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     }

   150 }