Demonstrate the loading of image files into icons for use in a Swing user interface : Icon « Swing « Java Tutorial






/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.util.List;

import javax.swing.AbstractAction;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JToolBar;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;

/**
 * This application is intended to demonstrate the loading of image files into
 * icons for use in a Swing user interface. It creates a toolbar with a
 * thumbnail preview of each image. Clicking on the thumbnail will show the full
 * image in the main display area.
 * 
 * IconDemoApp.java requires the following files: <br>
 * The following files are copyright 2006 spriggs.net and licensed under a
 * Creative Commons License (http://creativecommons.org/licenses/by-sa/3.0/)
 * <br>
 * images/sunw01.jpg <br>
 * images/sunw02.jpg <br>
 * images/sunw03.jpg <br>
 * images/sunw04.jpg <br>
 * images/sunw05.jpg <br>
 * 
 * @author Collin Fagan
 * @date 7/25/2007
 * @version 2.0
 */
public class IconDemoApp extends JFrame {

  private JLabel photographLabel = new JLabel();
  private JToolBar buttonBar = new JToolBar();

  private String imagedir = "images/";

  private MissingIcon placeholderIcon = new MissingIcon();

  /**
   * List of all the descriptions of the image files. These correspond one to
   * one with the image file names
   */
  private String[] imageCaptions = { "Original SUNW Logo", "The Clocktower",
      "Clocktower from the West", "The Mansion", "Sun Auditorium" };

  /**
   * List of all the image files to load.
   */
  private String[] imageFileNames = { "sunw01.jpg", "sunw02.jpg", "sunw03.jpg",
      "sunw04.jpg", "sunw05.jpg" };

  /**
   * Main entry point to the demo. Loads the Swing elements on the "Event
   * Dispatch Thread".
   * 
   * @param args
   */
  public static void main(String args[]) {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        IconDemoApp app = new IconDemoApp();
        app.setVisible(true);
      }
    });
  }

  /**
   * Default constructor for the demo.
   */
  public IconDemoApp() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setTitle("Icon Demo: Please Select an Image");

    // A label for displaying the pictures
    photographLabel.setVerticalTextPosition(JLabel.BOTTOM);
    photographLabel.setHorizontalTextPosition(JLabel.CENTER);
    photographLabel.setHorizontalAlignment(JLabel.CENTER);
    photographLabel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

    // We add two glue components. Later in process() we will add thumbnail
    // buttons
    // to the toolbar inbetween thease glue compoents. This will center the
    // buttons in the toolbar.
    buttonBar.add(Box.createGlue());
    buttonBar.add(Box.createGlue());

    add(buttonBar, BorderLayout.SOUTH);
    add(photographLabel, BorderLayout.CENTER);

    setSize(400, 300);

    // this centers the frame on the screen
    setLocationRelativeTo(null);

    // start the image loading SwingWorker in a background thread
    loadimages.execute();
  }

  /**
   * SwingWorker class that loads the images a background thread and calls
   * publish when a new one is ready to be displayed.
   * 
   * We use Void as the first SwingWroker param as we do not need to return
   * anything from doInBackground().
   */
  private SwingWorker<Void, ThumbnailAction> loadimages = new SwingWorker<Void, ThumbnailAction>() {

    /**
     * Creates full size and thumbnail versions of the target image files.
     */
    @Override
    protected Void doInBackground() throws Exception {
      for (int i = 0; i < imageCaptions.length; i++) {
        ImageIcon icon;
        icon = createImageIcon(imagedir + imageFileNames[i], imageCaptions[i]);

        ThumbnailAction thumbAction;
        if (icon != null) {

          ImageIcon thumbnailIcon = new ImageIcon(getScaledImage(icon
              .getImage(), 32, 32));

          thumbAction = new ThumbnailAction(icon, thumbnailIcon,
              imageCaptions[i]);

        } else {
          // the image failed to load for some reason
          // so load a placeholder instead
          thumbAction = new ThumbnailAction(placeholderIcon, placeholderIcon,
              imageCaptions[i]);
        }
        publish(thumbAction);
      }
      // unfortunately we must return something, and only null is valid to
      // return when the return type is void.
      return null;
    }

