kc3-lang/avir/avir_dil.h

• Show log

  Commit

• Hash : 89b14ca9
  Author : Thomas de Grivel
  Date : 2025-11-25T11:33:25
  

  change encoding to utf8-unix
  

Download

• avir_dil.h

• /**
   * @file avir_dil.h
   *
   * @version 3.1
   *
   * @brief Inclusion file for de-interleaved image resizing functions.
   *
   * This file includes the CImageResizerFilterStepDIL class which implements
   * image resizing functions in de-interleaved mode.
   *
   * AVIR Copyright (c) 2015-2025 Aleksey Vaneev
   *
   * See the "LICENSE" file for license.
   */
  
  namespace avir {
  
  /**
   * @brief De-interleaved filtering steps implementation class.
   *
   * This class implements scanline filtering functions in de-interleaved mode.
   * This means that pixels are processed in groups.
   *
   * @tparam fptype Floating point type to use for storing pixel elements.
   * SIMD types cannot be used.
   * @tparam fptypesimd The SIMD type used to store a pack of `fptype` values.
   */
  
  template< class fptype, class fptypesimd >
  class CImageResizerFilterStepDIL :
  	public CImageResizerFilterStep< fptype, fptype >
  {
  public:
  	using CImageResizerFilterStep< fptype, fptype > :: IsUpsample;
  	using CImageResizerFilterStep< fptype, fptype > :: ResampleFactor;
  	using CImageResizerFilterStep< fptype, fptype > :: Flt;
  	using CImageResizerFilterStep< fptype, fptype > :: FltOrig;
  	using CImageResizerFilterStep< fptype, fptype > :: FltLatency;
  	using CImageResizerFilterStep< fptype, fptype > :: Vars;
  	using CImageResizerFilterStep< fptype, fptype > :: InLen;
  	using CImageResizerFilterStep< fptype, fptype > :: InPrefix;
  	using CImageResizerFilterStep< fptype, fptype > :: InSuffix;
  	using CImageResizerFilterStep< fptype, fptype > :: InElIncr;
  	using CImageResizerFilterStep< fptype, fptype > :: OutLen;
  	using CImageResizerFilterStep< fptype, fptype > :: OutPrefix;
  	using CImageResizerFilterStep< fptype, fptype > :: OutSuffix;
  	using CImageResizerFilterStep< fptype, fptype > :: OutElIncr;
  	using CImageResizerFilterStep< fptype, fptype > :: PrefixDC;
  	using CImageResizerFilterStep< fptype, fptype > :: SuffixDC;
  	using CImageResizerFilterStep< fptype, fptype > :: RPosBuf;
  	using CImageResizerFilterStep< fptype, fptype > :: FltBank;
  	using CImageResizerFilterStep< fptype, fptype > :: EdgePixelCount;
  
  	/**
  	 * @brief Performs "packing" (de-interleaving) of a scanline, and type
  	 * conversion. If required, the sRGB gamma correction is applied.
  	 *
  	 * @param ip0 Input scanline, pixel elements interleaved.
  	 * @param op0 Output scanline, pixel elements are grouped, `l` elements
  	 * apart.
  	 * @param l The number of pixels to "pack".
  	 */
  
  	template< class Tin >
  	void packScanline( const Tin* const ip0, fptype* const op0,
  		const int l ) const
  	{
  		const int ElCount = Vars -> ElCount;
  		int j;
  
  		if( !Vars -> UseSRGBGamma )
  		{
  			for( j = 0; j < ElCount; j++ )
  			{
  				const Tin* ip = ip0 + j;
  				fptype* const op = op0 + j * InElIncr;
  				int i;
  
  				for( i = 0; i < l; i++ )
  				{
  					op[ i ] = (fptype) *ip;
  					ip += ElCount;
  				}
  			}
  		}
  		else
  		{
  			const int AlphaIndex = Vars -> AlphaIndex;
  			const fptype gm = (fptype) Vars -> InGammaMult;
  
  			for( j = 0; j < ElCount; j++ )
  			{
  				const Tin* ip = ip0 + j;
  				fptype* const op = op0 + j * InElIncr;
  				int i;
  
  				if( ElCount == 4 && j == AlphaIndex )
  				{
  					for( i = 0; i < l; i++ )
  					{
  						op[ i ] = (fptype) *ip * gm;
  						ip += ElCount;
  					}
  				}
  				else
  				{
  					for( i = 0; i < l; i++ )
  					{
  						op[ i ] = convertSRGB2Lin( *ip, gm );
  						ip += ElCount;
  					}
  				}
  			}
  		}
  	}
  
