Learning Java - Chapter 6 : Basics

The first step in drawing text involves choosing the font for the text. You can use the default or specify which of fonts you desire.

TextApplet.java

import java.applet.*;
import java.awt.*;

/** Demonstration of text drawing in AWT. **/
public class TextApplet extends Applet
{
public void paint (Graphics g ) {
String msg = "Set text in center";

  // Set the context color for lines and text
  g.setColor (Color.red);

  // Create the font and pass it to the Graphics context
  g.setFont (new Font ("Monospaced",Font.PLAIN,24));

  // Get measures needed to center the message
  FontMetrics fm = g.getFontMetrics ();

  // How many pixels wide is the string
  int msgWidth = fm.stringWidth (msg);

  // How far above the baseline can the font go?
  int ascent = fm.getMaxAscent ();

  // How far below the baseline?
  int descent= fm.getMaxDescent ();

  // Use the string width to find the starting point
  int msgX = getSize ().width/2 - msgWidth/2;

  // Use the vertical height of this font to find
  // the vertical starting coordinate
  int msgY = getSize ().height/2 - descent/2 + ascent/2;

  g.drawString (msg,msgX,msgY);
} // paint
} // class TextApplet

Here we create a Font object for the Monospace type with the given style and size. Then we pass it to the graphics context. We then obtain from the graphics context a FontMetrics object for the current font setting.

With the FontMetrics object we then obtain the stringwidth and the vertical dimensions neccessary to calculate where to draw the string. Note that the drawString method uses the horizontal and vertical coordinates passed in the arguments for the left baseline point of the string.

Latest update: Oct. 27, 2004