Different PageSize for each page in itext 7

Question

I need the page size to change to a certain page.

For example if page 3 i set pageSize A4.

If page 2 i set pageSize new Rectangle(155,155)

 String line = "Hello! Welcome to iTextPdf";
    Div div = new Div();
        for (int i = 0; i < 30; i++) {
            Paragraph element = new Paragraph();
            element.add(line + " " + i);
      

            paragraphs.add(element);

        }



--------------
  if(page==1) // This is just for an example. How I want it to be
   pdf.setDefaultPageSize(PageSize.A5);
   else if(page==3)
 element.setDefaultPageSize(PageSize.A4);

Answer 1

You can override the DocumentRenderer class and customize #addNewPage:

private static class CustomDocumentRenderer extends DocumentRenderer {
    public CustomDocumentRenderer(Document document) {
        super(document);
    }

    @Override
    protected PageSize addNewPage(PageSize customPageSize) {
        if (customPageSize != null) {
            document.getPdfDocument().addNewPage(customPageSize);
            return customPageSize;
        } else {
            PageSize pageSize = definePageSizeBasedOnPageNumber(document.getPdfDocument().getNumberOfPages() + 1);
            document.getPdfDocument().addNewPage(pageSize);
            return pageSize;
        }
    }

    private PageSize definePageSizeBasedOnPageNumber(int curPageNumber) {
        if (curPageNumber % 2 == 1) {
            return PageSize.A4;
        } else {
            return PageSize.A4.rotate();
        }
    }
}

Here we have a helper private method definePageSizeBasedOnPageNumber to define the page size based on the page number.

Using this customized renderer is very simple now: document.setRenderer(new CustomDocumentRenderer(document));

Full snippet of code at the highest execution level:

Document document = new Document(pdfDocument);
document.setRenderer(new CustomDocumentRenderer(document));

String line = "Hello! Welcome to iTextPdf";
for (int i = 0; i < 30; i++) {
    Paragraph element = new Paragraph();
    element.add(line + " " + i);
    document.add(element);
}

document.close();