  	/**
  	 * @brief Applies Linear to sRGB gamma correction to the specified
  	 * scanline, in-place.
  	 *
  	 * @param[in,out] p0 Scanline.
  	 * @param l The number of pixels to de-linearize.
  	 * @param Vars0 Image resizing-related variables.
  	 */
  
  	static void applySRGBGamma( fptype* const p0, const int l,
  		const CImageResizerVars& Vars0 )
  	{
  		const int ElCount = Vars0.ElCount;
  		const int AlphaIndex = Vars0.AlphaIndex;
  		const fptype gm = (fptype) Vars0.OutGammaMult;
  		int j;
  
  		for( j = 0; j < ElCount; j++ )
  		{
  			fptype* const p = p0 + j * l;
  			int i;
  
  			if( ElCount == 4 && j == AlphaIndex )
  			{
  				for( i = 0; i < l; i++ )
  				{
  					p[ i ] *= gm;
  				}
  			}
  			else
  			{
  				for( i = 0; i < l; i++ )
  				{
  					p[ i ] = convertLin2SRGB( p[ i ]) * gm;
  				}
  			}
  		}
  	}
  
  	/**
  	 * @brief Converts vertical scanline to horizontal scanline.
  	 *
  	 * This function is called by the image resizer when image is resized
  	 * vertically. This means that the vertical scanline is stored in the
  	 * same format produced by the packScanline() and maintained by other
  	 * filtering functions.
  	 *
  	 * @param ip Input vertical scanline, pixel elements are grouped, SrcLen
  	 * elements apart.
  	 * @param op Output buffer (temporary buffer used during resizing), pixel
  	 * elements are grouped, `l` elements apart.
  	 * @param SrcLen The number of pixels in the input scanline, also used to
  	 * calculate input buffer increment.
  	 * @param SrcIncr Input buffer increment to the next vertical pixel.
  	 */
  
  	void convertVtoH( const fptype* ip, fptype* op, const int SrcLen,
  		const int SrcIncr ) const
  	{
  		const int ElCount = Vars -> ElCount;
  		const int SrcElIncr = SrcIncr / ElCount;
  		const int ips1 = SrcElIncr;
  		const int ips2 = SrcElIncr * 2;
  		const int ips3 = SrcElIncr * 3;
  		const int ops1 = InElIncr;
  		const int ops2 = InElIncr * 2;
  		const int ops3 = InElIncr * 3;
  		int j;
  
  		if( ElCount == 1 )
  		{
  			for( j = 0; j < SrcLen; j++ )
  			{
  				op[ 0 ] = ip[ 0 ];
  				ip += SrcIncr;
  				op++;
  			}
  		}
  		else
  		if( ElCount == 4 )
  		{
  			for( j = 0; j < SrcLen; j++ )
  			{
  				op[ 0 ] = ip[ 0 ];
  				op[ ops1 ] = ip[ ips1 ];
  				op[ ops2 ] = ip[ ips2 ];
  				op[ ops3 ] = ip[ ips3 ];
  				ip += SrcIncr;
  				op++;
  			}
  		}
  		else
  		if( ElCount == 3 )
  		{
  			for( j = 0; j < SrcLen; j++ )
  			{
  				op[ 0 ] = ip[ 0 ];
  				op[ ops1 ] = ip[ ips1 ];
  				op[ ops2 ] = ip[ ips2 ];
  				ip += SrcIncr;
  				op++;
  			}
  		}
  		else
  		if( ElCount == 2 )
  		{
  			for( j = 0; j < SrcLen; j++ )
  			{
  				op[ 0 ] = ip[ 0 ];
  				op[ ops1 ] = ip[ ips1 ];
  				ip += SrcIncr;
  				op++;
  			}
  		}
  	}
  
