import java.awt.*;

/**
 * <P>ImageCanvas is a Canvas that holds an Image.  The Image can be
 * switched, but ImageCanvas assumes all Images have the same
 * dimensions of the first image.</P>
 *
 * @author Mark L. Irons
 * @version 1.0
 * @date 18-11-1998
 */
public class ImageCanvas extends Canvas
{
  ImageCanvasEventHandler eventHandler_ = null;
  Image image_                          = null;  // current image

  /**
   * This is provided for convenience only.  ImageCanvas objects
   * must be initialized by calling a constructor that has
   * parameters.
   */
  public ImageCanvas()
  {
  }

  /**
   * Creates an ImageCanvas with the specified event handler and
   * initial image.
   *
   * @param handler a callback function that handles events
   * generated by this ImageCanvas
   * @param Image initial Image to be displayed.  All subsequent
   * Images set with <CODE>setImage</CODE> should have the same
   * dimensions.
   */
  public ImageCanvas(ImageCanvasEventHandler handler, Image image)
  {
    eventHandler_ = handler;
    image_ = image;
    preferredSize();
    minimumSize();
  }

  public Dimension preferredSize()
  {
    return (new Dimension(image_.getWidth(this),image_.getHeight(this)));
  }

  public Dimension minimumSize()
  {
    return (new Dimension(image_.getWidth(this),image_.getHeight(this)));
  }

  public void paint(Graphics g)
  {
    super.paint(g);
    g.drawImage(image_,0,0,this);
  }

  /**
   * Draws the ImageCanvas
   */
  public void draw()
  {
    Graphics g = getGraphics();
    if ( g != null ) {
      g.drawImage(image_,0,0,this);
    }
  }

  /**
   * Sets the ImageCanvas to a new Image.  This should have the same
   * dimensions as the initial Image.
   */
  public void setImage(Image image)
  {
    image_ = image;
    draw();
  }

  /**
   * Handles a mouseDown event by calling the ImageCanvas' callback
   * (set in the constructor).
   */
  public boolean mouseDown(Event event, int x, int y)
  {
    eventHandler_.imageCanvasEvent(this);
    return true;
  }

  /**
   * Doesn't do anything right now
   */
  public boolean mouseUp(Event event, int x, int y)
  {
    return true;
  }

} // class ImageCanvas