java - 如何使图像与面板大小相同？

Question

我创建了一个包含图像的简单框架程序。但图像的大小与框架不同。如果我放大框架，图像大小保持不变？

如何使图像与框架大小相同？

这是我当前的代码:

    JPanel panel1 = new JPanel();
    ImageIcon image1 = new ImageIcon("C:\\Users\\Dark Mangetsu\\Downloads\\Ceng102_Lab10.1\\image\\flower.jpg");
    JLabel label1 = new JLabel(image1);
    panel1.add(label1);
    Color color1 = new Color (200, 0 ,100);
    panel1.setBorder(BorderFactory.createLineBorder(color1, 3));
    JFrame f = new JFrame("Frame");
    f.setLayout(new BorderLayout(5,5));
    f.add((panel1),BorderLayout.WEST);
    f.setSize(320,200);
    f.setVisible(true);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

Answer 1

您可以绘制图像而不是使用标签。

ImageIcon icon = new ImageIcon("C:\\Users\\Dark Mangetsu\\Downloads\\Ceng102_Lab10.1\\image\\flower.jpg");
Image image = icon.getImage();
JPanel panel1 = new JPanel() {
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(image, 0, 0, getWidth(), getHeight());
    }
};

也不确定，但我认为您可能希望将面板添加到中心而不是西边(如果您希望图像在框架中居中)。

也不是，如果您想要面板的preferredSize，您还必须覆盖面板的getPreferredSize()。

JPanel panel1 = new JPanel() {
    ...
    @Override
    public Dimension getPreferredSize() {
        return new Dimension(320, 200);
    }
};

然后你可以pack()框架，这是首选，而不是设置大小

f.pack();
//f.setSize(320, 200);

---

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class TestBackgroundResize {
    public TestBackgroundResize() {
        JFrame frame = new JFrame();
        frame.setContentPane(createBackgroundPanel());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    private JPanel createBackgroundPanel() {
        return new JPanel() {
            BufferedImage image;
            {
                try {
                    image = ImageIO.read(getClass().getResource("/marioblobs/mario.png"));
                } catch (IOException ex) {
                    Logger.getLogger(TestBackgroundResize.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                g.drawImage(image, 0, 0, getWidth(), getHeight(), this);
            }
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(320, 200);
            }
        };
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            public void run() {
                new TestBackgroundResize();
            }
        });
    }
}