JAVA项目--------一起来画画

一起来画画---模拟画图程序

• 代码
• • 画布
  • 图形选择窗体
  • 画图窗体
• 总结

代码

画布

package com.zr.draw;

import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.Image;

/*
 * 画布
 * */
@SuppressWarnings("serial")
public class DrawPictureCanvas extends Canvas{
	private Image image=null;
	
	//设置画板中的图片
	public void setImage(Image image) {
		this.image=image;
	}
	
	//重写paint()方法，在画布中绘制图像
	public void paint(Graphics g) {
		g.drawImage(image, 0, 0, null);//在画布上绘制图像
	}
	
	//重写update()方法，解决屏幕闪耀问题
	public void update(Graphics g) {
		paint(g);//重新执行paint()方法
	}
	
	public static void main(String[] args) {
		// TODO 自动生成的方法存根

	}

}
           

图形选择窗体

package com.zr.draw;

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;

/*
 * 图形选择窗体
 * */
@SuppressWarnings("serial")
public class DrawshapeJDialog extends JFrame{
	public String shape;
	public int weight;
	public int height;
	
	
	
	public DrawshapeJDialog() {
		setTitle("图形选择窗体");
		setBounds(800, 150, 200, 150);
		JPanel jp=new JPanel();
		jp.setLayout(new FlowLayout());
		JRadioButton OvalButton=new JRadioButton("椭圆");
		OvalButton.setSelected(true);
		jp.add(OvalButton);
		JRadioButton RectButton=new JRadioButton("矩形");
		jp.add(RectButton);
		getContentPane().add(jp,BorderLayout.NORTH);
		ButtonGroup group=new ButtonGroup();
		group.add(OvalButton);
		group.add(RectButton);
		JPanel jp1=new JPanel();
		jp1.setLayout(new FlowLayout());
		JLabel right=new JLabel("宽：");
		jp1.add(right);
		JTextField jtweight=new JTextField(5);
		jp1.add(jtweight);
		JLabel left=new JLabel("高");
		jp1.add(left);
		JTextField jtheight=new JTextField(5);
		jp1.add(jtheight);
		getContentPane().add(jp1,BorderLayout.CENTER);
		JButton ok=new JButton("确定");
		ok.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(OvalButton.isSelected()) {
					shape="椭圆";
				}else {
					shape="矩形";
				}
				weight=Integer.parseInt(jtweight.getText());
				height=Integer.parseInt(jtheight.getText());
				new DrawPictureFrame(shape,weight,height,true);
				setVisible(false);
			}
		});
		getContentPane().add(ok,BorderLayout.SOUTH);
		setVisible(true);
	}
	
}
           

画图窗体

import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JRadioButton;
import javax.swing.JToolBar;
import javax.swing.filechooser.FileNameExtensionFilter;

/*
 * 画图窗体
 * */
@SuppressWarnings("serial")
public class DrawPictureFrame extends JFrame {
	// 声明成员变量
	BufferedImage image = new BufferedImage(570, 390, BufferedImage.TYPE_INT_BGR);// 创建图片对象
	Graphics gs = image.getGraphics();// 获得图像的绘图对象
	Graphics2D g = (Graphics2D) gs;// 将绘图对象强转为Graphics2D
	DrawPictureCanvas canvas = new DrawPictureCanvas();// 创建画布对象
	Color foreColor = Color.BLACK;// 定义前景色
	Color backgroundColor = Color.WHITE;// 定义背景色

	// 鼠标绘制点横纵坐标
	int x = -1;
	int y = -1;
	boolean rubber = false;// 橡皮标志变量

	// 工具栏对象
	private JToolBar toolbar;// 工具栏
	private JButton eraserButton;// 橡皮按钮
	private JRadioButton strokeButton1;// 细线单选按钮
	private JRadioButton strokeButton2;// 粗线单选按钮
	private JRadioButton strokeButton3;// 较粗单选按钮
	private JButton backgroundButton;// 背景色按钮
	private JButton foregroundButton;// 前景色按钮
	private JButton clearButton;// 清除按钮
	private JButton saveButton;// 保存按钮
	private JButton shapeButton;// 图形按钮

	// 图形对象
	private Shape shape;
	private String shapes;
	private int weight;
	private int height;
	boolean shaper = false;// 图像标志变量

