pb.java

java画图程序 实现了圆、矩形、直线等功能 适合初学者练习

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

class Point implements Serializable {
		int x, y;
		Color col;
		int tool;
		int boarder;

		Point(int x, int y, Color col, int tool, int boarder) {
		   this.x = x;
		   this.y = y;
		   this.col = col;
		   this.tool = tool;
		   this.boarder = boarder;
		}
}

class paintboard extends Frame implements ActionListener, MouseMotionListener,
   MouseListener, ItemListener {
		int x = -1, y = -1;
		int con = 1;// 画笔大小
		int Econ = 5;// 橡皮大小
		
		int toolFlag = 0;// toolFlag:工具标记
		// toolFlag工具对应表：
		// （0--画笔）；（1--橡皮）；（2--清除）；
		// （3--直线）；（4--圆）；（5--矩形）；
		
		Color c = new Color(0, 0, 0); // 画笔颜色
		BasicStroke size = new BasicStroke(con, BasicStroke.CAP_BUTT,
		    BasicStroke.JOIN_BEVEL);// 画笔粗细
		Point cutflag = new Point(-1, -1, c, 6, con);// 截断标志
		
		Vector paintInfo = null;// 点信息向量组
		int n = 1;
		
		FileInputStream picIn = null;
		FileOutputStream picOut = null;
		
		ObjectInputStream VIn = null;
		ObjectOutputStream VOut = null;
		
		// *工具面板--画笔，直线，圆，矩形，多边形,橡皮，清除*/
		Panel toolPanel;
		Button eraser, drLine, drCircle, drRect;
		Button clear, pen;
		Choice ColChoice, SizeChoice, EraserChoice;
		Button colchooser;
		Label 颜色, 大小B, 大小E;
		// 保存功能
		Button openPic, savePic;
		FileDialog openPicture, savePicture;

		paintboard(String s) {
		   super(s);
		   addMouseMotionListener(this);
		   addMouseListener(this);
		
		   paintInfo = new Vector();
		
		   /* 各工具按钮及选择项 */
		   // 颜色选择
		   ColChoice = new Choice();
		   ColChoice.add("black");
		   ColChoice.add("red");
		   ColChoice.add("blue");
		   ColChoice.add("green");
		   ColChoice.addItemListener(this);
		   // 画笔大小选择
		   SizeChoice = new Choice();
		   SizeChoice.add("1");
		   SizeChoice.add("3");
		   SizeChoice.add("5");
		   SizeChoice.add("7");
		   SizeChoice.add("9");
		   SizeChoice.addItemListener(this);
		   // 橡皮大小选择
		   EraserChoice = new Choice();
		   EraserChoice.add("5");
		   EraserChoice.add("9");
		   EraserChoice.add("13");
		   EraserChoice.add("17");
		   EraserChoice.addItemListener(this);
		   // //////////////////////////////////////////////////
		   toolPanel = new Panel();
		
		   clear = new Button("清除");
		   eraser = new Button("橡皮");
		   pen = new Button("画笔");
		   drLine = new Button("画直线");
		   drCircle = new Button("画圆形");
		   drRect = new Button("画矩形");
		
		   openPic = new Button("打开图画");
		   savePic = new Button("保存图画");
		
		   colchooser = new Button("显示调色板");
		
		   // 各组件事件监听
		   clear.addActionListener(this);
		   eraser.addActionListener(this);
		   pen.addActionListener(this);
		   drLine.addActionListener(this);
		   drCircle.addActionListener(this);
		   drRect.addActionListener(this);
		   openPic.addActionListener(this);
		   savePic.addActionListener(this);
		   colchooser.addActionListener(this);
		
		   颜色 = new Label("画笔颜色", Label.CENTER);
		   大小B = new Label("画笔大小", Label.CENTER);
		   大小E = new Label("橡皮大小", Label.CENTER);
		   // 面板添加组件
		   toolPanel.add(openPic);
		   toolPanel.add(savePic);
		
		   toolPanel.add(pen);
		   toolPanel.add(drLine);
		   toolPanel.add(drCircle);
		   toolPanel.add(drRect);
		
		   toolPanel.add(颜色);
		   toolPanel.add(ColChoice);
		   toolPanel.add(大小B);
		   toolPanel.add(SizeChoice);
		   toolPanel.add(colchooser);
		
		   toolPanel.add(eraser);
		   toolPanel.add(大小E);
		   toolPanel.add(EraserChoice);
		
		   toolPanel.add(clear);
		   // 工具面板到APPLET面板
		   add(toolPanel, BorderLayout.NORTH);
		
		   setBounds(60, 60, 900, 600);
		   setVisible(true);
		   validate();
		   // dialog for save and load
		
		   openPicture = new FileDialog(this, "打开图画", FileDialog.LOAD);
		   openPicture.setVisible(false);
		   savePicture = new FileDialog(this, "保存图画", FileDialog.SAVE);
		   savePicture.setVisible(false);
		
		   openPicture.addWindowListener(new WindowAdapter() {
		    public void windowClosing(WindowEvent e) {
		     openPicture.setVisible(false);
		    }
		   });
		
		   savePicture.addWindowListener(new WindowAdapter() {
		    public void windowClosing(WindowEvent e) {
		     savePicture.setVisible(false);
		    }
		   });
		
		   addWindowListener(new WindowAdapter() {
		    public void windowClosing(WindowEvent e) {
		     System.exit(0);
		    }
		   });
		