  	/**
  	 * @brief Performs "unpacking" of a scanline, and type conversion.
  	 *
  	 * Truncation is used when floating point is converted to integer.
  	 * The unpacking function assumes that scanline is stored in the style
  	 * produced by the packScanline() function.
  	 *
  	 * @param ip0 Input scanline, pixel elements are grouped, `l` elements
  	 * apart.
  	 * @param op0 Output scanline, pixel elements are interleaved.
  	 * @param l The number of pixels to "unpack".
  	 * @param Vars0 Image resizing-related variables. `ElCount` is assumed to
  	 * be equal to `ElCountIO`.
  	 */
  
  	template< class Tout >
  	static void unpackScanline( const fptype* const ip0, Tout* const op0,
  		const int l, const CImageResizerVars& Vars0 )
  	{
  		const int ElCount = Vars0.ElCount;
  		int j;
  
  		for( j = 0; j < ElCount; j++ )
  		{
  			const fptype* const ip = ip0 + j * l;
  			Tout* op = op0 + j;
  			int i;
  
  			for( i = 0; i < l; i++ )
  			{
  				*op = (Tout) ip[ i ];
  				op += ElCount;
  			}
  		}
  	}
  
  	/**
  	 * @brief Prepares input scanline buffer for *this* filtering step.
  	 *
  	 * Left- and right-most pixels are replicated to make sure no buffer
  	 * overrun happens. Such approach also allows to bypass any pointer
  	 * range checks.
  	 *
  	 * @param Src Source buffer.
  	 */
  
  	void prepareInBuf( fptype* Src ) const
  	{
  		if( IsUpsample || InPrefix + InSuffix == 0 )
  		{
  			return;
  		}
  
  		int j;
  
  		for( j = 0; j < Vars -> ElCount; j++ )
  		{
  			replicateArray( Src, 1, Src - InPrefix, InPrefix, 1 );
  			fptype* const Src2 = Src + InLen - 1;
  			replicateArray( Src2, 1, Src2 + 1, InSuffix, 1 );
  			Src += InElIncr;
  		}
  	}
  
  	/**
  	 * @brief Peforms scanline upsampling with filtering.
  	 *
  	 * @param Src Source scanline buffer (length = this -> InLen). Source
  	 * scanline increment will be equal to ElCount.
  	 * @param Dst Destination scanline buffer.
  	 */
  
  	void doUpsample( const fptype* Src, fptype* Dst ) const
  	{
  		const int elalign = Vars -> elalign;
  		const int opstep = ResampleFactor;
  		const fptype* const f = Flt;
  		const int flen = Flt.getCapacity();
  		int l;
  		int i;
  		int j;
  
  		for( j = 0; j < Vars -> ElCount; j++ )
  		{
  			const fptype* ip = Src;
  			fptype* op0 = &Dst[ -OutPrefix ];
  			memset( op0, 0, (size_t) ( OutPrefix + OutLen + OutSuffix ) *
  				sizeof( fptype ));
  
  			if( FltOrig.getCapacity() > 0 )
  			{
  				// Do not perform filtering, only upsample.
  
  				op0 += OutPrefix % ResampleFactor;
  				l = OutPrefix / ResampleFactor;
  
  				while( l > 0 )
  				{
  					op0[ 0 ] = ip[ 0 ];
  					op0 += opstep;
  					l--;
  				}
  
  				l = InLen - 1;
  
  				while( l > 0 )
  				{
  					op0[ 0 ] = ip[ 0 ];
  					op0 += opstep;
  					ip++;
  					l--;
  				}
  
  				l = OutSuffix / ResampleFactor;
  
  				while( l >= 0 )
  				{
  					op0[ 0 ] = ip[ 0 ];
  					op0 += opstep;
  					l--;
  				}
  
  				Src += InElIncr;
  				Dst += OutElIncr;
  				continue;
  			}
  
  			l = InPrefix;
  			fptypesimd ipv = (fptypesimd) ip[ 0 ];
  
  			while( l > 0 )
  			{
  				for( i = 0; i < flen; i += elalign )
  				{
  					fptypesimd :: addu( op0 + i,
  						fptypesimd :: load( f + i ) * ipv );
  				}
  
  				op0 += opstep;
  				l--;
  			}
  
  			l = InLen - 1;
  
  			while( l > 0 )
  			{
  				ipv = (fptypesimd) ip[ 0 ];
  
  				for( i = 0; i < flen; i += elalign )
  				{
  					fptypesimd :: addu( op0 + i,
  						fptypesimd :: load( f + i ) * ipv );
  				}
  
  				ip++;
  				op0 += opstep;
  				l--;
  			}
  
  			l = InSuffix;
  			ipv = (fptypesimd) ip[ 0 ];
  
  			while( l >= 0 )
  			{
  				for( i = 0; i < flen; i += elalign )
  				{
  					fptypesimd :: addu( op0 + i,
  						fptypesimd :: load( f + i ) * ipv );
  				}
  
