Media: Graphics, Audio,Video - Java - page 470

}

}

Drawing Centered Text in a Component

Problem

You want to draw text neatly centered in a component.

Solution

Measure the width and height of the string in the given font, and subtract it from the width
and height of the component. Divide by two, and use this as your drawing location.

Discussion

The program DrawStringDemo2 in Example 12-1 measures the width and height of a string
(see Figure 12-2 for some attributes of the text). The program then subtracts the size of the
text from the size of the component, divides this by two, and thereby centers the text in the
given component.

Example 12-1. DrawStringDemo2.java
public public class class DrawStringDemo2 DrawStringDemo2 extends extends JComponent {

private private static static final final long long serialVersionUID = - 6593901790809089107L ;

//-
String message = "Hello Java" ;

/** Called by the window system to draw the text. */
@Override
public

public void void paintComponent ( Graphics g ) {

// Get the current Font, and ask it for its FontMetrics.
FontMetrics fm = getFontMetrics ( getFont ());

// Use the FontMetrics to get the width of the String.
// Subtract this from width, divide by 2, that's our starting point.
int int textX = ( getSize (). width - fm . stringWidth ( message ))/ 2 ;

iif ( textX < 0 )

// If string too long, start at 0

textX = 0 ;