CD Ware Multimedia 1999 February/CDW0299.iso/Demos/Cafe/Source.bin/ImageButton.java

Java Source | 1998-03-18 | 17.7 KB | 613 lines

package symantec.itools.awt;

import java.awt.AWTException;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Event;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.image.FilteredImageSource;
import java.net.URL;
import java.beans.PropertyVetoException;
import java.beans.PropertyChangeListener;
import java.beans.VetoableChangeListener;
import java.beans.PropertyChangeEvent;
import java.text.MessageFormat;
import java.util.ResourceBundle;

//    01/18/97    RKM    Changed setImageURL to handle getImage returning null, added call to invalidate
//    01/29/97    TWB    Integrated changes from Macintosh
//    05/29/97    MSH    Updated to support Java 1.1
//     07/08/97    LAB    Changed the way the button is drawn.  Now it uses the offscreen
//                    Image.  Cleaned up the drawing code to be more universal.
//                    Added pressed and disabled images for those states.
//                    Changed data member url to imageURL.
//                    Added a preferedSize() method.
//    07/13/97    RKM    Fixed misspelling of prefered
//  07/30/97    CAR marked fields transient as needed
//                  implemented readObject
//     08/05/97    LAB    Added a call to clipRect in the updateButtonImage method to clip subsequent
//                    drawings to the internal button area (sans border and bevel). This should be
//                    removed when the VM interprets the base class' call to clipRect correctly.
//                    removed scale and center protected data members.  Added imageStyle protected
//                    data member.  Added public data members to define ImageStyles.  Deprecated
//                    setScaleMode, isScaleMode, setCenterMode, and isCenterMode.  Added
//                    ImageStyle property.
//     08/06/97    LAB    Removed the call to clipRect; now uses the base classes buttonImageGraphics
//                    Graphics to draw with, which inherits the clipping.
//  08/28/97    CAR "erase" image if Image URL is set to null

/**
 * The ImageButton component is similar to a regular button except that it
 * displays an image on the button's face. The image to use is specified with
 * a URL.
 * <p>
 * Use an ImageButton to:
 * <UL>
 * <DT>╖ Display an image in a button instead of text.</DT>
 * <DT>╖ Generate a train of action events while the user presses the button.</DT>
 * </UL>
 * <p>
 * @version 1.1, August 5, 1997
 * @author Symantec
 */
public class ImageButton extends ButtonBase
{
    /**
     * A constant indicating the image is to be tiled in the size of this component.
     */
    public static final int IMAGE_TILED = 0;
    /**
     * A constant indicating the image is to be centered in the size of this component.
     */
    public static final int IMAGE_CENTERED = 1;
    /**
     * A constant indicating the image is to be scaled to fit the size of this component.
     */
    public static final int IMAGE_SCALED_TO_FIT = 2;
    /**
     * A constant indicating the image is to be drawn normally in the upper left corner.
     */
    public static final int IMAGE_NORMAL = 3;

    /**
     * Constructs a new default ImageButton. Image scaling is off and center mode on.
     */
    public ImageButton()
    {
        try
        {
            setImageStyle(IMAGE_CENTERED);
        }
        catch (PropertyVetoException exc) {}
    }

    /**
     * Sets the URL of the image to display in the button.
     * @param u the URL of the image to display
     * @see #getImageURL
     * @exception PropertyVetoException
     * if the specified property value is unacceptable
     */
    public void setImageURL(URL u) throws PropertyVetoException
    {
        URL oldValue = imageURL;

        vetos.fireVetoableChange( "ImageURL", oldValue, u );

        // Remove old images
        enabledImage = null;
        if (disabledImage != null)
            disabledImage.flush();
        disabledImage = null;
        if (pressedImage != null)
            pressedImage.flush();
        pressedImage = null;

        // Load new image

        imageURL = u;
        if (imageURL != null) {
            Image image = getToolkit().getImage(imageURL);
            if (image != null)
            {
                MediaTracker mt = new MediaTracker(this);
                if (mt != null)
                {
                    try
                    {
                        mt.addImage(image, 0);
                        mt.waitForAll();
                    }
                    catch (InterruptedException ie)
                    {
                    }

                    if (mt.isErrorAny())
                    {
                        Object[] args = { image.toString() };
                        System.err.println(MessageFormat.format(errors.getString("ErrorLoadingImage"), args));
                        return;
                    }

                    enabledImage    = image;
                    disabledImage    = createImage(new FilteredImageSource(image.getSource(), new symantec.itools.awt.image.FadeFilter(0.333)));
                    pressedImage    = createImage(new FilteredImageSource(image.getSource(), new symantec.itools.awt.image.DarkenFilter(0.250)));

                    changes.firePropertyChange( "ImageURL", oldValue, u );
                }
            }
        }
        repaint();
    }

