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當我看的javadoc爲FontMetric.getAscent()我看到：Java：FontMetrics ascent不正確？
字體上升是從字體的基線到大多數字母數字字符頂部的距離。字體中的某些字符可能會延伸到字體上升線之上。
但我寫了一個快速的演示程序，我看到： 
，其中4條水平線的每一行文本是：由getDescent()
- 基線位置基線位置
- 基線位置上調
getAscent() - 基線位置由
getHeight()
通知所述的getAscent（）線和字符的頂部之間的空間上升。我查看了大部分的字體和大小，並且總是存在這種差距。 （而字體下降看起來恰到好處。）什麼給了？
package com.example.fonts;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.GraphicsEnvironment;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Arrays;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSpinner;
import javax.swing.JTextPane;
import javax.swing.SpinnerNumberModel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
public class FontMetricsExample extends JFrame
{
static final int marg = 10;
public FontMetricsExample()
{
super(FontMetricsExample.class.getSimpleName());
JPanel panel = new JPanel(new BorderLayout());
JPanel fontPanel = new JPanel(new BorderLayout());
final JTextPane textSource = new JTextPane();
textSource.setText("ABCDEFGHIJKLMNOPQRSTUVWXYZ\n"
+"abcdefghijklmnopqrstuvwxyz\n"
+"[email protected]#$%^&*()[]{}");
final SpinnerNumberModel fontSizeModel =
new SpinnerNumberModel(18, 4, 32, 1);
final String fonts[] =
GraphicsEnvironment.getLocalGraphicsEnvironment()
.getAvailableFontFamilyNames();
final JComboBox fontFamilyBox = new JComboBox(fonts);
fontFamilyBox.setSelectedItem("Arial");
final JPanel text = new JPanel() {
@Override protected void paintComponent(Graphics g) {
super.paintComponent(g);
String fontFamilyName =
fonts[fontFamilyBox.getSelectedIndex()];
int fontSize = fontSizeModel.getNumber().intValue();
Font f = new Font(fontFamilyName, 0, fontSize);
g.setFont(f);
FontMetrics fm = g.getFontMetrics();
int lineHeight = fm.getHeight();
String[] s0 = textSource.getText().split("\n");
int x0 = marg;
int y0 = getHeight()-marg-(marg+lineHeight)*s0.length;
for (int i = 0; i < s0.length; ++i)
{
y0 += marg+lineHeight;
String s = s0[i];
g.drawString(s, x0, y0);
int w = fm.stringWidth(s);
for (int yofs : Arrays.asList(
0, // baseline
-fm.getHeight(),
-fm.getAscent(),
fm.getDescent()))
{
g.drawLine(x0,y0+yofs,x0+w,y0+yofs);
}
}
}
};
final JSpinner fontSizeSpinner = new JSpinner(fontSizeModel);
fontSizeSpinner.getModel().addChangeListener(
new ChangeListener() {
@Override public void stateChanged(ChangeEvent e) {
text.repaint();
}
});
text.setMinimumSize(new Dimension(200,100));
text.setPreferredSize(new Dimension(400,150));
ActionListener repainter = new ActionListener() {
@Override public void actionPerformed(ActionEvent e) {
text.repaint();
}
};
textSource.getDocument().addDocumentListener(new DocumentListener() {
@Override public void changedUpdate(DocumentEvent e) {
text.repaint();
}
@Override public void insertUpdate(DocumentEvent e) {}
@Override public void removeUpdate(DocumentEvent e) {}
});
fontFamilyBox.addActionListener(repainter);
fontPanel.add(fontFamilyBox, BorderLayout.CENTER);
fontPanel.add(fontSizeSpinner, BorderLayout.EAST);
fontPanel.add(textSource, BorderLayout.SOUTH);
panel.add(fontPanel, BorderLayout.NORTH);
panel.add(text, BorderLayout.CENTER);
setContentPane(panel);
pack();
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new FontMetricsExample().setVisible(true);
}
}
使用'TextLayout'可能會有更好的運氣。 – 2011-08-10 11:34:04
@安德魯 - 謹慎闡述？ – 2011-08-10 13:02:02