一个用JAVA写的画图程序

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转载最新推荐文章于 2026-05-24 16:44:17 发布 2.4w 阅读 AI 写同款· GEO 优化 ›
Java绘图执行图像从源到目标的缩放，要将源矩形的第一个坐标映射到目标矩形的第一个坐标，源矩形的第二个坐标映射到目标矩形的第二个坐标，按需要缩放和翻转子图像，以保持这些映射关系。默认情况下，Graphics类使用的画笔属性是粗细为1个像素的正方形，而Graphics2D类可以调用setStroke()方法设置画笔的属性，如改变线条的粗细、虚实，定义线段端点的形状，风格等。使用Color类可以创建任意颜色的对象，不用担心平台是否支持该颜色，因为Java是以跨平台和与硬件无关的方式支持对颜色的管理。阅读详情
功能类似WINDOWS的画图程序，代码比较规范。对于刚刚接触图形界面开发的人很有帮助。（对我帮助也很大）
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
//定义画图的基本图形单元
public class MiniDrawPad extends JFrame //主类，扩展了JFrame类，用来生成主界面
{
    private ObjectInputStream input;
    private ObjectOutputStream output; //定义输入输出流，用来调用和保存图像文件
    private JButton choices[];         //按钮数组，存放以下名称的功能按钮
    private String names[] = {
        "New",
        "Open",
        "Save", //这三个是基本操作按钮，包括"新建"、"打开"、"保存"
        /*接下来是我们的画图板上面有的基本的几个绘图单元按钮*/
        "Pencil", //铅笔画，也就是用鼠标拖动着随意绘图
        "Line", //绘制直线
        "Rect", //绘制空心矩形
        "fRect", //绘制以指定颜色填充的实心矩形
        "Oval", //绘制空心椭圆
        "fOval", //绘制以指定颜色填充的实心椭圆
        "Circle", //绘制圆形
        "fCircle", //绘制以指定颜色填充的实心圆形
        "RoundRect", //绘制空心圆角矩形
        "frRect", //绘制以指定颜色填充的实心圆角矩形
        "Rubber", //橡皮擦，可用来擦去已经绘制好的图案
        "Color", //选择颜色按钮，可用来选择需要的颜色
        "Stroke", //选择线条粗细的按钮，输入需要的数值可以实现绘图线条粗细的变化
        "Word"      //输入文字按钮，可以在绘图板上实现文字输入
    };
    private String styleNames[] = {
        " 宋体 ", " 隶书 ", " 华文彩云 ", " 仿宋_GB2312 ", " 华文行楷 ",
        " 方正舒体 ", " Times New Roman ", " Serif ", " Monospaced ",
        " SonsSerif ", " Garamond "
    };            //可供选择的字体项
    //当然这里的灵活的结构可以让读者自己随意添加系统支持的字体
    private Icon items[];
    private String tipText[] = {
        //这里是鼠标移动到相应按钮上面上停留时给出的提示说明条
        //读者可以参照上面的按钮定义对照着理解
        "Draw a new picture",
        "Open a saved picture",
        "Save current drawing",
        "Draw at will",
        "Draw a straight line",
        "Draw a rectangle",
        "Fill a ractangle",
        "Draw an oval",
        "Fill an oval",
        "Draw a circle",
        "Fill a circle",
        "Draw a round rectangle",
        "Fill a round rectangle",
        "Erase at will",
        "Choose current drawing color",
        "Set current drawing stroke",
        "Write down what u want"
    };
    JToolBar buttonPanel;              //定义按钮面板
    private JLabel statusBar;            //显示鼠标状态的提示条
    private DrawPanel drawingArea;       //画图区域
    private int width = 800,  height = 550;    //定义画图区域初始大小
    drawings[] itemList = new drawings[5000]; //用来存放基本图形的数组
    private int currentChoice = 3;            //设置默认画图状态为随笔画
    int index = 0;                         //当前已经绘制的图形数目
    private Color color = Color.black;     //当前画笔颜色
    int R, G, B;                           //用来存放当前色彩值
    int f1, f2;                  //用来存放当前字体风格
    String style1;              //用来存放当前字体
    private float stroke = 1.0f;  //设置画笔粗细，默认值为1.0f
    JCheckBox bold, italic;      //定义字体风格选择框
    //bold为粗体，italic为斜体，二者可以同时使用
    JComboBox styles;
    public MiniDrawPad() //构造函数
    {
        super("Drawing Pad");
        JMenuBar bar = new JMenuBar();      //定义菜单条
        JMenu fileMenu = new JMenu("File");
        fileMenu.setMnemonic('F');
//新建文件菜单条
        JMenuItem newItem = new JMenuItem("New");
        newItem.setMnemonic('N');
        newItem.addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        newFile();      //如果被触发，则调用新建文件函数段
                    }
                });
        fileMenu.add(newItem);
//保存文件菜单项
        JMenuItem saveItem = new JMenuItem("Save");
        saveItem.setMnemonic('S');
        saveItem.addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        saveFile();     //如果被触发，则调用保存文件函数段
                    }
                });
        fileMenu.add(saveItem);
//打开文件菜单项
        JMenuItem loadItem = new JMenuItem("Load");
        loadItem.setMnemonic('L');
