Java如何實現簡單小畫板

今天小編給大家分享一下Java如何實現簡單小畫板的相關知識點，內容詳細，邏輯清晰，相信大部分人都還太了解這方面的知識，所以分享這篇文章給大家參考一下，希望大家閱讀完這篇文章后有所收獲，下面我們一起來了解一下吧。

Java制作簡單畫板，包括兩個類，一個主要畫板類Drawpad，一個畫板監聽器DrawListener類。

1、Drawpad類，包括畫板，畫板功能設計，保存圖片等

package Java課程設計;

import java.awt.Graphics;

import javax.imageio.ImageIO;
import javax.print.DocFlavor.STRING;
import javax.swing.ImageIcon;
import javax.swing.JDialog;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

import java.awt.AWTException;
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Shape;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;

import javax.swing.JButton;
import javax.swing.filechooser.FileNameExtensionFilter;
public class Drawpad {
     static Color color1;
public static void main(String[] args) {
    Drawpad dp = new Drawpad();
    dp.initUI();
     
}  
   //創建一個JFrame圖形窗口
    public void initUI() {
        JFrame jf = new JFrame();
        jf.setTitle("創意畫圖板(勿拖動)");
        jf.setSize(1500,1000);
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//關閉時退出
        jf.setLocationRelativeTo(null);//居中，不用定位窗口大小
        //創建字體，之后所有的字體為該字體
        Font f=new Font("方正仿宋簡體", Font.BOLD, 20);
        //創建畫筆監聽器
        DrawListener  dl = new DrawListener();
        //創建讀取圖片BufferedImage(將圖片加載到drawPanel面板中)和畫筆g，畫筆g為在保存圖片上進行圖畫。
                BufferedImage bi = new BufferedImage(1300,800, BufferedImage.TYPE_INT_ARGB);
                Graphics2D g = bi.createGraphics();
                //初始化時填充白色
                g.setColor(Color.WHITE);
                //先將圖片填充為白色
                g.fillRect(0, 0, 1300,800);
                
                
        //設置增加菜單欄，包括保存和新建兩個按鈕
        JMenuBar box=new JMenuBar();
        //在窗體上加菜單條,做一個菜單條,是菜單條，不是工具欄
        //創建menubtn1保存按鈕，并加上監聽器，以圖片的形式保存繪畫板上的內容
        JButton menubtn1=new JButton("保存");
        //為保存按鈕注冊監聽器
          menubtn1.addActionListener(new ActionListener(){
                 @Override
                 public void actionPerformed(ActionEvent arg0) {
                     //創建文件保存窗口
                     JFileChooser f=new JFileChooser("保存");
                     int returnVal = f.showSaveDialog(null);
                     
                    File    file1=null;
                    if(returnVal == JFileChooser.APPROVE_OPTION) {
                        file1 =f.getSelectedFile();
                        String name = f.getName(file1);
                        try {
                            
                            ImageIO.write(bi, "PNG", new File(f.getCurrentDirectory(),name+".png"));
                        } catch (IOException e) {
                            //需拋出異常
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }

                    }
                 }
              });
         /*JButton menubtn2=new JButton("打開");
          //為打開按鈕注冊監聽器
          menubtn1.addActionListener(new ActionListener(){
               @Override
               //獲取當前畫筆粗細
               public void actionPerformed(ActionEvent arg0) {
                   BufferedImage bimg = null;
                   JFileChooser f=new JFileChooser("打開");
                 int returnVal = f.showOpenDialog(null);
                 
                File    file1=null;
                if(returnVal == JFileChooser.APPROVE_OPTION) {
                    file1 =f.getSelectedFile();
                    String name = f.getName(file1);
                    try {
                      
