Baseline: 字体的基线，如g.drawString("Hello",x,BaselineY)
getAscent(): 字体的上差值，在所有的数字和字符中，其最高点到基线的距离
getDescent(): 字体的下差值，在所有的数字和字符中，其最低点到基线的距离
getLeading(): 当前行的Descend到下一行Ascend之间的距离
getHeigth(): 字体的高度= Ascent + Descent + Leading.
下面的示例代码在运行后，可以显示的给出各个参量所表示的具体范围。
1 public class MyTest extends JPanel {
2 public void paintComponent(Graphics g) {
3 super.paintComponent(g);
4 Graphics2D g2 = (Graphics2D) g;
5 g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING
6 , RenderingHints.VALUE_ANTIALIAS_ON);
7 g2.setFont(new Font("SansSerif", 0, 200));
8 FontMetrics fm = g2.getFontMetrics();
9 int baseline = 300;
10 g2.drawString("By", 200,baseline);
11 g2.setColor(Color.red);
12 g2.setFont(new Font("SansSerif", 0, 15));
13 //可以看出Height = Ascent + Descent + Leading
14 int ascent = fm.getAscent();
15 int descent = fm.getDescent();
16 int leading = fm.getLeading();
17 int height = fm.getHeight();
18 System.out.printf("Height = %d\tAscent = %d\tDescent = %d\tLeading = %d"
19 ,height,ascent,descent,leading);
20 //在文字上绘制每一个常量，用一条横线予以标注
21 g2.drawLine(100, baseline, 500, baseline);
22 g2.drawLine(100, baseline - ascent, 500, baseline - ascent);
23 g2.drawLine(100, baseline + descent, 500, baseline + descent);
24 g2.drawLine(100, baseline - ascent - leading, 500, baseline - ascent - leading);
25 //指出基线的位置，和其他常量作用的范围。
26 g2.drawString("Baseline",510,baseline);
27 g2.drawLine(480, baseline - ascent, 480, baseline);
28 //绘出Ascent的范围
29 g2.drawString("Ascent", 510, baseline - ascent/2);
30 g2.drawLine(480, baseline, 480, baseline + descent);
31 //绘出Descent的范围
32 g2.drawString("Descent", 510, baseline + descent/2);
33 //绘出Leading的范围
34 g2.drawLine(480, baseline - ascent, 480, baseline - ascent - leading);
35 g2.drawString("Leading", 510, baseline - ascent - leading/2);
36 //绘出Height的范围
37 g2.drawLine(100,baseline - ascent - leading,100, baseline + descent);
38 g2.drawString("Height", 30, baseline - ascent - leading + height/2);
39 }
40 public static void main(String[] args) {
41 JFrame frame = new JFrame();
42 frame.setTitle("Show Font's Metrics Info");
43 frame.addWindowListener(new WindowAdapter() {
44 public void windowClosing(WindowEvent e) {
45 System.exit(0);
46 }
47 });
48 frame.setContentPane(new MyTest());
49 frame.setSize(800, 500);
50 frame.setVisible(true);
51 }
52 }
8) 通过FontMetrics获取单个字符在指定字体上的宽度和高度，再逐个绘制每个字符。
1 public class MyTest extends JPanel {
2 public void paintComponent(Graphics g) {
3 super.paintComponent(g);
4 Graphics2D g2 = (Graphics2D) g;
5 g2.setRende