	// 菜单栏对象
	private JMenuItem strokeMenuItem1;// 细线菜单
	private JMenuItem strokeMenuItem2;// 粗线菜单
	private JMenuItem strokeMenuItem3;// 较粗菜单
	private JMenuItem clearMenuItem;// 清除菜单
	private JMenuItem foregroundMenuItem;// 前景色菜单
	private JMenuItem backgroundMenuItem; // 背景色菜单
	private JMenuItem eraserMenuItem;// 橡皮菜单
	private JMenuItem exitMenuItem;// 退出菜单
	private JMenuItem saveMenuItem;// 保存菜单

	// 水印对象
	private String shuiyin = "";// 水印
	private JMenuItem shuiyinMenuItem;// 水印菜单

	public DrawPictureFrame(String shape2, int weight2, int height2, boolean b) {
		this.shapes = shape2;
		this.weight = weight2;
		this.height = height2;
		this.shaper = b;
		setResizable(false);// 不可改变窗体大小
		setTitle("画图程序(水印内容：" + shuiyin + ")");// 标题
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setBounds(500, 100, 574, 460);

		init();
		setVisible(true);
		addListener();
	}// 构造方法

	private void init() {
		g.setColor(backgroundColor);// 用背景色设置绘图对象的颜色
		g.fillRect(0, 0, 570, 390);// 用背景色填充整个画布
		g.setColor(foreColor);// 用前景色设置绘图对象的颜色
		canvas.setImage(image);// 设置画布的图像
		getContentPane().add(canvas);// 将画布添加到窗体容器

		// 工具栏初始化
		toolbar = new JToolBar();
		getContentPane().add(toolbar, BorderLayout.NORTH);// 工具栏放于窗体最北部
		saveButton = new JButton("保存");
		toolbar.add(saveButton);
		toolbar.addSeparator();// 添加分隔条
		strokeButton1 = new JRadioButton("细线");
		strokeButton1.setSelected(true);
		toolbar.add(strokeButton1);
		strokeButton2 = new JRadioButton("粗线");
		toolbar.add(strokeButton2);
		strokeButton3 = new JRadioButton("较粗");
		ButtonGroup strokeButton = new ButtonGroup();// 定义按钮组，使这三个按钮只能被选一个
		strokeButton.add(strokeButton1);
		strokeButton.add(strokeButton2);
		strokeButton.add(strokeButton3);
		toolbar.add(strokeButton3);
		toolbar.addSeparator();// 添加分隔条
		backgroundButton = new JButton("背景颜色");
		toolbar.add(backgroundButton);
		foregroundButton = new JButton("前景颜色");
		toolbar.add(foregroundButton);
		toolbar.addSeparator();// 添加分隔条
		clearButton = new JButton("清除");
		toolbar.add(clearButton);
		eraserButton = new JButton("橡皮");
		toolbar.add(eraserButton);
		shapeButton = new JButton("图形");
		toolbar.add(shapeButton);

		// 菜单栏初始化
		JMenuBar menubar = new JMenuBar();// 创建菜单栏
		setJMenuBar(menubar);// 窗体载入菜单栏
		JMenu jm1 = new JMenu("系统");
		menubar.add(jm1);// 菜单栏添加菜单对象
		saveMenuItem = new JMenuItem("保存");
		jm1.add(saveMenuItem);
		shuiyinMenuItem = new JMenuItem("水印");
		jm1.add(shuiyinMenuItem);
		jm1.addSeparator();
		exitMenuItem = new JMenuItem("退出");
		jm1.add(exitMenuItem);
		JMenu jm2 = new JMenu("线型");
		menubar.add(jm2);
		strokeMenuItem1 = new JMenuItem("细线");
		jm2.add(strokeMenuItem1);
		strokeMenuItem2 = new JMenuItem("粗线");
		jm2.add(strokeMenuItem2);
		strokeMenuItem3 = new JMenuItem("较粗");
		jm2.add(strokeMenuItem3);
		JMenu jm3 = new JMenu("颜色");
		menubar.add(jm3);
		foregroundMenuItem = new JMenuItem("前景色");
		jm3.add(foregroundMenuItem);
		backgroundMenuItem = new JMenuItem("背景色");
		jm3.add(backgroundMenuItem);
		JMenu jm4 = new JMenu("编辑");
		menubar.add(jm4);
		clearMenuItem = new JMenuItem("清除");
		jm4.add(clearMenuItem);
		eraserMenuItem = new JMenuItem("橡皮");
		jm4.add(eraserMenuItem);
		menubar.setVisible(true);

