DcmQuantFloydSteinberg Class Reference

this class implements Floyd-Steinberg error diffusion. More...

Public Member Functions
	DcmQuantFloydSteinberg ()
	constructor
	~DcmQuantFloydSteinberg ()
	destructor
OFCondition	initialize (unsigned long cols)
	initializes the Floyd-Steinberg error vectors for an image with the given number of columns. More...
void	adjust (DcmQuantPixel &px, long col, long maxval)
	uses the Floyd-Steinberg error vectors to adjust the color of the current image pixel. More...
void	propagate (const DcmQuantPixel &px, const DcmQuantPixel &mapped, long col)
	propagates the Floyd-Steinberg error terms for one pixel. More...
void	startRow (long &col, long &limitcol)
	starts error diffusion for a new row. More...
void	finishRow ()
	finishes error diffusion for one image row. More...
void	nextCol (long &col) const
	increases or decreases the column number depending on the direction flag. More...

Private Member Functions
void	cleanup ()
	frees all memory allocated by the error vectors
	DcmQuantFloydSteinberg (const DcmQuantFloydSteinberg &src)
	private undefined copy constructor
DcmQuantFloydSteinberg &	operator= (const DcmQuantFloydSteinberg &src)
	private undefined copy assignment operator

Private Attributes
long *	thisrerr
	current red error vector. Points to an array of (columns + 2) entries.
long *	nextrerr
	red error vector for next row. Points to an array of (columns + 2) entries.
long *	thisgerr
	current green error vector. Points to an array of (columns + 2) entries.
long *	nextgerr
	green error vector for next row. Points to an array of (columns + 2) entries.
long *	thisberr
	current blue error vector. Points to an array of (columns + 2) entries.
long *	nextberr
	blue error vector for next row. Points to an array of (columns + 2) entries.
long *	temperr
	temporary pointer used for swapping error vectors
int	fs_direction
	boolean flag indicating in which direction (left to right/right to left) the FS distribution should be done. More...
unsigned long	columns
	number of columns in image

Detailed Description

this class implements Floyd-Steinberg error diffusion.

It is used during the color quantization of an image.

Member Function Documentation

adjust()

void DcmQuantFloydSteinberg::adjust ( DcmQuantPixel &  px, long  col, long  maxval  )

inline

uses the Floyd-Steinberg error vectors to adjust the color of the current image pixel.

Parameters

px	the original image pixel is passed in this parameter. Upon return, the pixel value contains the new value after error diffusion.
col	column in which the current pixel is located, must be [0..columns-1]
maxval	maximum value for each color component.

References DcmQuantPixel::assign(), DcmQuantPixel::getBlue(), DcmQuantPixel::getGreen(), and DcmQuantPixel::getRed().

finishRow()

void DcmQuantFloydSteinberg::finishRow ( )

inline

finishes error diffusion for one image row.

The direction flag is inverted and the error vectors for the "current" and "next" image row are swapped.

initialize()

OFCondition DcmQuantFloydSteinberg::initialize

(

unsigned long

cols

)

initializes the Floyd-Steinberg error vectors for an image with the given number of columns.

Parameters

cols	number of columns in image

Returns

EC_Normal if successful, an error code otherwise.

nextCol()

void DcmQuantFloydSteinberg::nextCol ( long &  col ) const

inline

increases or decreases the column number depending on the direction flag.

Parameters

col	column number, may become negative

propagate()

void DcmQuantFloydSteinberg::propagate ( const DcmQuantPixel &  px, const DcmQuantPixel &  mapped, long  col  )

inline

propagates the Floyd-Steinberg error terms for one pixel.

Parameters

px	color value the current image pixel should have (after adjustment)
mapped	color value (selected from the color LUT) the current image pixel really uses
col	column in which the current pixel is located, must be [0..columns-1]

References DcmQuantPixel::getBlue(), DcmQuantPixel::getGreen(), and DcmQuantPixel::getRed().

startRow()

void DcmQuantFloydSteinberg::startRow ( long &  col, long &  limitcol  )

inline

starts error diffusion for a new row.

The error vectors for the next image row are initialized to zero. The initial and last column of the current row are determined

Parameters

col	initial column for the current row returned in this parameter
limitcol	limit column (one past the last valid column) for the current row returned in this parameter. May become negative.

Member Data Documentation

fs_direction

int DcmQuantFloydSteinberg::fs_direction

private

boolean flag indicating in which direction (left to right/right to left) the FS distribution should be done.

Flag is inverted after each row.

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The documentation for this class was generated from the following file:

• dcmimage/include/dcmtk/dcmimage/diqtfs.h