midbresenhampanelline.java

利用Java采用中点Brasenham算法同时绘制多个圆。

/*
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 */

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 midBresenhamPanelLine extends JPanel implements MouseListener, ComponentListener,Runnable {

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

    public midBresenhamPanelLine() {
        this.setEnabled(true);
        PointLabel = new JLabel();
        this.add(PointLabel, "North");
        pointset = new Vector<Point>();
        pointtwo = new Vector<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.midBresenhamline();
        // repaint();
        }
    }

    public void midBresenhamline() {
        Point firstpoint, lastpoint;
        int x, y, dx, dy, e;
        float k;

        firstpoint = pointtwo.get(0);
        lastpoint = pointtwo.get(1);
        dx = lastpoint.x - firstpoint.x;
        dy = lastpoint.y - firstpoint.y;
        k = (float) dy / (float) dx;
        pointtwo.removeAllElements();
        PointLabel.setText("起点为：（" + firstpoint.x + "," + firstpoint.y + ");  终点为：(" + lastpoint.x + "," + lastpoint.y + ")  斜率为: k=" + k);

        if (k >= 0 && k < 1) {
            e = -dx;
            x = firstpoint.x;
            y = firstpoint.y;
            while (x <= lastpoint.x) {
                Point newpoint = new Point(x, y);
                pointset.add(newpoint);
                repaint();
                x++;
                e = e + 2 * dy;
                if (e > 0) {
                    y++;
                    e = e - 2 * dx;
                }
            }
        }
    }

    public void run() {
        while (true) {
            if (myThread.isAlive() && !myThread.isInterrupted()) {
                try {
                    repaint();
                    Thread.sleep(100);
                    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, current.y, current.x, current.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) {
    }
}