        loadItem.addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        loadFile();     //如果被触发，则调用打开文件函数段
                    }
                });
        fileMenu.add(loadItem);
        fileMenu.addSeparator();
//退出菜单项
        JMenuItem exitItem = new JMenuItem("Exit");
        exitItem.setMnemonic('X');
        exitItem.addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        System.exit(0); //如果被触发，则退出画图板程序
                    }
                });
        fileMenu.add(exitItem);
        bar.add(fileMenu);
//设置颜色菜单条
        JMenu colorMenu = new JMenu("Color");
        colorMenu.setMnemonic('C');
//选择颜色菜单项
        JMenuItem colorItem = new JMenuItem("Choose Color");
        colorItem.setMnemonic('O');
        colorItem.addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        chooseColor();  //如果被触发，则调用选择颜色函数段
                    }
                });
        colorMenu.add(colorItem);
        bar.add(colorMenu);
//设置线条粗细菜单条
        JMenu strokeMenu = new JMenu("Stroke");
        strokeMenu.setMnemonic('S');
//设置线条粗细菜单项
        JMenuItem strokeItem = new JMenuItem("Set Stroke");
        strokeItem.setMnemonic('K');
        strokeItem.addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        setStroke();
                    }
                });
        strokeMenu.add(strokeItem);
        bar.add(strokeMenu);
//设置提示菜单条
        JMenu helpMenu = new JMenu("Help");
        helpMenu.setMnemonic('H');
//设置提示菜单项
        JMenuItem aboutItem = new JMenuItem("About this Drawing Pad!");
        aboutItem.setMnemonic('A');
        aboutItem.addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        JOptionPane.showMessageDialog(null,
                                "This is a mini drawing pad!/nCopyright (c) 2002 Tsinghua University ",
                                " 画图板程序说明 ",
                                JOptionPane.INFORMATION_MESSAGE);
                    }
                });
        helpMenu.add(aboutItem);
        bar.add(helpMenu);
        items = new ImageIcon[names.length];
//创建各种基本图形的按钮
        drawingArea = new DrawPanel();
        choices = new JButton[names.length];
        buttonPanel = new JToolBar(JToolBar.VERTICAL);
        buttonPanel = new JToolBar(JToolBar.HORIZONTAL);
        ButtonHandler handler = new ButtonHandler();
        ButtonHandler1 handler1 = new ButtonHandler1();
//导入我们需要的图形图标，这些图标都存放在与源文件相同的目录下面
        for (int i = 0; i < choices.length; i++) {//items[i]=new ImageIcon( MiniDrawPad.class.getResource(names[i] +".gif"));
            //如果在jbuilder下运行本程序，则应该用这条语句导入图片
            items[i] = new ImageIcon(names[i] + ".gif");
            //默认的在jdk或者jcreator下运行，用此语句导入图片
            choices[i] = new JButton("", items[i]);
            choices[i].setToolTipText(tipText[i]);
            buttonPanel.add(choices[i]);
        }
//将动作侦听器加入按钮里面
        for (int i = 3; i < choices.length - 3; i++) {
            choices[i].addActionListener(handler);
        }
        choices[0].addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        newFile();
                    }
                });
        choices[1].addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        loadFile();
                    }
                });
        choices[2].addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                        saveFile();
                    }
                });
        choices[choices.length - 3].addActionListener(handler1);
        choices[choices.length - 2].addActionListener(handler1);
        choices[choices.length - 1].addActionListener(handler1);
//字体风格选择
        styles = new JComboBox(styleNames);
        styles.setMaximumRowCount(8);
        styles.addItemListener(
                new ItemListener() {
                    public void itemStateChanged(ItemEvent e) {
                        style1 = styleNames[styles.getSelectedIndex()];
                    }
                });
//字体选择
