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 */
25package java.awt.image;
26
27import java.awt.Image;
28import java.util.List;
29import java.util.Arrays;
30import java.util.Collections;
31import 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 9
54 */
55public 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 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 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    }
150}
151