    /**
     * Process all loaded images.
     */
    @Override
    protected void process(List<ThumbnailAction> chunks) {
      for (ThumbnailAction thumbAction : chunks) {
        JButton thumbButton = new JButton(thumbAction);
        // add the new button BEFORE the last glue
        // this centers the buttons in the toolbar
        buttonBar.add(thumbButton, buttonBar.getComponentCount() - 1);
      }
    }
  };

  /**
   * Creates an ImageIcon if the path is valid.
   * 
   * @param String -
   *            resource path
   * @param String -
   *            description of the file
   */
  protected ImageIcon createImageIcon(String path, String description) {
    java.net.URL imgURL = getClass().getResource(path);
    if (imgURL != null) {
      return new ImageIcon(imgURL, description);
    } else {
      System.err.println("Couldn't find file: " + path);
      return null;
    }
  }

  /**
   * Resizes an image using a Graphics2D object backed by a BufferedImage.
   * 
   * @param srcImg -
   *            source image to scale
   * @param w -
   *            desired width
   * @param h -
   *            desired height
   * @return - the new resized image
   */
  private Image getScaledImage(Image srcImg, int w, int h) {
    BufferedImage resizedImg = new BufferedImage(w, h,
        BufferedImage.TYPE_INT_RGB);
    Graphics2D g2 = resizedImg.createGraphics();
    g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
        RenderingHints.VALUE_INTERPOLATION_BILINEAR);
    g2.drawImage(srcImg, 0, 0, w, h, null);
    g2.dispose();
    return resizedImg;
  }

  /**
   * Action class that shows the image specified in it's constructor.
   */
  private class ThumbnailAction extends AbstractAction {

    /**
     * The icon if the full image we want to display.
     */
    private Icon displayPhoto;

    /**
     * @param Icon -
     *            The full size photo to show in the button.
     * @param Icon -
     *            The thumbnail to show in the button.
     * @param String -
     *            The descriptioon of the icon.
     */
    public ThumbnailAction(Icon photo, Icon thumb, String desc) {
      displayPhoto = photo;

      // The short description becomes the tooltip of a button.
      putValue(SHORT_DESCRIPTION, desc);

      // The LARGE_ICON_KEY is the key for setting the
      // icon when an Action is applied to a button.
      putValue(LARGE_ICON_KEY, thumb);
    }

    /**
     * Shows the full image in the main area and sets the application title.
     */
    public void actionPerformed(ActionEvent e) {
      photographLabel.setIcon(displayPhoto);
      setTitle("Icon Demo: " + getValue(SHORT_DESCRIPTION).toString());
    }
  }
}

/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *  - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *  - Neither the name of Sun Microsystems nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * The "missing icon" is a white box with a black border and a red x. It's used
 * to display something when there are issues loading an icon from an external
 * location.
 * 
 * @author Collin Fagan
 * @date 7/25/2007
 */
class MissingIcon implements Icon {

  private int width = 32;
  private int height = 32;

  private BasicStroke stroke = new BasicStroke(4);

  public void paintIcon(Component c, Graphics g, int x, int y) {
    Graphics2D g2d = (Graphics2D) g.create();

    g2d.setColor(Color.WHITE);
    g2d.fillRect(x + 1, y + 1, width - 2, height - 2);

    g2d.setColor(Color.BLACK);
    g2d.drawRect(x + 1, y + 1, width - 2, height - 2);

    g2d.setColor(Color.RED);

    g2d.setStroke(stroke);
    g2d.drawLine(x + 10, y + 10, x + width - 10, y + height - 10);
    g2d.drawLine(x + 10, y + height - 10, x + width - 10, y + 10);

    g2d.dispose();
  }

  public int getIconWidth() {
    return width;
  }

  public int getIconHeight() {
    return height;
  }

}








14.116.Icon
14.116.1.Creating an Icon(implement Icon interface)
14.116.2.State-Aware Icon DefinitionState-Aware Icon Definition
14.116.3.implements Icon, SwingConstants
14.116.4.Demonstrate the loading of image files into icons for use in a Swing user interface
14.116.5.An empty icon with arbitrary width and height.
14.116.6.An icon for painting a square swatch of a specified Color.
14.116.7.Arrow Icon
14.116.8.Creates a transparent icon.
14.116.9.Layered Icon