package com.kaige123.paint; import java.awt.Color; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JColorChooser; import javax.swing.JFileChooser; import javax.swing.JFrame; import javax.swing.JPanel; /***凯哥*/ public class PaintJFrame extends JFrame implements ActionListener {JButton jb1 = new JButton("线");JButton jb2 = new JButton("矩形");JButton jb3 = new JButton("圆");JButton jb4 = new JButton("颜色");JButton jb5 = new JButton("保存"); // 画笔的颜色是什么? Color selectColor = Color.black; // 绘画区域 MyJPanel jp = new MyJPanel(this); public void actionPerformed(ActionEvent e) { if (jb1 == e.getSource()) { // 线 jp.setType("线");} else if (jb2 == e.getSource()) { // 矩形 jp.setType("矩形");} else if (jb3 == e.getSource()) { // 圆 jp.setType("圆");} else if (jb4 == e.getSource()) { // 颜色 // 这里弹出一个颜色的选择器 用他来选择颜色 JColorChooser jc = new JColorChooser(); // 打开颜色选择器 并得到颜色选择器选择的颜色 selectColor = jc.showDialog(this, "请选择颜色", selectColor); // 把选好的颜色设置在按钮背景上 jb4.setBackground(selectColor);} else if (jb5 == e.getSource()) { // 保存 JFileChooser jf = new JFileChooser();jf.showSaveDialog(this);jp.save(jf.getSelectedFile());}} // 构造器 public PaintJFrame() { this.getContentPane().setBackground(Color.BLACK); // 设置这个画板的底色 为白色 jp.setBackground(Color.white);jp.setBounds(65, 10, 515, 550); // 把绘画板 添加到窗口中 this.add(jp); // 把按钮关联事件 注册事件 jb1.addActionListener(this);jb2.addActionListener(this);jb3.addActionListener(this);jb4.addActionListener(this);jb5.addActionListener(this); // 设置按钮的位置 jb1.setBounds(1, 10, 60, 30);jb2.setBounds(1, 40, 60, 30);jb3.setBounds(1, 70, 60, 30);jb4.setBounds(1, 100, 60, 30);jb5.setBounds(1, 130, 60, 30); // 添加按钮到窗口之中 this.add(jb1); this.add(jb2); this.add(jb3); this.add(jb4); this.add(jb5);jb4.setBackground(selectColor); // 没有布局 我们自己定义组件的摆放方式 this.setLayout(null); // 设置窗口的标题  this.setTitle("凯哥制作的画板 欢迎使用  www.kaige123.com "); // 设置窗口的大小 this.setSize(600, 600); // 显示窗口 this.setVisible(true); } public static void main(String[] args) { new PaintJFrame();}} package com.kaige123.paint; import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import java.awt.image.BufferedImage; import java.io.File; import java.util.Vector; import javax.imageio.ImageIO; import javax.swing.JPanel; /**凯哥*/ //写一个类 去改造这个画板  public class MyJPanel extends JPanel implements MouseListener { public class Info {String type = ""; int x; int y; int x1; int y1;Color c;} private PaintJFrame jf = null;MyJPanel(PaintJFrame jf) { this.jf = jf; // 把事件关联到这个面板上 注册事件 this.addMouseListener(this);} private String type; public void setType(String type) { this.type = type;} int x, y; // 鼠标的按下 public void mousePressed(MouseEvent e) {x = e.getX();y = e.getY();}  Vector<Info> infos = new Vector<Info>(); public void paint(Graphics g) { // 重绘 super.paint(g); for (Info i : infos) {g.setColor(i.c); if (i.type.equalsIgnoreCase("线")) {g.drawLine(i.x, i.y, i.x1, i.y1);} else if (i.type.equalsIgnoreCase("矩形")) {g.drawRect(i.x, i.y, i.x1, i.y1);} else if (i.type.equalsIgnoreCase("圆")) {g.drawOval(i.x, i.y, i.x1, i.y1);}}} public void save(File f) { // 在内存中创建了一个照片 BufferedImage image = new BufferedImage(this.getWidth(), this.getHeight(), BufferedImage.TYPE_INT_RGB);Graphics g = image.getGraphics(); // 给照片设置背景颜色 g.setColor(Color.white);g.fillRect(0, 0, this.getWidth() + 1, this.getHeight() + 1); for (Info i : infos) {g.setColor(i.c); if (i.type.equalsIgnoreCase("线")) {  g.drawLine(i.x, i.y, i.x1, i.y1);  } else if (i.type.equalsIgnoreCase("矩形")) {  g.drawRect(i.x, i.y, i.x1, i.y1);  } else if (i.type.equalsIgnoreCase("圆")) {g.drawOval(i.x, i.y, i.x1, i.y1);}} //捕获异常 try {ImageIO.write(image, "jpeg", f);} catch (Exception e) {}} // 鼠标的松开 public void mouseReleased(MouseEvent e) { int x1 = e.getX(); int y1 = e.getY();Graphics2D g = (Graphics2D) this.getGraphics();g.setColor(jf.selectColor);Info info = new Info();info.c = jf.selectColor;info.type = type; if (type.equalsIgnoreCase("线")) {g.drawLine(x, y, x1, y1);info.x = x;info.y = y;info.x1 = x1;info.y1 = y1;  } else if (type.equalsIgnoreCase("矩形")) {g.drawRect(x, y, x1 - x, y1 - y);info.x = x;info.y = y;info.x1 = x1 - x;info.y1 = y1 - y;  } else if (type.equalsIgnoreCase("圆")) {g.drawOval(x, y, x1 - x, y1 - y);info.x = x;info.y = y;info.x1 = x1 - x;info.y1 = y1 - y;}  infos.add(info);} public void mouseClicked(MouseEvent e) {} public void mouseEntered(MouseEvent e) {} public void mouseExited(MouseEvent e) {}}

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