/*

 * Copyright (c) 1997, 2005, Oracle and/or its affiliates. All rights reserved.

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package java.awt.image;

import java.awt.GraphicsEnvironment;

import java.awt.color.ICC_Profile;

import java.awt.geom.Rectangle2D;

import java.awt.Rectangle;

import java.awt.geom.Point2D;

import java.awt.RenderingHints;

import sun.awt.image.ImagingLib;

import java.util.Arrays;

/**

 * This class performs an arbitrary linear combination of the bands

 * in a {@code Raster}, using a specified matrix.

 * <p>

 * The width of the matrix must be equal to the number of bands in the

 * source {@code 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.

 * <p>

 * For example, a 3-banded {@code Raster} might have the following

 * transformation applied to each pixel in order to invert the second band of

 * the {@code Raster}.

 * <pre>

 *   [ 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 ]

 * </pre>

 *

 * <p>

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

 */

public class BandCombineOp implements  RasterOp {

    float[][] matrix;

    int nrows = 0;

    int ncols = 0;

    RenderingHints hints;

    /**

     * Constructs a {@code BandCombineOp} with the specified matrix.

     * The width of the matrix must be equal to the number of bands in

     * the source {@code 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.

     * <p>

     * 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 {@code RenderingHints} argument can be

     * null.

     *

     * @param matrix The matrix to use for the band combine operation.

     * @param hints The {@code RenderingHints} object for this operation.

     * Not currently used so it can be null.

     */

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

        nrows = matrix.length;

        ncols = matrix[0].length;

        this.matrix = new float[nrows][];

        for (int i=0; i < nrows; i++) {

            /* Arrays.copyOf is forgiving of the source array being

             * too short, but it is also faster than other cloning

             * methods, so we provide our own protection for short

             * matrix rows.

             */

            if (ncols > matrix[i].length) {

                throw new IndexOutOfBoundsException("row "+i+" too short");

            }

            this.matrix[i] = Arrays.copyOf(matrix[i], ncols);

        }

        this.hints  = hints;

    }

    /**

     * Returns a copy of the linear combination matrix.

     *

     * @return The matrix associated with this band combine operation.

     */

    public final float[][] getMatrix() {

        float[][] ret = new float[nrows][];

        for (int i = 0; i < nrows; i++) {

            ret[i] = Arrays.copyOf(matrix[i], ncols);

        }

        return ret;

    }

    /**

     * Transforms the {@code Raster} using the matrix specified in the

     * constructor. An {@code 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.

     * <p>

     * 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.

     *

     * @param src The {@code Raster} to be filtered.

     * @param dst The {@code Raster} in which to store the results

     * of the filter operation.

     *

     * @return The filtered {@code Raster}.

     *

     * @throws IllegalArgumentException If the number of bands in the

     * source or destination is incompatible with the matrix.

     */

    public WritableRaster filter(Raster src, WritableRaster dst) {

        int nBands = src.getNumBands();

        if (ncols != nBands && ncols != (nBands+1)) {

            throw new IllegalArgumentException("Number of columns in the "+

                                               "matrix ("+ncols+

                                               ") must be equal to the number"+

                                               " of bands ([+1]) in src ("+

                                               nBands+").");

        }

        if (dst == null) {

            dst = createCompatibleDestRaster(src);

        }

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

            throw new IllegalArgumentException("Number of rows in the "+

                                               "matrix ("+nrows+

                                               ") must be equal to the number"+

                                               " of bands ([+1]) in dst ("+

                                               nBands+").");

        }

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

            return dst;

        }

        int[] pixel = null;

        int[] dstPixel = new int[dst.getNumBands()];

        float accum;

        int sminX = src.getMinX();

        int sY = src.getMinY();

        int dminX = dst.getMinX();

        int dY = dst.getMinY();

        int sX;

        int dX;

        if (ncols == nBands) {

            for (int y=0; y < src.getHeight(); y++, sY++, dY++) {

                dX = dminX;

                sX = sminX;

                for (int x=0; x < src.getWidth(); x++, sX++, dX++) {

                    pixel = src.getPixel(sX, sY, pixel);

                    for (int r=0; r < nrows; r++) {

                        accum = 0.f;

                        for (int c=0; c < ncols; c++) {

                            accum += matrix[r][c]*pixel[c];

                        }

                        dstPixel[r] = (int) accum;

                    }

                    dst.setPixel(dX, dY, dstPixel);

                }

            }

        }

        else {

            // Need to add constant

            for (int y=0; y < src.getHeight(); y++, sY++, dY++) {

                dX = dminX;

                sX = sminX;

                for (int x=0; x < src.getWidth(); x++, sX++, dX++) {

                    pixel = src.getPixel(sX, sY, pixel);

                    for (int r=0; r < nrows; r++) {

                        accum = 0.f;

                        for (int c=0; c < nBands; c++) {

                            accum += matrix[r][c]*pixel[c];

                        }

                        dstPixel[r] = (int) (accum+matrix[r][nBands]);

                    }

                    dst.setPixel(dX, dY, dstPixel);

                }

            }

        }

        return dst;

    }

    /**

     * 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 {@code IllegalArgumentException} may be thrown if the number of

     * bands in the source is incompatible with the matrix.  See

     * the class comments for more details.

     *

     * @param src The {@code Raster} to be filtered.

     *

     * @return The {@code 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 Rectangle2D getBounds2D (Raster src) {

        return src.getBounds();

    }

    /**

     * Creates a zeroed destination {@code Raster} with the correct size

     * and number of bands.

     * An {@code IllegalArgumentException} may be thrown if the number of

     * bands in the source is incompatible with the matrix.  See

     * the class comments for more details.

     *

     * @param src The {@code Raster} to be filtered.

     *

     * @return The zeroed destination {@code Raster}.

     */

    public WritableRaster createCompatibleDestRaster (Raster src) {

        int nBands = src.getNumBands();

        if ((ncols != nBands) && (ncols != (nBands+1))) {

            throw new IllegalArgumentException("Number of columns in the "+

                                               "matrix ("+ncols+

                                               ") must be equal to the number"+

                                               " of bands ([+1]) in src ("+

                                               nBands+").");

        }

        if (src.getNumBands() == nrows) {

            return src.createCompatibleWritableRaster();

        }

        else {

            throw new IllegalArgumentException("Don't know how to create a "+

                                               " compatible Raster with "+

                                               nrows+" bands.");

        }

    }

    /**

     * Returns the location of the corresponding destination point given a

     * point in the source {@code Raster}.  If {@code 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 {@code srcPt}.

     *

     * @param srcPt The {@code Point2D} that represents the point in

     *              the source {@code Raster}

     * @param dstPt The {@code Point2D} in which to store the result.

     *

     * @return The {@code Point2D} in the destination image that

     * corresponds to the specified point in the source image.

     */

    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 operation.

     *

     * @return The {@code RenderingHints} object associated with this

     * operation.  Returns null if no hints have been set.

     */

    public final RenderingHints getRenderingHints() {

        return hints;

    }

}