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

                }
                   
                   
               }
            });*/
          
        //創建menubtn3退出按鈕，并加上監聽器，退出程序
          JButton menubtn3=new JButton("退出");
          menubtn3.addActionListener(new ActionListener(){
                   @Override
                   //獲取當前畫筆粗細
                   public void actionPerformed(ActionEvent arg0) {
                       int ret=JOptionPane.showConfirmDialog(null, "你確定要退出嗎", "確認退出", JOptionPane.YES_NO_OPTION);
                       if(ret==JOptionPane.YES_OPTION){
                           //“確認”退出程序
                           System.exit(0);
                       }
                   }
                });
          box.add(menubtn1);
         // box.add(menubtn2);
          box.add(menubtn3);
        //jf.setJMenuBar(box);
        
        jf.setJMenuBar(box);
        
        //jf用BorderLayout布局
        
        //北邊,畫板模式功能欄
        JPanel funcPanel=new JPanel();
        jf.add(funcPanel,BorderLayout.NORTH);
        
        //中間,畫布
        JPanel drawPanel=new JPanel();
        jf.add(drawPanel,BorderLayout.CENTER);
        drawPanel.setPreferredSize(new Dimension(1000,700));
        drawPanel.setBackground(dl.background);
        //一定要在畫布上加上監聽器!!1若畫布沒有加上監聽器，無法顯示
        drawPanel.addMouseListener(dl);
        drawPanel.addMouseMotionListener(dl);
        
        //南邊,為畫筆顏色選擇按鈕
        JPanel colorPanel=new JPanel();
        jf.add(colorPanel,BorderLayout.SOUTH);
        
        //右邊,為選擇背景顏色按鈕、畫筆粗細選擇按鈕
        JPanel backgroundPanel=new JPanel();
        jf.add(backgroundPanel,BorderLayout.EAST);
        backgroundPanel.setPreferredSize(new Dimension(150,1000));
        
        //左邊,獲取當前狀態如:背景顏色、畫筆顏色、畫筆性質
        JPanel nowPanel=new JPanel();
        jf.add(nowPanel,BorderLayout.WEST);
        nowPanel.setPreferredSize(new Dimension(180,1000));
        
        //左邊放入當前狀態Panel
        nowPanel.setBackground(Color.WHITE);
         JLabel label2=new JLabel("當前背景顏色");
          label2.setFont(f);
           nowPanel.add(label2);
           //放入當前背景顏色
           JButton nowbackgroundColor=new JButton();
           nowbackgroundColor.setPreferredSize(new Dimension(60,60));
           nowbackgroundColor.setBackground(Color.WHITE);//背景初始化為灰色
           nowPanel.add(nowbackgroundColor);
           //放入當前畫筆
           JLabel label3=new JLabel("請選擇畫筆模式");
              label3.setFont(f);
               nowPanel.add(label3);
           //放入當前畫筆顏色
           JButton nowColor=new JButton();
           nowColor.setPreferredSize(new Dimension(60,60));
           nowColor.setBackground(Color.BLACK);//畫筆顏色初始化為黑色色
           nowPanel.add(nowColor);
          
            //獲取當前畫筆模式
            JLabel label4=new JLabel("當前畫筆模式");
              label4.setFont(f);
               nowPanel.add(label4);
               JTextField text=new JTextField(dl.btncontent); //獲得選擇畫筆模式的按鈕內容，得到當前畫筆模式
               text.setPreferredSize(new Dimension (160,60));
               text.setFont(f);
               text.setEditable(false);  //不可改
            nowPanel.add(text);
            //獲取當前畫筆粗細狀態
            JLabel label6=new JLabel("當前畫筆粗細(中)");  //默認粗細為中
              label6.setFont(f);
               nowPanel.add(label6);
               JTextField text1=new JTextField("請選擇畫筆粗細");
               text1.setPreferredSize(new Dimension (160,60));
               text1.setFont(f);
               text1.setEditable(false); //不可編輯
            nowPanel.add(text1);
            //輸入需要添加的文字
            JLabel label7=new JLabel("請輸入文字:");
              label7.setFont(f);
               nowPanel.add(label7);
               JTextField text2=new JTextField();
               text2.setPreferredSize(new Dimension (160,60));
               text2.setFont(f);
               nowPanel.add(text2); 
               JLabel label8=new JLabel("請輸入文字樣式:");
                  label8.setFont(f);
                   nowPanel.add(label8);
                   JTextField text3=new JTextField("方正仿宋簡體");
                   text3.setPreferredSize(new Dimension (160,60));
                   text3.setFont(f);
                   nowPanel.add(text3);
                   JLabel label9=new JLabel("請輸入文字大小:");
                      label9.setFont(f);
                       nowPanel.add(label9);
                       JTextField text4=new JTextField("20");
                       text4.setPreferredSize(new Dimension (160,60));
                       text4.setFont(f);
                       nowPanel.add(text4);
            //為獲取文字內容加一個按鈕并加上監聽器
               JButton getcontent=new JButton("獲取文字");
               getcontent .setFont(f);
                getcontent.setBackground(Color.YELLOW);
                getcontent.addActionListener(new ActionListener(){
                    @Override
                    public void actionPerformed(ActionEvent e) {
                         String content=text2.getText();
                        String mode=text3.getText();
                        String size=text4.getText();
                        dl.mode=mode; //獲取文字樣式
                           dl.content=content; //獲取文字內容
                           dl.size=size; //獲取文字大小
                    }
                 });
                nowPanel.add(getcontent);
                
