JScrollPane和缩放图像

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class ImageZoomExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Image Zoom Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        // 创建一个JScrollPane
        JScrollPane scrollPane = new JScrollPane();
        frame.add(scrollPane);
        
        // 创建一个自定义的JPanel，用于显示图像
        ImagePanel imagePanel = new ImagePanel();
        scrollPane.setViewportView(imagePanel);
        
        // 加载图像
        ImageIcon imageIcon = new ImageIcon("path/to/image.jpg");
        imagePanel.setImage(imageIcon.getImage());
        
        // 添加鼠标滚轮监听器，实现缩放功能
        scrollPane.addMouseWheelListener(new MouseAdapter() {
            public void mouseWheelMoved(MouseWheelEvent e) {
                int notches = e.getWheelRotation();
                if (notches < 0) {
                    // 向上滚动，放大图像
                    imagePanel.zoomIn();
                } else {
                    // 向下滚动，缩小图像
                    imagePanel.zoomOut();
                }
            }
        });
        
        frame.setSize(800, 600);
        frame.setVisible(true);
    }
}

class ImagePanel extends JPanel {
    private Image image;
    private double scale = 1.0;
    
    public void setImage(Image image) {
        this.image = image;
        repaint();
    }
    
    public void zoomIn() {
        scale *= 1.1;
        repaint();
    }
    
    public void zoomOut() {
        scale /= 1.1;
        repaint();
    }
    
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        if (image != null) {
            int width = (int) (image.getWidth(null) * scale);
            int height = (int) (image.getHeight(null) * scale);
            int x = (getWidth() - width) / 2;
            int y = (getHeight() - height) / 2;
            g.drawImage(image, x, y, width, height, null);
        }
    }
}