avir::CImageResizerFilterStep< fptype, fptypeatom > Class Template Reference

Image resizer's filtering step class. More...

#include <avir.h>

Inheritance diagram for avir::CImageResizerFilterStep< fptype, fptypeatom >:

Classes
struct	CResizePos
	Resizing position structure. More...
class	CRPosBuf
	Resizing positions buffer class. More...
class	CRPosBufArray
	Resizing positions buffer array class. More...

Public Attributes
double	DCGain
	DC gain which was applied to the filter. Not defined if ResampleFactor = 0.
int	EdgePixelCount
	The number of edge pixels added. Affects the initial position within the input scanline, used to produce edge pixels. This variable is used and should be defined when IsUpsample=false and ResampleFactor>0. When assigning this variable it is also necessary to update InPrefix, OutLen and Vars.o variables.
CBuffer< fptype >	Flt
	Filter to use at this step.
CDSPFracFilterBankLin< fptype > *	FltBank
	Filter bank in use by *this resizing step.
int	FltLatency
	Filter's latency (group delay, shift) in pixels.
CFltBuffer	FltOrig
	Originally-designed filter. This buffer may not be assigned. Assigned by filters that precede the resizing step if such filter is planned to be embedded into the interpolation filter as "external" filter. If IsUpsample=true and this filter buffer is not empty, the upsampling step will not itself apply any filtering over upsampled input scanline.
int	InBuf
	Input buffer index, 0 or 1.
int	InElIncr
	Pixel element increment within the input buffer, used during de-interleaved processing: in this case each image's channel is stored independently, InElIncr elements apart.
int	InLen
	Input scanline's length in pixels.
int	InPrefix
	Required input prefix pixels. These prefix pixels will be filled with source scanline's first pixel value. If IsUpsample is "true", this is the additional number of times the first pixel will be filtered before processing scanline, this number is also reflected in the OutPrefix.
int	InSuffix
	Required input suffix pixels. These suffix pixels will be filled with source scanline's last pixel value. If IsUpsample is "true", this is the additional number of times the last pixel will be filtered before processing scanline, this number is also reflected in the OutSuffix.
bool	IsUpsample
	"True" if this step is an upsampling step, "false" if downsampling step. Should be set to "false" if ResampleFactor equals 0.
int	OutBuf
	Output buffer index. 0 or 1; 2 for the last step.
int	OutElIncr
	Pixel element increment within the output buffer, used during de-interleaved processing. Equals to the InBufElIncr of the next step.
int	OutLen
	Length of the resulting scanline.
int	OutPrefix
	Required output prefix pixels. These prefix pixels will not be pre-filled with any values. Value is valid only if IsUpsample equals "true".
int	OutSuffix
	Required input suffix pixels. These suffix pixels will not be pre-filled with any values. Value is valid only if IsUpsample equals "true".
CBuffer< fptype >	PrefixDC
	DC component fluctuations added at the start of the resulting scanline, used when IsUpsample equals "true".
int	ResampleFactor
	Resample factor (>=1). If 0, this is a resizing step. This value should be >1 if IsUpsample equals "true".
CRPosBuf *	RPosBuf
	Resizing positions buffer. Used when ResampleFactor equals 0 (resizing step).
CBuffer< fptype >	SuffixDC
	DC component fluctuations added at the end of the resulting scanline, used when IsUpsample equals "true".
const CImageResizerVars *	Vars
	Image resizing-related variables.

Static Public Attributes
static const int	EdgePixelCountDef = 3
	The default number of pixels additionally produced at scanline edges during filtering. This is required to reduce edge artifacts.

Detailed Description

template<class fptype, class fptypeatom>
class avir::CImageResizerFilterStep< fptype, fptypeatom >

Image resizer's filtering step class.

Class defines data to perform a single filtering step over a whole horizontal or vertical scanline. Resizing consists of 1 or more steps that may be performed before the actual resizing takes place. Filtering may also follow a resizing step. Each step must ensure that scanline data contains enough pixels to perform the next step (which may be resizing) without exceeding scanline's bounds.

A derived class must implement several "const" and "static" functions that are used to perform the actual filtering in interleaved or de-interleaved mode.

Template Parameters

fptype	Floating point type to use for storing pixel elements. SIMD types can be used: in this case each element may hold a whole pixel.
fptypeatom	The atomic type the "fptype" consists of.