On reflection, Unicode fractions among the Latin-1 Supplement and Number Forms offer limited coverage, and fancy equations may be overkill. This example uses HTML in Swing Components.
Addendum: The approach shown lends itself fairly well to rendering mixed numbers. For editing, key bindings to + and / could be added for calculator-style input in a text component. I’ve used org.jscience.mathematics.number.Rational to model rational numbers, and this parser could be adapted to evaluating rational expressions.
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/** @see https://stackoverflow.com/questions/7448216 */
public class HTMLFractions extends JPanel {
private static int N = 8;
public HTMLFractions() {
this.setLayout(new GridLayout(N, N, N, N));
this.setBorder(BorderFactory.createEmptyBorder(N, N, N, N));
for (int r = 0; r < N; r++) {
for (int c = 0; c < N; c++) {
this.add(create(r + N, r + 1, c + 2));
}
}
}
private JLabel create(int w, int n, int d) {
StringBuilder sb = new StringBuilder();
sb.append("<html><body>");
sb.append(w);
sb.append("<sup>");
sb.append(n);
sb.append("</sup>");
sb.append("<font size=+1>/<font size=-1>");
sb.append("<sub>");
sb.append(d);
sb.append("</sub>");
sb.append("</html></body>");
JLabel label = new JLabel(sb.toString(), JLabel.CENTER);
label.setBorder(BorderFactory.createLineBorder(Color.lightGray));
return label;
}
private void display() {
JFrame f = new JFrame("HTMLFractions");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new HTMLFractions().display();
}
});
}
}