Module imagingbook.common

Package imagingbook.common.image

Class GridIndexer2D

java.lang.Object

imagingbook.common.image.GridIndexer2D

Direct Known Subclasses:

GridIndexer2D.DefaultValueIndexer, GridIndexer2D.ExceptionIndexer, GridIndexer2D.MirrorImageIndexer, GridIndexer2D.NearestBorderIndexer, GridIndexer2D.PeriodicImageIndexer

public abstract class GridIndexer2D
extends Object

Instances of this class perform the transformation between 2D image coordinates and indexes into the associated 1D pixel array and vice versa. As usual images are assumed to be stored in row-major order. Instances of this class do not hold any image data themselves, they just perform the indexing task. This is used, for example, by class PixelPack, which provides a universal image data container which uses GridIndexer2D internally.

The (abstract) method getIndex(int, int) returns the 1D array index for a pair of 2D image coordinates. It is implemented by the inner subclasses GridIndexer2D.DefaultValueIndexer, GridIndexer2D.MirrorImageIndexer and GridIndexer2D.NearestBorderIndexer. They exhibit different behaviors when accessing out-of-image coordinates (see OutOfBoundsStrategy).

Version:

2022/09/17

See Also:

• OutOfBoundsStrategy

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	GridIndexer2D.DefaultValueIndexer	This indexer returns -1 for coordinates outside the image bounds, indicating that a (predefined) default pixel value should be used.
static class	GridIndexer2D.ExceptionIndexer	This indexer throws an exception if coordinates outside image bounds are accessed.
static class	GridIndexer2D.MirrorImageIndexer	This indexer returns mirrored image values for coordinates outside the image bounds.
static class	GridIndexer2D.NearestBorderIndexer	This indexer returns the closest border pixel for coordinates outside the image bounds.
static class	GridIndexer2D.OutOfImageException	Exception to be thrown by GridIndexer2D.ExceptionIndexer.
static class	GridIndexer2D.PeriodicImageIndexer	This indexer returns repetitive image values for coordinates outside the image bounds.

Field Summary

Fields

Modifier and Type	Field	Description
static final OutOfBoundsStrategy	DefaultOutOfBoundsStrategy

Method Summary

Modifier and Type	Method	Description
static GridIndexer2D	create(int width, int height, OutOfBoundsStrategy obs)	Creates and returns a new GridIndexer2D with the specified size and OutOfBoundsStrategy.
static GridIndexer2D	create(ImageProcessor ip, OutOfBoundsStrategy obs)	Creates and returns a new GridIndexer2D for the specified image and OutOfBoundsStrategy.
int	getHeight()	Returns the height of the associated image.
abstract int	getIndex(int u, int v)	Returns the 1D array index for a given pair of image coordinates.
OutOfBoundsStrategy	getOutOfBoundsStrategy()	Returns the out-of-bounds strategy (see {qlink OutOfBoundsStrategy} used by this indexer.
int	getWidth()	Returns the width of the associated image.
protected int	getWithinBoundsIndex(int u, int v)	Returns the 1D array index for a given pair of image coordinates, assuming that the specified position is inside the image.

Methods inherited from class java.lang.Object

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

Field Details

DefaultOutOfBoundsStrategy

public static final OutOfBoundsStrategy DefaultOutOfBoundsStrategy

Method Details

create

public static GridIndexer2D create(int width,
 int height,
 OutOfBoundsStrategy obs)

Creates and returns a new GridIndexer2D with the specified size and OutOfBoundsStrategy.

Parameters:

width - grid size (horizontal)

height - grid size (vertical)

obs - out-of-bounds strategy

Returns:

a new GridIndexer2D

create

public static GridIndexer2D create(ImageProcessor ip,
 OutOfBoundsStrategy obs)

Creates and returns a new GridIndexer2D for the specified image and OutOfBoundsStrategy.

Parameters:

ip - the image to be associated with the returned indexer

obs - out-of-bounds strategy

Returns:

a new GridIndexer2D

getIndex

public abstract int getIndex(int u,
 int v)

Returns the 1D array index for a given pair of image coordinates. For u, v coordinates outside the image, the returned index depends on the implementing subclass of GridIndexer2D. As a general rule, this method either returns a valid 1D array index or throws an exception. Subclasses implement (override) this method.

Parameters:

u - x-coordinate

v - y-coordinate

Returns:

1D array index

getWithinBoundsIndex

protected int getWithinBoundsIndex(int u,
 int v)

Returns the 1D array index for a given pair of image coordinates, assuming that the specified position is inside the image.

Parameters:

u - x-coordinate

v - y-coordinate

Returns:

the associated 1D index

getWidth

public int getWidth()

Returns the width of the associated image.

Returns:

the image width

getHeight

public int getHeight()

Returns the height of the associated image.

Returns:

the image height

getOutOfBoundsStrategy

public OutOfBoundsStrategy getOutOfBoundsStrategy()

Returns the out-of-bounds strategy (see {qlink OutOfBoundsStrategy} used by this indexer.

Returns:

the out-of-bounds strategy