  				op0 += opstep;
  				l--;
  			}
  
  			const fptype* dc = SuffixDC;
  			l = SuffixDC.getCapacity();
  
  			for( i = 0; i < l; i += elalign )
  			{
  				fptypesimd :: addu( op0 + i,
  					fptypesimd :: load( dc + i ) * ipv );
  			}
  
  			ipv = (fptypesimd) Src[ 0 ];
  			op0 = Dst - InPrefix * opstep;
  			dc = PrefixDC;
  			l = PrefixDC.getCapacity();
  
  			for( i = 0; i < l; i += elalign )
  			{
  				fptypesimd :: addu( op0 + i,
  					fptypesimd :: load( dc + i ) * ipv );
  			}
  
  			Src += InElIncr;
  			Dst += OutElIncr;
  		}
  	}
  
  	/**
  	 * @brief Performs scanline filtering with optional downsampling.
  	 *
  	 * Function makes use of the symmetry of the filter.
  	 *
  	 * @param Src Source scanline buffer (length = this -> InLen). Source
  	 * scanline increment will be equal to 1.
  	 * @param Dst Destination scanline buffer.
  	 * @param DstIncr Destination scanline buffer increment, used for
  	 * horizontal or vertical scanline stepping.
  	 */
  
  	void doFilter( const fptype* const Src, fptype* Dst,
  		const int DstIncr ) const
  	{
  		const int ElCount = Vars -> ElCount;
  		const int elalign = Vars -> elalign;
  		const fptype* const f = &Flt[ 0 ];
  		const int flen = Flt.getCapacity();
  		const int ipstep = ResampleFactor;
  		int i;
  		int j;
  
  		if( ElCount == 1 )
  		{
  			const fptype* ip = Src - EdgePixelCount * ipstep - FltLatency;
  			fptype* op = Dst;
  			int l = OutLen;
  
  			while( l > 0 )
  			{
  				fptypesimd s = fptypesimd :: load( f ) *
  					fptypesimd :: loadu( ip );
  
  				for( i = elalign; i < flen; i += elalign )
  				{
  					s += fptypesimd :: load( f + i ) *
  						fptypesimd :: loadu( ip + i );
  				}
  
  				op[ 0 ] = s.hadd();
  				op += DstIncr;
  				ip += ipstep;
  				l--;
  			}
  		}
  		else
  		if( DstIncr == 1 )
  		{
  			for( j = 0; j < ElCount; j++ )
  			{
  				const fptype* ip = Src - EdgePixelCount * ipstep -
  					FltLatency + j * InElIncr;
  
  				fptype* op = Dst + j * OutElIncr;
  				int l = OutLen;
  
  				while( l > 0 )
  				{
  					fptypesimd s = fptypesimd :: load( f ) *
  						fptypesimd :: loadu( ip );
  
  					for( i = elalign; i < flen; i += elalign )
  					{
  						s += fptypesimd :: load( f + i ) *
  							fptypesimd :: loadu( ip + i );
  					}
  
  					op[ 0 ] = s.hadd();
  					op += DstIncr;
  					ip += ipstep;
  					l--;
  				}
  			}
  		}
  		else
  		{
  			const fptype* ip0 = Src - EdgePixelCount * ipstep - FltLatency;
  			fptype* op0 = Dst;
  			int l = OutLen;
  
  			while( l > 0 )
  			{
  				const fptype* ip = ip0;
  				fptype* op = op0;
  
  				for( j = 0; j < ElCount; j++ )
  				{
  					fptypesimd s = fptypesimd :: load( f ) *
  						fptypesimd :: loadu( ip );
  
  					for( i = elalign; i < flen; i += elalign )
  					{
  						s += fptypesimd :: load( f + i ) *
  							fptypesimd :: loadu( ip + i );
  					}
  
