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 * published by the Free Software Foundation.  Oracle designates this

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

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 * This code is distributed in the hope that it will be useful, but WITHOUT

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 * 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,

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 *

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package java.awt.image;

import java.awt.image.ImageConsumer;

import java.awt.image.ColorModel;

import java.util.Hashtable;

import java.awt.Rectangle;

/**

 * An ImageFilter class for scaling images using the simplest algorithm.

 * This class extends the basic ImageFilter Class to scale an existing

 * image and provide a source for a new image containing the resampled

 * image.  The pixels in the source image are sampled to produce pixels

 * for an image of the specified size by replicating rows and columns of

 * pixels to scale up or omitting rows and columns of pixels to scale

 * down.

 * <p>It is meant to be used in conjunction with a FilteredImageSource

 * object to produce scaled versions of existing images.  Due to

 * implementation dependencies, there may be differences in pixel values

 * of an image filtered on different platforms.

 *

 * @see FilteredImageSource

 * @see ImageFilter

 *

 * @author      Jim Graham

 */

public class ReplicateScaleFilter extends ImageFilter {

    /**

     * The width of the source image.

     */

    protected int srcWidth;

    /**

     * The height of the source image.

     */

    protected int srcHeight;

    /**

     * The target width to scale the image.

     */

    protected int destWidth;

    /**

     * The target height to scale the image.

     */

    protected int destHeight;

    /**

     * An {@code int} array containing information about a

     * row of pixels.

     */

    /**

     * An {@code int} array containing information about a

     * column of pixels.

     */

    /**

     * A {@code byte} array initialized with a size of

     * {@link #destWidth} and used to deliver a row of pixel

     * data to the {@link ImageConsumer}.

     */

    protected Object outpixbuf;

    /**

     * Constructs a ReplicateScaleFilter that scales the pixels from

     * its source Image as specified by the width and height parameters.

     * @param width the target width to scale the image

     * @param height the target height to scale the image

     * @throws IllegalArgumentException if {@code width} equals

     *         zero or {@code height} equals zero

     */

    public ReplicateScaleFilter(int width, int height) {

        if (width == 0 || height == 0) {

            throw new IllegalArgumentException("Width ("+width+

                                                ") and height ("+height+

                                                ") must be non-zero");

        }

        destWidth = width;

        destHeight = height;

    }

    /**

     * Passes along the properties from the source object after adding a

     * property indicating the scale applied.

     * This method invokes {@code super.setProperties},

     * which might result in additional properties being added.

     * <p>

     * Note: This method is intended to be called by the

     * {@code ImageProducer} of the {@code Image} whose pixels

     * are being filtered. Developers using

     * this class to filter pixels from an image should avoid calling

     * this method directly since that operation could interfere

     * with the filtering operation.

     */

    public void setProperties(Hashtable<?,?> props) {

        @SuppressWarnings("unchecked")

        Hashtable<Object,Object> p = (Hashtable<Object,Object>)props.clone();

        String key = "rescale";

        String val = destWidth + "x" + destHeight;

        Object o = p.get(key);

        if (o != null && o instanceof String) {

            val = ((String) o) + ", " + val;

        }

        p.put(key, val);

        super.setProperties(p);

    }

    /**

     * Override the dimensions of the source image and pass the dimensions

     * of the new scaled size to the ImageConsumer.

     * <p>

     * Note: This method is intended to be called by the

     * {@code ImageProducer} of the {@code Image} whose pixels

     * are being filtered. Developers using

     * this class to filter pixels from an image should avoid calling

     * this method directly since that operation could interfere

     * with the filtering operation.

     * @see ImageConsumer

     */

    public void setDimensions(int w, int h) {

        srcWidth = w;

        srcHeight = h;

        if (destWidth < 0) {

            if (destHeight < 0) {

                destWidth = srcWidth;

                destHeight = srcHeight;

            } else {

                destWidth = srcWidth * destHeight / srcHeight;

            }

        } else if (destHeight < 0) {

            destHeight = srcHeight * destWidth / srcWidth;

        }

        consumer.setDimensions(destWidth, destHeight);

    }

    private void calculateMaps() {

        srcrows = new int[destHeight + 1];

        for (int y = 0; y <= destHeight; y++) {

            srcrows[y] = (2 * y * srcHeight + srcHeight) / (2 * destHeight);

        }

        srccols = new int[destWidth + 1];

        for (int x = 0; x <= destWidth; x++) {

            srccols[x] = (2 * x * srcWidth + srcWidth) / (2 * destWidth);

        }

    }

    /**

     * Choose which rows and columns of the delivered byte pixels are

     * needed for the destination scaled image and pass through just

     * those rows and columns that are needed, replicated as necessary.

     * <p>

     * Note: This method is intended to be called by the

     * {@code ImageProducer} of the {@code Image} whose pixels

     * are being filtered. Developers using

     * this class to filter pixels from an image should avoid calling

     * this method directly since that operation could interfere

     * with the filtering operation.

     */

    public void setPixels(int x, int y, int w, int h,

                          int scansize) {

        if (srcrows == null || srccols == null) {

            calculateMaps();

        }

        int sx, sy;

        int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);

        int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);

        if (outpixbuf != null && outpixbuf instanceof byte[]) {

            outpix = (byte[]) outpixbuf;

        } else {

            outpix = new byte[destWidth];

            outpixbuf = outpix;

        }

        for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {

            int srcoff = off + scansize * (sy - y);

            int dx;

            for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {

                outpix[dx] = pixels[srcoff + sx - x];

            }

            if (dx > dx1) {

                consumer.setPixels(dx1, dy, dx - dx1, 1,

                                   model, outpix, dx1, destWidth);

            }

        }

    }

    /**

     * Choose which rows and columns of the delivered int pixels are

     * needed for the destination scaled image and pass through just

     * those rows and columns that are needed, replicated as necessary.

     * <p>

     * Note: This method is intended to be called by the

     * {@code ImageProducer} of the {@code Image} whose pixels

     * are being filtered. Developers using

     * this class to filter pixels from an image should avoid calling

     * this method directly since that operation could interfere

     * with the filtering operation.

     */

    public void setPixels(int x, int y, int w, int h,

                          int scansize) {

        if (srcrows == null || srccols == null) {

            calculateMaps();

        }

        int sx, sy;

        int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);

        int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);

        if (outpixbuf != null && outpixbuf instanceof int[]) {

            outpix = (int[]) outpixbuf;

        } else {

            outpix = new int[destWidth];

            outpixbuf = outpix;

        }

        for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {

            int srcoff = off + scansize * (sy - y);

            int dx;

            for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {

                outpix[dx] = pixels[srcoff + sx - x];

            }

            if (dx > dx1) {

                consumer.setPixels(dx1, dy, dx - dx1, 1,

                                   model, outpix, dx1, destWidth);

            }

        }

    }

}