        bold = new JCheckBox("BOLD");
        italic = new JCheckBox("ITALIC");
        checkBoxHandler cHandler = new checkBoxHandler();
        bold.addItemListener(cHandler);
        italic.addItemListener(cHandler);
        JPanel wordPanel = new JPanel();
        buttonPanel.add(bold);
        buttonPanel.add(italic);
        buttonPanel.add(styles);
        styles.setMinimumSize(new Dimension(50, 20));
        styles.setMaximumSize(new Dimension(100, 20));
        Container c = getContentPane();
        super.setJMenuBar(bar);
        c.add(buttonPanel, BorderLayout.NORTH);
        c.add(drawingArea, BorderLayout.CENTER);
        statusBar = new JLabel();
        c.add(statusBar, BorderLayout.SOUTH);
        statusBar.setText("     Welcome To The Little Drawing Pad!!!  :)");
        createNewItem();
        setSize(width, height);
        show();
    }
//按钮侦听器ButtonHanler类，内部类，用来侦听基本按钮的操作
    public class ButtonHandler implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            for (int j = 3; j < choices.length - 3; j++) {
                if (e.getSource() == choices[j]) {
                    currentChoice = j;
                    createNewItem();
                    repaint();
                }
            }
        }
    }
//按钮侦听器ButtonHanler1类，用来侦听颜色选择、画笔粗细设置、文字输入按钮的操作
    public class ButtonHandler1 implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if (e.getSource() == choices[choices.length - 3]) {
                chooseColor();
            }
            if (e.getSource() == choices[choices.length - 2]) {
                setStroke();
            }
            if (e.getSource() == choices[choices.length - 1]) {
                JOptionPane.showMessageDialog(null,
                        "Please hit the drawing pad to choose the word input position",
                        "Hint", JOptionPane.INFORMATION_MESSAGE);
                currentChoice = 14;
                createNewItem();
                repaint();
            }
        }
    }
//鼠标事件mouseA类，继承了MouseAdapter，用来完成鼠标相应事件操作
    class mouseA extends MouseAdapter {
        public void mousePressed(MouseEvent e) {
            statusBar.setText("     Mouse Pressed @:[" + e.getX() +
                    ", " + e.getY() + "]");//设置状态提示
            itemList[index].x1 = itemList[index].x2 = e.getX();
            itemList[index].y1 = itemList[index].y2 = e.getY();
            //如果当前选择的图形是随笔画或者橡皮擦，则进行下面的操作
            if (currentChoice == 3 || currentChoice == 13) {
                itemList[index].x1 = itemList[index].x2 = e.getX();
                itemList[index].y1 = itemList[index].y2 = e.getY();
                index++;
                createNewItem();
            }
            //如果当前选择的图形式文字输入，则进行下面操作
            if (currentChoice == 14) {
                itemList[index].x1 = e.getX();
                itemList[index].y1 = e.getY();
                String input;
                input = JOptionPane.showInputDialog(
                        "Please input the text you want!");
                itemList[index].s1 = input;
                itemList[index].x2 = f1;
                itemList[index].y2 = f2;
                itemList[index].s2 = style1;
                index++;
                currentChoice = 14;
                createNewItem();
                drawingArea.repaint();
            }
        }
        public void mouseReleased(MouseEvent e) {
            statusBar.setText("     Mouse Released @:[" + e.getX() +
                    ", " + e.getY() + "]");
            if (currentChoice == 3 || currentChoice == 13) {
                itemList[index].x1 = e.getX();
                itemList[index].y1 = e.getY();
            }
            itemList[index].x2 = e.getX();
            itemList[index].y2 = e.getY();
            repaint();
            index++;
            createNewItem();
        }
        public void mouseEntered(MouseEvent e) {