                //最后在當前狀態畫板中加一個清除畫布內容的功能
                JButton clear=new JButton("清除");
                  clear.setFont(f);
                    clear.setBackground(Color.RED);
                    clear.addActionListener(dl);
                    nowPanel.add(clear);
                    
        //添加按鈕到北邊（每個按鈕寫兩行代碼太多，通過數組方式添加按鈕）
                //加入標簽（選擇畫筆模式）
                JLabel labelh =new JLabel("選擇畫筆模式");
                labelh.setFont(f);
                funcPanel.add(labelh);
                //將按鈕名字保存在數組中，后依次存儲
        String[] btnstr= {"畫筆","直線","矩形","填充矩形","圓","填充圓","弧線","噴槍","波形","分形","長方體","九宮格遞歸","文字","橡皮"};
        //將畫筆狀態按鈕防置panel中
        for( int i=0;i<btnstr.length;i++) {
            JButton btn=new JButton(btnstr[i]);
            funcPanel.add(btn);
            btn .setFont(f);
            btn.setBackground(Color.white);
            //加上畫筆監聽器
            btn.addActionListener(dl);
            //加上監聽器：獲取當前 畫筆模式
            btn.addActionListener(new ActionListener(){
                @Override
                public void actionPerformed(ActionEvent e) {
                    text.setText(btn.getText()); //在當前模式加入選取的畫筆模式
                }
             });
            
        };
        
        //在BrderLayout布局SOUTH添加選擇顏色按鈕
        JLabel label =new JLabel("選擇畫筆(橡皮)顏色");
        label.setFont(f);
        colorPanel.add(label);
        
         //添加顏色按鈕
        Color[] colorArray = { Color.BLUE, Color.GREEN, Color.RED, 
                Color.BLACK,Color.ORANGE,Color.PINK,Color.CYAN,
                Color.MAGENTA,Color.DARK_GRAY,Color.GRAY,
                Color.LIGHT_GRAY,Color.YELLOW,Color.WHITE};
        
        //在布局管理器中添加顏色按鈕
        for( int i=0;i<colorArray.length;i++) {
            
            JButton button = new JButton();
            button.setBackground(colorArray[i]);
            button.setPreferredSize(new Dimension(50, 50));
            button.addActionListener(dl);
            colorPanel.add(button);
            //獲取當前狀態的畫筆顏色
            button.addActionListener(new ActionListener(){
                @Override
                public void actionPerformed(ActionEvent e) {
                    nowColor.setBackground(button.getBackground());  //在當前畫筆顏色按鈕加入選擇的按鈕顏色
                }
             });
        };
        
      funcPanel.setBackground(Color.gray);
      