  					op[ 0 ] = s.hadd();
  					ip += InElIncr;
  					op += OutElIncr;
  				}
  
  				ip0 += ipstep;
  				op0 += DstIncr;
  				l--;
  			}
  		}
  	}
  
  	/**
  	 * @brief Performs resizing of a single scanline.
  	 *
  	 * This function does not "know" about the length of the source scanline
  	 * buffer. This buffer should be padded with enough pixels so that
  	 * `SrcPos - FilterLenD2` is always positive, and
  	 * `SrcPos + ( DstLineLen - 1 ) * k + FilterLenD2 + 1` does not exceed
  	 * source scanline's buffer length. SrcLine's increment is assumed to be
  	 * equal to 1.
  	 *
  	 * @param SrcLine Source scanline buffer.
  	 * @param DstLine Destination (resized) scanline buffer.
  	 * @param DstLineIncr Destination scanline position increment, used for
  	 * horizontal or vertical scanline stepping.
  	 * @param xx Temporary buffer, of size FltBank.getFilterLen(), must be
  	 * aligned by fpclass :: fpalign.
  	 */
  
  	void doResize( const fptype* SrcLine, fptype* DstLine,
  		int DstLineIncr, fptype* const xx ) const
  	{
  		const int IntFltLen = FltBank -> getFilterLen();
  		const int ElCount = Vars -> ElCount;
  		const int elalign = Vars -> elalign;
  		const typename CImageResizerFilterStep< fptype, fptype > ::
  			CResizePos* rpos = &(*RPosBuf)[ 0 ];
  
  		int DstLineLen = OutLen;
  		int i;
  		int j;
  
  #define AVIR_RESIZE_PART1 \
  			while( DstLineLen > 0 ) \
  			{ \
  				const fptypesimd x = (fptypesimd) rpos -> x; \
  				const fptype* ftp = rpos -> ftp; \
  				const fptype* ftp2 = rpos -> ftp + IntFltLen; \
  				const fptype* Src = SrcLine + rpos -> SrcOffs;
  
  #define AVIR_RESIZE_PART1nx \
  			while( DstLineLen > 0 ) \
  			{ \
  				const fptype* ftp = rpos -> ftp; \
  				const fptype* Src = SrcLine + rpos -> SrcOffs;
  
  #define AVIR_RESIZE_PART2 \
  				DstLine += DstLineIncr; \
  				rpos++; \
  				DstLineLen--; \
  			}
  
  		if( ElCount == 1 )
  		{
  			if( FltBank -> getOrder() == 1 )
  			{
  				AVIR_RESIZE_PART1
  
  				fptypesimd sum = ( fptypesimd :: load( ftp ) +
  					fptypesimd :: load( ftp2 ) * x ) *
  					fptypesimd :: loadu( Src );
  
  				for( i = elalign; i < IntFltLen; i += elalign )
  				{
  					sum += ( fptypesimd :: load( ftp + i ) +
  						fptypesimd :: load( ftp2 + i ) * x ) *
  						fptypesimd :: loadu( Src + i );
  				}
  
  				DstLine[ 0 ] = sum.hadd();
  
  				AVIR_RESIZE_PART2
  			}
  			else
  			{
  				AVIR_RESIZE_PART1nx
  
  				fptypesimd sum = fptypesimd :: load( ftp ) *
  					fptypesimd :: loadu( Src );
  
  				for( i = elalign; i < IntFltLen; i += elalign )
  				{
  					sum += fptypesimd :: load( ftp + i ) *
  						fptypesimd :: loadu( Src + i );
  				}
  
  				DstLine[ 0 ] = sum.hadd();
  
  				AVIR_RESIZE_PART2
  			}
  		}
  		else
  		if( DstLineIncr == 1 )
  		{
  			// Horizontal-oriented processing, element loop is outer.
  
  			const int SrcIncr = InElIncr;
  			const int DstLineElIncr = OutElIncr - DstLineIncr * DstLineLen;
  
  			if( FltBank -> getOrder() == 1 )
  			{
  				for( j = 0; j < ElCount; j++ )
  				{
  					AVIR_RESIZE_PART1
  
  					fptypesimd sum = 0.0;
  
  					for( i = 0; i < IntFltLen; i += elalign )
  					{
  						sum += ( fptypesimd :: load( ftp + i ) +
  							fptypesimd :: load( ftp2 + i ) * x ) *
  							fptypesimd :: loadu( Src + i );
  					}
  
  					DstLine[ 0 ] = sum.hadd();
  
  					AVIR_RESIZE_PART2
  
  					DstLine += DstLineElIncr;
  					SrcLine += SrcIncr;
  					DstLineLen = OutLen;
  					rpos = &(*RPosBuf)[ 0 ];
  				}
  			}
  			else
  			{
  				for( j = 0; j < ElCount; j++ )
  				{
  					AVIR_RESIZE_PART1nx
  
  					fptypesimd sum = fptypesimd :: load( ftp ) *
  						fptypesimd :: loadu( Src );
  
  					for( i = elalign; i < IntFltLen; i += elalign )
  					{
  						sum += fptypesimd :: load( ftp + i ) *
  							fptypesimd :: loadu( Src + i );
  					}
  
