FontTest.java Source code

Introduction

Here is the source code for FontTest.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;

import javax.swing.JComponent;
import javax.swing.JFrame;

/**
 * @version 1.33 2007-04-14
 * @author Cay Horstmann
 */
public class FontTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                FontFrame frame = new FontFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

/**
 * A frame with a text message component
 */
class FontFrame extends JFrame {
    public FontFrame() {
        setTitle("FontTest");
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

        // add component to frame

        FontComponent component = new FontComponent();
        add(component);
    }

    public static final int DEFAULT_WIDTH = 300;
    public static final int DEFAULT_HEIGHT = 200;
}

/**
 * A component that shows a centered message in a box.
 */
class FontComponent extends JComponent {
    public void paintComponent(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        String message = "Hello, World!";

        Font f = new Font("Serif", Font.BOLD, 36);
        g2.setFont(f);

        // measure the size of the message

        FontRenderContext context = g2.getFontRenderContext();
        Rectangle2D bounds = f.getStringBounds(message, context);

        // set (x,y) = top left corner of text

        double x = (getWidth() - bounds.getWidth()) / 2;
        double y = (getHeight() - bounds.getHeight()) / 2;

        // add ascent to y to reach the baseline

        double ascent = -bounds.getY();
        double baseY = y + ascent;

        // draw the message

        g2.drawString(message, (int) x, (int) baseY);

        g2.setPaint(Color.LIGHT_GRAY);

        // draw the baseline

        g2.draw(new Line2D.Double(x, baseY, x + bounds.getWidth(), baseY));

        // draw the enclosing rectangle

        Rectangle2D rect = new Rectangle2D.Double(x, y, bounds.getWidth(), bounds.getHeight());
        g2.draw(rect);
    }
}