Java中实现图片的裁剪

悠悠 2022-05-16 03:47 376阅读 0赞

我们将通过以下步骤来学习：

1.  输入图像，指定要处理的图像路径
2.  允许用户拖放要剪裁的部分
3.  选择后使用 Robot 类来确定剪裁部分的坐标
4.  剪裁所选图像并保持

代码由两个文件组成，一个是ImagePanel.java，另外一个文件是CopyImage.java。下面是代码实现：

ImagePanel.java文件如下
    package com.application.sample;
    
    import java.awt.Dimension;  
    import java.awt.Graphics;  
    import java.awt.Image;  
    import javax.swing.ImageIcon;  
    import javax.swing.JPanel; 
    
    public class ImagePanel extends JPanel{
    	private Image img;
    	
    	public ImagePanel(String path)
    	{
    		this(new ImageIcon(path).getImage());
    	}
    	
    	public ImagePanel(Image img)
    	{
    		this.img=img;
    		Dimension size=new Dimension(img.getWidth(null),img.getHeight(null));
    		setPreferredSize(size);
    		setMinimumSize(size);
    		setMaximumSize(size);
    		setSize(size);
    		setLayout(null);
    	}
    	
    	public void paintComponent(Graphics g)
    	{
    		g.drawImage(img, 0, 0, null);
    	}
    }

CopyImage.java文件如下：
    package com.application.sample;
    
    import java.awt.Graphics;
    import java.awt.Rectangle;
    import java.awt.Robot;
    import java.awt.event.*;
    import java.io.*;
    import javax.swing.JFrame;
    import javax.imageio.ImageIO;
    import java.awt.image.BufferedImage;
    import java.math.*;
    
    public class CopyImage extends JFrame 
    	implements MouseListener,MouseMotionListener{
    	
    	int drag_status=0,c1,c2,c3,c4;
    	
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		new CopyImage().start("D:\\插入排序.jpg");  
    	}
    	
    	public void start(String path)
    	{
    		ImagePanel image=new ImagePanel(path);
    		add(image);
    		setSize(400,400);
    		setVisible(true);
    		addMouseListener(this);
    		addMouseMotionListener(this);
    		this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    	}
    	
    	public void draggedScreen()throws Exception  
    	{          
    		int w = c1 - c3;          
    		int h = c2 - c4;          
    		w =Math.abs(w);          
    		h =Math.abs(h);         
    		Robot robot = new Robot();          
    		BufferedImage img = robot.createScreenCapture(new Rectangle(c1, c2,w,h));   
    		File save_path=new File("D:\\screen1.jpg");          
    		ImageIO.write(img, "JPG", save_path);      
    		System.out.println("Cropped image saved successfully."); 
    	}  
    
    	@Override
    	public void mouseClicked(MouseEvent e) {
    		// TODO Auto-generated method stub
    		
    	}
    
    	@Override
    	public void mouseEntered(MouseEvent e) {
    		// TODO Auto-generated method stub
    		
    	}
    
    	@Override
    	public void mouseExited(MouseEvent e) {
    		// TODO Auto-generated method stub
    		
    	}
    
    	@Override
    	public void mousePressed(MouseEvent e) {
    		// TODO Auto-generated method stub
    		repaint();      
    		c1=e.getX();      
    		c2=e.getY(); 
    	}
    
    	@Override
    	public void mouseReleased(MouseEvent e) {
    		// TODO Auto-generated method stub
    		repaint();      
    		if(drag_status==1)      
    		{      
    			c3=e.getX();      
    			c4=e.getY();      
    			try     
    			{      
    				draggedScreen();      
    			}      
    			catch(Exception error)      
    			{          
    				error.printStackTrace();      
    			}     
    		}  
    	}
    
    	@Override
    	public void mouseDragged(MouseEvent e) {
    		// TODO Auto-generated method stub
    		repaint();   
    		drag_status=1;      
    		c3=e.getX();      
    		c4=e.getY(); 
    	}
    
    	@Override
    	public void mouseMoved(MouseEvent e) {
    		// TODO Auto-generated method stub
    		
    	}
    	
    	public void paint(Graphics g)
    	{
    		super.paint(g);     
    		int w = c1 - c3;     
    		int h = c2 - c4;     
    		w = w * -1;     
    		h = h * -1;     
    		if(w<0)          
    			w = w * -1;     
    		g.drawRect(c1, c2, w, h);
    	}
    }

运行结果如下所示：

原图片如下：

![1352559793_3999.jpg][]

裁剪所得的图片如下所示：

![1352559888_9357.jpg][]

[1352559793_3999.jpg]: https://img-my.csdn.net/uploads/201211/10/1352559793_3999.jpg
[1352559888_9357.jpg]: https://img-my.csdn.net/uploads/201211/10/1352559888_9357.jpg