  					DstLine[ 0 ] = sum.hadd();
  
  					AVIR_RESIZE_PART2
  
  					DstLine += DstLineElIncr;
  					SrcLine += SrcIncr;
  					DstLineLen = OutLen;
  					rpos = &(*RPosBuf)[ 0 ];
  				}
  			}
  		}
  		else
  		{
  			const int SrcIncr = InElIncr;
  			const int DstLineElIncr = OutElIncr;
  			DstLineIncr -= DstLineElIncr * ElCount;
  
  			if( FltBank -> getOrder() == 1 )
  			{
  				AVIR_RESIZE_PART1
  
  				for( i = 0; i < IntFltLen; i += elalign )
  				{
  					( fptypesimd :: load( ftp + i ) +
  						fptypesimd :: load( ftp2 + i ) * x ).store( xx + i );
  				}
  
  				for( j = 0; j < ElCount; j++ )
  				{
  					fptypesimd sum = fptypesimd :: load( xx ) *
  						fptypesimd :: loadu( Src );
  
  					for( i = elalign; i < IntFltLen; i += elalign )
  					{
  						sum += fptypesimd :: load( xx + i ) *
  							fptypesimd :: loadu( Src + i );
  					}
  
  					DstLine[ 0 ] = sum.hadd();
  					DstLine += DstLineElIncr;
  					Src += SrcIncr;
  				}
  
  				AVIR_RESIZE_PART2
  			}
  			else
  			{
  				AVIR_RESIZE_PART1nx
  
  				for( j = 0; j < ElCount; j++ )
  				{
  					fptypesimd sum = fptypesimd :: load( ftp ) *
  						fptypesimd :: loadu( Src );
  
  					for( i = elalign; i < IntFltLen; i += elalign )
  					{
  						sum += fptypesimd :: load( ftp + i ) *
  							fptypesimd :: loadu( Src + i );
  					}
  
  					DstLine[ 0 ] = sum.hadd();
  					DstLine += DstLineElIncr;
  					Src += SrcIncr;
  				}
  
  				AVIR_RESIZE_PART2
  			}
  		}
  
  #undef AVIR_RESIZE_PART2
  #undef AVIR_RESIZE_PART1nx
  #undef AVIR_RESIZE_PART1
  	}
  
  	/**
  	 * @copydoc doResize()
  	 */
  
  	void doResize2( const fptype* SrcLine, fptype* DstLine,
  		int DstLineIncr, fptype* const xx ) const
  	{
  		doResize( SrcLine, DstLine, DstLineIncr, xx );
  	}
  };
  
  /**
   * @brief Image resizer's default de-interleaved dithering class.
   *
   * This class defines an object that performs rounding, clipping and dithering
   * operations over horizontal scanline pixels before scanline is stored in the
   * output buffer.
   *
   * This ditherer implementation uses de-interleaved SIMD algorithm.
   *
   * @tparam fptype Floating point type to use for storing pixel data. SIMD
   * types cannot be used.
   * @tparam fptypesimd The SIMD type used to store a pack of `fptype` values.
   */
  
  template< class fptype, class fptypesimd >
  class CImageResizerDithererDefDIL
  {
  public:
  	/**
  	 * @brief Initializes the ditherer object.
  	 *
  	 * @param aLen Scanline length in pixels to process.
  	 * @param aVars Image resizing-related variables.
  	 * @param aTrMul Bit-depth truncation multiplier. 1 - no additional
  	 * truncation.
  	 * @param aPkOut Peak output value allowed.
  	 */
  
  	void init( const int aLen, const CImageResizerVars& aVars,
  		const double aTrMul, const double aPkOut )
  	{
  		Len = aLen;
  		Vars = &aVars;
  		LenE = aLen * Vars -> ElCount;
  		TrMul0 = aTrMul;
  		PkOut0 = aPkOut;
  	}
  
