// mas964 ps4
// Take three clicks and draw them connected somehow

import java.applet.*;
import java.awt.*;
import java.lang.Math;
import DoubleBufferApplet;

public class ThreePointStatic extends DoubleBufferApplet {
  int x[], y[];
  int numPoints;

  public void drawImage() {
    Graphics g = imageBuffer.getGraphics();

    this.clearImageBuffer();
    g.setColor(this.getForeground());
    if (numPoints != 3)
      System.out.println("drawImage called without 3 points set.");

    if (false) {
      int i;
      for (i = 0; i < 3; i++)
	g.fillRect(x[i]-2, y[i]-2, 5, 5);
    }

    int d0, d1, a0, a1, maxd, r;

    // figure out angle and distance from last point to first two
    d0 = (int)distance(x[2], y[2], x[0], y[0]);
    a0 = (int)angle(x[2], y[2], x[0], y[0]);
    d1 = (int)distance(x[2], y[2], x[1], y[1]);
    a1 = (int)angle(x[2], y[2], x[1], y[1]);

    // tunable parameters.
    int ringSpacing = 6, ringThickness = 3, arcLength = 24;
    double randomArcProbability = 0.7;
    
    maxd = Math.max(imageBufferSize.width, imageBufferSize.height);
    maxd += maxd % (ringSpacing);		  // round up to nearest
    
    for (r = maxd; r > 0; r -= ringSpacing) {	  // draw rings from outside in
      if (r <= d0)				  
	thickCenteredArc(g, x[2], y[2], r, ringThickness,
			 a0 - arcLength/2, arcLength);
      if (r <= d1)
	thickCenteredArc(g, x[2], y[2], r, ringThickness,
			 a1 - arcLength / 2, arcLength);
      if (Math.random() < randomArcProbability) {
	int randomAngle = (int) (Math.random() * 360);
	thickCenteredArc(g, x[2], y[2], r, ringThickness,
			 randomAngle - arcLength/2, arcLength);
      }
    }
    // wedge in the middle
    thickCenteredArc(g, x[2], y[2], ringSpacing, ringSpacing,
		     a0 - arcLength / 2, arcLength);
    thickCenteredArc(g, x[2], y[2], ringSpacing, ringSpacing,
		     a1 - arcLength / 2, arcLength);

    int m;
    m = (y[0] - y[2]) / (x[2] - x[0]);
    // g.drawLine(x[2], y[2], x[0], y[0]);
    // g.drawLine(x[2], y[2], x[1], y[1]);
    
    repaint(); 
  }

  // simple interface to drawing arcs that handles centering, radius, thickness
  // assumes circular arcs. Must be drawn from the outside in.
  public void thickCenteredArc(Graphics g, int x, int y, int radius, int thickness, int sa, int ea) {
    Color c = g.getColor();
    g.fillArc(x - radius, y - radius, radius*2, radius*2, sa, ea);
    g.setColor(this.getBackground());
    // fudge the arc a bit wider - necessary to handle edges...
    g.fillArc(x - (radius - thickness), y - (radius - thickness),
	      (radius-thickness)*2, (radius-thickness)*2, sa - 1, ea + 2);
    g.setColor(c);
  }

  public double distance(int x1, int y1, int x2, int y2) {
    return Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
  }

  // convert the angle to degrees in the format requred by Graphics.drawArc
  public double angle(int x1, int y1, int x2, int y2) {
    double radians = Math.atan2(x1 - x2, y1 - y2);
    return (radians * 180 / Math.PI) + 90;
  }
  
  // collect three mouse clicks
  public boolean mouseDown(Event e, int mouseX, int mouseY) {
    x[numPoints] = mouseX;
    y[numPoints] = mouseY;
    numPoints++;
    if (numPoints == 3) {
      drawImage();
      numPoints = 0;
    }

    return true;
  }

  public void init() {
    x = new int[3];
    y = new int[3];
    this.setBackground(Color.white);
    this.setForeground(Color.black);
    update(getGraphics());
    super.init();

    x[0] = 40; y[0] = 150;
    x[1] = 270; y[1] = 290;
    x[2] = 150; y[2] = 50;
    numPoints = 3;
    drawImage();
    numPoints = 0;
  }
}