Render XHTML on one page to PDF

Question

I have XHTML containing shop receipt. I am trying to generate PDF out of it. Generation is not problem at all. But I would like to have "break-less" page (whole content fits to one page).

I have Koltin Spring project and using flying-saucer.

org.xhtmlrenderer:flying-saucer-pdf-itext5:9.1.22

Code is simple as this:

fun generatePDF(templateString: String): ByteArrayOutputStream {
    val renderer = ITextRenderer()

    renderer.sharedContext.also {
        it.isPrint = true
        it.isInteractive = false
        it.textRenderer.setSmoothingThreshold(0F)
    }

    renderer.setDocumentFromString(templateString, baseUrl)
    renderer.layout()

    val baos = ByteArrayOutputStream()

    renderer.createPDF(baos)
    renderer.finishPDF()

    return baos
}

Is it somehow possible to do it?

Note: I've found some information about page size in the documentation, but I am not sure how to use it if I don't know the exact size (items in receipt are calculated).