/*

 * Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package javax.swing;

import java.awt.*;

import java.awt.image.*;

import java.beans.ConstructorProperties;

import java.beans.Transient;

import java.net.URL;

import java.io.Serializable;

import java.io.ObjectOutputStream;

import java.io.ObjectInputStream;

import java.io.IOException;

import java.util.Locale;

import javax.accessibility.*;

import sun.awt.AppContext;

import java.lang.reflect.Field;

import java.security.*;

/**

 * An implementation of the Icon interface that paints Icons

 * from Images. Images that are created from a URL, filename or byte array

 * are preloaded using MediaTracker to monitor the loaded state

 * of the image.

 *

 * <p>

 * For further information and examples of using image icons, see

 * <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/icon.html">How to Use Icons</a>

 * in <em>The Java Tutorial.</em>

 *

 * <p>

 * <strong>Warning:</strong>

 * Serialized objects of this class will not be compatible with

 * future Swing releases. The current serialization support is

 * appropriate for short term storage or RMI between applications running

 * the same version of Swing.  As of 1.4, support for long term storage

 * has been added to the <code>java.beans</code> package.

 * Please see {@link java.beans.XMLEncoder}.

 *

 * @author Jeff Dinkins

 * @author Lynn Monsanto

 */

public class ImageIcon implements Icon, Serializable, Accessible {

    /* Keep references to the filename and location so that

     * alternate persistence schemes have the option to archive

     * images symbolically rather than including the image data

     * in the archive.

     */

    transient private String filename;

    transient private URL location;

    transient Image image;

    transient int loadStatus = 0;

    ImageObserver imageObserver;

    String description = null;

    // Fields for twisted backward compatibility only. DO NOT USE.

    protected final static Component component;

    protected final static MediaTracker tracker;

    static {

        component = AccessController.doPrivileged(new PrivilegedAction<Component>() {

            public Component run() {

                try {

                    final Component component = createNoPermsComponent();

                    // 6482575 - clear the appContext field so as not to leak it

                    Field appContextField =

                            Component.class.getDeclaredField("appContext");

                    appContextField.setAccessible(true);

                    appContextField.set(component, null);

                    return component;

                } catch (Throwable e) {

                    // We don't care about component.

                    // So don't prevent class initialisation.

                    e.printStackTrace();

                    return null;

                }

            }

        });

        tracker = new MediaTracker(component);

    }

    private static Component createNoPermsComponent() {

        // 7020198 - set acc field to no permissions and no subject

        // Note, will have appContext set.

        return AccessController.doPrivileged(

                new PrivilegedAction<Component>() {

                    public Component run() {

                        return new Component() {

                        };

                    }

                },

                new AccessControlContext(new ProtectionDomain[]{

                        new ProtectionDomain(null, null)

                })

        );

    }

    /**

     * Id used in loading images from MediaTracker.

     */

    private static int mediaTrackerID;

    private final static Object TRACKER_KEY = new StringBuilder("TRACKER_KEY");

    int width = -1;

    int height = -1;

    /**

     * Creates an ImageIcon from the specified file. The image will

     * be preloaded by using MediaTracker to monitor the loading state

     * of the image.

     * @param filename the name of the file containing the image

     * @param description a brief textual description of the image

     * @see #ImageIcon(String)

     */

    public ImageIcon(String filename, String description) {

        image = Toolkit.getDefaultToolkit().getImage(filename);

        if (image == null) {

            return;

        }

        this.filename = filename;

        this.description = description;

        loadImage(image);

    }

    /**

     * Creates an ImageIcon from the specified file. The image will

     * be preloaded by using MediaTracker to monitor the loading state

     * of the image. The specified String can be a file name or a

     * file path. When specifying a path, use the Internet-standard

     * forward-slash ("/") as a separator.

     * (The string is converted to an URL, so the forward-slash works

     * on all systems.)

     * For example, specify:

     * <pre>

     *    new ImageIcon("images/myImage.gif") </pre>

     * The description is initialized to the <code>filename</code> string.

     *

     * @param filename a String specifying a filename or path

     * @see #getDescription

     */

    @ConstructorProperties({"description"})

    public ImageIcon (String filename) {

        this(filename, filename);

    }

    /**

     * Creates an ImageIcon from the specified URL. The image will

     * be preloaded by using MediaTracker to monitor the loaded state

     * of the image.

