Class BandCombineOp

public class BandCombineOp
extends Object
implements RasterOp

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.

Constructors

BandCombineOp

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

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.

Methods

getMatrix

public final float[][] getMatrix()

Returns a copy of the linear combination matrix.

Returns:

The matrix associated with this band combine operation.

filter

public WritableRaster filter(Raster src,
                             WritableRaster dst)

Specified by:

filter in interface RasterOp

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.

getBounds2D

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.

Specified by:

getBounds2D in interface RasterOp

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.

createCompatibleDestRaster

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.

Specified by:

createCompatibleDestRaster in interface RasterOp

Parameters:

src - The Raster to be filtered.

Returns:

The zeroed destination Raster.

getPoint2D

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.

Specified by:

getPoint2D in interface RasterOp

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.

getRenderingHints

public final RenderingHints getRenderingHints()

Returns the rendering hints for this operation.

Specified by:

getRenderingHints in interface RasterOp

Returns:

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