---
category: swing
folder: JustifiedLabel
title: JLabelの文字揃え
tags: [JLabel, Alignment, GlyphVector]
author: aterai
pubdate: 2008-03-31T00:41:18+09:00
description: JLabelで、左右中央両端などの文字揃えをテストします。
image: https://lh4.googleusercontent.com/_9Z4BYR88imo/TQTOwQzSk-I/AAAAAAAAAc4/bD-z_hTSHB8/s800/JustifiedLabel.png
---
* 概要 [#summary]
`JLabel`で、左右中央両端などの文字揃えをテストします。
#download(https://lh4.googleusercontent.com/_9Z4BYR88imo/TQTOwQzSk-I/AAAAAAAAAc4/bD-z_hTSHB8/s800/JustifiedLabel.png)
* サンプルコード [#sourcecode]
#code(link){{
JLabel l0 = new JLabel("打率");
JLabel l1 = new JLabel("打率", SwingConstants.RIGHT);
JLabel l2 = new JustifiedLabel("打率");
JLabel l3 = new JLabel("出塁率", SwingConstants.CENTER);
JLabel l4 = new JustifiedLabel("出塁率");
JLabel l5 = new JustifiedLabel("チーム出塁率");
// ...
class JustifiedLabel extends JLabel {
private GlyphVector gvtext;
private int prevWidth = -1;
public JustifiedLabel() {
this(null);
}
public JustifiedLabel(String str) {
super(str);
}
@Override public void setText(String text) {
super.setText(text);
prevWidth = -1;
}
@Override protected void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g.create();
Insets ins = getInsets();
int w = getSize().width - ins.left - ins.right;
if (w != prevWidth) {
gvtext = getJustifiedGlyphVector(
w, getText(), getFont(), g2.getFontRenderContext());
prevWidth = w;
}
if (Objects.nonNull(gvtext)) {
g2.setPaint(getBackground());
g2.fillRect(0, 0, getWidth(), getHeight());
g2.setPaint(getForeground());
g2.drawGlyphVector(gvtext, ins.left, ins.top + getFont().getSize());
} else {
super.paintComponent(g);
}
g2.dispose();
}
private GlyphVector getJustifiedGlyphVector(
int width, String str, Font font, FontRenderContext frc) {
GlyphVector gv = font.createGlyphVector(frc, str);
Rectangle2D r = gv.getVisualBounds();
float jwidth = (float) width;
float vwidth = (float) r.getWidth();
if (jwidth > vwidth) {
int num = gv.getNumGlyphs();
float xx = (jwidth - vwidth) / (float) (num - 1);
float xpos = num == 1 ? (jwidth - vwidth) * .5f : 0f;
Point2D gmPos = new Point2D.Double(0d, 0d);
for (int i = 0; i < num; i++) {
GlyphMetrics gm = gv.getGlyphMetrics(i);
gmPos.setLocation(xpos, 0);
gv.setGlyphPosition(i, gmPos);
xpos += gm.getAdvance() + xx;
}
return gv;
}
return null;
}
}
}}
* 解説 [#explanation]
`JLabel`の文字揃えは、デフォルトが左揃えで、その他に右揃え、中央揃えがあります。両端揃え(文字の均等割り付け)は存在しないので、上記のサンプルでは`JustifiedLabel`(幅が足りない場合などは通常の`JLabel`と同様に`...`で省略)を作成して使用しています。
- `JLabel`の文字揃えは左揃え(デフォルトは`SwingConstants.LEADING`, `ComponentOrientation.LEFT_TO_RIGHT`で`SwingConstants.LEFT`)、右揃え(`SwingConstants.TRAILING`, `ComponentOrientation.LEFT_TO_RIGHT`で`SwingConstants.RIGHT`)、中央揃え(`SwingConstants.CENTER`)が設定可能
- `JLabel`の文字揃えに両端揃え(文字の均等割り付け)は存在しないので、上記のサンプルでは`JustifiedLabel`を独自に作成
-- 幅が足りない場合は通常の`JLabel`と同様に`...`で省略
----
- `JTextPane`に挿入、一文字の場合などのテスト
#code{{
import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.*;
public class JustifiedLabelDemo {
public JComponent makeUI() {
String s = "\u2605";
JTextPane textPane = new JTextPane();
textPane.insertComponent(new JustifiedLabel(s));
textPane.replaceSelection(": 111\n");
textPane.insertComponent(new JustifiedLabel(s + s));
textPane.replaceSelection(": 2222222\n");
textPane.insertComponent(new JustifiedLabel(s + s + s));
textPane.replaceSelection(": 3333\n");
textPane.insertComponent(new JustifiedLabel(s + s + s + s));
textPane.replaceSelection(": 4444444\n");
textPane.insertComponent(new JustifiedLabel(s + s + s + s + s));
textPane.replaceSelection(": 555\n");
return new JScrollPane(textPane);
}
public static void main(String[] args) {
EventQueue.invokeLater(JustifiedLabelDemo::createAndShowGui);
}
public static void createAndShowGui() {
UIManager.put("swing.boldMetal", Boolean.FALSE);
JFrame f = new JFrame();
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
f.getContentPane().add(new JustifiedLabelDemo().makeUI());
f.setSize(320, 240);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
class JustifiedLabel extends JLabel {
private GlyphVector gvText;
private int prevWidth = -1;
public JustifiedLabel() {
this(null);
}
public JustifiedLabel(String str) {
super(str);
Dimension d = getPreferredSize();
int baseline = getBaseline(d.width, d.height);
setAlignmentY(baseline / (float) d.height);
}
@Override public Dimension getMinimumSize() {
return getPreferredSize();
}
@Override public Dimension getPreferredSize() {
Dimension d = super.getPreferredSize();
d.width = getWidth();
return d;
}
@Override public int getWidth() {
return 120;
}
@Override protected void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
Insets i = getInsets();
int w = getWidth() - i.left - i.right;
if (w != prevWidth) {
gvText = getJustifiedGlyphVector(getText(), getFont(), g2.getFontRenderContext());
prevWidth = w;
}
if (gvText != null) {
g2.drawGlyphVector(gvText, i.left, i.top + getFont().getSize2D());
} else {
super.paintComponent(g);
}
}
private GlyphVector getJustifiedGlyphVector(String str, Font font, FontRenderContext frc) {
GlyphVector gv = font.createGlyphVector(frc, str);
Rectangle2D r = gv.getVisualBounds();
float width = (float) getWidth();
float viewWidth = (float) r.getWidth();
if (width < viewWidth) return null;
int num = gv.getNumGlyphs();
float xx = (width - viewWidth) / (float) (num - 1);
float xpos = num == 1 ? (width - viewWidth) * .5f : 0f;
Point2D gmPos = new Point2D.Double(0d, 0d);
if (num == 1) System.out.println(gmPos);
for (int i = 0; i < num; i++) {
GlyphMetrics gm = gv.getGlyphMetrics(i);
gmPos.setLocation(xpos, 0);
gv.setGlyphPosition(i, gmPos);
xpos += gm.getAdvance() + xx;
}
return gv;
}
}
}}
* 参考リンク [#reference]
- [[JTableのセル内文字列を両端揃えにする>Swing/InterIdeographJustify]]
-- [https://docs.oracle.com/javase/jp/8/docs/api/java/awt/font/TextLayout.html#getJustifiedLayout-float- TextLayoutTextLayout#getJustifiedLayout(float) (Java Platform SE 8)]メソッドを使用して`JTable`のセルで両端揃えを行うサンプル
* コメント [#comment]
#comment
#comment