            statusBar.setText("     Mouse Entered @:[" + e.getX() +
                    ", " + e.getY() + "]");
        }
        public void mouseExited(MouseEvent e) {
            statusBar.setText("     Mouse Exited @:[" + e.getX() +
                    ", " + e.getY() + "]");
        }
    }
//鼠标事件mouseB类继承了MouseMotionAdapter，用来完成鼠标拖动和鼠标移动时的相应操作
    class mouseB extends MouseMotionAdapter {
        public void mouseDragged(MouseEvent e) {
            statusBar.setText("     Mouse Dragged @:[" + e.getX() +
                    ", " + e.getY() + "]");
            if (currentChoice == 3 || currentChoice == 13) {
                itemList[index - 1].x1 = itemList[index].x2 = itemList[index].x1 = e.getX();
                itemList[index - 1].y1 = itemList[index].y2 = itemList[index].y1 = e.getY();
                index++;
                createNewItem();
            } else {
                itemList[index].x2 = e.getX();
                itemList[index].y2 = e.getY();
            }
            repaint();
        }
        public void mouseMoved(MouseEvent e) {
            statusBar.setText("     Mouse Moved @:[" + e.getX() +
                    ", " + e.getY() + "]");
        }
    }
//选择字体风格时候用到的事件侦听器类，加入到字体风格的选择框中
    private class checkBoxHandler implements ItemListener {
        public void itemStateChanged(ItemEvent e) {
            if (e.getSource() == bold) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    f1 = Font.BOLD;
                } else {
                    f1 = Font.PLAIN;
                }
            }
            if (e.getSource() == italic) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    f2 = Font.ITALIC;
                } else {
                    f2 = Font.PLAIN;
                }
            }
        }
    }
//画图面板类，用来画图
    class DrawPanel extends JPanel {
        public DrawPanel() {
            setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
            setBackground(Color.white);
            addMouseListener(new mouseA());
            addMouseMotionListener(new mouseB());
        }
        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g;    //定义画笔
            int j = 0;
            while (j <= index) {
                draw(g2d, itemList[j]);
                j++;
            }
        }
        void draw(Graphics2D g2d, drawings i) {
            i.draw(g2d);//将画笔传入到各个子类中，用来完成各自的绘图
        }
    }
//新建一个画图基本单元对象的程序段
    void createNewItem() {
        if (currentChoice == 14)//进行相应的游标设置
        {
            drawingArea.setCursor(Cursor.getPredefinedCursor(Cursor.TEXT_CURSOR));
        } else {
            drawingArea.setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
        }
        switch (currentChoice) {
            case 3:
                itemList[index] = new Pencil();
                break;
            case 4:
                itemList[index] = new Line();
                break;
            case 5:
                itemList[index] = new Rect();
                break;
            case 6:
                itemList[index] = new fillRect();
                break;
            case 7:
                itemList[index] = new Oval();
                break;
            case 8:
                itemList[index] = new fillOval();
                break;
            case 9:
                itemList[index] = new Circle();
                break;
            case 10:
                itemList[index] = new fillCircle();
                break;
            case 11:
                itemList[index] = new RoundRect();
                break;
            case 12:
                itemList[index] = new fillRoundRect();
                break;
            case 13:
                itemList[index] = new Rubber();
                break;
            case 14:
                itemList[index] = new Word();
                break;
        }
        itemList[index].type = currentChoice;
        itemList[index].R = R;
