Simplest Print rectangle of known dimensions in mm

Question

I'm trying to get an applet in a browser to print properly.
I want to provide metric coordinates and have them honoured!
I've ported a parametric CAD system to java but can't get the printouts to be sensible! So close and yet so far...
I only need to draw lines, so the simple Graphics interface will be fine, but I'm not sure if there is a print callback I should hook to or if paint is what to use...
public void paint(Graphics g) {
  // I'd like to set a scale here so that the units I give are 10 microns
  g.drawRect(0, 0, 5000, 10000); // This should then print a 5cm x 10cm box
}In C++ I'd have to set a mapping mode, I've found things like MediaSize and implementing Printable but I can't find anything for simple JDK1.6.0_10
Swing forum mentions a print callback: Printable's method implementation:
public int print (Graphics g, PageFormat pf, int idx) throws PrinterException...
I don't even know what Swing is, and hope I don't have to learn just to draw a rectangle!
I've wasted far too much time trying to find this out for myself!
Help! This should be sooooo easy!

Answer 1

Looks like I have to answer this myself...
Three evenings later, I've figured out a way.
This is the answer I was hoping for!
import java.applet.*;
import java.awt.*;
import java.awt.print.*;
import java.awt.event.*;
public class ScaledPrintExample extends Applet implements Printable, MouseListener {
  public void init() {
    setBackground(Color.white);
    addMouseListener(this);
  public void mousePressed (MouseEvent e) {}
  public void mouseReleased(MouseEvent e) {}
  public void mouseClicked (MouseEvent e) {Print();}
  public void mouseEntered (MouseEvent e) {}
  public void mouseExited  (MouseEvent e) {}
  public void Print() {
    PrinterJob printerJob = PrinterJob.getPrinterJob();
    PageFormat pageFormat = printerJob.defaultPage();
    pageFormat.setOrientation(PageFormat.PORTRAIT);
    printerJob.setPrintable(this, pageFormat);
    printerJob.setJobName("Print Test");
    try {if(printerJob.printDialog()) printerJob.print();} catch (PrinterException e) {}
  public int print(Graphics g1, PageFormat pf, int pageIndex) {
    if(pageIndex!=0) return Printable.NO_SUCH_PAGE;
    Graphics2D g=(Graphics2D)g1;
    g.translate(pf.getImageableX(), pf.getImageableY());
    g.setStroke(new BasicStroke(0.0f));
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    paint(g);
    Toolkit.getDefaultToolkit().beep();
    return Printable.PAGE_EXISTS;
  public void paint(Graphics g1) {
    Graphics2D g = (Graphics2D) g1; // Have to use the 72dpi to convert
    g.drawRect(0,0, 1*72, 2*72); // 1" by 2" box
    int n=2540/72; // 1 unit = 10 microns if divided by n (my existing C++ uses 10 micron units). To stay with integer math, use division, so that n is large.
    g.drawRect(0,0, 1000/n, 2000/n); // 1cm by 2cm box
}