     * @param location the URL for the image

     * @param description a brief textual description of the image

     * @see #ImageIcon(String)

     */

    public ImageIcon(URL location, String description) {

        image = Toolkit.getDefaultToolkit().getImage(location);

        if (image == null) {

            return;

        }

        this.location = location;

        this.description = description;

        loadImage(image);

    }

    /**

     * Creates an ImageIcon from the specified URL. The image will

     * be preloaded by using MediaTracker to monitor the loaded state

     * of the image.

     * The icon's description is initialized to be

     * a string representation of the URL.

     * @param location the URL for the image

     * @see #getDescription

     */

    public ImageIcon (URL location) {

        this(location, location.toExternalForm());

    }

    /**

     * Creates an ImageIcon from the image.

     * @param image the image

     * @param description a brief textual description of the image

     */

    public ImageIcon(Image image, String description) {

        this(image);

        this.description = description;

    }

    /**

     * Creates an ImageIcon from an image object.

     * If the image has a "comment" property that is a string,

     * then the string is used as the description of this icon.

     * @param image the image

     * @see #getDescription

     * @see java.awt.Image#getProperty

     */

    public ImageIcon (Image image) {

        this.image = image;

        Object o = image.getProperty("comment", imageObserver);

        if (o instanceof String) {

            description = (String) o;

        }

        loadImage(image);

    }

    /**

     * Creates an ImageIcon from an array of bytes which were

     * read from an image file containing a supported image format,

     * such as GIF, JPEG, or (as of 1.3) PNG.

     * Normally this array is created

     * by reading an image using Class.getResourceAsStream(), but

     * the byte array may also be statically stored in a class.

     *

     * @param  imageData an array of pixels in an image format supported

     *         by the AWT Toolkit, such as GIF, JPEG, or (as of 1.3) PNG

     * @param  description a brief textual description of the image

     * @see    java.awt.Toolkit#createImage

     */

    public ImageIcon (byte[] imageData, String description) {

        this.image = Toolkit.getDefaultToolkit().createImage(imageData);

        if (image == null) {

            return;

        }

        this.description = description;

        loadImage(image);

    }

    /**

     * Creates an ImageIcon from an array of bytes which were

     * read from an image file containing a supported image format,

     * such as GIF, JPEG, or (as of 1.3) PNG.

     * Normally this array is created

     * by reading an image using Class.getResourceAsStream(), but

     * the byte array may also be statically stored in a class.

     * If the resulting image has a "comment" property that is a string,

     * then the string is used as the description of this icon.

     *

     * @param  imageData an array of pixels in an image format supported by

     *             the AWT Toolkit, such as GIF, JPEG, or (as of 1.3) PNG

     * @see    java.awt.Toolkit#createImage

     * @see #getDescription

     * @see java.awt.Image#getProperty

     */

    public ImageIcon (byte[] imageData) {

        this.image = Toolkit.getDefaultToolkit().createImage(imageData);

        if (image == null) {

            return;

        }

        Object o = image.getProperty("comment", imageObserver);

        if (o instanceof String) {

            description = (String) o;

        }

        loadImage(image);

    }

    /**

     * Creates an uninitialized image icon.

     */

    public ImageIcon() {

    }

    /**

     * Loads the image, returning only when the image is loaded.

     * @param image the image

     */

    protected void loadImage(Image image) {

        MediaTracker mTracker = getTracker();

        synchronized(mTracker) {

            int id = getNextID();

            mTracker.addImage(image, id);

            try {

                mTracker.waitForID(id, 0);

            } catch (InterruptedException e) {

                System.out.println("INTERRUPTED while loading Image");

            }

            loadStatus = mTracker.statusID(id, false);

            mTracker.removeImage(image, id);

            width = image.getWidth(imageObserver);

            height = image.getHeight(imageObserver);

        }

    }

    /**

     * Returns an ID to use with the MediaTracker in loading an image.

     */

    private int getNextID() {

        synchronized(getTracker()) {

            return ++mediaTrackerID;

        }

    }

    /**

     * Returns the MediaTracker for the current AppContext, creating a new

     * MediaTracker if necessary.

     */

    private MediaTracker getTracker() {

        Object trackerObj;

        AppContext ac = AppContext.getAppContext();

        // Opt: Only synchronize if trackerObj comes back null?

        // If null, synchronize, re-check for null, and put new tracker

        synchronized(ac) {

            trackerObj = ac.get(TRACKER_KEY);

            if (trackerObj == null) {

                Component comp = new Component() {};

                trackerObj = new MediaTracker(comp);

                ac.put(TRACKER_KEY, trackerObj);

            }

        }

        return (MediaTracker) trackerObj;

    }

    /**

     * Returns the status of the image loading operation.

