net.rptools.lib.image.ThumbnailManager.java Source code

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Here is the source code for net.rptools.lib.image.ThumbnailManager.java

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/*
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package net.rptools.lib.image;

import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import net.rptools.lib.MD5Key;
import net.rptools.lib.swing.SwingUtil;
import org.apache.commons.io.FileUtils;

public class ThumbnailManager {
    private final File thumbnailLocation;
    private final Dimension thumbnailSize;

    public ThumbnailManager(File thumbnailLocation, Dimension thumbnailSize) {
        this.thumbnailLocation = thumbnailLocation;
        this.thumbnailSize = thumbnailSize;
    }

    public File getThumbnailLocation() {
        return thumbnailLocation;
    }

    public Dimension getThumbnailSize() {
        return thumbnailSize;
    }

    public Image getThumbnail(File file) throws IOException {
        // Cache
        BufferedImage thumbnail = getCachedThumbnail(file);
        if (thumbnail != null) {
            return thumbnail;
        }
        // Create
        return createThumbnail(file);
    }

    private Image createThumbnail(File file) throws IOException {
        // Gather info
        File thumbnailFile = getThumbnailFile(file);
        if (thumbnailFile.exists()) {
            return ImageUtil.getImage(thumbnailFile);
        }

        Image image = ImageUtil.getImage(file);
        Dimension imgSize = new Dimension(image.getWidth(null), image.getHeight(null));

        // Test if we Should we bother making a thumbnail ?
        // Jamz: New size 100k (was 30k) and put in check so we're not creating thumbnails LARGER than the original...
        if (file.length() < 102400
                || (imgSize.width <= thumbnailSize.width && imgSize.height <= thumbnailSize.height)) {
            return image;
        }
        // Transform the image
        SwingUtil.constrainTo(imgSize, Math.min(image.getWidth(null), thumbnailSize.width),
                Math.min(image.getHeight(null), thumbnailSize.height));
        BufferedImage thumbnailImage = new BufferedImage(imgSize.width, imgSize.height,
                ImageUtil.pickBestTransparency(image));

        Graphics2D g = thumbnailImage.createGraphics();
        g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
        g.drawImage(image, 0, 0, imgSize.width, imgSize.height, null);
        g.dispose();

        // Use png to preserve transparency
        FileUtils.writeByteArrayToFile(thumbnailFile, ImageUtil.imageToBytes(thumbnailImage, "png"));

        return thumbnailImage;
    }

    public void clearImageThumbCache() {
        try {
            if (thumbnailLocation != null) {
                FileUtils.cleanDirectory(thumbnailLocation);
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private BufferedImage getCachedThumbnail(File file) {
        File thumbnailFile = getThumbnailFile(file);

        if (!thumbnailFile.exists()) {
            return null;
        }
        try {
            // Check that it hasn't changed on disk
            if (file.lastModified() > thumbnailFile.lastModified()) {
                return null;
            }
            // Get the thumbnail
            BufferedImage thumbnail = ImageIO.read(thumbnailFile);

            // Check that we have the size we want
            if (thumbnail.getWidth() != thumbnailSize.width && thumbnail.getHeight() != thumbnailSize.height) {
                return null;
            }
            return thumbnail;
        } catch (IOException ioe) {
            return null;
        }
    }

    private File getThumbnailFile(File file) {
        MD5Key key = new MD5Key(file.getAbsolutePath().getBytes());
        return new File(thumbnailLocation.getPath(), key.toString());
    }
}