Map.java

import javax.swing.JFrame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Color;
import java.awt.Font;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import java.awt.Dimension;
import javax.swing.JComponent;
import java.awt.geom.Line2D;

/**
 * Displays the map and draws the current tour and status on top of it.
 * Also maps from lat/lng to coordinates in the context of this component. 
 * 
 * @author @gcschmit
 * @version 02jun2020
 */
public class Map extends JComponent 
{
 private static final int WIDTH = 800;
 private static final int HEIGHT = 600;

 private static final double MIN_LAT = 50.19395025319712;
	private static final double MAX_LAT = 30.320009196592867;
	private static final double MIN_LNG = -103.57812500000001;
	private static final double MAX_LNG = -68.42187500000001;

 private BufferedImage mapImage;
 private Tour tour;
 private int gen;

 /**
 * Constructs a new Map.
 */
 public Map()
 {
 try
 {
 this.mapImage = ImageIO.read(new File("map.png"));
 }
 catch (IOException e)
 {
 }
 }
 
 /**
 * Overrides JComponent's getPreferredSize method to return a size large enough to
 * encapsulate the map
 *
 * @returns the preferred size for the component
 * 
 */
 @Override
 public Dimension getPreferredSize()
 {
 // the component needs to be large enough to encapsulate the map
 return new Dimension(WIDTH, HEIGHT);
 }
 
 /**
 * Sets the tour and generation to display on this map to the specified tour and generation.
 * These will be displayed the next time the paintComponent method is invoked by
 * the run-time.
 * 
 * @param currentTour the tour to display on this map 
 * @param generation the generation to display on this map
 */
 public void setCurrentTour(Tour currentTour, int generation)
 {
 this.tour = currentTour;
 this.gen = generation;
 
 // ask the Java Run-Time to invoke the paintComponent method at the next opportunity
 this.repaint();
 }

 /**
 * This method is invoked by the Java Run-Time whenever the component needs to be redrawn.
 * It does not need to be invoked explicitly. It draws both the map and the current tour.
 * It will be invoked shortly after the setCurrentTour method is invoked.
 *
 * @param g the graphics object to be used for all graphics operations
 * 
 */
 @Override
 public void paintComponent(Graphics g)
 {
 Graphics2D g2 = (Graphics2D)g;

 // scale the Google map image file to this component
 g2.drawImage(this.mapImage, 0, 0, this.getWidth(), this.getHeight(),
 0, 0, 1600, 1200, null);

 drawTour(g2);

 // draw the current status (i.e., generation and current best tour)
 String status = String.format("Map [%3d] %s", gen, (this.tour == null ? "<null>" : tour));
 g2.setColor(Color.BLACK);
 g2.drawString(status, 200, 25);
 }
 
 private void drawTour(Graphics2D g2) 
 {
 if(this.tour == null)
 {
 return;
 }
 
 final int OFFSET = 20;
 City[] cities = this.tour.getCities();
 
 g2.setFont(new Font("SansSerif", Font.BOLD, 16));
 
 double x1, y1, x2, y2;
 for (int i = 0; i < cities.length; i++) 
 {
 x1 = Map.lngToX(cities[i].getLng(), this.getWidth());
 y1 = Map.latToY(cities[i].getLat(), this.getHeight());
 
 int nextCityIndex = i + 1;
 if(i == cities.length - 1) // loop back to the first city
 {
 nextCityIndex = 0;
 }
 
 x2 = Map.lngToX(cities[nextCityIndex].getLng(), this.getWidth());
 y2 = Map.latToY(cities[nextCityIndex].getLat(), this.getHeight());
 
 Line2D.Double path = new Line2D.Double(x1, y1, x2, y2);
 
 g2.setColor(Color.BLUE);
 g2.draw(path);
 g2.setColor(Color.RED);
 g2.drawString(Integer.toString(i), (float)(x1 - OFFSET), (float)(y1 + OFFSET));
 }
 }
 
 /**
 * Converts the specified longitude to the x coordinate in the context of this component
 * 
 * @param lng the longitude value to convert
 * @return the x coordinate that corresponds to the specified longitude
 */
 public static double lngToX(double lng, double width)
 {
 return (lng - MIN_LNG) / (MAX_LNG - MIN_LNG) * width;
 }
 
 /**
 * Converts the specified latitude to the y coordinate in the context of this component
 * 
 * @param lng the latitude value to convert
 * @return the y coordinate that corresponds to the specified latitude
 */
 public static double latToY(double lat, double height)
 {
 return (lat - MIN_LAT) / (MAX_LAT - MIN_LAT) * height;
 }
 
 
 
 
}