sl@0: // Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: // All rights reserved.
sl@0: // This component and the accompanying materials are made available
sl@0: // under the terms of "Eclipse Public License v1.0"
sl@0: // which accompanies this distribution, and is available
sl@0: // at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: //
sl@0: // Initial Contributors:
sl@0: // Nokia Corporation - initial contribution.
sl@0: //
sl@0: // Contributors:
sl@0: //
sl@0: // Description:
sl@0: //
sl@0: 
sl@0: const TUint32 KRBMask = 0x00ff00ff;
sl@0: const TUint32 KAGMask = 0xff00ff00;
sl@0: const TUint32 KGMask  = 0x0000ff00;
sl@0: 
sl@0: //Algoriths for Premultiplied alpha screenmode/pixel format.
sl@0: 
sl@0: inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMask)
sl@0: 	{
sl@0: 	if(aMask)
sl@0: 		{
sl@0: 		if(aMask == 0xff) // opaque, so unchanged
sl@0: 			{
sl@0: 			return aSrcPixel;
sl@0: 			}
sl@0: 		else
sl@0: 			{
sl@0: 			return PMABlend_noChecks(aDestPixel, aSrcPixel, aMask);
sl@0: 			}
sl@0: 		}
sl@0: 	 else // completely transparent
sl@0: 		{
sl@0: 		return aDestPixel;
sl@0:  		}
sl@0: 	}
sl@0: 
sl@0: inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel)
sl@0: 	{
sl@0: 	TUint8 mask = (TUint8)(aSrcPixel >> 24);
sl@0: 	return PMAPixelBlend(aDestPixel, aSrcPixel, mask);
sl@0: 	}
sl@0: 
sl@0: inline TUint32 PMABlend_noChecks(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMaskingFactor)
sl@0: 	{
sl@0: 	TUint32 src_c = aSrcPixel & KRBMask;
sl@0: 	TUint32 dst_c = aDestPixel  & KRBMask;
sl@0: 	const TUint32 mask = 0x0100 - aMaskingFactor;
sl@0: 	dst_c = (src_c +  ((mask * dst_c)>>8)) & KRBMask;
sl@0: 	src_c = (aSrcPixel & KAGMask)>>8;
sl@0: 	TUint32 dst_ag = (aDestPixel & KAGMask)>>8;
sl@0: 	dst_c |= ((src_c +  ((mask * dst_ag)>>8)) & KRBMask)<<8;
sl@0: 	return dst_c;
sl@0: 	}
sl@0: 
sl@0: inline void PMABlend_noChecksInplace(TUint32& aDest_io, const TUint32& aSrcPixel, TUint8 aMaskingFactor)
sl@0: 	{
sl@0: 	TUint32 src_c = aSrcPixel & KRBMask;
sl@0: 	TUint32 dst_ag = (aDest_io & KAGMask) >> 8;
sl@0: 	aDest_io = aDest_io  & KRBMask;
sl@0: 	const TUint32 mask = 0x0100 - aMaskingFactor;
sl@0: 	aDest_io = (src_c +  ((mask * aDest_io) >> 8)) & KRBMask;
sl@0: 	src_c = (aSrcPixel & KAGMask) >> 8;
sl@0: 	aDest_io |= ((src_c +  ((mask * dst_ag) >> 8)) & KRBMask)<<8;
sl@0: 	}
sl@0: 
sl@0: inline void PMAInplaceBlend(TUint32& aDest_io, TUint32& aSrc_in)
sl@0: 	{
sl@0: 	TUint8 mask = (TUint8)(aSrc_in >> 24);
sl@0: 	if(mask)
sl@0: 		{
sl@0: 		if(mask == 0xff) // opaque, so dst = src.
sl@0: 			{
sl@0: 			aDest_io = aSrc_in;
sl@0: 			}
sl@0: 		else
sl@0: 			{
sl@0: 			PMABlend_noChecksInplace(aDest_io, aSrc_in, mask);
sl@0: 			}
sl@0: 		}
sl@0: 	//else src completely transparent, so dst unchanged.
sl@0: 	}
sl@0: 
sl@0: inline TUint32 NonPMA2PMAPixel(TUint32 aPixel)
sl@0: 	{
sl@0: 	TUint8 tA = (TUint8)(aPixel >> 24);
sl@0: 	if (tA==0)
sl@0: 		{ 
sl@0: 		return 0;
sl@0: 		}
sl@0: 	if (tA==0xff) 
sl@0: 		{
sl@0: 		return aPixel;
sl@0: 		}
sl@0: 
sl@0: 	// Use a bias value of 128 rather than 255, but also add 1/256 of the numerator 
sl@0: 	// before dividing the sum by 256.
sl@0: 
sl@0: 	TUint32 tap1=tA+1;
sl@0: 	TUint32 scaledRB = (aPixel & KRBMask) * tap1;
sl@0: 	TUint32 scaledG = (aPixel & KGMask ) * tap1;
sl@0: 	return (aPixel & 0xff000000) | ((scaledRB>>8) & KRBMask) | ((scaledG>>8)& KGMask);
sl@0: 	}
sl@0: 
sl@0: inline TUint32 PMA2NonPMAPixel(TUint32 aPixel, const TUint16* aNormTable)
sl@0: 	{
sl@0: 	TUint8 alpha = (TUint8)(aPixel >> 24);
sl@0: 	if (alpha==0)
sl@0: 		{ 
sl@0: 		return 0;
sl@0: 		}
sl@0: 	if (alpha==0xff) 
sl@0: 		{
sl@0: 		return aPixel;
sl@0: 		}
sl@0: 	TUint16 norm = aNormTable[alpha];
sl@0: 	TUint32 norm_rb = (((aPixel & KRBMask) * norm) >> 8) & KRBMask;
sl@0: 	TUint32 norm_g =  (((aPixel & KGMask ) * norm) >> 8) & KGMask;
sl@0: 	return ((aPixel & 0xff000000) | norm_rb | norm_g);
sl@0: 	}
sl@0: 
sl@0: inline void Convert2PMA(TUint32& aInOutValue)
sl@0: 	{
sl@0: 	aInOutValue = NonPMA2PMAPixel(aInOutValue);
sl@0: 	}
sl@0: 
sl@0: inline void Convert2NonPMA(TUint32& aInOutValue, const TUint16* aNormTable)
sl@0: 	{
sl@0: 	aInOutValue = PMA2NonPMAPixel(aInOutValue, aNormTable);
sl@0: 	}