/*

 * Copyright (c) 2015, 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

 * or visit www.oracle.com if you need additional information or have any

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 */

package java.awt.image;

import java.awt.Graphics;

import java.awt.Image;

/**

 * This class provides default implementations of several {@code Image} methods

 * for classes that want to implement the {@code MultiResolutionImage}

 * interface.

 *

 * For example,

 * <pre> {@code

 * public class CustomMultiResolutionImage extends AbstractMultiResolutionImage {

 *

 *     final Image[] resolutionVariants;

 *

 *     public CustomMultiResolutionImage(Image... resolutionVariants) {

 *          this.resolutionVariants = resolutionVariants;

 *     }

 *

 *     public Image getResolutionVariant(

 *             double destImageWidth, double destImageHeight) {

 *         // return a resolution variant based on the given destination image size

 *     }

 *

 *     public List<Image> getResolutionVariants() {

 *         return Collections.unmodifiableList(Arrays.asList(resolutionVariants));

 *     }

 *

 *     protected Image getBaseImage() {

 *         return resolutionVariants[0];

 *     }

 * }

 * } </pre>

 *

 * @see java.awt.Image

 * @see java.awt.image.MultiResolutionImage

 *

 * @since 9

 */

public abstract class AbstractMultiResolutionImage extends java.awt.Image

        implements MultiResolutionImage {

    /**

     * This method simply delegates to the same method on the base image and

     * it is equivalent to: {@code getBaseImage().getWidth(observer)}.

     *

     * @return the width of the base image, or -1 if the width is not yet known

     * @see #getBaseImage()

     *

     * @since 9

     */

    @Override

    public int getWidth(ImageObserver observer) {

        return getBaseImage().getWidth(observer);

    }

    /**

     * This method simply delegates to the same method on the base image and

     * it is equivalent to: {@code getBaseImage().getHeight(observer)}.

     *

     * @return the height of the base image, or -1 if the height is not yet known

     * @see #getBaseImage()

     *

     * @since 9

     */

    @Override

    public int getHeight(ImageObserver observer) {

        return getBaseImage().getHeight(observer);

    }

    /**

     * This method simply delegates to the same method on the base image and

     * it is equivalent to: {@code getBaseImage().getSource()}.

     *

     * @return the image producer that produces the pixels for the base image

     * @see #getBaseImage()

     *

     * @since 9

     */

    @Override

    public ImageProducer getSource() {

        return getBaseImage().getSource();

    }

    /**

     * As per the contract of the base {@code Image#getGraphics()} method,

     * this implementation will always throw {@code UnsupportedOperationException}

     * since only off-screen images can return a {@code Graphics} object.

     *

     * @return throws {@code UnsupportedOperationException}

     * @throws UnsupportedOperationException this method is not supported

     */

    @Override

    public Graphics getGraphics() {

        throw new UnsupportedOperationException("getGraphics() not supported"

                + " on Multi-Resolution Images");

    }

    /**

     * This method simply delegates to the same method on the base image and

     * it is equivalent to: {@code getBaseImage().getProperty(name, observer)}.

     *

     * @return the value of the named property in the base image

     * @see #getBaseImage()

     *

     * @since 9

     */

    @Override

    public Object getProperty(String name, ImageObserver observer) {

        return getBaseImage().getProperty(name, observer);

    }

    /**

     * Return the base image representing the best version of the image for

     * rendering at the default width and height.

     *

     * @return the base image of the set of multi-resolution images

     *

     * @since 9

     */

    protected abstract Image getBaseImage();

}