drawpanel.java

这是一个经典的程序

package kc.test.kmeans;

import voronoi.VoronoiSegment;
import voronoi.Vertex;

import java.awt.*;
import java.awt.geom.Rectangle2D;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
import java.awt.event.*;
import java.util.*;

public class DrawPanel extends Canvas implements MouseListener, MouseMotionListener,
        ComponentListener
{
    private ArrayList<Point> points;
    private ArrayList<Centroid> clusters;

    private ArrayList<CentroidNode> centroids;

    private ArrayList<Point> points_cloned;
    private ArrayList<Centroid> clusters_cloned;

    private BufferedImage bi;
    private Graphics2D big;
    private Dimension dim;

    private boolean dragging;
    private CentroidNode dragNode;
    private Centroid dragCenter;

    private KMeansAlgorithm algorithm;

    private static final int POINT_SIZE = 6;
    private static final int CENTROID_SIZE = 10;

    private CommandPanel command;

    public DrawPanel(CommandPanel cmd) {
        addMouseMotionListener(this);
        addMouseListener(this);
        addComponentListener(this);

        algorithm = new KMeansAlgorithm();

        points = new ArrayList<Point>();
        clusters = new ArrayList<Centroid>();

        centroids = new ArrayList<CentroidNode>();

        command = cmd;
        command.setState(1, 0);
    }

    public void initialize() {
        Random r = new Random();

        points.clear();
        clusters.clear();
        centroids.clear();

        for (int j=0; j<command.getClusters(); j++) {
            int x = (int) dim.getWidth() - 100;
            x = r.nextInt(x) + 50;
            int y = (int) dim.getHeight() - 80;
            y = r.nextInt(y) + 40;

            CentroidNode c = new CentroidNode(x, y, command.getDeviationX(),
                    command.getDeviationY(), command.getNodes());
            centroids.add(c);
        }

        algorithm.setInit(false);
        command.setState(2, 0);
        repaint();
    }

    public void reset() {
        if (points_cloned != null) {
            points = points_cloned;
            clusters = clusters_cloned;
            algorithm.setInit(false);
            command.setState(3, 0);
            repaint();
        }
    }

    public void start() {
        Random r = new Random(new Date().getTime());

        points.clear();
        clusters.clear();

        // copy points from centroidNodes to pointlist
        for (CentroidNode n : centroids) {
            for (java.awt.geom.Point2D p : n.nodes) {
                points.add(new Point(p));
            }

            int x = r.nextInt((int) dim.getWidth() - 100) + 50;
            int y = r.nextInt((int) dim.getWidth() - 80) + 40;

            int rr = r.nextInt(256);
            int gg = r.nextInt(256);
            int bb = r.nextInt(256);
            clusters.add(new Centroid(new java.awt.geom.Point2D.Double(x, y), new Color(rr, gg, bb)));
        }

        points_cloned = new ArrayList<Point>();
        for (Point p : points) {
            points_cloned.add(p.clone());
        }

        clusters_cloned = new ArrayList<Centroid>();
        for (Centroid c : clusters) {
            clusters_cloned.add(c.clone());
        }

        algorithm.init(points, clusters);

        command.setState(4, 0);
        repaint();
    }

    public void step() {
        algorithm.step();
        repaint();
    }

    public void run() {
        int iterations = algorithm.run();
        command.setState(5, iterations);
        repaint();
    }

    public void mouseDragged(MouseEvent e) {
        if(dragging){
            updateLocation(e);
        }
    }

    public void mousePressed(MouseEvent e) {
        // check wether we want to drag a centroid
        int x = e.getX();
        int y = e.getY();

        // if algorithm is not yet initialized, we can change layout of data items
        if (!algorithm.isInitialized()) {
            for (CentroidNode n : centroids) {
                if (n.box.contains(x, y)) {
                    dragging = true;
                    dragNode = n;
                    break;
                }
            }

            if (!dragging) {
                CentroidNode c = new CentroidNode(e.getX(), e.getY(), command.getDeviationX(),
                        command.getDeviationY(), command.getNodes());
                centroids.add(c);
            }
        } else {
            for (Centroid c : clusters) {
                Shape s = new Ellipse2D.Double((int) c.getP().getX() - CENTROID_SIZE / 2,
                        (int) c.getP().getY() - CENTROID_SIZE / 2, CENTROID_SIZE, CENTROID_SIZE);
                if (s.contains(x, y)) {
                    dragging = true;
                    dragCenter = c;
                    break;
                }
            }
        }
    }

    public void mouseReleased(MouseEvent e) {
        dragging = false;
        dragNode = null;
        dragCenter = null;
        repaint();
    }

    public void mouseMoved(MouseEvent e) {}
    public void mouseEntered(MouseEvent e) {}
    public void mouseExited(MouseEvent e) {}
    public void mouseClicked(MouseEvent e) {}

    // These methods are required by MouseMotionListener.
    public void updateLocation(MouseEvent e){
        if (dragNode != null)
            dragNode.setPosition(e.getX(), e.getY());
        if (dragCenter != null)
            dragCenter.getP().setLocation(e.getX(), e.getY());
        repaint();
    }

    public void paint(Graphics g){
        Graphics2D g2 = (Graphics2D)g;
        // Draws the buffered image to the screen.
        g2.drawImage(bi, 0, 0, this);
    }

    public void update(Graphics g){
        // Clears the rectangle that was previously drawn.
        big.setColor(Color.white);
        big.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1.0f));
        big.fillRect(0, 0, dim.width, dim.height);

        if (algorithm.isInitialized())
           drawAlgo();
        else
           drawPlacing();

        paint(g);
    }

    private void drawPlacing() {
        Rectangle2D.Float r = new Rectangle2D.Float();

        for(CentroidNode n: centroids) {
            big.setColor(Color.black);
            for (java.awt.geom.Point2D p : n.nodes) {
                big.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.4f));
                big.fillOval((int) p.getX() - POINT_SIZE / 2, (int) p.getY() - POINT_SIZE / 2, POINT_SIZE, POINT_SIZE);
                big.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1.0f));
                big.drawOval((int) p.getX() - POINT_SIZE / 2, (int) p.getY() - POINT_SIZE / 2, POINT_SIZE, POINT_SIZE);
            }

            r.setRect(n.box);
            big.setColor(Color.red);
            big.fill(r);
        }
    }

    private void drawAlgo() {
        for(Point p : points) {
            drawPoint((int) p.getP().getX(), (int) p.getP().getY(), POINT_SIZE, p.getColor(), p.getColor(), 0.4f);
        }

        for (Centroid c : clusters) {
            java.awt.geom.Point2D old = null;
            if (command.getShowHistory()) {
                for (java.awt.geom.Point2D hp : c.getHistory()) {
                    if (old != null) {
                        big.setColor(Color.black);
                        big.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1.0f));
                        drawArrow(big, (int) old.getX(), (int) old.getY(), (int) hp.getX(), (int) hp.getY());
                    }

                    drawPoint((int) hp.getX(), (int) hp.getY(), CENTROID_SIZE, Color.gray, c.getColor(), 0.8f);
                    old = hp;
                }