如何在 Java 中高效实现基于网格的像素编辑器，特别是对于大型网格，而不依赖于每个单元格的 JButton？

用 Java 实现基于网格的像素编辑器

为了提高 Spark 编程熟练程度，开发人员经常着手创建像素编辑器等基础应用程序。像素编辑器的核心功能涉及用户选择颜色并修改画布上的网格单元，类似于流行的图像编辑器。

经常出现的一个问题是用于实现这种基于网格的 Java 组件的最佳选择系统。虽然使用 JButton 作为单个单元可能看起来很直观，但它可能变得低效且不切实际，特别是对于较大的网格。

幸运的是，存在更有效的方法。通过利用drawImage()方法并缩放鼠标坐标，开发人员可以创建相当大的像素。

为了演示此技术，请考虑以下示例：

Grid.java

<code class="java">// Import required Java library
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;

/**
 * This class extends JPanel to create a grid-based pixel editor.
 * @see <a href="https://stackoverflow.com/questions/2900801">Original question</a>
 */
public class Grid extends JPanel implements MouseMotionListener {

    // Create buffered image for drawing
    private final BufferedImage img;
    // Image and panel dimensions
    private int imgW, imgH, paneW, paneH;

    public Grid(String name) {
        // Initialize basic attributes
        super(true);
        // Get the image icon and its dimensions
        Icon icon = UIManager.getIcon(name);
        imgW = icon.getIconWidth();
        imgH = icon.getIconHeight();
        // Set preferred size for the panel
        this.setPreferredSize(new Dimension(imgW * 10, imgH * 10));
        // Create a BufferedImage for the image
        img = new BufferedImage(imgW, imgH, BufferedImage.TYPE_INT_ARGB);

        // Get Graphics2D object for drawing
        Graphics2D g2d = (Graphics2D) img.getGraphics();
        // Draw the image icon on the BufferedImage
        icon.paintIcon(null, g2d, 0, 0);
        // Dispose the Graphics2D object
        g2d.dispose();

        // Add MouseMotionListener to the panel
        this.addMouseMotionListener(this);
    }

    @Override
    protected void paintComponent(Graphics g) {
        // Get current panel dimensions
        paneW = this.getWidth();
        paneH = this.getHeight();
        // Draw the image on the panel with scaling
        g.drawImage(img, 0, 0, paneW, paneH, null);
    }

    @Override
    public void mouseMoved(MouseEvent e) {
        // Calculate mouse coordinates scaled to image size
        Point p = e.getPoint();
        int x = p.x * imgW / paneW;
        int y = p.y * imgH / paneH;
        // Get the pixel color at the calculated scaled coordinates
        int c = img.getRGB(x, y);
        // Set tooltip text with color information
        this.setToolTipText(x + "," + y + ": "
            + String.format("%08X", c));
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        // Mouse drag functionality is not implemented in this example
    }

    // Helper method to create the GUI
    private static void create() {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new Grid("Tree.closedIcon"));
        f.pack();
        f.setVisible(true);
    }

    // Main method to run the application
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                create();
            }
        });
    }
}</code>

通过利用此技术，开发人员可以轻松创建具有大型可扩展网格的像素编辑器，在保持效率的同时增强用户体验。

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