		}
		
		public void paint(Graphics g) {
		   Graphics2D g2d = (Graphics2D) g;
		
		   Point p1, p2;
		
		   n = paintInfo.size();
		
		   if (toolFlag == 2)
		    g.clearRect(0, 0, getSize().width, getSize().height);// 清除
		
		   for (int i = 0; i < n; i++) {
		    p1 = (Point) paintInfo.elementAt(i);
		    p2 = (Point) paintInfo.elementAt(i + 1);
		    size = new BasicStroke(p1.boarder, BasicStroke.CAP_BUTT,
		      BasicStroke.JOIN_BEVEL);
		
		    g2d.setColor(p1.col);
		    g2d.setStroke(size);
		
		    if (p1.tool == p2.tool) {
		     switch (p1.tool) {
		     case 0:// 画笔
		
		      Line2D line1 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
		      g2d.draw(line1);
		      break;
		
		     case 1:// 橡皮
		      g.clearRect(p1.x, p1.y, p1.boarder, p1.boarder);
		      break;
		
		     case 3:// 画直线
		      Line2D line2 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
		      g2d.draw(line2);
		      break;
		
		     case 4:// 画圆
		      Ellipse2D ellipse = new Ellipse2D.Double(p1.x, p1.y, Math
		        .abs(p2.x - p1.x), Math.abs(p2.y - p1.y));
		      g2d.draw(ellipse);
		      break;
		
		     case 5:// 画矩形
		      Rectangle2D rect = new Rectangle2D.Double(p1.x, p1.y, Math
		        .abs(p2.x - p1.x), Math.abs(p2.y - p1.y));
		      g2d.draw(rect);
		      break;
		
		     case 6:// 截断，跳过
		      i = i + 1;
		      break;
		
		     default:
		     }// end switch
		    }// end if
		   }// end for
		}
		
		public void itemStateChanged(ItemEvent e) {
		   if (e.getSource() == ColChoice)// 预选颜色
		   {
		    String name = ColChoice.getSelectedItem();
		
		    if (name == "black") {
		     c = new Color(0, 0, 0);
		    } else if (name == "red") {
		     c = new Color(255, 0, 0);
		    } else if (name == "green") {
		     c = new Color(0, 255, 0);
		    } else if (name == "blue") {
		     c = new Color(0, 0, 255);
		    }
		   } else if (e.getSource() == SizeChoice)// 画笔大小
		   {
		    String selected = SizeChoice.getSelectedItem();
		
		    if (selected == "1") {
		     con = 1;
		     size = new BasicStroke(con, BasicStroke.CAP_BUTT,
		       BasicStroke.JOIN_BEVEL);
		
		    } else if (selected == "3") {
		     con = 3;
		     size = new BasicStroke(con, BasicStroke.CAP_BUTT,
		       BasicStroke.JOIN_BEVEL);
		
		    } else if (selected == "5") {
		     con = 5;
		     size = new BasicStroke(con, BasicStroke.CAP_BUTT,
		       BasicStroke.JOIN_BEVEL);
		
		    } else if (selected == "7") {
		     con = 7;
		     size = new BasicStroke(con, BasicStroke.CAP_BUTT,
		       BasicStroke.JOIN_BEVEL);
		
		    } else if (selected == "9") {
		     con = 9;
		     size = new BasicStroke(con, BasicStroke.CAP_BUTT,
		       BasicStroke.JOIN_BEVEL);
		
		    }
		   } else if (e.getSource() == EraserChoice)// 橡皮大小
		   {
		    String Esize = EraserChoice.getSelectedItem();
		
		    if (Esize == "5") {
		     Econ = 5 * 2;
		    } else if (Esize == "9") {
		     Econ = 9 * 2;
		    } else if (Esize == "13") {
		     Econ = 13 * 2;
		    } else if (Esize == "17") {
		     Econ = 17 * 3;
		    }
		
