import java.awt.*;
import java.util.*;

/**
    Program:  H2
    Purpose:  do click-and-drag drawing + drag-isometries ("sticky interface")
	                 in hyperbolic 2-space
    @author:  Paul Garrett, garrett@math.umn.edu
    @version: Mon Jul  6 20:18:45 CDT 1998
*/

public class H2 extends java.applet.Applet {

  final static int radius = 150;
  final static int xinset = 30;
  final static int yinset = 25;
  final static Point center = new Point(xinset+radius, yinset+radius);

  int height, width;
  Color background_color, foreground_color;

  Point first, second;

  Vector v; // of Points, connected in pairs

  Graphics osg;
  Image osi;

  Button clear, draw, move;
  boolean queryDraw; // in draw mode or not

  Point basePt, newPt; // from mousedown, for "sticky" motion...

  Complex[][] mapMx; // the cumulative linear fractional transformation
  // applied to the original points

  /*
	* //__EDIT__ what about additions to already-drawn + already-rotated points!?
	*
	* Some possible overflow/roundoff problems...?!
	*/

/****************************
 *
 * Make it run also from command line...
 * 
 */

  public static void main(String[] argv) {
	 Frame fr = new Frame("at command line");
	 fr.addNotify();
	 fr.setLayout(null);
	 // fr needs space for buttons, too
	 fr.resize(2*xinset+2*radius+50,2*yinset+2*radius); // would be setSize() in 1.1
	 fr.show();
	 H2 hyp = new H2();
	 fr.add(hyp);
	 hyp.resize(2*xinset+2*radius+50,2*yinset+2*radius); // would be setSize() in 1.1
	 hyp.init();
  }

  /******************* end of command-line main(), etc. ******************/

  public void init() {

    setFont(new Font("TimesRoman", Font.PLAIN, 14));

	 background_color = new Color(0xbaaaaa);
	 foreground_color = new Color(0x503030);
	 width = 2*xinset+2*radius;
	 height = 2*yinset+2*radius;
	 setBackground(background_color);
    setForeground(foreground_color);

	 v = new Vector();

	 osi = createImage(2*radius+1+50+xinset, 2*radius+1);
	 osg = osi.getGraphics();

	 setLayout(null);

	 clear = new Button("clear");
	 add(clear);
	 clear.move(30 + 2*radius, 40);
	 clear.resize(60,30);

	 move = new Button("move");
	 add(move);
	 move.move(30 + 2*radius, 80);
	 move.resize(60,30);

	 draw = new Button("draw");
	 add(draw);
	 draw.move(30 + 2*radius, 120);
	 draw.resize(60,30);

	 queryDraw = true;

	 mapMx = new Complex[2][2];
	 mapMx[0][0] = new Complex(1,0);
	 mapMx[0][1] = new Complex(0,0);
	 mapMx[1][0] = new Complex(0,0);
	 mapMx[1][1] = new Complex(1,0); // starts as identity matrix
  }

  /****************************************************************/
  
  public void update(Graphics g) {
	 paint(g); // avoid flicker...
  }

  public synchronized void paint(Graphics g) {
	 if (osg != null) { // otherwise may get null pointer exception...
		osg.setColor(background_color);
		osg.fillRect(0,0,2*radius+1+xinset+ 50, 2*radius+1);
		osg.setColor(Color.black);
		
		osg.drawOval(0, 0, 2*radius, 2*radius); 

		Enumeration en = v.elements();
		while (en.hasMoreElements()) {
		  Complex.drawGeodesic(osg, (Point[]) en.nextElement(), mapMx, radius);
		}
		if (second != null && queryDraw == true) {
		  Point[] pp = {first, second};
		  Complex.drawGeodesic(osg, pp, mapMx, radius);
		}
		g.drawImage(osi, xinset, yinset, this);
	 }
  }

/************************************************************/

  public boolean mouseDown(Event e, int x, int y) {
	 if ((x-center.x)*(x-center.x) + (y-center.y)*(y-center.y) < radius*radius) {
		if (queryDraw) {
		  second = null; //__EDIT__ note this!
		  first = new Point(x-xinset,y-yinset);
		  return true;
		}
		else { // non-draw = move mode
		  basePt = new Point(x-xinset,y-yinset);
		  newPt = null;
		  return true;
		}
	 }
	 else { // outside the picture
		return false;
	 }
  }

  public boolean mouseDrag(Event e, int x, int y) {
	  if ((x-center.x)*(x-center.x) + (y-center.y)*(y-center.y) < radius*radius) {
		 if (queryDraw) {
			if (first != null) {
			  second = new Point(x-xinset,y-yinset);
			  repaint();
			  return true;
			}
			else { // trying to draw, but no first point initialized
			  return true;
			}
		 }
		 else { // non-drawing case
			if (basePt != null) {
			  newPt = new Point(x-xinset,y-yinset);
			  Complex.updateMapMx(mapMx, basePt, newPt, (double) radius);
			  repaint();
			  basePt = new Point(x-xinset,y-yinset); //__EDIT__ to repeatedly increment
			  return true;
			}
			else {
			  return true; // trying to drag, but no legal base point
			}
		 }
	  }
	  else { // outside of the model entirely
		 return false;
	  }
  }

  public boolean mouseUp(Event e, int x, int y) {
	 if ((x-center.x)*(x-center.x) + (y-center.y)*(y-center.y) < radius*radius) {
		if (queryDraw) {
		  if (first != null && second != null) {
			 Point[] pp = {first, new Point(x-xinset,y-yinset)};
			 v.addElement(pp);
			 repaint();
			 first = null;
			 second = null;
			 return true;
		  }
		  else {
			 return true; // no legitimate pair of points to push onto Vector v
		  }
		}
		else { // non-draw case
		  basePt = null;
		  newPt = null;
		  return true;
		}
	 }
	 else { // outside of model
		return false;
	 }
  }

  public final synchronized boolean action(Event e, Object arg) {
	 if (e.target instanceof Button) {
      if (arg.toString().equals("clear")) {
		  v.removeAllElements();
		  repaint();
		}
		else if (arg.toString().equals("move")) {
		  queryDraw = false;
		  repaint();
		}
		else if (arg.toString().equals("draw")) {
		  queryDraw = true;
		  mapMx[0][0] = new Complex(1,0);
		  mapMx[1][0] = new Complex(0,0);
		  mapMx[0][1] = new Complex(0,0);
		  mapMx[1][1] = new Complex(1,0);
		  repaint();
		}
	 }
	 return false;
  }
  
}

/**************************************************
*
*   The End
*
***************************************************/