     * @return the loading status as defined by java.awt.MediaTracker

     * @see java.awt.MediaTracker#ABORTED

     * @see java.awt.MediaTracker#ERRORED

     * @see java.awt.MediaTracker#COMPLETE

     */

    public int getImageLoadStatus() {

        return loadStatus;

    }

    /**

     * Returns this icon's <code>Image</code>.

     * @return the <code>Image</code> object for this <code>ImageIcon</code>

     */

    @Transient

    public Image getImage() {

        return image;

    }

    /**

     * Sets the image displayed by this icon.

     * @param image the image

     */

    public void setImage(Image image) {

        this.image = image;

        loadImage(image);

    }

    /**

     * Gets the description of the image.  This is meant to be a brief

     * textual description of the object.  For example, it might be

     * presented to a blind user to give an indication of the purpose

     * of the image.

     * The description may be null.

     *

     * @return a brief textual description of the image

     */

    public String getDescription() {

        return description;

    }

    /**

     * Sets the description of the image.  This is meant to be a brief

     * textual description of the object.  For example, it might be

     * presented to a blind user to give an indication of the purpose

     * of the image.

     * @param description a brief textual description of the image

     */

    public void setDescription(String description) {

        this.description = description;

    }

    /**

     * Paints the icon.

     * The top-left corner of the icon is drawn at

     * the point (<code>x</code>, <code>y</code>)

     * in the coordinate space of the graphics context <code>g</code>.

     * If this icon has no image observer,

     * this method uses the <code>c</code> component

     * as the observer.

     *

     * @param c the component to be used as the observer

     *          if this icon has no image observer

     * @param g the graphics context

     * @param x the X coordinate of the icon's top-left corner

     * @param y the Y coordinate of the icon's top-left corner

     */

    public synchronized void paintIcon(Component c, Graphics g, int x, int y) {

        if(imageObserver == null) {

           g.drawImage(image, x, y, c);

        } else {

           g.drawImage(image, x, y, imageObserver);

        }

    }

    /**

     * Gets the width of the icon.

     *

     * @return the width in pixels of this icon

     */

    public int getIconWidth() {

        return width;

    }

    /**

     * Gets the height of the icon.

     *

     * @return the height in pixels of this icon

     */

    public int getIconHeight() {

        return height;

    }

    /**

     * Sets the image observer for the image.  Set this

     * property if the ImageIcon contains an animated GIF, so

     * the observer is notified to update its display.

     * For example:

     * <pre>

     *     icon = new ImageIcon(...)

     *     button.setIcon(icon);

     *     icon.setImageObserver(button);

     * </pre>

     *

     * @param observer the image observer

     */

    public void setImageObserver(ImageObserver observer) {

        imageObserver = observer;

    }

    /**

     * Returns the image observer for the image.

     *

     * @return the image observer, which may be null

     */

    @Transient

    public ImageObserver getImageObserver() {

        return imageObserver;

    }

    /**

     * Returns a string representation of this image.

     *

     * @return a string representing this image

     */

    public String toString() {

        if (description != null) {

            return description;

        }

        return super.toString();

    }

    private void readObject(ObjectInputStream s)

        throws ClassNotFoundException, IOException

    {

        s.defaultReadObject();

        int w = s.readInt();

        int h = s.readInt();

        int[] pixels = (int[])(s.readObject());

        if (pixels != null) {

            Toolkit tk = Toolkit.getDefaultToolkit();

            ColorModel cm = ColorModel.getRGBdefault();

            image = tk.createImage(new MemoryImageSource(w, h, cm, pixels, 0, w));

            loadImage(image);

        }

    }

    private void writeObject(ObjectOutputStream s)

        throws IOException

    {

        s.defaultWriteObject();

        int w = getIconWidth();

        int h = getIconHeight();

        int[] pixels = image != null? new int[w * h] : null;

        if (image != null) {

            try {

                PixelGrabber pg = new PixelGrabber(image, 0, 0, w, h, pixels, 0, w);

                pg.grabPixels();

                if ((pg.getStatus() & ImageObserver.ABORT) != 0) {

                    throw new IOException("failed to load image contents");

                }

            }

            catch (InterruptedException e) {

                throw new IOException("image load interrupted");

            }

        }

        s.writeInt(w);

        s.writeInt(h);

        s.writeObject(pixels);

    }

    /**

     * --- Accessibility Support ---

     */