		   }
		
		}
		
		public void mouseDragged(MouseEvent e) {
		   Point p1;
		   switch (toolFlag) {
		   case 0:// 画笔
		    x = (int) e.getX();
		    y = (int) e.getY();
		    p1 = new Point(x, y, c, toolFlag, con);
		    paintInfo.addElement(p1);
		    repaint();
		    break;
		
		   case 1:// 橡皮
		    x = (int) e.getX();
		    y = (int) e.getY();
		    p1 = new Point(x, y, null, toolFlag, Econ);
		    paintInfo.addElement(p1);
		    repaint();
		    break;
		
		   default:
		   }
		}
		
		public void mouseMoved(MouseEvent e) {
		}
		
		public void update(Graphics g) {
		   paint(g);
		}
		
		public void mousePressed(MouseEvent e) {
		   Point p2;
		   switch (toolFlag) {
		   case 3:// 直线
		    x = (int) e.getX();
		    y = (int) e.getY();
		    p2 = new Point(x, y, c, toolFlag, con);
		    paintInfo.addElement(p2);
		    break;
		
		   case 4: // 圆
		    x = (int) e.getX();
		    y = (int) e.getY();
		    p2 = new Point(x, y, c, toolFlag, con);
		    paintInfo.addElement(p2);
		    break;
		
		   case 5: // 矩形
		    x = (int) e.getX();
		    y = (int) e.getY();
		    p2 = new Point(x, y, c, toolFlag, con);
		    paintInfo.addElement(p2);
		    break;
		
		   default:
		   }
		}
		
		public void mouseReleased(MouseEvent e) {
		   Point p3;
		   switch (toolFlag) {
		   case 0:// 画笔
		    paintInfo.addElement(cutflag);
		    break;
		
		   case 1: // eraser
		    paintInfo.addElement(cutflag);
		    break;
		
		   case 3:// 直线
		    x = (int) e.getX();
		    y = (int) e.getY();
		    p3 = new Point(x, y, c, toolFlag, con);
		    paintInfo.addElement(p3);
		    paintInfo.addElement(cutflag);
		    repaint();
		    break;
		
		   case 4: // 圆
		    x = (int) e.getX();
		    y = (int) e.getY();
		    p3 = new Point(x, y, c, toolFlag, con);
		    paintInfo.addElement(p3);
		    paintInfo.addElement(cutflag);
		    repaint();
		    break;
		
		   case 5: // 矩形
		    x = (int) e.getX();
		    y = (int) e.getY();
		    p3 = new Point(x, y, c, toolFlag, con);
		    paintInfo.addElement(p3);
		    paintInfo.addElement(cutflag);
		    repaint();
		    break;
		
		   default:
		   }
		}
		
		public void mouseEntered(MouseEvent e) {
		}
		
		public void mouseExited(MouseEvent e) {
		}
		
		public void mouseClicked(MouseEvent e) {
		}
		
		public void actionPerformed(ActionEvent e) {
		
		   if (e.getSource() == pen)// 画笔
		   {
		    toolFlag = 0;
		   }
		
		   if (e.getSource() == eraser)// 橡皮
		   {
		    toolFlag = 1;
		   }
		
		   if (e.getSource() == clear)// 清除
		   {
		    toolFlag = 2;
		    paintInfo.removeAllElements();
		    repaint();
		   }
		
		   if (e.getSource() == drLine)// 画线
		   {
		    toolFlag = 3;
		   }
		
		   if (e.getSource() == drCircle)// 画圆
		   {
		    toolFlag = 4;
		   }
		
		   if (e.getSource() == drRect)// 画矩形
		   {
		    toolFlag = 5;
		   }
		
		   if (e.getSource() == colchooser)// 调色板
		   {
		    Color newColor = JColorChooser.showDialog(this, "调色板", c);
		    c = newColor;
		   }
		
		   if (e.getSource() == openPic)// 打开图画
		   {
		
		    openPicture.setVisible(true);
		
		    if (openPicture.getFile() != null) {
		     int tempflag;
		     tempflag = toolFlag;
		     toolFlag = 2;
		     repaint();
		
		     try {
		      paintInfo.removeAllElements();
		      File filein = new File(openPicture.getDirectory(),
		        openPicture.getFile());
		      picIn = new FileInputStream(filein);
		      VIn = new ObjectInputStream(picIn);
		      paintInfo = (Vector) VIn.readObject();
		      VIn.close();
		      repaint();
		      toolFlag = tempflag;
		
		     }
		
		     catch (ClassNotFoundException IOe2) {
		      repaint();
		      toolFlag = tempflag;
		      System.out.println("can not read object");
		     } catch (IOException IOe) {
		      repaint();
		      toolFlag = tempflag;
		      System.out.println("can not read file");
		     }
		    }
		
		   }
		
		   if (e.getSource() == savePic)// 保存图画
		   {
		    savePicture.setVisible(true);
		    try {
		     File fileout = new File(savePicture.getDirectory(), savePicture
		       .getFile());
		     picOut = new FileOutputStream(fileout);
		     VOut = new ObjectOutputStream(picOut);
		     VOut.writeObject(paintInfo);
		     VOut.close();
		    } catch (IOException IOe) {
		     System.out.println("can not write object");
		    }
		
		   }
		}
}// end paintboard

public class pb {
		public static void main(String args[]) {
		   new paintboard("画图程序");
		}
}