Java 画图板

用Java做一个画图板，主要分四个步骤：

创建画布，并设置画布可见
给画布添加菜单栏（我是以菜单的形式做的各种功能）
设置监听器
用监听器监测事件，绘图

创建画布

//面板参数
JFrame jf = new JFrame("画图板");
jf.setSize(1800,900);
jf.setLocationRelativeTo(null);
jf.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
jf.setLayout(new BorderLayout());


//设置可见
jf.setVisible(true);
Graphics g = jf.getGraphics();

加菜单栏

//创建菜单
JMenuBar jb = new JMenuBar();
jb.setSize(1800,50);
jf.add(jb,BorderLayout.NORTH);

//添加形状栏
JMenu menu1 = new JMenu("形状");
jb.add(menu1);
//形状栏下子目录
String[] arr = {"直线","曲线","椭圆","矩形","等腰三角形"};
//使用for循环将其导入形状
for (int i=0;i<arr.length;i++){
	JMenuItem menuItem = new JMenuItem(arr[i]);
	menu1.add(menuItem);
}

设置监听器

//创建监听器
DrawListener dl = new DrawListener();
//将监听器添加到各个组件上面
for (int i=0;i<arr.length;i++){
	JMenuItem menuItem = new JMenuItem(arr[i]);
	menu1.add(menuItem);
	menuItem.addActionListener(dl);
	……
//给窗体加监听器
if.addMouseListener(dl);
jf.addMouseMotionListener(dl);
dl.g = g;
}

监听事件&颜色板

//利用type接受事件信息
String action = e.getActionCommand();
type=action;

//判断颜色
if(action.equals("")){
	Object srcobj = e.getSource();
	JButton srcBtn = (JButton) srcobj;
	Color color = srcBtn.getBackGround();
	g.setColor(color);
}

画曲线

	public void mousePressed(MouseEvent e) {
		// TODO Auto-generated method stub
		x1=e.getX();
		y1=e.getY();
		}
	public void mouseDragged(MouseEvent e) {
		// TODO Auto-generated method stub
		x3=e.getX();
		y3=e.getY();
		if("曲线".equals(type)){
			x3=e.getX();
			y3=e.getY();
			g.drawLine(x1, y1, x3, y3);
			x1=x3;
			y1=y3;
		}
	}

下面附上全部代码：

DrawUI

package drawing_board2;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;

public class DrawUI extends JFrame{

    //创建监听器
  	DrawListener dl = new DrawListener();
	
  	public void showUI(){
		//设置画图板
		JFrame jf = new JFrame("画图板");
		jf.setSize(1800, 900);
		jf.setLocationRelativeTo(null);
		jf.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
		jf.setLayout(new BorderLayout());
			
		
		//设置菜单栏
		JMenuBar jb = new JMenuBar();
		jb.setSize(1800, 50);
		//将菜单栏对象放在窗体的菜单栏中
		jf.add(jb,BorderLayout.NORTH);
		
		//形状栏
		JMenu menu1 = new JMenu("形状");
		jb.add(menu1);
		String[] arr = {"直线","曲线","椭圆","矩形","等腰三角形"};
		for (int i = 0; i < arr.length; i++){
			JMenuItem menuItem = new JMenuItem(arr[i]);
			menu1.add(menuItem);
			menuItem.addActionListener(dl);		
		}
		
		//分形
		JMenu menu2 = new JMenu("分形图案");
		jb.add(menu2);
		String[] arr2 = {"分形1","分形2","分形3","分形4"};
		for (int i=0;i<arr2.length;i++){
			JMenuItem menuItem2 = new JMenuItem(arr2[i]);
			menu2.add(menuItem2);
			menuItem2.addActionListener(dl);
		}
		
		//清屏
		JMenu menu3 = new JMenu("清屏");
		jb.add(menu3);
		JMenuItem menuItem = new JMenuItem("清屏");
		menu3.add(menuItem);
		menuItem.addActionListener(dl);
		
		//颜色按钮
		Color[] ColorBtn = {Color.BLUE,Color.cyan,Color.GRAY,Color.orange,Color.PINK,Color.YELLOW};
		Dimension ColorBtnSize = new Dimension(30,20);
		for(int i=0;i<ColorBtn.length;i++){
			JButton color = new JButton();
			color.setPreferredSize(ColorBtnSize);
			color.setBackground(ColorBtn[i]);
			jb.add(color);
			color.addActionListener(dl);
		}
		
		//增加滑杆
		
		
		//给窗体加监听器
		jf.addMouseListener(dl);
		jf.addMouseMotionListener(dl);
		
		//设置可见
		jf.setVisible(true);
		Graphics g = jf.getGraphics();
		
		dl.g = g;
		