    /**
     * Returns the URL of the image being displayed in the button.
     * @see #setImageURL
     */
    public URL getImageURL()
    {
        return imageURL;
    }

    /**
     * Sets the new panel image style.
     * @param newStyle the new panel image style, one of
     * IMAGE_TILED, IMAGE_CENTERED, IMAGE_SCALED_TO_FIT, or IMAGE_NORMAL.
     * @exception PropertyVetoException
     * if the specified property value is unacceptable
     * @see #getImageStyle
     * @see #IMAGE_TILED
     * @see #IMAGE_CENTERED
     * @see #IMAGE_SCALED_TO_FIT
     * @see #IMAGE_NORMAL
     */
    public void setImageStyle(int newStyle) throws PropertyVetoException
    {
        if (newStyle != imageStyle)
        {
            Integer oldValue = new Integer(imageStyle);
            Integer newValue = new Integer(newStyle);

            vetos.fireVetoableChange("ImageStyle", oldValue, newValue);

            imageStyle = newStyle;
            repaint();

            changes.firePropertyChange("ImageStyle", oldValue, newValue);
        }
    }

    /**
     * Gets the current panel image style.
     * @return the current panel image style, one of
     * IMAGE_TILED, IMAGE_CENTERED, IMAGE_SCALED_TO_FIT, or IMAGE_NORMAL.
     * @see #setImageStyle
     * @see #IMAGE_TILED
     * @see #IMAGE_CENTERED
     * @see #IMAGE_SCALED_TO_FIT
     */
    public int getImageStyle()
    {
        return imageStyle;
    }

    /**
     * @deprecated
     * @see #setImageStyle
     * @exception PropertyVetoException
     * if the specified property value is unacceptable
     */
    public void setScaleMode(boolean flag) throws PropertyVetoException
    {
        if (flag)
        {
            setImageStyle(IMAGE_SCALED_TO_FIT);
        }
        else
        {
            setImageStyle(IMAGE_NORMAL);
        }
    }

    /**
     * @deprecated
     * @see #getImageStyle
     */
    public boolean isScaleMode()
    {
        return (getImageStyle() == IMAGE_SCALED_TO_FIT);
    }

    /**
     * @deprecated
     * @see #isScaleMode
     */
    public boolean getScaleMode()
    {
        return isScaleMode();
    }

    /**
     * @deprecated
     * @see #setImageStyle
     * @exception PropertyVetoException
     * if the specified property value is unacceptable
     */
    public void setCenterMode(boolean flag) throws PropertyVetoException
    {
        if (flag)
        {
            setImageStyle(IMAGE_CENTERED);
        }
        else
        {
            setImageStyle(IMAGE_NORMAL);
        }
    }

    /**
     * @deprecated
     * @see #getImageStyle
     */
    public boolean isCenterMode()
    {
        return (getImageStyle() == IMAGE_CENTERED);
    }

    /**
     * @deprecated
     * @see #isCenterMode
     */
    public boolean getCenterMode()
    {
        return isCenterMode();
    }

    /**
     * Is the given image style valid for this button.
     * @param i the given image style
     * @return true if the given image style is acceptable, false if not.
     */
    public boolean isValidImageStyle(int i)
    {
        switch(i)
        {
               case IMAGE_TILED:
            case IMAGE_CENTERED:
            case IMAGE_SCALED_TO_FIT:
            case IMAGE_NORMAL:
                return true;
            default:
                return false;
        }
    }

    /**
     * Returns the recommended dimensions to properly display this component.
     * This is a standard Java AWT method which gets called to determine
     * the recommended size of this component.
     */
    public Dimension getPreferredSize()
    {
        Dimension defaultSize = super.getPreferredSize();

        if (enabledImage == null)
            return defaultSize;

        return new Dimension(defaultSize.width + enabledImage.getWidth(this), defaultSize.height + enabledImage.getHeight(this));
    }

