Graphics and Java 2D - Java: How to Program Early Objects - page 567

Method or constant Description

Graphics methods for manipulating Font s
public Font getFont()

Returns a Font object reference representing the
current font.

public void setFont(Font f)

Sets the current font to the font, style and size
specified by the Font object reference f .

Fig. 13.10 | Font -related methods and constants. (Part 2 of 2.)

Class Font 's constructor takes three arguments—the font name , font style and font
size . The font name is any font currently supported by the system on which the program
is running, such as standard Java fonts Monospaced , SansSerif and Serif . The font style
is Font.PLAIN , Font.ITALIC or Font.BOLD (each is a static field of class Font ). Font
styles can be used in combination (e.g., Font.ITALIC + Font.BOLD ). The font size is mea-
sured in points. A point is 1/72 of an inch. Graphics method setFont sets the current
drawing font—the font in which text will be displayed—to its Font argument.

Portability Tip 13.2
The number of fonts varies across systems. Java provides five font names— Serif , Mono-
spaced , SansSerif , Dialog and DialogInput —that can be used on all Java platforms.
The Java runtime environment (JRE) on each platform maps these logical font names to
actual fonts installed on the platform. The actual fonts used may vary by platform.

The application of Figs. 13.11-13.12 displays text in four different fonts, with each
font in a different size. Figure 13.11 uses the Font constructor to initialize Font objects (in
lines 17, 21, 25 and 30) that are each passed to Graphics method setFont to change the
drawing font. Each call to the Font constructor passes a font name ( Serif , Monospaced or
SansSerif ) as a string, a font style ( Font.PLAIN , Font.ITALIC or Font.BOLD ) and a font
size. Once Graphics method setFont is invoked, all text displayed following the call will
appear in the new font until the font is changed. Each font's information is displayed in
lines 18, 22, 26 and 31-32 using method drawString . The coordinates passed to draw-
String correspond to the lower-left corner of the baseline of the font. Line 29 changes the
drawing color to red, so the next string displayed appears in red. Lines 31-32 display infor-
mation about the final Font object. Method getFont of class Graphics returns a Font
object representing the current font. Method getName returns the current font name as a
string. Method getSize returns the font size in points.

Software Engineering Observation 13.2
To change the font, you must create a new Font object. Font objects are immutable—class
Font has no set methods to change the characteristics of the current font.

Figure 13.12 contains the main method, which creates a JFrame to display a Font-
JPanel . We add a FontJPanel object to this JFrame (line 15), which displays the graphics
created in Fig. 13.11.