This section explains how to create a basic printing program that displays a print dialog and prints the text "Hello World" to the selected printer.
Printing task usually consists of two parts:
- Job control — Creating a print job, associating it with a printer, specifying the number of copies, and user print dialog interaction.
- Page Imaging — Drawing content to a page, and managing content that spans pages (pagination).
First create the printer job. The class representing a printer job and most other related classes is located in the
java.awt.print
package.import java.awt.print.*; PrinterJob job = PrinterJob.getPrinterJob();Next provide code that renders the content to the page by implementing the
Printable
interface.class HelloWorldPrinter implements Printable { ... } .. job.setPrintable(new HelloWorldPrinter());An application typically displays a print dialog so that the user can adjust various options such as number of copies, page orientation, or the destination printer.
boolean doPrint = job.printDialog();This dialog appears until the user either approves or cancels printing. The
doPrint
variable will be true if the user gave a command to go ahead and print. If thedoPrint
variable is false, the user cancelled the print job. Since displaying the dialog at all is optional, the returned value is purely informational.If the
doPrint
variable is true, then the application will request that the job be printed by calling thePrinterJob.print
method.if (doPrint) { try { job.print(); } catch (PrinterException e) { /* The job did not successfully complete */ } }The
PrinterException
will be thrown if there is problem sending the job to the printer. However, since thePrinterJob.print
method returns as soon as the job is sent to the printer, the user application cannot detect paper jams or paper out problems. This job control boilerplate is sufficient for basic printing uses.The
Printable
interface has only one method:public int print(Graphics graphics, PageFormat pf, int page) throws PrinterException;The
PageFormat
class describes the page orientation (portrait or landscape) and its size and imageable area in units of 1/72nd of an inch. Imageable area accounts for the margin limits of most printers (hardware margin). The imageable area is the space inside these margins, and in practice if is often further limited to leave space for headers or footers.A
page
parameter is the zero-based page number that will be rendered.The following code represents the full
Printable
implementation:import java.awt.print.*; import java.awt.*; public class HelloWorldPrinter implements Printable { public int print(Graphics g, PageFormat pf, int page) throws PrinterException { if (page > 0) { /* We have only one page, and 'page' is zero-based */ return NO_SUCH_PAGE; } /* User (0,0) is typically outside the imageable area, so we must * translate by the X and Y values in the PageFormat to avoid clipping */ Graphics2D g2d = (Graphics2D)g; g2d.translate(pf.getImageableX(), pf.getImageableY()); /* Now we perform our rendering */ g.drawString("Hello world!", 100, 100); /* tell the caller that this page is part of the printed document */ return PAGE_EXISTS; } }The complete code for this example is inHelloWorldPrinter.java
.Sending a
Graphics
instance to the printer is essentially the same as rendering it to the screen. In both cases you need to perform the following steps:
- To draw a test string is as easy as the other operations that were described for drawing to a
Graphics2D
.- Printer graphics have a higher resolution, which should be transparent to most code.
- The
Printable.print()
method is called by the printing system, just as theComponent.paint()
method is called to paint a Component on the display. The printing system will call thePrintable.print()
method for page 0, 1,.. etc until theprint()
method returnsNO_SUCH_PAGE
.- The
print()
method may be called with the same page index multiple times until the document is completed. This feature is applied when the user specifies attributes such as multiple copies with collate option.- The PageFormat's imageable area determines the clip area. Imageable area is also important in calculating pagination, or how to span content across printed pages, since page breaks are determined by how much can fit on each page.
Note: A call to theprint()
method may be skipped for certain page indices if the user has specified a different page range that does not involve a particular page index.