java画直线算法 DDA 计算机图形学

= m =直线的斜率

(2－1)

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;

public class paint extends JFrame implements ActionListener {
	JButton btn;
	JLabel lbl1, lbl2, lbl3, lbl4;
	JTextField t1, t2, t3, t4;
	JPanel p1, p2, p3, p4;

	public paint() {
		super("DDA算法画直线");
		btn = new JButton("确定");
		btn.addActionListener(this);
		lbl1 = new JLabel("输入起点横坐标:");
		lbl2 = new JLabel("输入起点纵坐标:");
		lbl3 = new JLabel("输入终点横坐标:");
		lbl4 = new JLabel("输入终点纵坐标:");
		t1 = new JTextField(3);
		t2 = new JTextField(3);
		t3 = new JTextField(3);
		t4 = new JTextField(3);
		t1.addActionListener(this);
		t2.addActionListener(this);
		t3.addActionListener(this);
		t4.addActionListener(this);
		p1 = new JPanel();
		p1.setLayout(new GridLayout(2, 2));
		p1.add(lbl1);
		p1.add(t1);
		p1.add(lbl2);
		p1.add(t2);
		p1.add(lbl3);
		p1.add(t3);
		p1.add(lbl4);
		p1.add(t4);
		this.add(p1, "South");
		p2 = new JPanel();
		p2.setLayout(new BorderLayout());
		p2.add(btn);
		btn.setActionCommand("确定");
		this.add(p2, "North");
		this.setBackground(Color.white);
	}

	public void DDAdrawline(Graphics g) {
		int x0, x1, y0, y1;
		String s1, s2, s3, s4;
		float dx, dy, k, x,y;
		s1 = t1.getText();
		s2 = t2.getText();
		s3 = t3.getText();
		s4 = t4.getText();
		x0 = Integer.parseInt(s1);
		y0 = Integer.parseInt(s2);
		x1 = Integer.parseInt(s3);
		y1 = Integer.parseInt(s4);
		dy = y1 - y0;
		dx = x1 - x0;
		if (dx != 0) {
			k = dy / dx;
			if(k<1){
				y = y0;
				for (int xx = x0; xx <= x1; xx++) {
					g.drawString(".", xx, (int) (y + 0.5f));
					y = y + k;
				}
			}else{
				System.out.println(k+"!!!!!!!!!!!!");
				x = x0;
				for(int yy=y0;yy<y1;yy++){
					g.drawString(".", (int)(x),  yy);

					int lastY = yy;
					x = x + dx/dy;
				}
			}
		} else {
			for (int i = y0; i <= y1; i++) {
				g.drawString(".", x0, i);
			}
		}
	}

	public void actionPerformed(ActionEvent e) {
		String s = e.getActionCommand();
		if (s.equals("确定")) {
			Graphics g = this.getGraphics();
			g.clearRect(0, 0, 500, 500);
			DDAdrawline(g);
		}
	}

	public static void main(String[] args) {
		paint frame = new paint();
		frame.setSize(600, 600);
		frame.setLocation(450, 200);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}
}