package lawyer;

import java.awt.*;
import java.net.*;

/**
 * Provides a canvas on which to display Images.  The Canvas sizes itself so
 * that it will be able to display the largest Image it contains, so that the
 * parent Container doesn't need to adjust the layout at all.
 *
 * @author  David Danks
 * @version 1.0; July 24, 1998
 * @see	LessonManager
 */
public class ImageCanvas extends Canvas {

    /** @serial */
    Image images[];

    /** @serial */
    MediaTracker mt;

    /** @serial */
    int imageNum;

    /** @serial */
    int xMax, yMax;

    /** @serial */
    boolean door = false;

/**
 * The constructor loads all of the images, and sets the max sizes appropriately.
 *
 * @param   imageLocats	An array of the image URLs.
 */
    public ImageCanvas(URL imageLocats[]) {
	imageNum = 0; xMax = 0; yMax = 0;
	// set up the Image[] and MediaTracker object
	images = new Image[imageLocats.length];
	mt = new MediaTracker(this);
	for (int i=0; i<imageLocats.length; i++) {
		images[i] = 
		    Toolkit.getDefaultToolkit().getImage(imageLocats[i]); 
		mt.addImage(images[i], i); }
	//}
	// for now, we want to load all of the images.  Later, it will probably
	// be better to load them only when we need them, but I just want to
	// get this working.
	try { 
	    mt.waitForAll();
	    if (mt.isErrorAny()) {
		System.err.println("Error loading the images"); }
	    }
	catch (InterruptedException i) {
	    System.err.println("Image Loading interrupted"+i.toString()); }
	// set xMax and yMax
	for (int i=0; i<images.length; i++) {
	    xMax = Math.max(xMax, images[i].getWidth(this));
	    yMax = Math.max(yMax, images[i].getHeight(this));
	}
    }
    
/**
 * Allows us to add a sign to the door at the beginning of the lesson
 *
 * @param   b	<code>true</code>, if there should be a sign.  
 *		<code>false</code>, otherwise.
 */
    public void setDoorSign(boolean b) { door = b; }
/**
 * @return  The number of images contained in the ImageCanvas
 */
    public int getNumImages() { return images.length; }
/**
 * @return  A Dimension object encoding the size it wants to be
 */
    public Dimension getPreferredSize() {
	return new Dimension(xMax, yMax); }
/**
 * @return  A Dimension object encoding the size it has to be
 */
    public Dimension getMinimumSize() {
	return new Dimension(xMax, yMax); }
/**
 * Sets the current Image being displayed to <code>num</code>.  Requires a 
 * repaint() call to take effect.
 *
 * @param   num	The number of the Image to be displayed
 */
    public void setImageNum(int num) {
	if (num >= images.length) num = images.length-1;
	imageNum = num; }
/**
 * Advances the current Image number by one.  Requires a repaint() call.
 */
    public void incrementImageNum() {
	if (imageNum == images.length-1) { }
	else { imageNum++; }
    }
/**
 * Reduces the current Image number by one.  Requires a repaint() call.
 */
    public void decrementImageNum() {
	if (imageNum == 0) { }
	else { imageNum--; }
    }

/**
 * Draws the current Image on the Canvas.  If <code>door</code> is set, it also
 * draws a sign on the door (Note: the door code is very specific to the 
 * picture we are currently using.
 */
    public void paint(Graphics g) {
	g.drawImage(images[imageNum], 0, 0, this); 
	if (door) {
	    int x = 120; int y = 175;
	    int width = Math.max(g.getFontMetrics().stringWidth("Enter your"),
		g.getFontMetrics().stringWidth("name below"));
	    width += 10;
	    int height = g.getFontMetrics().getHeight()*3;
	    g.setColor(Color.gray.brighter());
	    g.fillRoundRect(x, y, width, height, width/5, height/5);
	    g.setColor(Color.black);
	    g.drawString("Enter your", 
		x+width/2-g.getFontMetrics().stringWidth("Enter your")/2,
		y+g.getFontMetrics().getHeight()/2+g.getFontMetrics().getAscent());
	    g.drawString("name below",
		x+width/2-g.getFontMetrics().stringWidth("name below")/2,
		y+g.getFontMetrics().getHeight()*3/2+g.getFontMetrics().getAscent());
	}
    }
}