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.Image;
28 import java.util.List;
29 import java.util.Arrays;
30 import java.util.Collections;
31 import java.util.Objects;
32
33 /**
34 * This class is an array-based implementation of
35 * the {@code AbstractMultiResolutionImage} class.
36 *
37 * This class will implement the
38 * {@code getResolutionVariant(double destImageWidth, double destImageHeight)}
39 * method using a simple algorithm which will return the first image variant
40 * in the array that is large enough to satisfy the rendering request. The
41 * last image in the array will be returned if no suitable image is found
42 * that is as large as the rendering request.
43 * <p>
44 * For best effect the array of images should be sorted with each image being
45 * both wider and taller than the previous image. The base image need not be
46 * the first image in the array. No exception will be thrown if the images
47 * are not sorted as suggested.
48 *
49 * @see java.awt.Image
50 * @see java.awt.image.MultiResolutionImage
51 * @see java.awt.image.AbstractMultiResolutionImage
52 *
53 * @since 1.9
54 */
55 public class BaseMultiResolutionImage extends AbstractMultiResolutionImage {
56
57 private final int baseImageIndex;
58 private final Image[] resolutionVariants;
59
60 /**
61 * Creates a multi-resolution image with the given resolution variants.
62 * The first resolution variant is used as the base image.
63 *
64 * @param resolutionVariants array of resolution variants sorted by image size
65 * @throws IllegalArgumentException if null or zero-length array is passed
66 * @throws NullPointerException if the specified {@code resolutionVariants}
67 * contains one or more null elements
68 *
69 * @since 1.9
70 */
71 public BaseMultiResolutionImage(Image... resolutionVariants) {
72 this(0, resolutionVariants);
73 }
74
75 /**
76 * Creates a multi-resolution image with the given base image index and
77 * resolution variants.
78 *
79 * @param baseImageIndex the index of base image in the resolution variants
80 * array
81 * @param resolutionVariants array of resolution variants sorted by image size
82 * @throws IllegalArgumentException if null or zero-length array is passed
83 * @throws NullPointerException if the specified {@code resolutionVariants}
84 * contains one or more null elements
85 * @throws IndexOutOfBoundsException if {@code baseImageIndex} is
86 * negative or greater than or equal to {@code resolutionVariants}
87 * length.
88 *
89 * @since 1.9
90 */
91 public BaseMultiResolutionImage(int baseImageIndex,
92 Image... resolutionVariants) {
93
94 if (resolutionVariants == null || resolutionVariants.length == 0) {
95 throw new IllegalArgumentException(
96 "Null or zero-length array is passed");
97 }
98
99 if (baseImageIndex < 0 || baseImageIndex >= resolutionVariants.length) {
100 throw new IndexOutOfBoundsException("Invalid base image index: "
101 + baseImageIndex);
102 }
103
104 this.baseImageIndex = baseImageIndex;
105 this.resolutionVariants = Arrays.copyOf(resolutionVariants,
106 resolutionVariants.length);
107
108 for (Image resolutionVariant : this.resolutionVariants) {
109 Objects.requireNonNull(resolutionVariant,
110 "Resolution variant can't be null");
111 }
112 }
113
114 @Override
115 public Image getResolutionVariant(double destImageWidth,
116 double destImageHeight) {
117
118 checkSize(destImageWidth, destImageHeight);
119
120 for (Image rvImage : resolutionVariants) {
121 if (destImageWidth <= rvImage.getWidth(null)
122 && destImageHeight <= rvImage.getHeight(null)) {
123 return rvImage;
124 }
125 }
126 return resolutionVariants[resolutionVariants.length - 1];
127 }
128
129 private static void checkSize(double width, double height) {
130 if (width <= 0 || height <= 0) {
131 throw new IllegalArgumentException(String.format(
132 "Width (%s) or height (%s) cannot be <= 0", width, height));
133 }
134
135 if (!Double.isFinite(width) || !Double.isFinite(height)) {
136 throw new IllegalArgumentException(String.format(
137 "Width (%s) or height (%s) is not finite", width, height));
138 }
139 }
140
141 @Override
142 public List<Image> getResolutionVariants() {
143 return Collections.unmodifiableList(Arrays.asList(resolutionVariants));
144 }
145
146 @Override
147 protected Image getBaseImage() {
148 return resolutionVariants[baseImageIndex];
149 }