import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;

public class ImagePanel extends JPanel {

	private static final int INIT_WIDTH = 320;
	private static final int INIT_HEIGHT = 240;
	private static final double INIT_ZOOM = 1.0;
	private static final int INIT_ROTATION = 0;


	private double zoom = INIT_ZOOM;

	/* 0: no rotation, 1: 90 degrees, etc. */
	private int rotation = INIT_ROTATION;

	private String whatever = null;

	private BufferedImage img = null;

	private AffineTransform trans = new AffineTransform();


	public ImagePanel () {
		setOpaque(true);
		setBackground(Color.black);
		setPreferredSize(new Dimension(INIT_WIDTH, INIT_HEIGHT));
	}

	private void setupTrans () {
		if (img != null) {
/*
			double centerX = (double)img.getWidth() / 2;
			double centerY = (double)img.getHeight() / 2;
*/
			double centerX = (double)getRotatedImageWidth() / 2;
			double centerY = (double)getRotatedImageHeight() / 2;
			// do zoom
			trans.setToScale(zoom, zoom);
			// move center back to center
			trans.translate(centerX, centerY);
			// rotate
			trans.rotate(rotation * Math.PI / 2);
			// move center of image to (0,0) for rotation
			trans.translate(-centerX, -centerY);
			setPreferredSize(getTransImageSize());
			//System.out.println(getTransImageSize());
		}
		revalidate();
		repaint();
	}

	public Dimension getTransImageSize () {
		Point p = (Point)trans.deltaTransform(new Point(img.getWidth(), img.getHeight()), new Point());
		return new Dimension(Math.abs(p.x), Math.abs(p.y));
	}

	protected boolean isRotated () {
		return rotation % 2 != 0;
	}

	protected int getRotatedImageWidth () {
		return isRotated() ? img.getHeight() : img.getWidth();
	}

	protected int getRotatedImageHeight () {
		return isRotated() ? img.getWidth() : img.getHeight();
	}

	public void setImage (BufferedImage img) {
		this.img = img;
		setupTrans();
	}

	public double getZoom () {
		return zoom;
	}

	public void setZoom (double f) {
		//System.out.println("setZoom(" + f + ")");
		if (f > 0) zoom = f;
		setupTrans();
	}

	public void zoomTo (int w, int h) {
		System.out.println("zoomTo("+w+","+h+")");
		if (img != null) {
			double xZoom = (double)w / getRotatedImageWidth();
			double yZoom = (double)h / getRotatedImageHeight();
			System.out.println(xZoom + ", " + yZoom);
			setZoom(Math.min(xZoom, yZoom));
		}
	}

	public int getRotation () {
		return rotation;
	}

	/** Rotation is in units of 90 degrees. */
	public void setRotation (int rotation) {
		this.rotation = rotation;
		setupTrans();
	}

	public void setWhatever (String whatever) {
		this.whatever = whatever;
		repaint();
	}
	public String getWhatever () {
		return whatever;
	}



	public void paintComponent (Graphics g) {
		Graphics2D g2 = (Graphics2D)g;

		super.paintComponent(g);
		if (img != null) {
			g2.drawImage(img, trans, this);
			if (whatever != null) {
				g.setColor(Color.black);
				g.drawString(whatever, 4*getWidth()/5, getHeight()-10);
			}
		} else {
			g.setColor(Color.white);
			g.drawString("[No image]", getWidth()/3, getHeight()/2);
		}
	}

}