如何在 JScrollPane 內的 Java 網格佈局中高效顯示大量圖像縮圖？

如何將影像縮圖新增至網格中的佈局？

這個問題著重於 SpringLayout 網格，以在 JScrollPane 中保存一系列影像縮圖。具體來說，當照片清單的大小可能很大時如何處理佈局。

所以基本上，您需要某種位於滾動窗格中的容器（通常稱為視圖）。您應該為此添加圖像。

在以下 Java 程式碼範例中，照片位於 JPanel 上，並且位於 JScrollPane 中：

import java.awt.BorderLayout;
導入 java.awt.Component; java.awt.Container;
導入java.awt.Dimension;
導入 java.awt.EventQueue;
導入 java.awt.FlowLayout;
導入 java.awt.Graphics;
導入🎜>導入java.awt.Graphics2D;
導入java.awt.Image;
導入java.awt.Insets;
導入java.awt.event.ActionEvent;
導入java.awt.event.ActionListener;
導入java.awt.geom.AffineTransform;
導入java.awt.image.BufferedImage;
導入java. io.File;
導入java.io.FileFilter;
導入java.io.IOException;
導入javax.imageio.ImageIO;
導入javax.swing.JButton;
導入javax.swing.JFrame;
導入 javax.swing.JPanel;
導入 javax.swing.JScrollPane;
導入javax.swing.SwingUtilities;
導入javax.swing.UIManager;

public class ImageGrid {

public static void main(String[] args) {
    new ImageGrid();
}

public ImageGrid() {
    EventQueue.invokeLater(new Runnable() {
        @Override
        public void run() {
            try {
                UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
            }

            JFrame frame = new JFrame("Testing");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setLayout(new BorderLayout());
            frame.add(new TestPane());
            frame.pack();
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);
        }
    });
}

public class TestPane extends JPanel {

    private JPanel imagesPane;

    public TestPane() {
        setLayout(new BorderLayout());
        imagesPane = new JPanel(new WrapLayout());
        add(new JScrollPane(imagesPane));
        JButton scan = new JButton("Scan");
        scan.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String path = "C:\Users\shane\Dropbox\Ponies";
                File[] files = new File(path).listFiles(new FileFilter() {
                    @Override
                    public boolean accept(File pathname) {
                        String name = pathname.getName().toLowerCase();
                        return pathname.isFile() && (name.endsWith(".png")
                                || name.endsWith(".jpg")
                                || name.endsWith(".gif"));
                    }
                });
                imagesPane.removeAll();
                for (File file : files) {
                    try {
                        ImagePane pane = new ImagePane(file);
                        imagesPane.add(pane);
                    } catch (Exception exp) {
                        exp.printStackTrace();
                    }
                }
                imagesPane.revalidate();
                imagesPane.repaint();
            }
        });
        add(scan, BorderLayout.SOUTH);
    }
}

public class ImagePane extends JPanel {

    private Image img;

    public ImagePane(File source) throws IOException {
        img = ImageIO.read(source);
        if (img.getWidth(this) > 200 || img.getHeight(this) > 200) {
            int width = img.getWidth(this);
            int height = img.getWidth(this);
            float scaleWidth = 200f / width;
            float scaleHeight = 200f / height;
            if (scaleWidth > scaleHeight) {
                width = -1;
                height = (int)(height * scaleHeight);
            } else {
                width = (int)(width * scaleWidth);
                height = -1;
            }
            img = img.getScaledInstance(width, height, Image.SCALE_SMOOTH);
        }
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(200, 200);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g.create();
        if (img != null) {

// int width = img.getWidth();

/ / int height = img.m.
// 浮點數 = 1f;
// AffineTransform at = new AffineTransform();
// at.translate(
// (getWidth() / 2) - ((img.getWidth() * scale) / 2) ,
// (getHeight() / 2) - ((img.getHeight() *比例) / 2));
// at.scale(scale, scale);
// g2d.setTransform(at);

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