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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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package java.awt.image;

import java.awt.color.ICC_Profile;

import java.awt.geom.Rectangle2D;

import java.awt.Rectangle;

import java.awt.RenderingHints;

import java.awt.geom.Point2D;

import sun.awt.image.ImagingLib;

/**

 * This class implements a convolution from the source

 * to the destination.

 * Convolution using a convolution kernel is a spatial operation that

 * computes the output pixel from an input pixel by multiplying the kernel

 * with the surround of the input pixel.

 * This allows the output pixel to be affected by the immediate neighborhood

 * in a way that can be mathematically specified with a kernel.

 *<p>

 * This class operates with BufferedImage data in which color components are

 * premultiplied with the alpha component.  If the Source BufferedImage has

 * an alpha component, and the color components are not premultiplied with

 * the alpha component, then the data are premultiplied before being

 * convolved.  If the Destination has color components which are not

 * premultiplied, then alpha is divided out before storing into the

 * Destination (if alpha is 0, the color components are set to 0).  If the

 * Destination has no alpha component, then the resulting alpha is discarded

 * after first dividing it out of the color components.

 * <p>

 * Rasters are treated as having no alpha channel.  If the above treatment

 * of the alpha channel in BufferedImages is not desired, it may be avoided

 * by getting the Raster of a source BufferedImage and using the filter method

 * of this class which works with Rasters.

 * <p>

 * If a RenderingHints object is specified in the constructor, the

 * color rendering hint and the dithering hint may be used when color

 * conversion is required.

 *<p>

 * Note that the Source and the Destination may not be the same object.

 * @see Kernel

 * @see java.awt.RenderingHints#KEY_COLOR_RENDERING

 * @see java.awt.RenderingHints#KEY_DITHERING

 */

public class ConvolveOp implements BufferedImageOp, RasterOp {

    Kernel kernel;

    int edgeHint;

    RenderingHints hints;

    /**

     * Edge condition constants.

     */

    /**

     * Pixels at the edge of the destination image are set to zero.  This

     * is the default.

     */

    public static final int EDGE_ZERO_FILL = 0;

    /**

     * Pixels at the edge of the source image are copied to

     * the corresponding pixels in the destination without modification.

     */

    public static final int EDGE_NO_OP     = 1;

    /**

     * Constructs a ConvolveOp given a Kernel, an edge condition, and a

     * RenderingHints object (which may be null).

     * @param kernel the specified <code>Kernel</code>

     * @param edgeCondition the specified edge condition

     * @param hints the specified <code>RenderingHints</code> object

     * @see Kernel

     * @see #EDGE_NO_OP

     * @see #EDGE_ZERO_FILL

     * @see java.awt.RenderingHints

     */

    public ConvolveOp(Kernel kernel, int edgeCondition, RenderingHints hints) {

        this.kernel   = kernel;

        this.edgeHint = edgeCondition;

        this.hints    = hints;

    }

    /**

     * Constructs a ConvolveOp given a Kernel.  The edge condition

     * will be EDGE_ZERO_FILL.

     * @param kernel the specified <code>Kernel</code>

     * @see Kernel

     * @see #EDGE_ZERO_FILL

     */

    public ConvolveOp(Kernel kernel) {

        this.kernel   = kernel;

        this.edgeHint = EDGE_ZERO_FILL;

    }

    /**

     * Returns the edge condition.

     * @return the edge condition of this <code>ConvolveOp</code>.

     * @see #EDGE_NO_OP

     * @see #EDGE_ZERO_FILL

     */

    public int getEdgeCondition() {

        return edgeHint;

    }

    /**

     * Returns the Kernel.

     * @return the <code>Kernel</code> of this <code>ConvolveOp</code>.

     */

    public final Kernel getKernel() {

        return (Kernel) kernel.clone();

    }

    /**

     * Performs a convolution on BufferedImages.  Each component of the

     * source image will be convolved (including the alpha component, if

     * present).

     * If the color model in the source image is not the same as that

     * in the destination image, the pixels will be converted

     * in the destination.  If the destination image is null,

     * a BufferedImage will be created with the source ColorModel.

     * The IllegalArgumentException may be thrown if the source is the

     * same as the destination.

     * @param src the source <code>BufferedImage</code> to filter

     * @param dst the destination <code>BufferedImage</code> for the

     *        filtered <code>src</code>

     * @return the filtered <code>BufferedImage</code>

     * @throws NullPointerException if <code>src</code> is <code>null</code>

     * @throws IllegalArgumentException if <code>src</code> equals

     *         <code>dst</code>

     * @throws ImagingOpException if <code>src</code> cannot be filtered

     */

    public final BufferedImage filter (BufferedImage src, BufferedImage dst) {

        if (src == null) {

            throw new NullPointerException("src image is null");

        }

        if (src == dst) {

            throw new IllegalArgumentException("src image cannot be the "+

                                               "same as the dst image");

        }

        boolean needToConvert = false;

        ColorModel srcCM = src.getColorModel();

        ColorModel dstCM;

        BufferedImage origDst = dst;

        // Can't convolve an IndexColorModel.  Need to expand it

        if (srcCM instanceof IndexColorModel) {

            IndexColorModel icm = (IndexColorModel) srcCM;

            src = icm.convertToIntDiscrete(src.getRaster(), false);

            srcCM = src.getColorModel();

