Question

用java编写一个简单的画图程序。不用复杂

Answer 1

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

//不规则图形的绘制

public class IrregularShapeDemo extends JFrame {

GeneralPath gPath= new GeneralPath(); //GeneralPath对象实例
Point aPoint;

//构造函数
public IrregularShapeDemo() {
super("不规则图形的绘制"); //调用父类构造函数
enableEvents(AWTEvent.MOUSE_EVENT_MASK|AWTEvent.MOUSE_MOTION_EVENT_MASK); //允许事件

setSize(300, 200); //设置窗口尺寸
setVisible(true); //设置窗口可视
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //关闭窗口时退出程序
}

public void paint(Graphics g) { //重载窗口组件的paint()方法
Graphics2D g2D = (Graphics2D)g; //获取图形环境
g2D.draw(gPath); //绘制路径
}

public static void main(String[] args) {
new IrregularShapeDemo();
}

protected void processMouseEvent(MouseEvent e) { //鼠标事件处理
if(e.getID() == MouseEvent.MOUSE_PRESSED) {
aPoint = e.getPoint(); //得到当前鼠标点
gPath = new GeneralPath(); //重新实例化GeneralPath对象
gPath.moveTo(aPoint.x,aPoint.y); //设置路径点
}
}

protected void processMouseMotionEvent(MouseEvent e) { //鼠标运动事件处理
if(e.getID() == MouseEvent.MOUSE_DRAGGED) {
aPoint = e.getPoint(); //得到当前鼠标点
gPath.lineTo(aPoint.x, aPoint.y); //设置路径
gPath.moveTo(aPoint.x, aPoint.y);
repaint(); //重绘组件
}
}
}

Answer 2

package s;//包名
　　import java.awt.*;
　　import java.awt.event.*;
　　import javax.swing.*;
　　public class Test extends JFrame {
　　int x1,y1,x2,y2;public Test(){
　　setVisible(true);
　　setSize(300,300) ;
　　addWindowListener(new WindowAdapter() {
　　public void windowClosing(WindowEvent e){
　　System.exit(0) ; }});
　　addMouseListener(
　　new MouseAdapter() {
　　public void mousePressed(MouseEvent e){
　　x1=e.getX();
　　y1=e.getY();} });
　　addMouseMotionListener(new MouseMotionAdapter() {
　　public void mouseDragged(MouseEvent e){
　　x2=e.getX() ;
　　y2=e.getY() ;
　　repaint(); }});
　　}
　　public void paint(Graphics g)
　　{
　　g.drawLine(x1,y1,x2,y2);
　　x1=x2;
　　y1=y2;
　　}
　　public static void main(String args[])
　　{
　　new Test();
　　}
　　}