public class

BandCombineOp

extends Object
implements RasterOp
java.lang.Object
   ↳ java.awt.image.BandCombineOp

Class Overview

This class performs an arbitrary linear combination of the bands in a Raster, using a specified matrix.

The width of the matrix must be equal to the number of bands in the source Raster, optionally plus one. If there is one more column in the matrix than the number of bands, there is an implied 1 at the end of the vector of band samples representing a pixel. The height of the matrix must be equal to the number of bands in the destination.

For example, a 3-banded Raster might have the following transformation applied to each pixel in order to invert the second band of the Raster. 

   [ 1.0   0.0   0.0    0.0  ]     [ b1 ]
   [ 0.0  -1.0   0.0  255.0  ]  x  [ b2 ]
   [ 0.0   0.0   1.0    0.0  ]     [ b3 ]
                                   [ 1 ]

Note that the source and destination can be the same object.

Summary

Public Constructors
BandCombineOp(float[][] matrix, RenderingHints hints)
Constructs a BandCombineOp with the specified matrix.
Public Methods
WritableRaster createCompatibleDestRaster(Raster src)
Creates a zeroed destination Raster with the correct size and number of bands.
WritableRaster filter(Raster src, WritableRaster dst)
Transforms the Raster using the matrix specified in the constructor.
final Rectangle2D getBounds2D(Raster src)
Returns the bounding box of the transformed destination.
final float[][] getMatrix()
Returns a copy of the linear combination matrix.
final Point2D getPoint2D(Point2D srcPt, Point2D dstPt)
Returns the location of the corresponding destination point given a point in the source Raster.
final RenderingHints getRenderingHints()
Returns the rendering hints for this operation.
[Expand]
Inherited Methods
From class java.lang.Object
From interface java.awt.image.RasterOp

Public Constructors

public BandCombineOp (float[][] matrix, RenderingHints hints)

Constructs a BandCombineOp with the specified matrix. The width of the matrix must be equal to the number of bands in the source Raster, optionally plus one. If there is one more column in the matrix than the number of bands, there is an implied 1 at the end of the vector of band samples representing a pixel. The height of the matrix must be equal to the number of bands in the destination.

The first subscript is the row index and the second is the column index. This operation uses none of the currently defined rendering hints; the RenderingHints argument can be null.

Parameters
matrix The matrix to use for the band combine operation.
hints The RenderingHints object for this operation. Not currently used so it can be null.

Public Methods

public WritableRaster createCompatibleDestRaster (Raster src)

Creates a zeroed destination Raster with the correct size and number of bands. An IllegalArgumentException may be thrown if the number of bands in the source is incompatible with the matrix. See the class comments for more details.

Parameters
src The Raster to be filtered.
Returns
  • The zeroed destination Raster.

public WritableRaster filter (Raster src, WritableRaster dst)

Transforms the Raster using the matrix specified in the constructor. An IllegalArgumentException may be thrown if the number of bands in the source or destination is incompatible with the matrix. See the class comments for more details.

If the destination is null, it will be created with a number of bands equalling the number of rows in the matrix. No exception is thrown if the operation causes a data overflow.

Parameters
src The Raster to be filtered.
dst The Raster in which to store the results of the filter operation.
Returns
  • The filtered Raster.
Throws
IllegalArgumentException If the number of bands in the source or destination is incompatible with the matrix.

public final Rectangle2D getBounds2D (Raster src)

Returns the bounding box of the transformed destination. Since this is not a geometric operation, the bounding box is the same for the source and destination. An IllegalArgumentException may be thrown if the number of bands in the source is incompatible with the matrix. See the class comments for more details.

Parameters
src The Raster to be filtered.
Returns
  • The Rectangle2D representing the destination image's bounding box.
Throws
IllegalArgumentException If the number of bands in the source is incompatible with the matrix.

public final float[][] getMatrix ()

Returns a copy of the linear combination matrix.

Returns
  • The matrix associated with this band combine operation.

public final Point2D getPoint2D (Point2D srcPt, Point2D dstPt)

Returns the location of the corresponding destination point given a point in the source Raster. If dstPt is specified, it is used to hold the return value. Since this is not a geometric operation, the point returned is the same as the specified srcPt.

Parameters
srcPt The Point2D that represents the point in the source Raster
dstPt The Point2D in which to store the result.
Returns
  • The Point2D in the destination image that corresponds to the specified point in the source image.

public final RenderingHints getRenderingHints ()

Returns the rendering hints for this operation.

Returns
  • The RenderingHints object associated with this operation. Returns null if no hints have been set.