java graphics绘图 drawString文字发光 代码

要让文字发光，可以使用 Java Graphics2D 的阴影效果来实现。以下是一个示例代码：

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.font.TextLayout;
import java.awt.geom.Rectangle2D;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class TextGlowExample extends JPanel {

    private static final long serialVersionUID = 1L;

    private String text = "Hello, World!";
    private Font font = new Font("Arial", Font.BOLD, 50);
    private Color color = Color.YELLOW;
    private int glowSize = 10;

    public TextGlowExample() {
        setPreferredSize(getPreferredSize());
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g;

        // 设置字体和颜色
        g2d.setFont(font);
        g2d.setColor(color);

        // 计算文字的大小和位置
        TextLayout textLayout = new TextLayout(text, font, g2d.getFontRenderContext());
        Rectangle2D bounds = textLayout.getBounds();
        int x = getWidth() / 2 - (int) bounds.getWidth() / 2;
        int y = getHeight() / 2 + (int) bounds.getHeight() / 2;

        // 开启抗锯齿和阴影效果
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
        g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
        g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
        g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
        g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);

        // 绘制文字的阴影
        g2d.setColor(Color.WHITE);
        for (int i = 0; i < glowSize; i++) {
            g2d.setStroke(new java.awt.BasicStroke((float) (glowSize - i)));
            textLayout.draw(g2d, x, y + i);
        }

        // 绘制文字
        g2d.setColor(color);
        g2d.setStroke(new java.awt.BasicStroke(1f));
        textLayout.draw(g2d, x, y);
    }

    @Override
    public java.awt.Dimension getPreferredSize() {
        return new java.awt.Dimension(300, 200);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Text Glow Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new TextGlowExample());
        frame.pack();
        frame.setVisible(true);
    }
}

在上面的代码中，我们使用了 `TextLayout` 类来计算文字的大小和位置，并使用了 `RenderingHints` 来开启抗锯齿和阴影效果。在绘制文字时，我们首先绘制了文字的阴影，然后再绘制文字本身，从而实现了发光的效果。