        }

        if (dst == null) {

            dst = createCompatibleDestImage(src, null);

            dstCM = srcCM;

            origDst = dst;

        }

        else {

            dstCM = dst.getColorModel();

            if (srcCM.getColorSpace().getType() !=

                dstCM.getColorSpace().getType())

            {

                needToConvert = true;

                dst = createCompatibleDestImage(src, null);

                dstCM = dst.getColorModel();

            }

            else if (dstCM instanceof IndexColorModel) {

                dst = createCompatibleDestImage(src, null);

                dstCM = dst.getColorModel();

            }

        }

        if (ImagingLib.filter(this, src, dst) == null) {

            throw new ImagingOpException ("Unable to convolve src image");

        }

        if (needToConvert) {

            ColorConvertOp ccop = new ColorConvertOp(hints);

            ccop.filter(dst, origDst);

        }

        else if (origDst != dst) {

            java.awt.Graphics2D g = origDst.createGraphics();

            try {

                g.drawImage(dst, 0, 0, null);

            } finally {

                g.dispose();

            }

        }

        return origDst;

    }

    /**

     * Performs a convolution on Rasters.  Each band of the source Raster

     * will be convolved.

     * The source and destination must have the same number of bands.

     * If the destination Raster is null, a new Raster will be created.

     * The IllegalArgumentException may be thrown if the source is

     * the same as the destination.

     * @param src the source <code>Raster</code> to filter

     * @param dst the destination <code>WritableRaster</code> for the

     *        filtered <code>src</code>

     * @return the filtered <code>WritableRaster</code>

     * @throws NullPointerException if <code>src</code> is <code>null</code>

     * @throws ImagingOpException if <code>src</code> and <code>dst</code>

     *         do not have the same number of bands

     * @throws ImagingOpException if <code>src</code> cannot be filtered

     * @throws IllegalArgumentException if <code>src</code> equals

     *         <code>dst</code>

     */

    public final WritableRaster filter (Raster src, WritableRaster dst) {

        if (dst == null) {

            dst = createCompatibleDestRaster(src);

        }

        else if (src == dst) {

            throw new IllegalArgumentException("src image cannot be the "+

                                               "same as the dst image");

        }

        else if (src.getNumBands() != dst.getNumBands()) {

            throw new ImagingOpException("Different number of bands in src "+

                                         " and dst Rasters");

        }

        if (ImagingLib.filter(this, src, dst) == null) {

            throw new ImagingOpException ("Unable to convolve src image");

        }

        return dst;

    }

    /**

     * Creates a zeroed destination image with the correct size and number

     * of bands.  If destCM is null, an appropriate ColorModel will be used.

     * @param src       Source image for the filter operation.

     * @param destCM    ColorModel of the destination.  Can be null.

     * @return a destination <code>BufferedImage</code> with the correct

     *         size and number of bands.

     */

    public BufferedImage createCompatibleDestImage(BufferedImage src,

                                                   ColorModel destCM) {

        BufferedImage image;

        int w = src.getWidth();

        int h = src.getHeight();

        WritableRaster wr = null;

        if (destCM == null) {

            destCM = src.getColorModel();

            // Not much support for ICM

            if (destCM instanceof IndexColorModel) {

                destCM = ColorModel.getRGBdefault();

            } else {

                /* Create destination image as similar to the source

                 *  as it possible...

                 */

                wr = src.getData().createCompatibleWritableRaster(w, h);

            }

        }

        if (wr == null) {

            /* This is the case when destination color model

             * was explicitly specified (and it may be not compatible

             * with source raster structure) or source is indexed image.

             * We should use destination color model to create compatible

             * destination raster here.

             */

            wr = destCM.createCompatibleWritableRaster(w, h);

        }

        image = new BufferedImage (destCM, wr,

                                   destCM.isAlphaPremultiplied(), null);

        return image;

    }

    /**

     * Creates a zeroed destination Raster with the correct size and number

     * of bands, given this source.

     */

    public WritableRaster createCompatibleDestRaster(Raster src) {

        return src.createCompatibleWritableRaster();

    }

    /**

     * Returns the bounding box of the filtered destination image.  Since

     * this is not a geometric operation, the bounding box does not

     * change.

     */

    public final Rectangle2D getBounds2D(BufferedImage src) {

        return getBounds2D(src.getRaster());

    }

    /**

     * Returns the bounding box of the filtered destination Raster.  Since

     * this is not a geometric operation, the bounding box does not

     * change.

     */

    public final Rectangle2D getBounds2D(Raster src) {

        return src.getBounds();

    }

    /**

     * Returns the location of the destination point given a

     * point in the source.  If dstPt is non-null, it will

     * be used to hold the return value.  Since this is not a geometric

     * operation, the srcPt will equal the dstPt.

     */

    public final Point2D getPoint2D(Point2D srcPt, Point2D dstPt) {

        if (dstPt == null) {

            dstPt = new Point2D.Float();

        }

        dstPt.setLocation(srcPt.getX(), srcPt.getY());

        return dstPt;

    }

    /**

     * Returns the rendering hints for this op.

     */

    public final RenderingHints getRenderingHints() {

        return hints;

    }

}