// mas964 ps2
// draw lines on mouse click that demonstrate rhythm

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

public class LineRhythm extends DoubleBufferApplet {
  protected int a1, b1, a2, b2, a3, b3, a4, b4;	  // moduli for lines

  public void randomizeConstants() {
    a1 = (int)(Math.random() * 9) + 2;		  // 2..10
    b1 = (int)(Math.random() * (a1 - 1)) + 1;	  // 1..a-1
    a2 = (int)(Math.random() * 9) + 2;		  // 2..10
    b2 = (int)(Math.random() * (a2 - 1)) + 1;	  // 1..a-1
    a3 = (int)(Math.random() * 9) + 2;		  // 2..10
    b3 = (int)(Math.random() * (a3 - 1)) + 1;	  // 1..a-1
    a4 = (int)(Math.random() * 9) + 2;		  // 2..10
    b4 = (int)(Math.random() * (a4 - 1)) + 1;	  // 1..a-1
  }
    
  // redraw the lines converging on a given x,y.
  // The lines are drawn according to the constants a# and b#.
  // Lines are interpolated from edges of the screen to the x,y
  // coordinate - getting b/a closer each time.
  // a# and b# are set elsewhere.
  public void redrawLines(int x, int y) {
    Graphics g = imageBuffer.getGraphics();

    this.clearImageBuffer();
    g.setColor(this.getForeground());

    int drawX, drawY, oldX, oldY;

    oldX = -100;
    drawX = 0;
    while (oldX < drawX - 1) {
      oldX = drawX;
      drawX += b1 * (x - drawX) / a1;
      g.drawLine(drawX, 0, drawX, imageBufferSize.height);
    }

    drawX = imageBufferSize.height;
    oldX = drawX + 100;
    while (oldX > drawX + 1) {
      oldX = drawX;
      drawX += b2 * (x - drawX) / a2;
      g.drawLine(drawX, 0, drawX, imageBufferSize.height);
    }

    oldY = -100;
    drawY = 0;
    while (oldY < drawY - 1) {
      oldY = drawY;
      drawY += b3 * (y - drawY) / a3;
      g.drawLine(0, drawY, imageBufferSize.width, drawY);
    }

    drawY = imageBufferSize.width;
    oldY = drawY + 100;
    while (oldY > drawY + 1) {
      oldY = drawY;
      drawY += b4 * (y - drawY) / a4;
      g.drawLine(0, drawY, imageBufferSize.width, drawY);
    }
    
    repaint();
  }

  public boolean mouseDown(Event e, int x, int y) {
    randomizeConstants();
    redrawLines(x, y);
    return true;
  }

  public boolean mouseDrag(Event e, int x, int y) {
    redrawLines(x, y);
    return true;
  }
  
  public void init() {
    this.setBackground(Color.white);
    this.setForeground(Color.black);
    randomizeConstants();
    super.init();
  }
}