midbresenhampanelcircle.java

利用Java采用中点Brasenham算法同时绘制多个圆。

/*
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 * and open the template in the editor.
 */
/**
 *
 * @author Administrator
 */
package bresenham;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Vector;
import javax.swing.JLabel;
import javax.swing.JPanel;

/**
 *
 * @author Lenovo
 */
public class midBresenhamPanelCircle extends JPanel implements MouseListener, ComponentListener,Runnable {

    JLabel PointLabel;
    Vector<Point> pointset;
    Vector<Point> pointtwo;
    Point circlePoint;
    Thread myThread;
    int temp=0;

    public midBresenhamPanelCircle() {
        this.setEnabled(true);
        PointLabel = new JLabel();
        this.add(PointLabel, "North");
        pointset = new Vector<Point>();
        pointtwo = new Vector<Point>();
        circlePoint = new Point();
        this.addMouseListener(this);

        myThread=new Thread(this);
        myThread.start();
    }

    public void mousePressed(MouseEvent e) {
        if (pointset.size() > 0) {
            pointset.removeAllElements();
        }
        Point p = new Point(e.getX(), e.getY());
        pointtwo.add(p);
        if (pointtwo.size() >= 2) {
            this.midBresenhamcircle();
        // repaint();
        }
    }

    public void midBresenhamcircle() {
        Point firstpoint, lastpoint;
        int x, y, dx, dy, d;
        int r;

        firstpoint = pointtwo.get(0);
        circlePoint = firstpoint;
        lastpoint = pointtwo.get(1);
        dx = lastpoint.x - firstpoint.x;
        dy = lastpoint.y - firstpoint.y;
        r = (int) Math.sqrt((double) (dx * dx + dy * dy));
        pointtwo.removeAllElements();
        
        PointLabel.setText("圆心为：（" + firstpoint.x + "," + firstpoint.y + ")  半径为:R=" + r);

        d = 1 - r;
        x = 0;         //firstpoint.x
        y = r;          //firstpoint.y+r
        while (x <= y) {
            Point newpoint = new Point(x, y);
            pointset.add(newpoint);
            repaint();
            if (d < 0) {
                d = d + 2 * x + 3;
            } else {
                d = d + 2 * (x - y) + 5;
                y--;
            }
            x++;
        }
    }

    public void run() {
        while (true) {
            if (myThread.isAlive() && !myThread.isInterrupted()) {
                try {
                    repaint();
                    Thread.sleep(200);
                    temp++;
                    if(temp==pointset.size()){
                       // myThread.interrupt();
                        temp=0;
                    }
                } catch (InterruptedException ex) {
                }
            } else {
                break;
            }
        }
    }

    @Override
    protected void paintComponent(Graphics g) {
        Point current;
        int size;
        g.clearRect(0, 0, getWidth(), this.PointLabel.getHeight() + 2);
        if (pointset.size() != 0) {
            size =temp+1;
            for (int i = 0; i < size; i++) {
                current = pointset.get(i);
                g.setColor(Color.RED);
                g.drawLine(current.x + circlePoint.x, current.y + circlePoint.y, current.x + circlePoint.x, current.y + circlePoint.y);
                g.drawLine(current.y + circlePoint.x, current.x + circlePoint.y, current.y + circlePoint.x, current.x + circlePoint.y);
                g.drawLine(-current.y + circlePoint.x, current.x + circlePoint.y, -current.y + circlePoint.x, current.x + circlePoint.y);
                g.drawLine(-current.x + circlePoint.x, current.y + circlePoint.y, -current.x + circlePoint.x, current.y + circlePoint.y);
                g.drawLine(-current.x + circlePoint.x, -current.y + circlePoint.y, -current.x + circlePoint.x, -current.y + circlePoint.y);
                g.drawLine(-current.y + circlePoint.x, -current.x + circlePoint.y, -current.y + circlePoint.x, -current.x + circlePoint.y);
                g.drawLine(current.y + circlePoint.x, -current.x + circlePoint.y, current.y + circlePoint.x, -current.x + circlePoint.y);
                g.drawLine(current.x + circlePoint.x, -current.y + circlePoint.y, current.x + circlePoint.x, -current.y + circlePoint.y);
            }
        }
    }

    public void mouseClicked(MouseEvent e) {
    }

    public void mouseReleased(MouseEvent e) {
    }

    public void mouseEntered(MouseEvent e) {
    }

    public void mouseExited(MouseEvent e) {
    }

    public void componentResized(ComponentEvent e) {
        repaint();
    }

    public void componentMoved(ComponentEvent e) {
    }

    public void componentShown(ComponentEvent e) {
    }

    public void componentHidden(ComponentEvent e) {
    }
}