java.awt.image

Class ConvolveOp

Implemented Interfaces:
BufferedImageOp, RasterOp

public class ConvolveOp
extends Object
implements BufferedImageOp, RasterOp

Convolution filter. ConvolveOp convolves the source image with a Kernel to generate a destination image. This involves multiplying each pixel and its neighbors with elements in the kernel to compute a new pixel. Each band in a Raster is convolved and copied to the destination Raster. For BufferedImages, convolution is applied to all components. Color conversion will be applied if needed. Note that this filter ignores whether the source or destination is alpha premultiplied. The reference spec states that data will be premultiplied prior to convolving and divided back out afterwards (if needed), but testing has shown that this is not the case with their implementation.

Field Summary

static int
EDGE_NO_OP
Edge pixels are copied from the source.
static int
EDGE_ZERO_FILL
Edge pixels are set to 0.

Constructor Summary

ConvolveOp(Kernel kernel)
Construct a ConvolveOp.
ConvolveOp(Kernel kernel, int edgeCondition, RenderingHints hints)
Construct a ConvolveOp.

Method Summary

BufferedImage
createCompatibleDestImage(BufferedImage src, ColorModel dstCM)
Creates an empty BufferedImage with the size equal to the source and the correct number of bands.
WritableRaster
createCompatibleDestRaster(Raster src)
BufferedImage
filter(BufferedImage src, BufferedImage dst)
Converts the source image using the kernel specified in the constructor.
WritableRaster
filter(Raster src, WritableRaster dest)
Converts the source raster using the kernel specified in the constructor.
Rectangle2D
getBounds2D(BufferedImage src)
Rectangle2D
getBounds2D(Raster src)
int
getEdgeCondition()
Get the edge condition for this Op.
Kernel
getKernel()
Returns (a clone of) the convolution kernel.
Point2D
getPoint2D(Point2D src, Point2D dst)
Returns the corresponding destination point for a source point.
RenderingHints
getRenderingHints()

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

EDGE_NO_OP

public static final int EDGE_NO_OP
Edge pixels are copied from the source.
Field Value:
1

EDGE_ZERO_FILL

public static final int EDGE_ZERO_FILL
Edge pixels are set to 0.
Field Value:
0

Constructor Details

ConvolveOp

public ConvolveOp(Kernel kernel)
Construct a ConvolveOp. The edge condition defaults to EDGE_ZERO_FILL.
Parameters:
kernel - The kernel to convolve with.

ConvolveOp

public ConvolveOp(Kernel kernel,
                  int edgeCondition,
                  RenderingHints hints)
Construct a ConvolveOp. The edge condition specifies that pixels outside the area that can be filtered are either set to 0 or copied from the source image.
Parameters:
kernel - The kernel to convolve with.
edgeCondition - Either EDGE_ZERO_FILL or EDGE_NO_OP.
hints - Rendering hints for color conversion, or null.

Method Details

createCompatibleDestImage

public BufferedImage createCompatibleDestImage(BufferedImage src,
                                               ColorModel dstCM)
Creates an empty BufferedImage with the size equal to the source and the correct number of bands. The new image is created with the specified ColorModel, or if no ColorModel is supplied, an appropriate one is chosen.
Specified by:
createCompatibleDestImage in interface BufferedImageOp
Parameters:
src - The source image.
dstCM - A color model for the destination image (may be null).
Returns:
The new compatible destination image.

createCompatibleDestRaster

public WritableRaster createCompatibleDestRaster(Raster src)
Specified by:
createCompatibleDestRaster in interface RasterOp

filter

public final BufferedImage filter(BufferedImage src,
                                  BufferedImage dst)
Converts the source image using the kernel specified in the constructor. The resulting image is stored in the destination image if one is provided; otherwise a new BufferedImage is created and returned. The source and destination BufferedImage (if one is supplied) must have the same dimensions.
Specified by:
filter in interface BufferedImageOp
Parameters:
src - The source image.
dst - The destination image.
Returns:
The convolved image.
Throws:
IllegalArgumentException - if the rasters and/or color spaces are incompatible.

filter

public final WritableRaster filter(Raster src,
                                   WritableRaster dest)
Converts the source raster using the kernel specified in the constructor. The resulting raster is stored in the destination raster if one is provided; otherwise a new WritableRaster is created and returned. If the convolved value for a sample is outside the range of [0-255], it will be clipped. The source and destination raster (if one is supplied) cannot be the same, and must also have the same dimensions.
Specified by:
filter in interface RasterOp
Parameters:
src - The source raster.
dest - The destination raster.
Returns:
The transformed raster.
Throws:
IllegalArgumentException - if the rasters identical.
ImagingOpException - if the convolution is not possible.

getBounds2D

public final Rectangle2D getBounds2D(BufferedImage src)
Specified by:
getBounds2D in interface BufferedImageOp

getBounds2D

public final Rectangle2D getBounds2D(Raster src)
Specified by:
getBounds2D in interface RasterOp

getEdgeCondition

public int getEdgeCondition()
Get the edge condition for this Op.
Returns:
The edge condition.

getKernel

public final Kernel getKernel()
Returns (a clone of) the convolution kernel.
Returns:
The convolution kernel.

getPoint2D

public final Point2D getPoint2D(Point2D src,
                                Point2D dst)
Returns the corresponding destination point for a source point. Because this is not a geometric operation, the destination and source points will be identical.
Specified by:
getPoint2D in interface BufferedImageOp
getPoint2D in interface RasterOp
Parameters:
src - The source point.
dst - The transformed destination point.
Returns:
The transformed destination point.

getRenderingHints

public final RenderingHints getRenderingHints()
Specified by:
getRenderingHints in interface BufferedImageOp
getRenderingHints in interface RasterOp

ConvolveOp.java -- Copyright (C) 2004, 2005, 2006, Free Software Foundation -- ConvolveOp This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.