  	/**
  	 * @copydoc CImageResizerDithererDefINL::isRecursive()
  	 */
  
  	static bool isRecursive()
  	{
  		return( false );
  	}
  
  	/**
  	 * @copydoc CImageResizerDithererDefINL::dither()
  	 */
  
  	void dither( fptype* const ResScanline ) const
  	{
  		const int elalign = Vars -> elalign;
  		const fptypesimd c0 = 0.0;
  		const fptypesimd PkOut = (fptypesimd) PkOut0;
  		int j;
  
  		if( TrMul0 == 1.0 )
  		{
  			// Optimization - do not perform bit truncation.
  
  			for( j = 0; j < LenE - elalign; j += elalign )
  			{
  				const fptypesimd z0 = round(
  					fptypesimd :: loadu( ResScanline + j ));
  
  				clamp( z0, c0, PkOut ).storeu( ResScanline + j );
  			}
  
  			const int lim = LenE - j;
  			const fptypesimd z0 = round(
  				fptypesimd :: loadu( ResScanline + j, lim ));
  
  			clamp( z0, c0, PkOut ).storeu( ResScanline + j, lim );
  		}
  		else
  		{
  			const fptypesimd TrMul = (fptypesimd) TrMul0;
  			const fptypesimd TrMulI = (fptypesimd) ( 1.0 / TrMul0 );
  
  			for( j = 0; j < LenE - elalign; j += elalign )
  			{
  				const fptypesimd z0 = round(
  					fptypesimd :: loadu( ResScanline + j ) * TrMulI ) * TrMul;
  
  				clamp( z0, c0, PkOut ).storeu( ResScanline + j );
  			}
  
  			const int lim = LenE - j;
  			const fptypesimd z0 = round( fptypesimd :: loadu(
  				ResScanline + j, lim ) * TrMulI ) * TrMul;
  
  			clamp( z0, c0, PkOut ).storeu( ResScanline + j, lim );
  		}
  	}
  
  protected:
  	int Len; ///< Scanline's length in pixels.
  	const CImageResizerVars* Vars; ///< Image resizing-related variables.
  	int LenE; ///< = LenE * ElCount.
  	double TrMul0; ///< Bit-depth truncation multiplier.
  	double PkOut0; ///< Peak output value allowed.
  };
  
  /**
   * @brief Image resizer's error-diffusion dithering class, de-interleaved
   * mode.
   *
   * This ditherer implements error-diffusion dithering which looks good, and
   * whose results are compressed by PNG well.
   *
   * @tparam fptype Floating point type to use for storing pixel data. SIMD
   * types cannot be used.
   * @tparam fptypesimd Processing type, SIMD can be used.
   */
  
  template< class fptype, class fptypesimd >
  class CImageResizerDithererErrdDIL
  {
  public:
  	/**
  	 * Function initializes the ditherer object.
  	 *
  	 * @param aLen Scanline length in pixels to process.
  	 * @param aVars Image resizing-related variables.
  	 * @param aTrMul Bit-depth truncation multiplier. 1 - no additional
  	 * truncation.
  	 * @param aPkOut Peak output value allowed.
  	 */
  
  	void init( const int aLen, const CImageResizerVars& aVars,
  		const double aTrMul, const double aPkOut )
  	{
  		Len = aLen;
  		Vars = &aVars;
  		LenE = aLen * Vars -> ElCount;
  		TrMul0 = aTrMul;
  		PkOut0 = aPkOut;
  
  		ResScanlineDith0.alloc( LenE + Vars -> ElCount, sizeof( fptype ));
  		ResScanlineDith = ResScanlineDith0 + Vars -> ElCount;
  		int i;
  
  		for( i = 0; i < LenE + Vars -> ElCount; i++ )
  		{
  			ResScanlineDith0[ i ] = 0.0;
  		}
  	}
  
  	/**
  	 * @copydoc CImageResizerDithererDefINL::isRecursive()
  	 */
  
  	static bool isRecursive()
  	{
  		return( true );
  	}
  
  	/**
  	 * @copydoc CImageResizerDithererDefINL::dither()
  	 */
  
  	void dither( fptype* const ResScanline )
  	{
  		const int ea = Vars -> elalign;
  		const fptypesimd c0 = 0;
  		const fptypesimd TrMul = (fptypesimd) TrMul0;
  		const fptypesimd TrMulI = (fptypesimd) ( 1.0 / TrMul0 );
  		const fptypesimd PkOut = (fptypesimd) PkOut0;
  		int j;
  
  		for( j = 0; j < LenE - ea; j += ea )
  		{
  			fptypesimd :: addu( ResScanline + j,
  				fptypesimd :: loadu( ResScanlineDith + j ));
  
