core.image
Class AccumImage

java.lang.Object
  core.image.ScalarImage
      core.image.AccumImage

Direct Known Subclasses:

Accum2Image

public class AccumImage

extends ScalarImage

Stores a monochrome float image with alpha = < width, height, float-buffer, alpha-buffer, minalpha, coverage >. An AccumImage extends ScalarImage to include an alpha component for every scalar value. The alpha values are pre-multiplied into the scalar, so to obtain the scalar value at a pixel, the alpha must be divided out of it. This sort of image is useful for accumulation operations. Each AccumImage also automatically maintains information about the coverage of the image. Every time a pixel surpasses the "minalpha" requirement, "coverage" is incremented to indicated the total count of such pixels.

Version:

1.0

Author:

Andreas Sundquist

Field Summary

float[]	a a[] stores all the alpha values for the corresponding array f[]
int	coverage coverage indicates the number of pixels whose alpha exceeds "minalpha"
double	minalpha minalpha defines the minimum alpha required for a pixel to be "covered"

Fields inherited from class core.image.ScalarImage

f, height, offset, size, width

Constructor Summary

AccumImage(int width, int height)
Constructs a new AccumImage = < width, height, zero-buffer, zero-buffer, 1.0, 0 >

Method Summary

void	Accumulate(int x, int y, double s) Adds "s" to the scalar value at (x, y) and increments the corresponding alpha value.
void	Accumulate(int x, int y, double s, double sa) Adds "s" and "sa" to the scalar and alpha values at (x, y) if it is in-bounds.
void	AccumulateBilinear(double x, double y, double s) Bilinearly accumulates "s" to the four integer grid points surrounding the continuous coordinate (x, y), weighting the alpha accumulation bilinearly as well.
void	AccumulateBilinear(Vec2 v, double s) Bilinearly accumulates "s" to the four integer grid points surrounding the continuous coordinate "v", weighting the alpha accumulation bilinearly as well.
void	Clear() Clears both the scalar and alpha components in "this"
void	Copy(AccumImage image) Copies the scalar and alpha values from the top-left corner of "image" to "this" Requires: "image" is at least as large as "this"
void	Copy(AccumImage image, int xorigin, int yorigin) Copies the scalar and alpha values from the sub-window of "image" starting at (xorigin, yorigin) to "this".
double	get(int x, int y) Returns: the value at (x, y) with the alpha divided out Requires: 0<=x
double	getAlpha(int x, int y) Returns: the alpha value at (x, y) Requires: 0<=x
boolean	hasSingularity() Returns: true if an scalar or alpha value in "this" is invalid
void	Normalize() Divides out the alpha component in "this", renormalizing it to 1.0
void	Normalize(int x, int y) Divides out the alpha component at coordinate (x, y) in "this", renormalizing it to 1.0 Requires: 0<=x
void	Set(int x, int y, double s, double sa) Sets the scalar and alpha value at (x, y) to (s, sa).
void	SetAlpha() Sets the scalar component of "this" to the alpha component
void	SetZero() Sets the samples in "this" to zero, with an alpha of 1.0

Methods inherited from class core.image.ScalarImage

Add, Clamp, Convolve3x3, Copy, Copy, getBilinear, getBilinear, inBounds, inBounds, inBounds, Modulate, Power, Rescale, Set, SetRandom, SetRandom, StretchBilinear, Vec2FieldMagnitude, Vec2FieldZero

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

a

public float[] a

a[] stores all the alpha values for the corresponding array f[]

minalpha

public double minalpha

minalpha defines the minimum alpha required for a pixel to be "covered"

coverage

public int coverage

coverage indicates the number of pixels whose alpha exceeds "minalpha"

Constructor Detail

AccumImage

public AccumImage(int width,
                  int height)

Constructs a new AccumImage = < width, height, zero-buffer, zero-buffer, 1.0, 0 >

Method Detail

SetZero

public void SetZero()

Sets the samples in "this" to zero, with an alpha of 1.0

Overrides:

SetZero in class ScalarImage

Clear

public void Clear()

Clears both the scalar and alpha components in "this"

Overrides:

Clear in class ScalarImage

SetAlpha

public void SetAlpha()

Sets the scalar component of "this" to the alpha component

Copy

public void Copy(AccumImage image,
                 int xorigin,
                 int yorigin)

Copies the scalar and alpha values from the sub-window of "image" starting at (xorigin, yorigin) to "this". Requires: the sub-window fits inside "image"

Copy

public void Copy(AccumImage image)

Copies the scalar and alpha values from the top-left corner of "image" to "this" Requires: "image" is at least as large as "this"

Normalize

public void Normalize()

Divides out the alpha component in "this", renormalizing it to 1.0

Normalize

public void Normalize(int x,
                      int y)

Divides out the alpha component at coordinate (x, y) in "this", renormalizing it to 1.0 Requires: 0<=x

get

public double get(int x,
                  int y)

Returns: the value at (x, y) with the alpha divided out Requires: 0<=x

Overrides:

get in class ScalarImage

getAlpha

public double getAlpha(int x,
                       int y)

Returns: the alpha value at (x, y) Requires: 0<=x

Set

public void Set(int x,
                int y,
                double s,
                double sa)

Sets the scalar and alpha value at (x, y) to (s, sa). If (x, y) is out-of-bounds, this has no effect.

Accumulate

public void Accumulate(int x,
                       int y,
                       double s)

Adds "s" to the scalar value at (x, y) and increments the corresponding alpha value. If (x, y) is out-of-bounds, it has no effect.

Overrides:

Accumulate in class ScalarImage

Accumulate

public void Accumulate(int x,
                       int y,
                       double s,
                       double sa)

Adds "s" and "sa" to the scalar and alpha values at (x, y) if it is in-bounds.

AccumulateBilinear

public void AccumulateBilinear(double x,
                               double y,
                               double s)

Bilinearly accumulates "s" to the four integer grid points surrounding the continuous coordinate (x, y), weighting the alpha accumulation bilinearly as well.

Overrides:

AccumulateBilinear in class ScalarImage

AccumulateBilinear

public void AccumulateBilinear(Vec2 v,
                               double s)

Bilinearly accumulates "s" to the four integer grid points surrounding the continuous coordinate "v", weighting the alpha accumulation bilinearly as well.

Overrides:

AccumulateBilinear in class ScalarImage

hasSingularity

public boolean hasSingularity()

Returns: true if an scalar or alpha value in "this" is invalid

Overrides:

hasSingularity in class ScalarImage