1 /*
   2  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package java.awt.image;
  26 
  27 import java.awt.Graphics;
  28 import java.awt.Image;
  29 
  30 /**
  31  * This class provides default implementations of several {@code Image} methods
  32  * for classes that want to implement the {@MultiResolutionImage} interface.
  33  *
  34  * For example,
  35  * <pre> {@code
  36  * public class CustomMultiResolutionImage extends AbstractMultiResolutionImage {
  37  *
  38  *     final Image[] resolutionVariants;
  39  *
  40  *     public CustomMultiResolutionImage(Image... resolutionVariants) {
  41  *          this.resolutionVariants = resolutionVariants;
  42  *     }
  43  *
  44  *     public Image getResolutionVariant(
  45  *             double destImageWidth, double destImageHeight) {
  46  *         // return a resolution variant based on the given destination image size
  47  *     }
  48  *
  49  *     public List<Image> getResolutionVariants() {
  50  *         return Collections.unmodifiableList(Arrays.asList(resolutionVariants));
  51  *     }
  52  *
  53  *     protected Image getBaseImage() {
  54  *         return resolutionVariants[0];
  55  *     }
  56  * }
  57  * } </pre>
  58  *
  59  * @see java.awt.Image
  60  * @see java.awt.image.MultiResolutionImage
  61  *
  62  * @since 9
  63  */
  64 public abstract class AbstractMultiResolutionImage extends java.awt.Image
  65         implements MultiResolutionImage {
  66 
  67     @Override
  68     public int getWidth(ImageObserver observer) {
  69         return getBaseImage().getWidth(observer);
  70     }
  71 
  72     @Override
  73     public int getHeight(ImageObserver observer) {
  74         return getBaseImage().getHeight(observer);
  75     }
  76 
  77     @Override
  78     public ImageProducer getSource() {
  79         return getBaseImage().getSource();
  80     }
  81 
  82     @Override
  83     public Graphics getGraphics() {
  84         throw new UnsupportedOperationException("getGraphics() not supported"
  85                 + " on Multi-Resolution Images");
  86     }
  87 
  88     @Override
  89     public Object getProperty(String name, ImageObserver observer) {
  90         return getBaseImage().getProperty(name, observer);
  91     }
  92 
  93     /**
  94      * Return the base image representing the best version of the image for
  95      * rendering at the default width and height.
  96      *
  97      * @return the base image of the set of multi-resolution images
  98      *
  99      * @since 9
 100      */
 101     protected abstract Image getBaseImage();
 102 }