      //添加背景主板顏色按鈕，并設置監聽器（背景顏色為按鈕顏色）
      JLabel label1=new JLabel("選擇背景顏色");
      label1.setFont(f);
       backgroundPanel.add(label1);
      Color[] backgroundArray= { Color.GREEN, Color.RED,
          Color.ORANGE,Color.PINK,Color.CYAN,
              Color.MAGENTA,Color.DARK_GRAY,Color.GRAY,
              Color.LIGHT_GRAY,Color.YELLOW,Color.WHITE,Color.BLACK};
      //將按鈕加入進去
      for( int i=0;i<backgroundArray.length;i++) {
            
          JButton button = new JButton();
          button.setBackground(backgroundArray[i]);
          button.setPreferredSize(new Dimension(50, 50));
          backgroundPanel.add(button);
          //添加監聽器，按下按鈕改變背景顏色，同時體現當前狀態
        button.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent arg0) {
                drawPanel.setBackground(button.getBackground()); //將背景顏色改為選取的背景顏色
                color1=button.getBackground();
                dl.background=color1;  //將背景顏色傳給DrawListener中的變量
                System.out.println(color1);
                g.setColor(color1);
                g.fillRect(0, 0, 1300,800);  //圖片畫筆填充背景顏色
                nowbackgroundColor.setBackground(button.getBackground());
            }
         });
        };
        
        //添加選擇畫筆粗細的按鈕,可選擇畫筆的粗細
        JLabel label5=new JLabel("選擇畫筆粗細");
          label5.setFont(f);
           backgroundPanel.add(label5);
           String[] Size={"細","中","粗"};
           //選擇畫筆模式的按鈕
           for(int i=0;i<3;i++){
               JButton graphsize=new JButton(Size[i]);
               graphsize.setFont(new Font("宋體", Font.BOLD, 15));
               graphsize.setBackground(Color.WHITE);
               graphsize.setPreferredSize(new Dimension(50, 50));
               backgroundPanel.add(graphsize);
               graphsize.addActionListener(dl);
               graphsize.addActionListener(new ActionListener(){
                   @Override
                   //獲取當前畫筆粗細
                   public void actionPerformed(ActionEvent e) {
                       text1.setText(graphsize.getText()); //獲取當前畫筆模式
                   }
                });
           }
        jf.setVisible(true);
        // 獲取這個界面的ｇｒａｐｈｉｃｓ屬性, 畫筆 g
        //Graphics2D g = (Graphics2D) drawPanel.getGraphics();
        //drawPanel.paintComponent(g);
         Graphics2D g1= (Graphics2D) drawPanel.getGraphics();
        
        //為畫筆添加監聽器
        drawPanel.addMouseListener(dl);
        dl.g =  g1;// 右傳左 
        dl.g3 = g;// 右傳左
        
    }
}

2、DrawListner類，畫板功能監聽器

package Java課程設計;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseMotionListener;
import java.awt.geom.AffineTransform;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

import java.awt.Color;
import java.util.ArrayList;
import java.util.Random;

import Java課程設計.Drawpad;
public class DrawListener implements MouseListener,ActionListener,MouseMotionListener {
    //獲取畫筆
    Graphics2D g;
    //獲取在保存圖片上的畫筆
        Graphics2D g3;
    //獲取按鈕內容
    String btnstr;
    Color background=Color.white; //背景顏色默認為白色
    Color graphcolor=Color.BLACK; //畫筆顏色默認為黑色
    JButton btn;
    int x1, y1, x2, y2;// 聲明坐標變量 
    int x3=400;
    int y3=0;
    int graphsize=3;//默認為中等畫筆
    String btncontent="畫筆"; //默認畫筆模式為畫筆
    String content;  //獲取文字中的文字內容
    String mode="方正仿宋簡體";  //文字樣式默認為“方正仿宋簡體”
    String size="20";
    
