Sams Teach Yourself Java™ in 24 Hours, Sixth Edition

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 Graphics2D object to define the drawing surface and objects that represent things to draw.

The Graphics2D object has methods used to draw text with a command such as the following:

comp2D.drawString("Draw, pardner!", 15, 40);

This draws the text “Draw, pardner!” at the coordinates (15,40). Drawing methods use the same (x,y) coordinate system as text. The (0,0) coordinate is at the upper-left corner of the container, x values increase to the right, and y values increase as you go down. You can determine the maximum (x,y) value you can use in an applet with the following statements:

int maxXValue = getSize().