JAVAFX BASICS - Introduction to Java Programming: Comprehensive Version - page 547

A color instance can be constructed using the following constructor:

public Color( double r, double g, double b, double opacity);

in which r , g , and b specify a color by its red, green, and blue components with values in the
range from 0.0 (darkest shade) to 1.0 (lightest shade). The opacity value defines the trans-
parency of a color within the range from 0.0 (completely transparent) to 1.0 (completely
opaque). This is known as the RGBA model, where RGBA stands for red, green, blue, and
alpha. The alpha value indicates the opacity. For example,

RBGA model

Color color = new Color( 0.25 , 0.14 , 0.333 , 0.51 );

The Color class is immutable. Once a Color object is created, its properties cannot be
changed. The brighter() method returns a new Color with a larger red, green, and blue
values and the darker() method returns a new Color with a smaller red, green, and blue
values. The opacity value is the same as in the original Color object.
You can also create a Color object using the static methods color(r, g, b) , color(r,
g, b, opacity) , rgb(r, g, b) , and rgb(r, g, b, opacity) .
Alternatively, you can use one of the many standard colors such as BEIGE , BLACK , BLUE ,
BROWN , CYAN , DARKGRAY , GOLD , GRAY , GREEN , LIGHTGRAY , MAGENTA , NAVY , ORANGE , PINK ,
RED , SILVER , WHITE , and YELLOW defined as constants in the Color class. The following
code, for instance, sets the fill color of a circle to red:

circle.setFill(Color.RED);

14.14

✓ ✓

How do you create a color? What is wrong about creating a Color using new
Color(1.2, 2.3, 3.5, 4) ? Which of two colors is darker, new Color(0, 0,
0, 1) or new Color(1, 1, 1, 1) ? Does invoking c.darker() change the color
value in c ?

Check

Point

14.15

How do you create a Color object with a random color?

14.16

How do you set a circle object c with blue fill color using the setFill method and
using the setStyle method?

14.8 The Font Class
A Font describes font name, weight, and size.

Key
Point

You can set fonts for rendering the text. The javafx.scene.text.Font class is used to
create fonts, as shown in Figure 14.10.
A Font instance can be constructed using its constructors or using its static methods. A
Font is defined by its name, weight, posture, and size. Times, Courier, and Arial are the
examples of the font names.You can obtain a list of available font family names by invoking
the static getFamilies() method. List is an interface that defines common methods for a
list. ArrayList is a concrete implmentation of List . The font postures are two constants:
FontPosture.ITALIC and FontPosture.REGULAR . For example, the following state-
ments create two fonts.

Font font1 = new Font( " SansSerif " , 16 );
Font font2 = Font.font( " Times New Roman " , FontWeight.BOLD,
FontPosture.ITALIC, 12 );

Listing 14.8 gives a program that displays a label using the font (Times New Roman, bold,
italic, and size 20), as shown in Figure 14.11.