/*
 * @(#)ImageIcon.java	1.46 00/04/06
 *
 * Copyright 1997-2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */
package javax.swing;

import java.awt.*;
import java.awt.image.*;
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.*;


/**
 * An implementation of the Icon interface that paints Icons
 * from Images. Images that are created from a URL or filename
 * 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://java.sun.com/docs/books/tutorial/uiswing/misc/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.  A future release of Swing will provide support for
 * long term persistence.
 * 
 * @version 1.46 04/06/00
 * @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;

    protected final static Component component = new Component() {};
    protected final static MediaTracker tracker = new MediaTracker(component);

    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
     */
    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 or JPEG.  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 or JPEG.
     * @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 or JPEG.  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 or JPEG
     * @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) {
	synchronized(tracker) {
	    tracker.addImage(image, 0);
	    try {
		tracker.waitForID(0, 0);
	    } catch (InterruptedException e) {
		System.out.println("INTERRUPTED while loading Image");
	    }
            loadStatus = tracker.statusID(0, false);
	    tracker.removeImage(image, 0);

	    width = image.getWidth(imageObserver);
	    height = image.getHeight(imageObserver);
	}
    }

    /**
     * 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>
     */
    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
     */
    public ImageObserver getImageObserver() {
        return imageObserver;
    }

    /**
     * Returns a string representation of this image.
     *
     * @return a string representing this image
     */
    public String toString() {
        return description;
    }

    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));
        } 
    }


    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 ---
     */

    private AccessibleImageIcon accessibleContext = null;

    /** 
     * Gets the AccessibleContext associated with this ImageIcon. 
     * For image icons, the AccessibleContext takes the form of an 
     * AccessibleImageIcon. 
     * A new AccessibleImageIcon instance is created if necessary.
     *
     * @return an AccessibleImageIcon that serves as the 
     *         AccessibleContext of this ImageIcon
     * @beaninfo
     *       expert: true
     *  description: The AccessibleContext associated with this ImageIcon.
     */
    public AccessibleContext getAccessibleContext() {
        if (accessibleContext == null) {
            accessibleContext = new AccessibleImageIcon();
        }
        return accessibleContext;
    }

    /**
     * This class implements accessibility support for the 
     * <code>ImageIcon</code> class.  It provides an implementation of the 
     * Java Accessibility API appropriate to image icon user-interface 
     * elements.
     * <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.  A future release of Swing will provide support for
     * long term persistence.
     */
    protected class AccessibleImageIcon extends AccessibleContext
        implements AccessibleIcon, Serializable {

	/*
	 * AccessibleContest implementation -----------------
	 */

        /**
         * Gets the role of this object.
         *
         * @return an instance of AccessibleRole describing the role of the
         * object
         * @see AccessibleRole
         */
        public AccessibleRole getAccessibleRole() {
            return AccessibleRole.ICON;
        }

        /**
         * Gets the state of this object.
         *
         * @return an instance of AccessibleStateSet containing the current
         * state set of the object
         * @see AccessibleState
         */
        public AccessibleStateSet getAccessibleStateSet() {
            return null;
        }

        /**
         * Gets the Accessible parent of this object.  If the parent of this
         * object implements Accessible, this method should simply return
         * getParent().
         *
         * @return the Accessible parent of this object -- can be null if this
         * object does not have an Accessible parent
         */
        public Accessible getAccessibleParent() {
            return null;
        }

        /**
         * Gets the index of this object in its accessible parent.
         *
         * @return the index of this object in its parent; -1 if this
         * object does not have an accessible parent.
         * @see #getAccessibleParent
         */
        public int getAccessibleIndexInParent() {
            return -1;
        }

        /**
         * Returns the number of accessible children in the object.  If all
         * of the children of this object implement Accessible, than this
         * method should return the number of children of this object.
         *
         * @return the number of accessible children in the object.
         */
        public int getAccessibleChildrenCount() {
	    return 0;
        }

        /**
         * Returns the nth Accessible child of the object.
         *
         * @param i zero-based index of child
         * @return the nth Accessible child of the object
         */
        public Accessible getAccessibleChild(int i) {
	    return null;
        }

        /**
         * Returns the locale of this object.
         *
         * @return the locale of this object
         */
	public Locale getLocale() throws IllegalComponentStateException {
            return null;
        }
	
	/*
	 * AccessibleIcon implementation -----------------
	 */

	/**
	 * Gets the description of the icon.  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 icon.
	 *
	 * @return the description of the icon
	 */
	public String getAccessibleIconDescription() {
	    return ImageIcon.this.getDescription();
	}
	
	/**
	 * Sets the description of the icon.  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 icon.
	 *
	 * @param description the description of the icon
	 */
	public void setAccessibleIconDescription(String description) {
	    ImageIcon.this.setDescription(description);
	}
	
	/**
	 * Gets the height of the icon.
	 *
	 * @return the height of the icon
	 */
	public int getAccessibleIconHeight() {
	    return ImageIcon.this.height;
	}

	/**
	 * Gets the width of the icon.
	 *
	 * @return the width of the icon
	 */
	public int getAccessibleIconWidth() {
	    return ImageIcon.this.width;
	}

        private void readObject(ObjectInputStream s)
	    throws ClassNotFoundException, IOException 
        {
	    s.defaultReadObject();
	}

        private void writeObject(ObjectOutputStream s) 
	    throws IOException 
        {
	    s.defaultWriteObject();
        }
    }  // AccessibleImageIcon
}