        itemList[index].G = G;
        itemList[index].B = B;
        itemList[index].stroke = stroke;
    }
//选择当前颜色程序段
    public void chooseColor() {
        color = JColorChooser.showDialog(MiniDrawPad.this,
                "Choose a color", color);
        R = color.getRed();
        G = color.getGreen();
        B = color.getBlue();
        itemList[index].R = R;
        itemList[index].G = G;
        itemList[index].B = B;
    }
//选择当前线条粗细程序段
    public void setStroke() {
        String input;
        input = JOptionPane.showInputDialog(
                "Please input a float stroke value! ( >0 )");
        stroke = Float.parseFloat(input);
        itemList[index].stroke = stroke;
    }
//保存图形文件程序段
    public void saveFile() {
        JFileChooser fileChooser = new JFileChooser();
        fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
        int result = fileChooser.showSaveDialog(this);
        if (result == JFileChooser.CANCEL_OPTION) {
            return;
        }
        File fileName = fileChooser.getSelectedFile();
        fileName.canWrite();
        if (fileName == null || fileName.getName().equals("")) {
            JOptionPane.showMessageDialog(fileChooser, "Invalid File Name",
                    "Invalid File Name", JOptionPane.ERROR_MESSAGE);
        } else {
            try {
                fileName.delete();
                FileOutputStream fos = new FileOutputStream(fileName);
                output = new ObjectOutputStream(fos);
                drawings record;
                output.writeInt(index);
                for (int i = 0; i < index; i++) {
                    drawings p = itemList[i];
                    output.writeObject(p);
                    output.flush();    //将所有图形信息强制转换成父类线性化存储到文件中
                }
                output.close();
                fos.close();
            } catch (IOException ioe) {
                ioe.printStackTrace();
            }
        }
    }
//打开一个图形文件程序段
    public void loadFile() {
        JFileChooser fileChooser = new JFileChooser();
        fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
        int result = fileChooser.showOpenDialog(this);
        if (result == JFileChooser.CANCEL_OPTION) {
            return;
        }
        File fileName = fileChooser.getSelectedFile();
        fileName.canRead();
        if (fileName == null || fileName.getName().equals("")) {
            JOptionPane.showMessageDialog(fileChooser, "Invalid File Name",
                    "Invalid File Name", JOptionPane.ERROR_MESSAGE);
        } else {
            try {
                FileInputStream fis = new FileInputStream(fileName);
                input = new ObjectInputStream(fis);
                drawings inputRecord;
                int countNumber = 0;
                countNumber = input.readInt();
                for (index = 0; index < countNumber; index++) {
                    inputRecord = (drawings) input.readObject();
                    itemList[index] = inputRecord;
                }
                createNewItem();
                input.close();
                repaint();
            } catch (EOFException endofFileException) {
                JOptionPane.showMessageDialog(this, "no more record in file",
                        "class not found", JOptionPane.ERROR_MESSAGE);
            } catch (ClassNotFoundException classNotFoundException) {
                JOptionPane.showMessageDialog(this, "Unable to Create Object",
                        "end of file", JOptionPane.ERROR_MESSAGE);
            } catch (IOException ioException) {
                JOptionPane.showMessageDialog(this, "error during read from file",
                        "read Error", JOptionPane.ERROR_MESSAGE);
            }
        }
    }
//新建一个文件程序段
    public void newFile() {
        index = 0;
        currentChoice = 3;
        color = Color.black;
        stroke = 1.0f;
        createNewItem();