    /**
     * Tells this component that it has been added to a container.
     * This is a standard Java AWT method which gets called by the AWT when
     * this component is added to a container. Typically, it is used to
     * create this component's peer.
     *
     * It has been overridden here to hook-up event listeners.
     *
     * @see #removeNotify
     */
    public synchronized void addNotify()
    {
        super.addNotify();
        errors = ResourceBundle.getBundle("symantec.itools.resources.ErrorsBundle");

        //Hook up listeners
        if (styleVeto == null)
        {
            styleVeto = new StyleVeto();
            addImageStyleListener(styleVeto);
        }
    }

    /**
     * Tells this component that it is being removed from a container.
     * This is a standard Java AWT method which gets called by the AWT when
     * this component is removed from a container. Typically, it is used to
     * destroy the peers of this component and all its subcomponents.
     *
     * It has been overridden here to unhook event listeners.
     *
     * @see #addNotify
     */
    public synchronized void removeNotify()
    {
        //Unhook listeners
        if (styleVeto != null)
        {
            removeImageStyleListener(styleVeto);
            styleVeto = null;
        }

        super.removeNotify();
    }

    /**
     * Adds a listener for all event changes.
     * @param listener the listener to add.
     * @see #removePropertyChangeListener
     */
    public synchronized void addPropertyChangeListener(PropertyChangeListener listener)
    {
        super.addPropertyChangeListener(listener);
        changes.addPropertyChangeListener(listener);
    }

    /**
     * Removes a listener for all event changes.
     * @param listener the listener to remove.
     * @see #addPropertyChangeListener
     */
    public synchronized void removePropertyChangeListener(PropertyChangeListener listener)
    {
        super.removePropertyChangeListener(listener);
        changes.removePropertyChangeListener(listener);
    }

    /**
     * Adds a vetoable listener for all event changes.
     * @param listener the listener to add.
     * @see #removeVetoableChangeListener
     */
    public synchronized void addVetoableChangeListener(VetoableChangeListener listener)
    {
        super.addVetoableChangeListener(listener);
        vetos.addVetoableChangeListener(listener);
    }

    /**
     * Removes a vetoable listener for all event changes.
     * @param listener the listener to remove.
     * @see #addVetoableChangeListener
     */
    public synchronized void removeVetoableChangeListener(VetoableChangeListener listener)
    {
        super.removeVetoableChangeListener(listener);
        vetos.removeVetoableChangeListener(listener);
    }

    /**
     * Adds a listener for the ImageStyle property changes.
     * @param listener the listener to add.
     * @see #removeImageStyleListener(java.beans.PropertyChangeListener)
     */
    public synchronized void addImageStyleListener(PropertyChangeListener listener)
    {
        changes.addPropertyChangeListener("ImageStyle", listener);
    }

    /**
     * Removes a listener for the ImageStyle property changes.
     * @param listener the listener to remove.
     * @see #addImageStyleListener(java.beans.PropertyChangeListener)
     */
    public synchronized void removeImageStyleListener(PropertyChangeListener listener)
    {
        changes.removePropertyChangeListener("ImageStyle", listener);
    }

    /**
     * Adds a vetoable listener for the ImageStyle property changes.
     * @param listener the listener to add.
     * @see #removeImageStyleListener(java.beans.VetoableChangeListener)
     */
    public synchronized void addImageStyleListener(VetoableChangeListener listener)
    {
        vetos.addVetoableChangeListener("ImageStyle", listener);
    }

    /**
     * Removes a vetoable listener for the ImageStyle property changes.
     * @param listener the listener to remove.
     * @see #addImageStyleListener(java.beans.VetoableChangeListener)
     */
    public synchronized void removeImageStyleListener(VetoableChangeListener listener)
    {
        vetos.removeVetoableChangeListener("ImageStyle", listener);
    }

    /**
     * This is the PropertyChangeEvent handling inner class for the constrained ImageStyle property.
     * Handles vetoing BevelHeights that are not valid.
     */
    class StyleVeto implements java.beans.VetoableChangeListener, java.io.Serializable
    {
        /**
         * This method gets called when an attempt to change the constrained ImageStyle property is made.
         * Ensures the given image style is valid for this button.
         *
         * @param     e a <code>PropertyChangeEvent</code> object describing the
         *             event source and the property that has changed.
         * @exception PropertyVetoException if the recipient wishes the property
         *              change to be rolled back.
         */
        public void vetoableChange(PropertyChangeEvent e) throws PropertyVetoException
        {
            int i = ((Integer)e.getNewValue()).intValue();
            if (!isValidImageStyle(i))
            {
                throw new PropertyVetoException(errors.getString("InvalidImageStyle") + i, e);
            }
        }
    }

