williamr@2: // Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).
williamr@2: // All rights reserved.
williamr@2: // This component and the accompanying materials are made available
williamr@2: // 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
williamr@2: // which accompanies this distribution, and is available
williamr@2: // at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".
williamr@2: //
williamr@2: // Initial Contributors:
williamr@2: // Nokia Corporation - initial contribution.
williamr@2: //
williamr@2: // Contributors:
williamr@2: //
williamr@2: // Description:
williamr@2: //
williamr@2: 
williamr@2: const TUint32 KRBMask = 0x00ff00ff;
williamr@2: const TUint32 KAGMask = 0xff00ff00;
williamr@2: const TUint32 KGMask  = 0x0000ff00;
williamr@2: 
williamr@2: //Algoriths for Premultiplied alpha screenmode/pixel format.
williamr@2: 
williamr@2: inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMask)
williamr@2: 	{
williamr@2: 	if(aMask)
williamr@2: 		{
williamr@2: 		if(aMask == 0xff) // opaque, so unchanged
williamr@2: 			{
williamr@2: 			return aSrcPixel;
williamr@2: 			}
williamr@2: 		else
williamr@2: 			{
williamr@2: 			return PMABlend_noChecks(aDestPixel, aSrcPixel, aMask);
williamr@2: 			}
williamr@2: 		}
williamr@2: 	 else // completely transparent
williamr@2: 		{
williamr@2: 		return aDestPixel;
williamr@2:  		}
williamr@2: 	}
williamr@2: 
williamr@2: inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel)
williamr@2: 	{
williamr@2: 	TUint8 mask = (TUint8)(aSrcPixel >> 24);
williamr@2: 	return PMAPixelBlend(aDestPixel, aSrcPixel, mask);
williamr@2: 	}
williamr@2: 
williamr@2: inline TUint32 PMABlend_noChecks(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMaskingFactor)
williamr@2: 	{
williamr@2: 	TUint32 src_c = aSrcPixel & KRBMask;
williamr@2: 	TUint32 dst_c = aDestPixel  & KRBMask;
williamr@2: 	const TUint32 mask = 0x0100 - aMaskingFactor;
williamr@2: 	dst_c = (src_c +  ((mask * dst_c)>>8)) & KRBMask;
williamr@2: 	src_c = (aSrcPixel & KAGMask)>>8;
williamr@2: 	TUint32 dst_ag = (aDestPixel & KAGMask)>>8;
williamr@2: 	dst_c |= ((src_c +  ((mask * dst_ag)>>8)) & KRBMask)<<8;
williamr@2: 	return dst_c;
williamr@2: 	}
williamr@2: 
williamr@2: inline void PMABlend_noChecksInplace(TUint32& aDest_io, TUint32& aSrcPixel,TUint8& aMaskingFactor)
williamr@2: 	{
williamr@2: 	TUint32 src_c = aSrcPixel & KRBMask;
williamr@2: 	TUint32 dst_ag = (aDest_io & KAGMask) >> 8;
williamr@2: 	aDest_io = aDest_io  & KRBMask;
williamr@2: 	const TUint32 mask = 0x0100 - aMaskingFactor;
williamr@2: 	aDest_io = (src_c +  ((mask * aDest_io) >> 8)) & KRBMask;
williamr@2: 	src_c = (aSrcPixel & KAGMask) >> 8;
williamr@2: 	aDest_io |= ((src_c +  ((mask * dst_ag) >> 8)) & KRBMask)<<8;
williamr@2: 	}
williamr@2: 
williamr@2: inline void PMAInplaceBlend(TUint32& aDest_io, TUint32& aSrc_in)
williamr@2: 	{
williamr@2: 	TUint8 mask = (TUint8)(aSrc_in >> 24);
williamr@2: 	if(mask)
williamr@2: 		{
williamr@2: 		if(mask == 0xff) // opaque, so dst = src.
williamr@2: 			{
williamr@2: 			aDest_io = aSrc_in;
williamr@2: 			}
williamr@2: 		else
williamr@2: 			{
williamr@2: 			PMABlend_noChecksInplace(aDest_io, aSrc_in, mask);
williamr@2: 			}
williamr@2: 		}
williamr@2: 	//else src completely transparent, so dst unchanged.
williamr@2: 	}
williamr@2: 
williamr@2: inline TUint32 NonPMA2PMAPixel(TUint32 aPixel)
williamr@2: 	{
williamr@2: 	TUint8 tA = (TUint8)(aPixel >> 24);
williamr@2: 	if (tA==0)
williamr@2: 		{ 
williamr@2: 		return 0;
williamr@2: 		}
williamr@2: 	if (tA==0xff) 
williamr@2: 		{
williamr@2: 		return aPixel;
williamr@2: 		}
williamr@2: 
williamr@2: 	// Use a bias value of 128 rather than 255, but also add 1/256 of the numerator 
williamr@2: 	// before dividing the sum by 256.
williamr@2: 
williamr@2: 	TUint32 tap1=tA+1;
williamr@2: 	TUint32 scaledRB = (aPixel & KRBMask) * tap1;
williamr@2: 	TUint32 scaledG = (aPixel & KGMask ) * tap1;
williamr@2: 	return (aPixel & 0xff000000) | ((scaledRB>>8) & KRBMask) | ((scaledG>>8)& KGMask);
williamr@2: 	}
williamr@2: 
williamr@2: inline TUint32 PMA2NonPMAPixel(TUint32 aPixel, const TUint16* aNormTable)
williamr@2: 	{
williamr@2: 	TUint8 alpha = (TUint8)(aPixel >> 24);
williamr@2: 	if (alpha==0)
williamr@2: 		{ 
williamr@2: 		return 0;
williamr@2: 		}
williamr@2: 	if (alpha==0xff) 
williamr@2: 		{
williamr@2: 		return aPixel;
williamr@2: 		}
williamr@2: 	TUint16 norm = aNormTable[alpha];
williamr@2: 	TUint32 norm_rb = (((aPixel & KRBMask) * norm) >> 8) & KRBMask;
williamr@2: 	TUint32 norm_g =  (((aPixel & KGMask ) * norm) >> 8) & KGMask;
williamr@2: 	return ((aPixel & 0xff000000) | norm_rb | norm_g);
williamr@2: 	}
williamr@2: 
williamr@2: inline void Convert2PMA(TUint32& aInOutValue)
williamr@2: 	{
williamr@2: 	aInOutValue = NonPMA2PMAPixel(aInOutValue);
williamr@2: 	}
williamr@2: 
williamr@2: inline void Convert2NonPMA(TUint32& aInOutValue, const TUint16* aNormTable)
williamr@2: 	{
williamr@2: 	aInOutValue = PMA2NonPMAPixel(aInOutValue, aNormTable);
williamr@2: 	}