wordpanel.java

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package displayword;

import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.JPanel;

/**
 * <p>Title: DisplayWord</p>
 * <p>Description: 应用Java 2D API绘制文字</p>
 * <p>Copyright: Copyright (c) 2004</p>
 * <p>Company: 北京师范大学计算机系</p>
 * @author 张良博
 * @version 1.0
 */

public class WordPanel extends JPanel {
  public void paintComponent(Graphics g){
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D)g;
    String message = "Hello!";
    Font f = new Font("Serif", Font.BOLD, 48);//创建一个新的字体字体对象
    g2.setFont(f);
      // 测量文本的长度
    FontRenderContext context = g2.getFontRenderContext();
    Rectangle2D bounds = f.getStringBounds(message, context);//返回包围字符串的矩形
    double x = (getWidth() - bounds.getWidth()) / 2;
    double y = (getHeight() - bounds.getHeight()) / 2;
      // 增加y达到基线
    double ascent = -bounds.getY();
    double baseY = y + ascent;
    g2.drawString(message, (int)x, (int)(baseY));
    g2.setPaint(Color.gray);
      // 绘制基线
    g2.draw(new Line2D.Double(x, baseY, x + bounds.getWidth(), baseY));
      // 绘制包围字符串的矩形
    Rectangle2D rect = new Rectangle2D.Double(x, y, bounds.getWidth(), bounds.getHeight());
    g2.draw(rect);
  }
}