Learning Java

Printing

Earlier in this chapter, we hinted at the possibility that you could draw the same stuff on the screen and the printer. It’s true; all you really need to do is get a Graphics2D that represents a printer rather than an area of the screen. Java 2’s Printing API provides the necessary plumbing. There isn’t room here to describe the whole Printing API, but we will provide you with a short example that will let you get your feet wet (and your paper blackened).

The printing classes are tucked away in the java.awt.print package. You can print anything that implements the Printable interface. This interface has only one method—you guessed it, print( ). This method, like the paint( ) methods we’ve already worked with, accepts a Graphics object that represents the drawing surface of the printer’s page. It also accepts a PageFormat object that encapsulates information about the paper on which you’re printing. Finally, print( ) is passed the number of the page that is being rendered.

Your print( ) implementation should either render the requested page or state that it doesn’t exist. You can do this by returning special values from print( ), either Printable.PAGE_EXISTS or Printable.NO_SUCH_PAGE.

You can control a print job, including showing print and page setup dialogs, using the PrinterJob class. The following class will enable you to get something on paper:

//file: UnbelievablySimplePrint.java import java.awt.*; import java.awt.print.*; public class UnbelievablySimplePrint implements ...