    //九宮格遞歸方法,畫出九宮格
    public void dg(int x,int y,int width,int height) {
        //九宮格函數，九宮格的實現
         if(width<3) {
                return;
                }
        if(width>90) {
        g.fillRect(x+width/3, y+height/3, width/3, height/3);
        g3.fillRect(x+width/3, y+height/3, width/3, height/3);
        dg(x, y, width/3, height/3);
        dg(x+width/3, y, width/3, height/3);
        dg(x+(width/3)*2, y, width/3, height/3);
        dg(x, y+height/3, width/3, height/3);
        dg(x, y+(height/3)*2, width/3, height/3);
        
        dg(x+width/3, y+height/3, width/3, height/3);
        dg(x+width/3, y+(height/3)*2, width/3, height/3);
        
        dg(x+(width/3)*2, y+height/3, width/3, height/3);
        dg(x+(width/3)*2, y+(height/3)*2, width/3, height/3);
        
        }
      //九宮格的實現
       else {
           g.drawOval(x+width/3, y+height/3, width/3, height/3);
           g3.drawOval(x+width/3, y+height/3, width/3, height/3);
           dg(x, y, width/3, height/3);
           dg(x+width/3, y, width/3, height/3);
            dg(x+(width/3)*2, y, width/3, height/3);
            dg(x, y+height/3, width/3, height/3);
            dg(x, y+(height/3)*2, width/3, height/3);
            
            dg(x+width/3, y+height/3, width/3, height/3);
            dg(x+width/3, y+(height/3)*2, width/3, height/3);
            
            dg(x+(width/3)*2, y+height/3, width/3, height/3);
            dg(x+(width/3)*2, y+(height/3)*2, width/3, height/3);
       }    
    
    }
    //判斷是顏色按鈕還是畫筆按鈕,改變的全部是畫筆按鈕
    public void actionPerformed(ActionEvent e) {
        btnstr=e.getActionCommand();  //獲取按鈕的文字內容
        //g.setColor(Color.black);
        //如果為顏色按鈕，將畫筆改顏色
        if(btnstr.equals("清除")){
            //重新填充背景，同時將畫筆置為背景顏色
             System.out.println(background);
            g.setColor(background);//保存圖片畫筆填充背景顏色
            g.fillRect(0, 0, 1300, 800);
            g3.setColor(background);//畫筆重新填充背景
            g3.fillRect(0, 0, 1300, 800);
            g.setColor(graphcolor);
            g3.setColor(graphcolor);
        }
        else{
        if(btnstr.equals("")) {
            //獲取點擊內容,將其內容強制轉換成JButton
           btn=(JButton) e.getSource();
            //獲取顏色按鈕顏色
           graphcolor=btn.getBackground();
            
        }
        //若為畫筆粗細，獲取粗細大小
        else if(btnstr.equals("細")){
            graphsize=1;  //畫筆大小為細，大小size為1
        }
        else if(btnstr.equals("中")){
            graphsize=3;
        }
        else if(btnstr.equals("粗")){
            graphsize=5;
        }
        else{
            btncontent=btnstr; //獲取畫筆模式按鈕的內容
        }
        }
    }
    //鼠標點擊方法
    @Override
    public void mouseClicked(MouseEvent e) {
        System.out.println("點擊");
    }
   //鼠標按下方法
    @Override
    public void mousePressed(MouseEvent e) {
        System.out.println("按下");
        x1=e.getX();
        y1 =e.getY();
    }
    //重寫鼠標釋放時的方法
    @Override
    public void mouseReleased(MouseEvent e) {
        g.setColor(graphcolor);//獲取保存畫筆的顏色
        g3.setColor(graphcolor); //獲取畫板畫筆的顏色
        
