java - 如何使用图像作为背景并在其前面放置图像？

Question

我尝试了很多方法，但没有一个成功。他们要么不显示图像，要么让背景图像消失......你有什么建议吗？这是我的代码:

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class Main extends JFrame{

int x, y;
Image Dak;
Image Levels;
private Image dbImage;
private Graphics dbg;

public Main(){

 setTitle("Help de Pieten");
 setSize(2000, 720);
 setResizable(true);
 setVisible(true);
 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

              try {
 this.setContentPane(
 new JLabel(new ImageIcon(ImageIO.read(new  File("Image1.gif")))));
} catch (IOException e) {}

validate(); 

ImageIcon i = new ImageIcon("Image2.gif");
    Levels = i.getImage();


    x = 100;
    y = 100;
}    

public void paint(Graphics g){
        dbImage = createImage(getWidth(), getHeight());
    dbg = dbImage.getGraphics();
    paintComponent(dbg);
    g.drawImage(dbImage, 0, 0, this);
}


public void paintComponent(Graphics g){

 g.drawImage(Levels, x, y, this);
   repaint();
}

public static void main(String[] args) {
    Main main = new Main();

}

}

那么如何在不使背景消失的情况下获得背景前面的图像呢？

Answer 1

首先，避免覆盖 paint顶级容器的方法，如 JFrame ，它们不是双缓冲的，并且它们具有复杂的组件层次结构，您不想参与其中

相反，从 JPanel 扩展开始，Swing 组件默认情况下是双缓冲的，因此您无需担心自己全部实现并覆盖它的 paintComponent方法并在其中执行您的自定义绘画。

看看Performing Custom Painting和 Painting in AWT and Swing了解更多详情。

Swing 中的绘制遵循“画家 Canvas ”范例，也就是说，首先绘制的内容将被接下来绘制的内容覆盖，因此为此，请确保先绘制背景，然后绘制每个图层您希望它出现的顺序。

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
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.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Images {

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

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

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

    public class TestPane extends JPanel {

        private BufferedImage background;
        private BufferedImage foreground;

        public TestPane() {
            try {
                background = ImageIO.read(new File("background image"));
                foreground = ImageIO.read(new File("foreground image"));
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }

        @Override
        public Dimension getPreferredSize() {
            return background == null ? new Dimension(200, 200) : new Dimension(background.getWidth(), background.getHeight());
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            if (background != null) {
                int x = (getWidth() - background.getWidth()) / 2;
                int y = (getHeight() - background.getHeight()) / 2;
                g2d.drawImage(background, x, y, this);

            }
            if (foreground != null) {
                int x = (getWidth() - foreground.getWidth()) / 2;
                int y = (getHeight() - foreground.getHeight()) / 2;
                g2d.drawImage(foreground, x, y, this);
            }
            g2d.dispose();
        }

    }

}