java - Using PrinterJob to print an Image (Graphics2D)

Question

Is there a way I can rig a PrinterJob in Java to NOT actually print to a printer so that I can get the graphics objects for each page? I tried setting the PrintService to null, but Java wouldn't allow that.

This is so that I can retrieve an accurate Print Preview for the document without essentially rebuilding PrinterJobs functions from the ground-up in a different context.

Here's the code for the print function in my program:

public int print(Graphics graphics, PageFormat pageFormat, int page) throws PrinterException {

    deepCopyString = string;

    FontMetrics metrics = graphics.getFontMetrics(font);
    int lineHeight = metrics.getHeight();

    arrangePage(graphics, pageFormat, metrics);

    if (page > pageBreaks.length){
        return NO_SUCH_PAGE;
    }

    Graphics2D g = (Graphics2D) graphics;

    g.translate(pageFormat.getImageableX(), pageFormat.getImageableY());
    g.setFont(font);

    int begin = (page == 0) ? 0 : pageBreaks[page-1];
    int end = (page == pageBreaks.length) ? lines.length : pageBreaks[page];

    int y = 0;
    int x = 0;

    for (int line = begin; line < end; line++){
        x = 0;
        y += lineHeight;

        checkSyntax(line);

        String l = lines[line];

        for (int c = 0; c < l.length(); c++){
            applySyntax(c, line);

            metrics = graphics.getFontMetrics(font);
            String ch = Character.toString(l.charAt(c));

            g.setFont(font);
            g.drawString(ch, x, y);

            x += metrics.charWidth(l.charAt(c));
            //System.out.println(c + "/"+l.length());
        }

        //g.drawString(lines[line], 0, y);
    }

    reset();

    records.add(g);

    return PAGE_EXISTS;
}

You can already see that the Graphics objects are recorded so that I can paint them in another component, but it's rather useless seeing as it will go ahead and send these to my printer before the record can be completed.

This may be a bad idea in general, and I'm pretty new to printing. If this is seriously a bad way to go about this, feel free to direct me to a source that'll explain a better way.

Answer 1

Basically, you want to create you own Graphics context to which you can paint. You also need to construct a PageFormat that can be past to the print method.

public class TestPrint implements Printable  {

    private BufferedImage background;
    public static final float DPI = 72;

    public static void main(String[] args) {
        new TestPrint();
    }

    public TestPrint() {

        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (Exception ex) {
                }

                try {
                    background = ImageIO.read(new File("C:/Users/shane/Dropbox/MegaTokyo/MgkGrl_Yuki_by_fredrin.jpg"));
                } catch (IOException ex) {
                    ex.printStackTrace();
                }

                float width = cmToPixel(21f, DPI);
                float height = cmToPixel(29.7f, DPI);

                Paper paper = new Paper();
                float margin = cmToPixel(1, DPI);
                paper.setImageableArea(margin, margin, width - (margin * 2), height - (margin * 2));
                PageFormat pf = new PageFormat();
                pf.setPaper(paper);

                BufferedImage img = new BufferedImage(Math.round(width), Math.round(height), BufferedImage.TYPE_INT_RGB);
                Graphics2D g2d = img.createGraphics();
                g2d.setColor(Color.WHITE);
                g2d.fill(new Rectangle2D.Float(0, 0, width, height));
                try {
                    g2d.setClip(new Rectangle2D.Double(pf.getImageableX(), pf.getImageableY(), pf.getImageableWidth(), pf.getImageableHeight()));
                    print(g2d, pf, 0);
                } catch (PrinterException ex) {
                    ex.printStackTrace();
                }
                g2d.dispose();

                JFrame frame = new JFrame("Test");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JLabel(new ImageIcon(img)));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);

            }
        });

    }

    public float cmToPixel(float cm, float dpi) {

        return (dpi / 2.54f) * cm;

    }

    public int print(Graphics graphics, PageFormat pageFormat, int page) throws PrinterException {

        if (page > 0) {
            return NO_SUCH_PAGE;
        }

        Graphics2D g = (Graphics2D) graphics;

        g.translate(pageFormat.getImageableX(), pageFormat.getImageableY());
        if (background != null) {

            int x = (int)Math.round((pageFormat.getImageableWidth() - background.getWidth()) / 2f);
            int y = (int)Math.round((pageFormat.getImageableHeight() - background.getHeight()) / 2f);

            g.drawImage(background, x, y, null);

        }

        g.setColor(Color.BLACK);
        g.draw(new Rectangle2D.Double(0, 0, pageFormat.getImageableWidth() - 1, pageFormat.getImageableHeight() - 1));

        return PAGE_EXISTS;
    }
}

Now, obviously, there are going to be difference to what is printed to the screen and what's printed to the printer, because we're not actually using the same hardware device, but the basic concept applies