        x2=e.getX();
        y2 =e.getY();
        //選取畫筆模式為直線時
        if(btncontent.equals("直線")) {
            g.setStroke(new BasicStroke(graphsize)); //保存畫筆進行畫圖
        g.drawLine(x1, y1, x2, y2);//畫筆畫直線
        g3.setStroke(new BasicStroke(graphsize));//置畫筆大小
        g3.drawLine(x1, y1, x2, y2);
        }
        //選取畫筆模式為波形時
        else if(btncontent.equals("波形")) {
            //波形函數
            g.setStroke(new BasicStroke(graphsize)); //置畫筆大小
            g3.setStroke(new BasicStroke(graphsize));
            double x4 = 0,y4 = 0;
            double a2=1.40,b2=1.56,c2=1.40,d2=-6.56;
            //波形函數
            for(int i=0;i<5000;i++) {
                double x5=Math.sin(a2*x4)-Math.cos(b2*y4);
                double y5=Math.sin(c2*x4)-Math.cos(d2*y4);
                x4=x5;
                y4=y5;
                int px=(int)(x5*100+x1);
                int py=(int)(y5*100+y1);
                //畫波形
                g.drawLine(px, py, px, py);
                g3.drawLine(px, py, px, py);
                }
        }
        //選取畫筆模式為矩形時
        else if(btncontent.equals("矩形")) {
            g.setStroke(new BasicStroke(graphsize)); //獲取矩形畫筆的大小
            g.drawRect(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2-x1), Math.abs(y2-y1));//畫矩形
            g3.setStroke(new BasicStroke(graphsize)); 
            g3.drawRect(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2-x1), Math.abs(y2-y1));
        }
        //選取的畫筆模式為填充矩形
        else if(btncontent.equals("填充矩形")){
            //畫填充矩形
            g.fillRect(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2-x1), Math.abs(y2-y1));
            g3.fillRect(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2-x1), Math.abs(y2-y1));
        }
        //長方體函數
        else if(btncontent.equals("長方體")){
            g.setStroke(new BasicStroke(graphsize));//獲取長方體畫筆大小
             g.setColor(btn.getBackground());//將畫筆顏色置選擇畫筆顏色按鈕顏色
             //長方體函數
                g.fillRect(Math.min(x1,x2),Math.min(y1,y2),Math.abs(x1-x2),Math.abs(y1-y2));
                g3.setStroke(new BasicStroke(graphsize));
                 g3.setColor(btn.getBackground());
                    g3.fillRect(Math.min(x1,x2),Math.min(y1,y2),Math.abs(x1-x2),Math.abs(y1-y2));
                int a,b,c,d;
                a=Math.min(x1, x2);
                b=Math.max(x1, x2);
                c=Math.min(y1, y2);
                d=Math.max(y1, y2);

                int m=(int)((b-a)*Math.cos(Math.PI/4)*Math.sin(Math.PI/4));
                int n=(int)((b-a)*Math.cos(Math.PI/4)*Math.sin(Math.PI/4));
                //頂面
                g.setColor(btn.getBackground());
                g.fillPolygon(new int[] {a, a+m, b+m,b},new int[] {c,c-n,c-n,c},4);
                //右側面
                g.setColor(btn.getBackground());
                g.fillPolygon(new int[] {b, b, b+m,b+m},new int[] {c,d,d-n,c-n},4);
                g3.setColor(btn.getBackground());
                g3.fillPolygon(new int[] {a, a+m, b+m,b},new int[] {c,c-n,c-n,c},4);
                //右側面
                g3.setColor(btn.getBackground());
                g3.fillPolygon(new int[] {b, b, b+m,b+m},new int[] {c,d,d-n,c-n},4);
        }
        //分形函數
        else if(btncontent.equals("分形")){
            g.setStroke(new BasicStroke(graphsize));  //獲取畫筆大小
            g3.setStroke(new BasicStroke(graphsize));
            double x = 0,y = 0;
            //分形函數實現
            double a1=-1.8,b=-2.0,c=-0.5,d=-0.9;
            for(int i=0;i<5000;i++) {
            double x3=Math.sin(a1*y)-c*Math.cos(a1*x);
            double y3=Math.sin(b*x)-d*Math.cos(b*y);
            x=x3;
            y=y3;
            int px=(int)(x3*100+x1);
            int py=(int)(y3*100+y1);
            g.drawLine(px, py, px, py);
            g3.drawLine(px, py, px, py);
        }
        }
        //畫圓
        else if(btncontent.equals("圓")) {
            g.setStroke(new BasicStroke(graphsize));//獲取畫筆大小
            g.drawOval(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2-x1), Math.abs(y2-y1));//畫圓
            g3.setStroke(new BasicStroke(graphsize));
            g3.drawOval(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2-x1), Math.abs(y2-y1));
        }
        //畫填充圓
        else if(btncontent.equals("填充圓")){
            g.fillOval(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2-x1), Math.abs(y2-y1));//畫填充圓
            g3.fillOval(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2-x1), Math.abs(y2-y1));
        }
        //當選取模式為文字
        else if(btncontent.equals("文字")){
            //獲取畫筆大小
            g.setStroke(new BasicStroke(15));
        Font font = new Font(mode, Font.BOLD, Integer.parseInt(size)); //獲得文字內容，文字大小，文字樣式    
         g.setFont(font); //在畫筆中置文字樣式和大小
            g.drawString(content, x1, y1); //寫上文字內容
            g3.setStroke(new BasicStroke(15));
             g3.setFont(font);//放入文字樣式和大小
            g3.drawString(content, x1, y1);
        }
        //當畫筆模式為弧線時
        else if(btncontent.equals("弧線")){
            g.setStroke(new BasicStroke(graphsize));//獲取畫筆大小
            //弧線函數
             g.drawArc(x1, y1, 100, 60, 0, 180);
             g3.setStroke(new BasicStroke(graphsize));
             g3.drawArc(x1, y1, 100, 60, 0, 180);
        }
        //九宮格遞歸，調用九宮格函數
        else if(btncontent.equals("九宮格遞歸")) {
            //九宮格遞歸實現
              dg(0,50,600,600);
          }
        System.out.println("釋放");
        
