ag = (aDest_io & KAGMask) >> 8;

	aDest_io = aDest_io  & KRBMask;

	const TUint32 mask = 0x0100 - aMaskingFactor;

	aDest_io = (src_c +  ((mask * aDest_io) >> 8)) & KRBMask;

	src_c = (aSrcPixel & KAGMask) >> 8;

	aDest_io |= ((src_c +  ((mask * dst_ag) >> 8)) & KRBMask)<<8;

	}

inline void PMAInplaceBlend(TUint32& aDest_io, TUint32& aSrc_in)

	{

	TUint8 mask = (TUint8)(aSrc_in >> 24);

	if(mask)

		{

		if(mask == 0xff) // opaque, so dst = src.

			{

			aDest_io = aSrc_in;

			}

		else

			{

			PMABlend_noChecksInplace(aDest_io, aSrc_in, mask);

			}

		}

	//else src completely transparent, so dst unchanged.

	}

inline TUint32 NonPMA2PMAPixel(TUint32 aPixel)

	{

	TUint8 tA = (TUint8)(aPixel >> 24);

	if (tA==0)

		{ 

		return 0;

		}

	if (tA==0xff) 

		{

		return aPixel;

		}

	// Use a bias value of 128 rather than 255, but also add 1/256 of the numerator 

	// before dividing the sum by 256.

	TUint32 tap1=tA+1;

	TUint32 scaledRB = (aPixel & KRBMask) * tap1;

	TUint32 scaledG = (aPixel & KGMask ) * tap1;

	return (aPixel & 0xff000000) | ((scaledRB>>8) & KRBMask) | ((scaledG>>8)& KGMask);

	}

inline TUint32 PMA2NonPMAPixel(TUint32 aPixel, const TUint16* aNormTable)

	{

	TUint8 alpha = (TUint8)(aPixel >> 24);

	if (alpha==0)

		{ 

		return 0;

		}

	if (alpha==0xff) 

		{

		return aPixel;

		}

	TUint16 norm = aNormTable[alpha];

	TUint32 norm_rb = (((aPixel & KRBMask) * norm) >> 8) & KRBMask;

	TUint32 norm_g =  (((aPixel & KGMask ) * norm) >> 8) & KGMask;

	return ((aPixel & 0xff000000) | norm_rb | norm_g);

	}

inline void Convert2PMA(TUint32& aInOutValue)

	{

	aInOutValue = NonPMA2PMAPixel(aInOutValue);

	}

inline void Convert2NonPMA(TUint32& aInOutValue, const TUint16* aNormTable)

	{

	aInOutValue = PMA2NonPMAPixel(aInOutValue, aNormTable);

	}