// mas964 ps4
// Take two clicks and draw them connected somehow
// this applet prefers to be 354x354

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

public class TwoPointStatic extends DoubleBufferApplet {
  int x1, x2, y1, y2;
  int numPoints = 0;
  
  int numCircles, maxDimension, spacing, circleRadius;

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

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

    maxDimension = Math.max(imageBufferSize.width, imageBufferSize.height);
    numCircles = 16;
    spacing = maxDimension / numCircles;	     // should divide size
    circleRadius = 9;
    
    // draw a grid of circles
    int x, y;
    if (true)
      for (x = 0; x < numCircles; x++)
	for (y = 0; y < numCircles; y++)
	  drawOpen(g, x, y);

    // find the nearest places to where was clicked ("logical coordinates")
    int logX1, logY1, logX2, logY2;
    logX1 = x1 / spacing;
    logY1 = y1 / spacing;
    logX2 = x2 / spacing;
    logY2 = y2 / spacing;

    // draw two clicked on points filled.
    drawFill(g, logX1, logY1);
    drawFill(g, logX2, logY2);

    // now draw a line that connects the two points in pieces
    // we are trying to draw from logX1, logY1 to logX2, logY2

    // now draw vertically from first - but overshoot
    int overY;
    if (logY2 > logY1) {
      overY = logY2 + (numCircles - logY2) / 2;
      for (y = logY1; y <= overY; y++)
	drawFill(g, logX1, y);
    } else {
      overY = logY2 / 2;
      for (y = logY1; y >= overY; y--)
	drawFill(g, logX1, y);
    }

    // now draw horizontally from second - but overshoot
    int overX;
    if (logX2 > logX1) {
      overX = logX2 + (numCircles - logX2) / 2;
      for (x = logX1; x <= overX; x++)
	drawFill(g, x, overY);
    } else {
      overX = logX2/2;
      for (x = logX1; x >= overX; x--)
	drawFill(g, x, overY);
    }

    // now draw back up to the right level
    if (logY2 > overY)
      for (y = overY; y <= logY2; y++)
	drawFill(g, overX, y);
    else
      for (y = overY; y >= logY2; y--)
	drawFill(g, overX, y);

    // and come back in
    if (logX2 > overX)
      for (x = overX; x <= logX2; x++)
	drawFill(g, x, logY2);
    else
      for (x = overX; x >= logX2; x--)
	drawFill(g, x, logY2);
    
    repaint(); 
  }

  public void drawOpen(Graphics g, int x, int y) {
    thickCenteredCircle(g, x * spacing + spacing/2, y * spacing + spacing/2,
			circleRadius, 4);
  }

  public void drawFill(Graphics g, int x, int y) {
    thickCenteredCircle(g, x * spacing + spacing/2, y * spacing + spacing/2,
			circleRadius, -1);
  }
  
  // draw a circle of given thickness, etc. If thickness is 0 or radius,
  // then just draw a filled circle
  public void thickCenteredCircle(Graphics g, int x, int y, int radius, int thickness) {
    Color c = g.getColor();
    g.fillOval(x - radius, y - radius, radius * 2 + 1, radius * 2 + 1);
    if (thickness > 0 && thickness < radius) {
      g.setColor(this.getBackground());
      g.fillOval(x - (radius - thickness), y - (radius - thickness),
		 (radius - thickness) * 2 + 1, (radius - thickness) * 2 + 1);
      g.setColor(c);
    }
  }

  // collect three two clicks
  public boolean mouseDown(Event e, int mouseX, int mouseY) {
    if (numPoints == 0) {
      x1 = mouseX;
      y1 = mouseY;
      numPoints++;
    } else {
      x2 = mouseX;
      y2 = mouseY;
      drawImage();
      numPoints = 0;
    }
    return true;
  }

  public void init() {
    this.setBackground(Color.white);
    this.setForeground(Color.black);
    super.init();
    update(getGraphics());
    x1 = 100;
    y1 = 100;
    x2 = 200;
    y2 = 200;
    drawImage();
    numPoints = 0;
  }
}