DcmQuantFloydSteinberg Class Reference

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

List of all members.

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.
void adjust (DcmQuantPixel &px, long col, long maxval)
 uses the Floyd-Steinberg error vectors to adjust the color of the current image pixel.
void propagate (const DcmQuantPixel &px, const DcmQuantPixel &mapped, long col)
 propagates the Floyd-Steinberg error terms for one pixel.
void startRow (long &col, long &limitcol)
 starts error diffusion for a new row.
void finishRow ()
 finishes error diffusion for one image row.
void nextCol (long &col) const
 increases or decreases the column number depending on the direction flag.

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.
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.

Definition at line 52 of file diqtfs.h.

Member Function Documentation

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.

Definition at line 75 of file diqtfs.h.

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

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.

Definition at line 165 of file diqtfs.h.

References fs_direction, nextberr, nextgerr, nextrerr, temperr, thisberr, thisgerr, and thisrerr.

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.

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

Definition at line 183 of file diqtfs.h.

References fs_direction.

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]

Definition at line 94 of file diqtfs.h.

References fs_direction, DcmQuantPixel::getBlue(), DcmQuantPixel::getGreen(), DcmQuantPixel::getRed(), nextberr, nextgerr, nextrerr, thisberr, thisgerr, and thisrerr.

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.

Definition at line 144 of file diqtfs.h.

References columns, fs_direction, nextberr, nextgerr, and nextrerr.

Member Data Documentation

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.

Definition at line 223 of file diqtfs.h.

Referenced by finishRow(), nextCol(), propagate(), and startRow().

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

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