    }
    @Override
    //鼠標進入方法
    public void mouseEntered(MouseEvent e) {
        System.out.println("進入");
    }

    @Override
    //鼠標離開界面方法
    public void mouseExited(MouseEvent e) {
        System.out.println("離開");
    }
    @Override
    public void mouseMoved(MouseEvent e) {
        
    }
    //重寫鼠標移動函數
    @Override
    public void mouseDragged(MouseEvent e) {
        g.setColor(graphcolor); //獲取畫筆顏色
        g3.setColor(graphcolor);
        // TODO Auto-generated method stub
        x2=e.getX();
        y2 =e.getY();
        //當為畫筆時
        if(btncontent.equals("畫筆")){
            
        g.setStroke(new BasicStroke(graphsize));    //獲取當前畫筆大小        
        //畫筆實現
                g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                g.drawLine(x1, y1, x2, y2);
                g3.setStroke(new BasicStroke(graphsize));            
                g3.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                g3.drawLine(x1, y1, x2, y2);
                x1 = x2;
                y1 = y2;
                }
        //橡皮擦
         if(btncontent.equals("橡皮")){
             //將畫筆顏色置為背景顏色
             g.setColor(background);
             g3.setColor(background);
            g.setStroke(new BasicStroke(30));    //將橡皮擦的大小置大小為30                        
            g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g.drawLine(x1, y1, x2, y2);
            
            g3.setStroke(new BasicStroke(30));                            
            g3.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g3.drawLine(x1, y1, x2, y2);
            x1 = x2;
            y1 = y2;   
            //使用過后，將畫筆顏色重新置為原來顏色
            g.setColor(graphcolor);
            g3.setColor(graphcolor);
        }
         //噴槍函數
         
        else if(btncontent.equals("噴槍")){
                g.setStroke(new BasicStroke(graphsize));      //不用加粗，獲取畫筆大小                        
                g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                g3.setStroke(new BasicStroke(graphsize));      //不用加粗                        
                g3.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                //噴槍實現函數
                for(int k=0;k<20;k++){
                    Random i=new Random();       
                    int a=i.nextInt(10);
                    int b=i.nextInt(20);
                    g.drawLine(x2+a, y2+b, x2+a, y2+b);
                    g3.drawLine(x2+a, y2+b, x2+a, y2+b);
        }
        }
        
    }


}

畫板演示:

保存圖片:

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