How to change font size of JButton according to its size?
15,085
Solution 1
See how you go with this code using GlyphVector
to determine the largest Font
that will fit.
- The GUI was a little shaky unless there was a delay between setting the frame visible and adding the
ComponentListener
. I solved that by delaying adding the listener using a single shot SwingTimer
. - Is is based on
Calculet
which is a fully functioning (if simple) calculator using theScriptEngine
.
import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.util.ArrayList;
import javax.script.*;
import javax.swing.border.Border;
class SwingCalculator implements ActionListener, KeyListener {
JTextField io;
ScriptEngine engine;
ArrayList<JButton> controls;
final BufferedImage textImage = new BufferedImage(
100, 100,
BufferedImage.TYPE_INT_ARGB);
public int getMaxFontSizeForControls() {
Graphics2D g = textImage.createGraphics();
FontRenderContext frc = g.getFontRenderContext();
int maxSize = 500;
for (JButton b : controls) {
// skip the = button..
if (!b.getText().equals("=")) {
int max = getMaxFontSizeForControl(b, frc);
if (maxSize > max) {
maxSize = max;
}
}
}
g.dispose();
return maxSize;
}
public int getMaxFontSizeForControl(JButton button, FontRenderContext frc) {
Rectangle r = button.getBounds();
Insets m = button.getMargin();
Insets i = button.getBorder().getBorderInsets(button);
Rectangle viewableArea = new Rectangle(
r.width -
(m.right + m.left + i.left + i.right),
r.height -
(m.top + m.bottom + i.top + i.bottom)
);
Font font = button.getFont();
int size = 1;
boolean tooBig = false;
while (!tooBig) {
Font f = font.deriveFont((float) size);
GlyphVector gv = f.createGlyphVector(frc, button.getText());
Rectangle2D box = gv.getVisualBounds();
if (box.getHeight() > viewableArea.getHeight()
|| box.getWidth() > viewableArea.getWidth()) {
tooBig = true;
size--;
}
size++;
}
return size;
}
SwingCalculator() {
// obtain a reference to the JS engine
engine = new ScriptEngineManager().getEngineByExtension("js");
JPanel gui = new JPanel(new BorderLayout(2, 2));
controls = new ArrayList<JButton>();
JPanel text = new JPanel(new GridLayout(0, 1, 3, 3));
gui.add(text, BorderLayout.NORTH);
io = new JTextField(15);
Font font = io.getFont();
font = font.deriveFont(font.getSize() * 1.7f);
io.setFont(font);
io.setHorizontalAlignment(SwingConstants.TRAILING);
io.setFocusable(false);
text.add(io);
JPanel buttons = new JPanel(new GridLayout(4, 4, 2, 2));
gui.add(buttons, BorderLayout.CENTER);
addButton(buttons, "7");
addButton(buttons, "8");
addButton(buttons, "9");
addButton(buttons, "/");
addButton(buttons, "4");
addButton(buttons, "5");
addButton(buttons, "6");
addButton(buttons, "*");
addButton(buttons, "1");
addButton(buttons, "2");
addButton(buttons, "3");
addButton(buttons, "-");
addButton(buttons, "0");
addButton(buttons, ".");
addButton(buttons, "C");
addButton(buttons, "+");
JButton equals = new JButton("=");
equals.addKeyListener(this);
controls.add(equals);
equals.addActionListener(this);
gui.add(equals, BorderLayout.EAST);
gui.setBorder(new EmptyBorder(5, 5, 5, 5));
final JFrame f = new JFrame("Calculet");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setContentPane(gui);
f.pack();
f.setMinimumSize(f.getSize());
f.setLocationByPlatform(true);
f.setVisible(true);
final ComponentListener cl = new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent e) {
int ii = getMaxFontSizeForControls();
for (JButton b : controls) {
if (!b.getText().equals("=")) {
b.setFont(b.getFont().deriveFont((float) ii));
}
}
}
};
ActionListener al = new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
f.addComponentListener(cl);
}
};
Timer t = new Timer(500, al);
t.setRepeats(false);
t.start();
}
public void addButton(Container c, String text) {
JButton b = new JButton(text);
b.addActionListener(this);
b.addKeyListener(this);
controls.add(b);
c.add(b);
}
public void calculateResult() {
try {
Object result = engine.eval(io.getText());
if (result == null) {
io.setText("Output was 'null'");
} else {
io.setText(result.toString());
}
} catch (ScriptException se) {
io.setText(se.getMessage());
}
}
public void actionPerformed(ActionEvent ae) {
String command = ae.getActionCommand();
if (command.equals("C")) {
io.setText("");
} else if (command.equals("=")) {
calculateResult();
} else {
io.setText(io.getText() + command);
}
}
private JButton getButton(String text) {
for (JButton button : controls) {
String s = button.getText();
if (text.endsWith(s)
|| (s.equals("=")
&& (text.equals("Equals") || text.equals("Enter")))) {
return button;
}
}
return null;
}
/*
* START - Because I hate mice.
*/
public void keyPressed(KeyEvent ke) {
}
public void keyReleased(KeyEvent ke) {
String s = ke.getKeyText(ke.getKeyCode());
JButton b = getButton(s);
if (b != null) {
b.requestFocusInWindow();
b.doClick();
}
}
public void keyTyped(KeyEvent ke) {
}
public static void main(String[] args) {
Runnable r = new Runnable() {
@Override
public void run() {
new SwingCalculator();
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency
SwingUtilities.invokeLater(r);
}
}
Solution 2
Compare the approaches shown here and here. The former uses an available JComponent.sizeVariant
.
The latter cites an example using FontMentrics
.
Or TextLayout
.
Author by
Andrew Vershinin
Updated on June 04, 2022Comments
-
Andrew Vershinin almost 2 years
I have a java application - a calculator. I want to resize font of buttons dynamically with resizing the window of the app. How to implement it?
My idea is using ComponentEvents. I have initial size of the window of application and initial fonts' sizes. I want to change font size according to button's size, affected by window size change. The problem is how to use the ratio [initial window size] / [initial font size] in the overriden method? The ratio is different for each font.
import javax.swing.*; import java.awt.*; import java.awt.event.ComponentEvent; import java.awt.event.ComponentListener; public class Main extends JFrame { public Main() { super("Test"); JPanel cPane = (JPanel) getContentPane(); cPane.setLayout(new BorderLayout()); MyButton sampleButton = new MyButton("Sample text"); sampleButton.setFont(new Font("Sans Serif", Font.PLAIN, 20)); MyButton a, b, c, d; a = new MyButton("a"); b = new MyButton("b"); c = new MyButton("c"); d = new MyButton("d"); cPane.add(a, BorderLayout.PAGE_START); cPane.add(b, BorderLayout.PAGE_END); cPane.add(c, BorderLayout.LINE_START); cPane.add(d, BorderLayout.LINE_END); cPane.add(sampleButton, BorderLayout.CENTER); setSize(300, 200); setResizable(true); setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); setVisible(true); } public static void main(String... args) { new Main(); } class MyButton extends JButton implements ComponentListener { public MyButton(String title) { super(title); } @Override public void componentResized(ComponentEvent e) { //resizing font } @Override public void componentMoved(ComponentEvent e) { } @Override public void componentShown(ComponentEvent e) { } @Override public void componentHidden(ComponentEvent e) { } } }