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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package java.awt.image;

import java.awt.Image;
import java.util.List;
import java.util.Arrays;
import java.util.Collections;
import java.util.Objects;


This class is an array-based implementation of the AbstractMultiResolutionImage class. This class will implement the getResolutionVariant(double destImageWidth, double destImageHeight) method using a simple algorithm which will return the first image variant in the array that is large enough to satisfy the rendering request. The last image in the array will be returned if no suitable image is found that is as large as the rendering request. 

For best effect the array of images should be sorted with each image being
both wider and taller than the previous image.  The base image need not be
the first image in the array. No exception will be thrown if the images
are not sorted as suggested.

See Also:
Since:9
/**
 * This class is an array-based implementation of
 * the {@code AbstractMultiResolutionImage} class.
 *
 * This class will implement the
 * {@code getResolutionVariant(double destImageWidth, double destImageHeight)}
 * method using a simple algorithm which will return the first image variant
 * in the array that is large enough to satisfy the rendering request. The
 * last image in the array will be returned if no suitable image is found
 * that is as large as the rendering request.
 * <p>
 * For best effect the array of images should be sorted with each image being
 * both wider and taller than the previous image.  The base image need not be
 * the first image in the array. No exception will be thrown if the images
 * are not sorted as suggested.
 *
 * @see java.awt.Image
 * @see java.awt.image.MultiResolutionImage
 * @see java.awt.image.AbstractMultiResolutionImage
 *
 * @since 9
 */
public class BaseMultiResolutionImage extends AbstractMultiResolutionImage {

    private final int baseImageIndex;
    private final Image[] resolutionVariants;

    
Creates a multi-resolution image with the given resolution variants.
The first resolution variant is used as the base image.

Params:
  • resolutionVariants – array of resolution variants sorted by image size
Throws:
Since:9
/**
     * Creates a multi-resolution image with the given resolution variants.
     * The first resolution variant is used as the base image.
     *
     * @param resolutionVariants array of resolution variants sorted by image size
     * @throws IllegalArgumentException if null or zero-length array is passed
     * @throws NullPointerException if the specified {@code resolutionVariants}
     *          contains one or more null elements
     *
     * @since 9
     */
    public BaseMultiResolutionImage(Image... resolutionVariants) {
        this(0, resolutionVariants);
    }

    
Creates a multi-resolution image with the given base image index and
resolution variants.

Params:
  • baseImageIndex – the index of base image in the resolution variants
       array
  • resolutionVariants – array of resolution variants sorted by image size
Throws:
Since:9
/**
     * Creates a multi-resolution image with the given base image index and
     * resolution variants.
     *
     * @param baseImageIndex the index of base image in the resolution variants
     *        array
     * @param resolutionVariants array of resolution variants sorted by image size
     * @throws IllegalArgumentException if null or zero-length array is passed
     * @throws NullPointerException if the specified {@code resolutionVariants}
     *          contains one or more null elements
     * @throws IndexOutOfBoundsException if {@code baseImageIndex} is
     *          negative or greater than or equal to {@code resolutionVariants}
     *          length.
     *
     * @since 9
     */
    public BaseMultiResolutionImage(int baseImageIndex,
                                    Image... resolutionVariants) {

        if (resolutionVariants == null || resolutionVariants.length == 0) {
            throw new IllegalArgumentException(
                    "Null or zero-length array is passed");
        }

        if (baseImageIndex < 0 || baseImageIndex >= resolutionVariants.length) {
            throw new IndexOutOfBoundsException("Invalid base image index: "
                    + baseImageIndex);
        }

        this.baseImageIndex = baseImageIndex;
        this.resolutionVariants = Arrays.copyOf(resolutionVariants,
                                                resolutionVariants.length);

        for (Image resolutionVariant : this.resolutionVariants) {
            Objects.requireNonNull(resolutionVariant,
                                   "Resolution variant can't be null");
        }
    }

    @Override
    public Image getResolutionVariant(double destImageWidth,
                                      double destImageHeight) {

        checkSize(destImageWidth, destImageHeight);

        for (Image rvImage : resolutionVariants) {
            if (destImageWidth <= rvImage.getWidth(null)
                    && destImageHeight <= rvImage.getHeight(null)) {
                return rvImage;
            }
        }
        return resolutionVariants[resolutionVariants.length - 1];
    }

    private static void checkSize(double width, double height) {
        if (width <= 0 || height <= 0) {
            throw new IllegalArgumentException(String.format(
                    "Width (%s) or height (%s) cannot be <= 0", width, height));
        }

        if (!Double.isFinite(width) || !Double.isFinite(height)) {
            throw new IllegalArgumentException(String.format(
                    "Width (%s) or height (%s) is not finite", width, height));
        }
    }

    @Override
    public List<Image> getResolutionVariants() {
        return Collections.unmodifiableList(Arrays.asList(resolutionVariants));
    }

    @Override
    protected Image getBaseImage() {
        return resolutionVariants[baseImageIndex];
    }
}