Sams Teach Yourself Java™ in 24 Hours (Covering Java 7 and Android)

ptg7068951

Drawing Lines and Shapes 329

public voidpaintComponent(Graphics comp) {
Graphics2D comp2D = (Graphics2D) comp;
comp2D.setColor(Color.orange);
comp2D.drawString(“Go, Buccaneers!”, 5, 50);
}

Unlike the setBackground()method, which you can call directly on a con-
tainer, you must call the setColor()method on a Graphics2Dobject.

Creating Custom Colors

You can create custom colors in Java by specifying their Standard Red
Green Blue (sRGB) value. sRGBdefines a color by the amount of red,
green, and blue present in the color. Each value ranges from 0 (none of that
color) to 255 (the maximum amount).

The constructor Color(int, int, int)takes arguments representing the
red, green, and blue values. The following code draws a panel that dis-
plays light orange text (230 red, 220 green, 0 blue) on a dark red (235 red,
50 green, 50 blue) background:

importjava.awt.;
importjavax.swing.;

public classGoBucs extendsJPanel {
Color lightOrange= new Color(230, 220, 0);
Color darkRed= newColor(235, 50, 50);

public voidpaintComponent(Graphics comp) {
Graphics2D comp2D = (Graphics2D) comp;
comp2D.setColor(darkRed);
comp2D.fillRect(0, 0, 200, 100);
comp2D.setColor(lightOrange);
comp2D.drawString(“Go, Buccaneers!”, 5, 50);
}
}

This example calls the fillRect()method of Graphics2Dto draw a filled-
in rectangle using the current color.

Drawing Lines and Shapes

Drawing shapes such as lines and rectangles is as easy in a Java program
as displaying text. All you need is a Graphics2Dobject to define the draw-
ing surface and objects that represent things to draw.

NOTE

sRGB values enable the cre-

ation of 16.5 million possible

combinations,though most

computer monitors only offer a

close approximation for most of

them. For guidance on whether

burnt-midnight blue goes well

with medium-faded-baby green,

readSams Teach Yourself Color

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