    /**
     * Draws the button in the buttonImage offscreen image.
     * @see symantec.itools.awt.ButtonBase#updateButtonImage
     */
    protected void updateButtonImage()
    {
        super.updateButtonImage();

        Image img;

        if(pressed)
            img = pressedImage;
        else
            img = isEnabled() ? enabledImage : disabledImage;


        Dimension s        = size();
        int x            = bevel + 1 + pressedAdjustment;
          int y            = bevel + 1 + pressedAdjustment;
        int w            = s.width    - bevel - bevel - 2;
        int h            = s.height    - bevel - bevel - 2;

        if (img == null) {
            buttonImageGraphics.clearRect(x, y, w, h);
            return;
        }

        int imageWidth    = img.getWidth(this);
        int imageHeight    = img.getHeight(this);

        switch(imageStyle)
        {
            case IMAGE_CENTERED:
            default:
            {
                buttonImageGraphics.drawImage
                    (img, x + ((w - imageWidth) / 2), y + ((h - imageHeight) / 2), this);

                break;
            }
            case IMAGE_TILED:
            {
                //Calculate number of images that should be drawn horizontally
                int numHImages = w / imageWidth;

                //Don't forget remainders
                if (w % imageWidth != 0)
                    numHImages++;

                //Calculate number of images that should be drawn vertically
                int numVImages = h / imageHeight;

                //Don't forget remainders
                if (h % imageHeight != 0)
                    numVImages++;

                int hOff;
                int vOff = y;
                for (int vCount = 0; vCount < numVImages; vCount++)
                {
                    hOff = x;
                    for (int hCount = 0; hCount < numHImages; hCount++)
                    {
                        buttonImageGraphics.drawImage(img, hOff, vOff, imageWidth, imageHeight, this);

                        //Increment to next column
                        hOff += imageWidth;
                    }

                    //Increment to next row
                    vOff += imageHeight;
                }
                break;
            }
            case IMAGE_SCALED_TO_FIT:
            {
                buttonImageGraphics.drawImage(img, x, y, w, h, this);
                break;
            }
            case IMAGE_NORMAL:
            {
                buttonImageGraphics.drawImage(img, x, y, this);
                break;
            }
        }
    }

    private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, ClassNotFoundException
    {
        in.defaultReadObject();

        if (imageURL != null) {
            Image image = getToolkit().getImage(imageURL);
            if (image != null)
            {
                MediaTracker mt = new MediaTracker(this);
                if (mt != null)
                {
                    try
                    {
                        mt.addImage(image, 0);
                        mt.waitForAll();
                    }
                    catch (InterruptedException ie)
                    {
                    }

                    if (mt.isErrorAny())
                    {
                        Object[] args = { image.toString() };
                        System.err.println(MessageFormat.format(errors.getString("ErrorLoadingImage"), args));
                        return;
                    }

                    enabledImage    = image;
                    disabledImage    = createImage(new FilteredImageSource(image.getSource(), new symantec.itools.awt.image.FadeFilter(0.333)));
                    pressedImage    = createImage(new FilteredImageSource(image.getSource(), new symantec.itools.awt.image.DarkenFilter(0.250)));
                }
            }
        }

    }

    /**
     * Determines how to draw the image.
     */
    protected int imageStyle;

    /**
     * The URL for the button's image
     */
    protected URL imageURL = null;

    /**
     * The normally displayed image
     */
    transient protected Image enabledImage = null;

    /**
     * The image displayed when the button is disabled
     */
    transient protected Image disabledImage    = null;

    /**
     * The image displayed when the button is pressed
     */
    transient protected Image pressedImage = null;
    /**
     * Error strings.
     */
    transient protected ResourceBundle errors;

    private StyleVeto styleVeto = null;
    private symantec.itools.beans.VetoableChangeSupport vetos   = new symantec.itools.beans.VetoableChangeSupport(this);
    private symantec.itools.beans.PropertyChangeSupport changes = new symantec.itools.beans.PropertyChangeSupport(this);

}