	}// init()初始化

	private void addListener() {
		// 画板添加鼠标移动事件监听
		canvas.addMouseMotionListener(new MouseMotionAdapter() {
			public void mouseDragged(final MouseEvent e) {// 当鼠标拖拽式
				if (x > 0 && y > 0) {
					if (rubber) {// 若使用橡皮
						g.setColor(backgroundColor);// 绘图工具使用背景色
						g.fillRect(x, y, 10, 10);// 在鼠标划过的位置填充正方形

					} else {// 若使用画笔
						g.drawLine(x, y, e.getX(), e.getY());// 在鼠标划过的位置画直线
					}
				}
				// 上次鼠标绘制点的x,y坐标
				x = e.getX();
				y = e.getY();
				canvas.repaint();// 更新画布
			}

			public void mouseMoved(final MouseEvent arg0) {
				if (rubber) {
					Toolkit kit = Toolkit.getDefaultToolkit();// 获得系统默认的组建工具包
					URL imgURL = DrawPictureFrame.class.getResource("3.png");// 获取图片地址
					Image img = kit.createImage(imgURL);// 利用工具包获得图片
					Cursor c = kit.createCustomCursor(img, new Point(0, 0), "clear");// 利用工具包创建一个自定义光标对象
					setCursor(c);// 使用自定义光标
				} else {
					setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));// 设置鼠标指针为十字形
				}
			}
		});

		// 画板添加鼠标单击事件监听器
		canvas.addMouseListener(new MouseAdapter() {
			public void mouseReleased(final MouseEvent arg0) {// 当鼠标抬起
				x = -1;
				y = -1;
			}

			public void mousePressed(final MouseEvent e) {// 当鼠标按下
				if (shaper) {
					if (shapes == "矩形") {
						int fangX = e.getX() - weight;
						int fangY = e.getY() - height;
						shape = new Rectangle2D.Double(fangX, fangY, weight, height);
						g.setColor(foreColor);// 绘图工具使用前景色
						g.draw(shape);
					} else if (shapes == "椭圆") {
						int yuanX = e.getX() - weight / 2;
						int yuanY = e.getY() - height / 2;
						shape = new Ellipse2D.Double(yuanX, yuanY, weight, height);
						g.setColor(foreColor);// 绘图工具使用前景色
						g.draw(shape);
					}
					canvas.repaint();// 更新画布
				}
			}
		});

		// 调节画笔粗细事件监听
		strokeButton1.addActionListener(new ActionListener() {// 细线按钮添加动作监听
			public void actionPerformed(ActionEvent e) {
				// 设置画笔属性
				BasicStroke bs = new BasicStroke(1, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER);
				g.setStroke(bs);// 画图工具使用此画笔
			}
		});
		strokeButton2.addActionListener(new ActionListener() {// 粗线按钮添加动作监听
			public void actionPerformed(ActionEvent e) {
				// 设置画笔属性
				BasicStroke bs = new BasicStroke(2, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER);
				g.setStroke(bs);// 画图工具使用此画笔
			}
		});
		strokeButton3.addActionListener(new ActionListener() {// 较粗按钮添加动作监听
			public void actionPerformed(ActionEvent e) {
				// 设置画笔属性
				BasicStroke bs = new BasicStroke(4, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER);
				g.setStroke(bs);// 画图工具使用此画笔
			}
		});

		// 背景颜色和画笔颜色选择事件监听
		backgroundButton.addActionListener(new ActionListener() {// 背景颜色按钮添加动作监听事件
			public void actionPerformed(final ActionEvent arg0) {
				// 打开选择颜色对话框,默认选中为青色
				Color bgColor = JColorChooser.showDialog(DrawPictureFrame.this, "选择颜色对话框", Color.CYAN);
				if (bgColor != null) {
					backgroundColor = bgColor;
				}
				backgroundButton.setBackground(bgColor);
				g.setColor(backgroundColor);// 用背景色设置绘图对象的颜色
				g.fillRect(0, 0, 570, 390);// 用背景色填充整个画布
				g.setColor(foreColor);// 用前景色设置绘图对象的颜色
				canvas.repaint();// 更新画布
			}
		});
		foregroundButton.addActionListener(new ActionListener() {// 前景颜色按钮添加动作监听事件
			public void actionPerformed(ActionEvent e) {
				Color fColor = JColorChooser.showDialog(DrawPictureFrame.this, "选择颜色对话框", Color.CYAN);
				if (fColor != null) {
					foreColor = fColor;
				}
				foregroundButton.setBackground(foreColor);
				g.setColor(foreColor);
			}
		});