	}

	public void paint (Graphics g){
		super.paint(g);
	}
	
	public static void main(String[] args){
		DrawUI ui = new DrawUI();
		ui.showUI();
	}
}

DrawListener

package drawing_board2;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

import javax.swing.JButton;

public class DrawListener implements MouseListener,ActionListener,MouseMotionListener{
	
	Graphics g;
	String type="";
	
	int x1,y1,x2,y2,x3,y3,x4,y4;
	
	public void setGraphics(Graphics arg){
		g=arg;
	}
	
	@Override
	public void actionPerformed(ActionEvent e) {
		// TODO Auto-generated method stub
		String action = e.getActionCommand();
		type=action;
		
		//调颜色
		if(action.equals("")){
			Object srcobj = e.getSource();
			JButton srcBtn = (JButton) srcobj;
			Color color = srcBtn.getBackground();
			g.setColor(color);
		}
		
	}

	@Override
	public void mouseClicked(MouseEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void mousePressed(MouseEvent e) {
		// TODO Auto-generated method stub
		x1=e.getX();
		y1=e.getY();
	}

	@Override
	public void mouseReleased(MouseEvent e) {
		// TODO Auto-generated method stub
		x2=e.getX();
		y2=e.getY();
		
	}

	@Override
	public void mouseEntered(MouseEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void mouseExited(MouseEvent e) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void mouseDragged(MouseEvent e) {
		// TODO Auto-generated method stub
		x3=e.getX();
		y3=e.getY();
		if("曲线".equals(type)){
			x3=e.getX();
			y3=e.getY();
			g.drawLine(x1, y1, x3, y3);
			x1=x3;
			y1=y3;
		}
	}

	@Override
	public void mouseMoved(MouseEvent e) {
		// TODO Auto-generated method stub
		
		if("直线".equals(type)){
			g.drawLine(x1,y1,x2,y2);
		}
		else if("椭圆".equals(type)){
			g.drawOval(Math.min(x1, x2),Math.min(y1, y2),Math.abs(x1-x2),Math.abs(y1-y2));
		}
		else if("矩形".equals(type)){
			g.drawRect(Math.min(x1, x2),Math.min(y1, y2),Math.abs(x1-x2),Math.abs(y1-y2));
		}
		else if("等腰三角形".equals(type)){
			g.drawLine(x1, y1, x2, y1);
			g.drawLine(x1, y1, (x1+x2)/2, y2);
			g.drawLine(x2, y1, (x1+x2)/2, y2);
		}
		//分形
		else if("分形1".equals(type)){
			double x = 0;
			double y = 0;
			double a= -1.8,b=-2.0,c=-0.5,d=-0.9;
			for(int i=0;i<25500;i++){
				double temx = Math.sin(a*y)+c*Math.cos(a*x);
				double temy = Math.sin(b*x)+d*Math.cos(b*y);
				int x1=(int)(temx*130+500);
				int y1=(int)(temy*130+400);
				
				g.drawLine(x1, y1, x1, y1);
				x=temx;
				y=temy;
			}}
		
		else if("分形2".equals(type)){
			for(int i=0;i<=180;i++){     
				for(int j=0;j<=180;j++){   
					double r=Math.PI/45*i*(1-Math.sin(Math.PI/45*j))*20;   
					double x=r*Math.cos(Math.PI/45*j)*Math.sin(Math.PI/45*i)+300;  
					double y=-r*Math.sin(Math.PI/45*j)+200;    
					Color c=Color.getHSBColor(i*j/8100.0f, 0.9999f,0.9999f);   
					g.setColor(c);      
					g.drawOval((int)(2*x/3+300), (int)(2*y/3+50), 1,1);   
//					try{    Thread.sleep(1);    
//					}
//					catch(Exception e1){}       
					}
			}}
		
		else if("分形3".equals(type)){
			double x = 0;
			double y = 0;
			double a= 1.7,b=1.7,c=0.6,d=1.2;
			for(int i=0;i<50000;i++){
				double temx = Math.sin(a*y)+c*Math.cos(a*x);
				double temy = Math.sin(b*x)+d*Math.cos(b*y);
				int x1=(int)(-temx*130+800);
				int y1=(int)(-temy*130+400);
				g.setColor(new Color(i/250,i/500,i/250));
				g.drawLine(x1, y1, x1, y1);
				x=temx;
				y=temy;
		}
		}
		
		else if ("清屏".equals(type)){
			g.clearRect(0, 70, 1800,900);
		}
	}
	}

在这里插入图片描述

drz_cs_dn

发布了45 篇原创文章 · 获赞 14 · 访问量 2495

私信关注

创建画布

加菜单栏

设置监听器

监听事件&颜色板

画曲线

猜你喜欢