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 /** 68 * This method simply delegates to the same method on the base image and 69 * it is equivalent to: {@code getBaseImage().getWidth(observer)}. 70 * @return returns an integer value of the image width 71 * @see #getBaseImage() 72 * 73 * @since 9 74 */ 75 @Override 76 public int getWidth(ImageObserver observer) { 77 return getBaseImage().getWidth(observer); 78 } 79 80 /** 81 * This method simply delegates to the same method on the base image and 82 * it is equivalent to: {@code getBaseImage().getHeight(observer)}. 83 * 84 * @return returns an integer value of the image height 85 * @see #getBaseImage() 86 * 87 * @since 9 88 */ 89 @Override 90 public int getHeight(ImageObserver observer) { 91 return getBaseImage().getHeight(observer); 92 } 93 94 /** 95 * This method simply delegates to the same method on the base image and 96 * it is equivalent to: {@code getBaseImage().getSource()}. 97 * 98 * @return returns an ImageProducer object reference to the source image 99 * @see #getBaseImage() 100 * 101 * @since 9 102 */ 103 @Override 104 public ImageProducer getSource() { 105 return getBaseImage().getSource(); 106 } 107 108 /** 109 * As per the contract of the base {@code Image#getGraphics()} method, 110 * this implementation will always throw {@code UnsupportedOperationException} 111 * since only off-screen images can return a {@code Graphics} object. 112 * @return Only {@code UnsupportedOperationException} is thrown 113 * @throws UnsupportedOperationException this method is not supported 114 */ 115 @Override 116 public Graphics getGraphics() { 117 throw new UnsupportedOperationException("getGraphics() not supported" 118 + " on Multi-Resolution Images"); 119 } 120 121 /** 122 * This method simply delegates to the same method on the base image and 123 * it is equivalent to: {@code getBaseImage().getProperty(name, observer)}. 124 * 125 * @return returns an Object corresponding to the property of base image 126 * @see #getBaseImage() 127 * 128 * @since 9 129 */ 130 @Override 131 public Object getProperty(String name, ImageObserver observer) { 132 return getBaseImage().getProperty(name, observer); 133 } 134 135 /** 136 * Return the base image representing the best version of the image for 137 * rendering at the default width and height. 138 * 139 * @return the base image of the set of multi-resolution images 140 * 141 * @since 9 142 */ 143 protected abstract Image getBaseImage(); 144 }