		// 清除事件监听
		clearButton.addActionListener(new ActionListener() {// 清除按钮添加动作监听事件
			public void actionPerformed(ActionEvent e) {
				g.setColor(Color.WHITE);// 将画笔颜色变为白色
				g.fillRect(0, 0, 570, 390);// 用白色色填充整个画布
				g.setColor(foreColor);// 用前景色设置绘图对象的颜色
				canvas.repaint();// 更新画布
			}
		});

		// 橡皮事件监听
		eraserButton.addActionListener(new ActionListener() {// 橡皮、画笔按钮添加动作监听事件
			public void actionPerformed(ActionEvent e) {
				if (eraserButton.getText().equals("橡皮")) {
					rubber = true;
					eraserButton.setText("画笔");
					eraserMenuItem.setText("画笔");
				} else {
					rubber = false;
					eraserButton.setText("橡皮");
					eraserMenuItem.setText("橡皮");
					g.setColor(foreColor);
				}
			}
		});

		// 图形事件监听
		shapeButton.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				new DrawshapeJDialog();
				setVisible(false);

			}
		});
		// 保存事件监听
		saveButton.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {

				String path;

				JFileChooser chooser = new JFileChooser();
				FileNameExtensionFilter filter = new FileNameExtensionFilter("图片文件", "JPG", "GIF", "PNG");
				chooser.setFileFilter(filter);
				int res = chooser.showSaveDialog(null);
				if (res == JFileChooser.APPROVE_OPTION) {
					path = chooser.getSelectedFile().getAbsolutePath() + ".PNG";// 获得保存路径
					try {
						File file = new File(path);
						ImageIO.write(image, "PNG", file);
					} catch (IOException e1) {
						e1.printStackTrace();
					}
				}

			}
		});

		// 保存菜单事件监听
		saveMenuItem.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {

				String path;

				JFileChooser chooser = new JFileChooser();
				FileNameExtensionFilter filter = new FileNameExtensionFilter("图片文件", "JPG", "GIF", "PNG");
				chooser.setFileFilter(filter);
				int res = chooser.showSaveDialog(null);
				if (res == JFileChooser.APPROVE_OPTION) {
					path = chooser.getSelectedFile().getAbsolutePath() + ".PNG";// 获得保存路径
					try {
						File file = new File(path);
						ImageIO.write(image, "PNG", file);
					} catch (IOException e1) {
						e1.printStackTrace();
					}
				}

