Question

我一直在大型项目中工作，其功能之一应该是打印主窗口的内容。我检查了API并找到了这个例子：

http://docs.oracle.com/javase/tutorial/2d/printing/gui.html

它非常有用，我尝试在我的程序中使用该代码，方法是将它放在我的打印按钮的actionperformed方法中：

PrinterJob job = PrinterJob.getPrinterJob();
     job.setPrintable(this);
     boolean ok = job.printDialog();
     if (ok) {
         try {

             job.print();
         } catch (PrinterException ex) {
          /* The job did not successfully complete */
         }
     }

如果我点击打印按钮，我会看到一个打印机对话框，当我告诉它打印时，它只会打印一个空白文档。我知道上面的代码并不是我所需要的，正如我在API的例子中看到的那样有一个print（）方法，但显然它们从不调用它，所以它非常令人困惑。我试过多次打电话和使用它，但没有成功。

另外，我认为当我最终打印时，我的窗口需要以横向打印，甚至可能需要一些缩放。有关如何做到这一点的任何想法？

我希望有任何有用的帮助来帮助我成功实现此代码。我知道我应该能够通过检查文档来自己完成（我已经尝试了近两天），但我无法让它工作。我通过互联网学会了所有我熟悉的编程。任何帮助将不胜感激。

Answer 1

这是一个简单的解决方案。我有一个实现可打印的Printer类，它将处理打印作业：

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;
    }
}

接下来，要打印它：

JFrame yourComponent = new JFrame();
PrinterJob pjob = PrinterJob.getPrinterJob();
PageFormat preformat = pjob.defaultPage();
preformat.setOrientation(PageFormat.LANDSCAPE);
PageFormat postformat = pjob.pageDialog(preformat);
//If user does not hit cancel then print.
if (preformat != postformat) {
    //Set print component
    pjob.setPrintable(new Printer(yourComponent), postformat);
    if (pjob.printDialog()) {
        pjob.print();
    }
}

Answer 2

这是我对这个想法的歪曲......

打印以适合......

A4-Fit

打印填写......

A4-Fill

public class TestPrinting {

    public static void main(String[] args) {    
        try {
            printComponentToFile(new PrintForm(), true);
            printComponentToFile(new PrintForm(), false);
        } catch (PrinterException exp) {
            exp.printStackTrace();
        }
    }

    public static void printComponent(JComponent comp, boolean fill) throws PrinterException {
        PrinterJob pjob = PrinterJob.getPrinterJob();
        PageFormat pf = pjob.defaultPage();
        pf.setOrientation(PageFormat.LANDSCAPE);

        PageFormat postformat = pjob.pageDialog(pf);
        if (pf != postformat) {
            //Set print component
            pjob.setPrintable(new ComponentPrinter(comp, fill), postformat);
            if (pjob.printDialog()) {
                pjob.print();
            }
        }    
    }

    public static void printComponentToFile(Component comp, boolean fill) throws PrinterException {    
        Paper paper = new Paper();
        paper.setSize(8.3 * 72, 11.7 * 72);
        paper.setImageableArea(18, 18, 559, 783);

        PageFormat pf = new PageFormat();
        pf.setPaper(paper);
        pf.setOrientation(PageFormat.LANDSCAPE);

        BufferedImage img = new BufferedImage(
                        (int) Math.round(pf.getWidth()),
                        (int) Math.round(pf.getHeight()),
                        BufferedImage.TYPE_INT_RGB);

        Graphics2D g2d = img.createGraphics();
        g2d.setColor(Color.WHITE);
        g2d.fill(new Rectangle(0, 0, img.getWidth(), img.getHeight()));
        ComponentPrinter cp = new ComponentPrinter(comp, fill);
        try {
            cp.print(g2d, pf, 0);
        } finally {
            g2d.dispose();
        }

        try {
            ImageIO.write(img, "png", new File("Page-" + (fill ? "Filled" : "") + ".png"));
        } catch (IOException ex) {
            ex.printStackTrace();
        }        
    }

    public static class ComponentPrinter implements Printable {

        private Component comp;
        private boolean fill;

        public ComponentPrinter(Component comp, boolean fill) {
            this.comp = comp;
            this.fill = fill;
        }

        @Override
        public int print(Graphics g, PageFormat format, int page_index) throws PrinterException {

            if (page_index > 0) {
                return Printable.NO_SUCH_PAGE;
            }

            Graphics2D g2 = (Graphics2D) g;
            g2.translate(format.getImageableX(), format.getImageableY());

            double width = (int) Math.floor(format.getImageableWidth());
            double height = (int) Math.floor(format.getImageableHeight());

            if (!fill) {

                width = Math.min(width, comp.getPreferredSize().width);
                height = Math.min(height, comp.getPreferredSize().height);

            }

            comp.setBounds(0, 0, (int) Math.floor(width), (int) Math.floor(height));
            if (comp.getParent() == null) {
                comp.addNotify();
            }
            comp.validate();
            comp.doLayout();
            comp.printAll(g2);
            if (comp.getParent() != null) {
                comp.removeNotify();
            }

            return Printable.PAGE_EXISTS;
        }

    }

}

一些更广泛的问题......

您或多或少地负责打印组件的布局。至少你会想确保它们适合或者你有某种溢出机制......
您可能需要“欺骗”屏幕上尚未显示的组件，认为它们是......因此addNotify / validate / {{1}周围的所有肮脏}}。即使在屏幕上显示，如果修改其边界，也可能需要调用这些方法。

打印JFrame及其组件

2 个答案: