Question

Many people who generate PDFs need to bind them. A good binding requires that every other page support an alternate margin size on its left and right sides. I know JasperReports did not support this in its 3.x series. Is this supported in the 4.x series?

Answer 1

You can accomplish marginMirroring as mentioned by Dave, by subclassing JRPdfExporter, overriding the method, exportReportToStream. Unfortunately, you will need to copy the source for this method into your override. In your override, you will modify the page loop, like so:

for(int pageIndex = startPageIndex; pageIndex <= endPageIndex; pageIndex++)
{
    int margin = marginLeft;
    if (pageIndex % 2 == 1) margin = marginRight;

    parameters.put(JRExporterParameter.OFFSET_X, margin);
    setOffset();
    ...

The constructor for my subclass takes in the margins:

public MirroringJRPdfExporter(int left, int right, int top, int bottom) {
    this.marginLeft = left;
    this.marginRight = right;
    this.marginTop = top;
    this.marginBottom = bottom;
}    

I took in top and bottom too, just in case I needed to mirror that for page flipping.

Another unfortunate note, exportReportToStream uses a helper, JRPdfExporterTagHelper, and calls 2 methods, init and setPdfWriter, which are protected, so your subclass will not compile unless you subclass the helper too and expose those methods to your subclass. I did this:

public class JRPdfExporterTagHelper extends
        net.sf.jasperreports.engine.export.JRPdfExporterTagHelper {

    protected JRPdfExporterTagHelper(JRPdfExporter exporter) {
        super(exporter);
    }

    public void setPdfWriter2(PdfWriter pdfWriter) {
        setPdfWriter(pdfWriter);
    }

    public void init2(PdfContentByte pdfContentByte) {
        init(pdfContentByte);
    }
} 

Then, I call it like this:

MirroringJRPdfExporter exporter = new MirroringJRPdfExporter(72, 36, 44, 31);

exporter.setParameter(JRExporterParameter.JASPER_PRINT, print);
exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, output);
exporter.exportReport();