			}
		});
		// 退出菜单事件监听
		exitMenuItem.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				System.exit(0);
			}
		});
		// 细线菜单事件监听
		strokeMenuItem1.addActionListener(new ActionListener() {// 细线按钮添加动作监听
			public void actionPerformed(ActionEvent e) {
				// 设置画笔属性
				BasicStroke bs = new BasicStroke(1, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER);
				strokeButton1.setSelected(true);
				g.setStroke(bs);// 画图工具使用此画笔
			}
		});
		// 粗线菜单事件监听
		strokeMenuItem2.addActionListener(new ActionListener() {// 粗线按钮添加动作监听
			public void actionPerformed(ActionEvent e) {
				// 设置画笔属性
				BasicStroke bs = new BasicStroke(2, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER);
				strokeButton2.setSelected(true);
				g.setStroke(bs);// 画图工具使用此画笔
			}
		});
		// 较粗菜单事件监听
		strokeMenuItem3.addActionListener(new ActionListener() {// 较粗按钮添加动作监听
			public void actionPerformed(ActionEvent e) {
				// 设置画笔属性
				BasicStroke bs = new BasicStroke(4, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER);
				strokeButton3.setSelected(true);
				g.setStroke(bs);// 画图工具使用此画笔
			}
		});
		// 前景色菜单事件监听
		foregroundMenuItem.addActionListener(new ActionListener() {// 前景颜色按钮添加动作监听事件
			public void actionPerformed(ActionEvent e) {
				Color fColor = JColorChooser.showDialog(DrawPictureFrame.this, "选择颜色对话框", Color.CYAN);
				if (fColor != null) {
					foreColor = fColor;
				}
				foregroundButton.setBackground(foreColor);
				foregroundMenuItem.setBackground(foreColor);
				g.setColor(foreColor);
			}
		});
		// 背景色菜单事件监听
		backgroundMenuItem.addActionListener(new ActionListener() {// 背景颜色按钮添加动作监听事件
			public void actionPerformed(final ActionEvent arg0) {
				// 打开选择颜色对话框,默认选中为青色
				Color bgColor = JColorChooser.showDialog(DrawPictureFrame.this, "选择颜色对话框", Color.CYAN);
				if (bgColor != null) {
					backgroundColor = bgColor;
				}
				backgroundButton.setBackground(bgColor);
				backgroundMenuItem.setBackground(bgColor);
				g.setColor(backgroundColor);// 用背景色设置绘图对象的颜色
				g.fillRect(0, 0, 570, 390);// 用背景色填充整个画布
				g.setColor(foreColor);// 用前景色设置绘图对象的颜色
				canvas.repaint();// 更新画布
			}
		});
		// 清除菜单事件监听
		clearMenuItem.addActionListener(new ActionListener() {// 清除按钮添加动作监听事件
			public void actionPerformed(ActionEvent e) {
				g.setColor(Color.WHITE);// 将画笔颜色变为白色
				g.fillRect(0, 0, 570, 390);// 用白色色填充整个画布
				g.setColor(foreColor);// 用前景色设置绘图对象的颜色
				canvas.repaint();// 更新画布
			}
		});
		// 橡皮菜单事件监听
		eraserMenuItem.addActionListener(new ActionListener() {// 橡皮、画笔按钮添加动作监听事件
			public void actionPerformed(ActionEvent e) {
				if (eraserMenuItem.getText().equals("橡皮")) {
					rubber = true;
					eraserMenuItem.setText("画笔");
					eraserButton.setText("画笔");
				} else {
					rubber = false;
					eraserButton.setText("橡皮");
					eraserMenuItem.setText("橡皮");
					g.setColor(foreColor);
				}
			}
		});
		// 水印菜单事件监听
		shuiyinMenuItem.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				shuiyin = JOptionPane.showInputDialog(DrawPictureFrame.this, "你想加什么水印？");
				if (null == shuiyin) {
					shuiyin = "";
				} else {
					setTitle("画图程序(水印内容：" + shuiyin + ")");// 修改窗体标题
					addWatermarK();
				}
			}
		});

		// 工具栏事件监听
		toolbar.addMouseMotionListener(new MouseMotionAdapter() {
			public void mouseMoved(final MouseEvent arg0) {
				setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));// 设置鼠标为默认光标
			}
		}); // 工具栏添加鼠标移动监听

	}// addListener()添加监听

	// 添加水印方法
	private void addWatermarK() {
		if (!"".equals(shuiyin.trim())) {
			g.rotate(Math.toRadians(-30));// 将图片旋转-30度
			Font font = new Font("楷体", Font.BOLD, 72);// 设置字体
			g.setFont(font);// 载入字体
			g.setColor(Color.GRAY);// 使用灰色
			AlphaComposite alpha = AlphaComposite.SrcOver.derive(0.5f);// 设置透明效果
			g.setComposite(alpha);// 使用透明效果
			g.drawString(shuiyin, 150, 500);// 绘制文字
			canvas.repaint();// 更新画布
			// 还原画布
			g.rotate(Math.toRadians(30));
			alpha = AlphaComposite.SrcOver.derive(1f);// 不透明
			g.setComposite(alpha);
			g.setColor(foreColor);
		}

	}

	public static void main(String[] args) {
		new DrawPictureFrame("", 0, 0, false);
	}// main方法

}
           

总结

• 大部分是对照的视频敲的，但也有一部分是自己想的。

不足：在图形处理上，没有办法从图形选择窗体传值给主窗体，就用了最简单的构造方法传值，但是带来的问题就是每次都是重新产生一个新的主窗体，原先画板上的内容消失。