// WorkArea.java
// 
// Mark F. Hulber
// May 1996
//
//
// WorkArea implements a scrollable drawing board in which the user can enter
//  points.  The points can be input to an algorithm of choice for processing
//  and display of the resulting output.  So far, two implementations of
//  the Convex Hull have been implemented (in separate classes) including
//  the "Gift Wrap" algorithm and the "Graham Scan"
//


import java.awt.*;

public class WorkArea extends Panel {

   Canvas canvas;
   Scrollbar hbar, vbar;
   java.util.Vector lines = new java.util.Vector(100,100);
   java.util.Vector results, results1, results2;
   giftWrap gr = new giftWrap();
   grahamScan gs = new grahamScan();
   int last_x, last_y;
   int offset_x, offset_y;
   int canvas_width, canvas_height;
   private int num_points = 0;
   Button clear;
   TextField textarea;
   Choice algo;
   String ALG = "Gift Wrap";

   public WorkArea(Button cl, TextField ta, Choice al){
      canvas = new Canvas();
      hbar = new Scrollbar(Scrollbar.HORIZONTAL);
      vbar = new Scrollbar(Scrollbar.VERTICAL); 
      this.setLayout(new BorderLayout(0,0));
      clear = cl;
      textarea = ta;
      algo = al;
      this.add("Center", canvas);
      this.add("South", hbar);
      this.add("East", vbar);
   }

   public Dimension preferredSize()
   {

     return new Dimension(1000,500);
   }

   public void paint(Graphics g){
      newPoint l1, l, m;
      for (int i = 0; i < lines.size(); i++) {
         l = (newPoint)lines.elementAt(i);
         g.fillOval(l.x-offset_x, l.y-offset_y, 4, 4);
      }
      if (ALG == "Gift Wrap") {
	if ((results1 != null) && (results1.size() > 0)) {
           l1 = (newPoint)results1.elementAt(0);
           m = (newPoint)results1.elementAt(0);
           for (int i = 0, j = 1; j < results1.size(); i++, j++) {
              l = (newPoint)results1.elementAt(i);
              m = (newPoint)results1.elementAt(j);
              g.drawLine(l.x-offset_x, l.y-offset_y, 
                                m.x-offset_x, m.y-offset_y);
	   }
           g.drawLine(m.x-offset_x, m.y-offset_y, l1.x-offset_x, 
                             l1.y-offset_y);
	}
      }
      else if (ALG == "Graham Scan") {
	if ((results2 != null) && (results2.size() > 2)) {
           l1 = (newPoint)results2.elementAt(0);
           m = (newPoint)results2.elementAt(0);
           for (int i = 0, j = 1; j < results2.size(); i++, j++) {
              l = (newPoint)results2.elementAt(i);
              m = (newPoint)results2.elementAt(j);
              g.drawLine(l.x-offset_x, l.y-offset_y, 
                                m.x-offset_x, m.y-offset_y);
	   }
           g.drawLine(m.x-offset_x, m.y-offset_y, l1.x-offset_x, 
                             l1.y-offset_y);
	}
      }
   }


   public boolean mouseDown(Event e, int x, int y) {
      newPoint l1, l, m;
      int nx, ny;
      Graphics g = canvas.getGraphics();
      last_x = x; last_y = y;
      g.fillOval(x, y, 4, 4);
      nx = x + offset_x;
      ny = y + offset_y;
      textarea.setText("x:["+nx+"] y:["+ny+"]");
      lines.addElement(new newPoint(nx, ny));
      if (ALG == "Gift Wrap") {
         results1 = gr.doWrap(lines);
      }
      else if (ALG == "Graham Scan") {
         results2 = gs.doGraham(lines);
      }
      this.update(g);
      return true;
   }

   public boolean mouseDrag(Event e, int x, int y) {
      int nx, ny;
      nx = x + offset_x;
      ny = y + offset_y;
      textarea.setText("x:["+nx+"] y:["+ny+"]");

      return true;
   }

   public boolean mouseMove(Event e, int x, int y) {
      int nx, ny;
      nx = x + offset_x;
      ny = y + offset_y;
      textarea.setText("x:["+nx+"] y:["+ny+"]");
      return true;
   }

   public boolean mouseUp(Event e, int x, int y) {
      return true;

   }

   public boolean mouseExit(Event e, int x, int y) {
      textarea.setText(ALG);   
      return true;
   }

   public boolean gotFocus(Event e) {

      this.update(canvas.getGraphics());
      return true;
   }

   public boolean mouseEnter(Event e, int x, int y) {

      this.update(canvas.getGraphics());
      return true;
   }
   
       
   public boolean handleEvent(Event e){

     if (e.target == hbar) {
        switch(e.id) {
        case Event.SCROLL_LINE_UP:
        case Event.SCROLL_LINE_DOWN:
        case Event.SCROLL_PAGE_UP:
        case Event.SCROLL_PAGE_DOWN:
        case Event.SCROLL_ABSOLUTE:
           offset_x = ((Integer)e.arg).intValue();
           break;
        }
        this.update(canvas.getGraphics());
        return true;
     }
     else if (e.target == vbar) {
        switch(e.id) {   
        case Event.SCROLL_LINE_UP:
        case Event.SCROLL_LINE_DOWN:
        case Event.SCROLL_PAGE_UP:
        case Event.SCROLL_PAGE_DOWN:
        case Event.SCROLL_ABSOLUTE:
           offset_y = ((Integer)e.arg).intValue();
           break;
        }
        this.update(canvas.getGraphics());
        return true;
     }
     else if (e.target == clear) {
        if (lines != null)
           lines.removeAllElements();
        if (results != null)
           results.removeAllElements();
        if (results1 != null)
           results1.removeAllElements();
        if (results2 != null)
           results2.removeAllElements();
        Graphics g = canvas.getGraphics();
        Rectangle r = canvas.bounds(); 
        g.fillRect(r.x, r.y, r.width, r.height);
        this.update(g);
        return true;
     }
     else if (e.target == algo) {
       if (e.arg.equals("Gift Wrap")) {
          textarea.setText("Gift Wrap");
          ALG = "Gift Wrap";
          results1 = gr.doWrap(lines);
       }
       else if (e.arg.equals("Graham Scan")){
          textarea.setText("Graham Scan");
          ALG = "Graham Scan";
          results2 = gs.doGraham(lines);
       }
       else if (e.arg.equals("Delaunay")){
          textarea.setText("Delaunay");
          ALG = "Delaunay";
       }
       Graphics g = canvas.getGraphics();
       this.update(g);
       return true;
     }
     return super.handleEvent(e);
   }

   public synchronized void reshape(int x, int y, int width, int height) {
   
      super.reshape(x, y, width, height);
      Dimension hbar_size = hbar.size();
      Dimension vbar_size = vbar.size();
      canvas_width = width - vbar_size.width;
      canvas_height = height - hbar_size.height;
      hbar.setValues(offset_x, canvas_width, 0, 2000-canvas_width);
      vbar.setValues(offset_y, canvas_height, 0, 2000-canvas_height);
      hbar.setPageIncrement(canvas_width/2);
      vbar.setPageIncrement(canvas_height/2);
      this.update(canvas.getGraphics());
   }
}