How to position text relative to page?

My code gives me inconsistent positions of text.

How do I set the position of text so that it is centered vertically relative to its page size? I want to position it say for example x number of points from right and centered vertically. The text of course is rotated 90 degrees.

int n = reader.getNumberOfPages();
PdfImportedPage page;
PdfCopy.PageStamp stamp;
for (int j = 0; j  n; ) {
    ++j;
    page = writer.getImportedPage(reader, j);
    stamp = writer.createPageStamp(page);
    Rectangle crop = reader.getCropBox(1);
    // add overlay text
    Phrase phrase = new Phrase("Overlay Text");
    ColumnText.showTextAligned(stamp.getOverContent(), Element.ALIGN_CENTER,
        phrase, crop.getRight(72f), crop.getHeight() / 2, 90);
    stamp.alterContents();
    writer.addPage(page);
}

The code above gives me inconsistent positions of text. In some pages, only a portion of the "Overlay text" is visible. Please help, I don't know how to properly use mediabox and cropbox and I'm new to iText.

Posted on StackOverflow on Jul 13, 2013 by euler

Regarding the inconsistent position: that should be fixed by adding the vertical offset:

crop.getRight(72f), crop.getBottom() + crop.getHeight() / 2

Do you see? You took the right border with a margin of 1 inch as x coordinate, but you forgot to take into account the y coordinate of the bottom of the page (it's not always 0). Normally, this should fix the positioning problem.