        repaint();//将有关值设置为初始状态，并且重画
    }
//主函数段
    public static void main(String args[]) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception e) {
        }//将界面设置为当前windows风格
        MiniDrawPad newPad = new MiniDrawPad();
        newPad.addWindowListener(
                new WindowAdapter() {
                    public void windowClosing(WindowEvent e) {
                        System.exit(0);
                    }
                });
    }
}
class drawings implements Serializable//父类，基本图形单元，用到串行化接口，保存时所用
{
    int x1, y1, x2, y2; //定义坐标属性
    int R, G, B;        //定义色彩属性
    float stroke;       //定义线条粗细属性
    int type;       //定义字体属性
    String s1;
    String s2;      //定义字体风格属性
    void draw(Graphics2D g2d) {
    }
    ;//定义绘图函数
}
/*******************************************************************************
下面是各种基本图形单元的子类，都继承自父类drawings，请仔细理解继承的概念
 ********************************************************************************/
class Line extends drawings //直线类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke,
                BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL));
        g2d.drawLine(x1, y1, x2, y2);
    }
}
class Rect extends drawings//矩形类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke));
        g2d.drawRect(Math.min(x1, x2), Math.min(y1, y2),
                Math.abs(x1 - x2), Math.abs(y1 - y2));
    }
}
class fillRect extends drawings//实心矩形类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke));
        g2d.fillRect(Math.min(x1, x2), Math.min(y1, y2),
                Math.abs(x1 - x2), Math.abs(y1 - y2));
    }
}
class Oval extends drawings//椭圆类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke));
        g2d.drawOval(Math.min(x1, x2), Math.min(y1, y2),
                Math.abs(x1 - x2), Math.abs(y1 - y2));
    }
}
class fillOval extends drawings//实心椭圆
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke));
        g2d.fillOval(Math.min(x1, x2), Math.min(y1, y2),
                Math.abs(x1 - x2), Math.abs(y1 - y2));
    }
}
class Circle extends drawings//圆类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke));
        g2d.drawOval(Math.min(x1, x2), Math.min(y1, y2),
                Math.max(Math.abs(x1 - x2), Math.abs(y1 - y2)),
                Math.max(Math.abs(x1 - x2), Math.abs(y1 - y2)));
    }
}
class fillCircle extends drawings//实心圆
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke));
        g2d.fillOval(Math.min(x1, x2), Math.min(y1, y2),
                Math.max(Math.abs(x1 - x2), Math.abs(y1 - y2)),
                Math.max(Math.abs(x1 - x2), Math.abs(y1 - y2)));
    }
}
class RoundRect extends drawings//圆角矩形类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke));
        g2d.drawRoundRect(Math.min(x1, x2), Math.min(y1, y2),
                Math.abs(x1 - x2), Math.abs(y1 - y2),
                50, 35);
    }
}
class fillRoundRect extends drawings//实心圆角矩形类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke));
        g2d.fillRoundRect(Math.min(x1, x2), Math.min(y1, y2),
                Math.abs(x1 - x2), Math.abs(y1 - y2),
                50, 35);
    }
}
class Pencil extends drawings//随笔画类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setStroke(new BasicStroke(stroke,
                BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL));
        g2d.drawLine(x1, y1, x2, y2);
    }
}
class Rubber extends drawings//橡皮擦类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(255, 255, 255));
        g2d.setStroke(new BasicStroke(stroke + 4,
                BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL));
        g2d.drawLine(x1, y1, x2, y2);
    }
}
class Word extends drawings//输入文字类
{
    void draw(Graphics2D g2d) {
        g2d.setPaint(new Color(R, G, B));
        g2d.setFont(new Font(s2, x2 + y2, ((int) stroke) * 18));
        if (s1 != null) {
            g2d.drawString(s1, x1, y1);
        }
    }
}