  			c0.storeu( ResScanlineDith + j );
  		}
  
  		int lim = LenE - j;
  		fptypesimd :: addu( ResScanline + j,
  			fptypesimd :: loadu( ResScanlineDith + j, lim ), lim );
  
  		c0.storeu( ResScanlineDith + j, lim );
  
  		const int Len1 = Len - 1;
  		fptype* rs = ResScanline;
  		fptype* rsd = ResScanlineDith;
  		int i;
  
  		for( i = 0; i < Vars -> ElCount; i++ )
  		{
  			for( j = 0; j < Len1; j++ )
  			{
  				// Perform rounding, noise estimation and saturation.
  
  				fptype* const rsj = rs + j;
  				const fptype z0 = round( rsj[ 0 ] * TrMulI ) * TrMul;
  				const fptype Noise = rsj[ 0 ] - z0;
  				rsj[ 0 ] = clamp( z0, (fptype) 0, PkOut );
  
  				fptype* const rsdj = rsd + j;
  				const fptype NoiseM1 = Noise * (fptype) 0.364842;
  				rsj[ 1 ] += NoiseM1;
  				rsdj[ -1 ] += Noise * (fptype) 0.207305;
  				rsdj[ 0 ] += NoiseM1;
  				rsdj[ 1 ] += Noise * (fptype) 0.063011;
  			}
  
  			// Process the last pixel element in scanline.
  
  			const fptype z1 = round( rs[ Len1 ] * TrMulI ) * TrMul;
  			const fptype Noise2 = rs[ Len1 ] - z1;
  			rs[ Len1 ] = clamp( z1, c0, PkOut );
  
  			rsd[ Len1 - 1 ] += Noise2 * (fptype) 0.207305;
  			rsd[ Len1 ] += Noise2 * (fptype) 0.364842;
  
  			rs += Len;
  			rsd += Len;
  		}
  	}
  
  protected:
  	int Len; ///< Scanline's length in pixels.
  	const CImageResizerVars* Vars; ///< Image resizing-related variables.
  	int LenE; ///< = LenE * ElCount.
  	double TrMul0; ///< Bit-depth truncation multiplier.
  	double PkOut0; ///< Peak output value allowed.
  	CBuffer< fptype > ResScanlineDith0; ///< Error propagation buffer for
  		///< dithering, first pixel unused.
  	fptype* ResScanlineDith; ///< Error propagation buffer pointer which skips
  		///< the first ElCount elements.
  };
  
  /**
   * @brief Floating-point processing definition and abstraction class for
   * de-interleaved processing.
   *
   * This class defines several constants and typedefs that point to classes
   * that should be used by the image resizing algorithm. This implementation
   * points to de-interleaved processing classes.
   *
   * @tparam afptype Floating point type to use for storing intermediate data
   * and variables. SIMD types should not be used.
   * @tparam afptypesimd SIMD type used to perform processing.
   * @tparam adith Ditherer class to use during processing.
   */
  
  template< class afptype, class afptypesimd,
  	class adith = CImageResizerDithererDefDIL< afptype, afptypesimd > >
  class fpclass_def_dil
  {
  public:
  	typedef afptype fptype; ///< Floating-point type to use during processing.
  	typedef afptype fptypeatom; ///< Atomic type `fptype` consists of.
  	static const int fppack = 1; ///< The number of atomic types stored in a
  		///< single `fptype` element.
  	static const int fpalign = sizeof( afptypesimd ); ///< Suggested alignment
  		///< size in bytes. This is not a required alignment, because image
  		///< resizing algorithm cannot be made to have a strictly aligned data
  		///< access in all cases (e.g. de-interleaved interpolation cannot
  		///< perform aligned accesses).
  	static const int elalign = sizeof( afptypesimd ) / sizeof( afptype ); ///<
  		///< Length alignment of arrays of elements. This applies to filters
  		///< and intermediate buffers: this constant forces filters and
  		///< scanlines to have a length which is a multiple of this value, for
  		///< more efficient SIMD implementation.
  	static const int packmode = 1; ///< 0 if interleaved packing, 1 if
  		///< de-interleaved.
  	typedef CImageResizerFilterStepDIL< fptype, afptypesimd > CFilterStep; ///<
  		///< Filtering step class to use during processing.
  	typedef adith CDitherer; ///< Ditherer class to use during processing.
  };
  
  } // namespace avir
  

Download