swing设置要在Java代码中打印的页边距

Question

我正试图打印一个JPanel。。。我有工作代码。但问题是，它正在从四个侧面打印JPanel和broad magin。。。请有人查一下我的密码。并建议我，我如何才能改变我的代码，将适合a4大小的纸张与最低限度的利润。这是激活操作的代码

btnNewButton.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        PrinterJob pjob = PrinterJob.getPrinterJob();
        PageFormat preformat = pjob.defaultPage();
        preformat.setOrientation(PageFormat.PORTRAIT);
        PageFormat postformat = pjob.pageDialog(preformat);

        if (preformat != postformat) {
            RepairBill r=new RepairBill();
            r.setVisible(false);
            pjob.setPrintable(new Printer(r.r), postformat); //r.r is the object for JPanel
            if (pjob.printDialog()) {
                try {
                    pjob.print();
                } catch (PrinterException e1) {
                        // TODO Auto-generated catch block
                        e1.printStackTrace();
                    }
                }
            }
        }
    });

打印机类代码

public static class Printer implements Printable {
    final Component comp;

    public Printer(Component comp) {
        this.comp = comp;
    }

    @Override
    public int print(Graphics g, PageFormat format, int page_index) throws PrinterException {
        if (page_index > 0) {
            return Printable.NO_SUCH_PAGE;
        }

        // get the bounds of the component
        Dimension dim = comp.getSize();
        double cHeight = dim.getHeight();
        double cWidth = dim.getWidth();

        // get the bounds of the printable area
        double pHeight = format.getImageableHeight();
        double pWidth = format.getImageableWidth();
        double pXStart = format.getImageableX();
        double pYStart = format.getImageableY();
        double xRatio = pWidth / cWidth;
        double yRatio = pHeight / cHeight;
        Graphics2D g2 = (Graphics2D) g;
        g2.translate(pXStart, pYStart);
        g2.scale(xRatio, yRatio);
        comp.paint(g2);
        return Printable.PAGE_EXISTS;
    }
}

plz see the screenshot of my output

Answer 1

我添加了边距：水平边距为1英寸，垂直边距为0.5英寸

检查页边距是否仍可打印（1 mm的页边距不可行）

我没有提及页面大小，因为这是一个物理设备问题，例如，无论某人有A4还是美国字母。人们可以在PrintJob中设置它，查看API和网络中的javadoc

现在按比例进行缩放

    // get the bounds of the component
    Dimension dim = comp.getSize();
    double cHeight = dim.getHeight();
    double cWidth = dim.getWidth();

    // get the bounds of the printable area
    double pHeight = format.getImageableHeight();
    double pWidth = format.getImageableWidth();
    double pXStart = format.getImageableX();
    double pYStart = format.getImageableY();
    double paperHeight = format.getHeight();
    double paperWidth = format.getWidth();

    final int INCH = 72;
    double vertMargin = 0.5 * INCH;
    double horMargin = 1 * INCH;

    // Check whether margins are enough, are printable.
    if (paperWidth - 2 * horMargin < pWidth) {
        pWidth = paperWidth - 2 * horMargin;
        pXStart = horMargin
    }
    if (paperHeight - 2 * vertMargin < pHeight) {
        pHeight = paperHeight - 2 * vertMargin;
        pYStart = vertMargin;
    }

    // Determine scaling
    double xRatio = pWidth / cWidth;
    double yRatio = pHeight / cHeight;
    double ratio = Math.min(xRatio, yRation); // Proportional

    Graphics2D g2 = (Graphics2D) g;
    g2.translate(pXStart, pYStart);
    g2.scale(ratio, ratio);
    comp.paint(g2);