Itext 7 - Vertical watermark using text - itext7

Question

I have been trying to add a watermark in a pdf using Itext 7. The watermark needs to be at the left side of each page and should be vertical. Something like shown in the following image:
Instead of being in centre, it should be at the left side of the page.
I tried the following code, but any angle I try it does not work for me -
File mergedDoc = new File(mergedFileName + ".pdf");
PdfDocument pdfDoc = new PdfDocument(new PdfWriter(mergedDoc));
Document document = new Document(pdfDoc);
PdfFont font = PdfFontFactory.createFont(FontProgramFactory.createFont(FontConstants.HELVETICA));
Paragraph verticalWatermark = new Paragraph("My vertical watermark").setFont(font).setFontSize(30);
for (int i = 1 + pdfDoc.getNumberOfPages(); i <= k; i++) {
PdfPage page = pdfDoc.getPage(i);
page.setIgnorePageRotationForContent(false);
over = new PdfCanvas(pdfDoc.getPage(i));
over.saveState();
over.setExtGState(gs1);
document.showTextAligned(verticalWatermark, 30f, 25f, i, TextAlignment.LEFT, VerticalAlignment.BOTTOM, 90);
over.restoreState();
pdfDoc.close();
document.close();
}
Any help would be appreciated.

Answer 1

Your code is wrong in many places.
You combine low-level operations such saveState()/restoreState() on a PdfCanvas in combination with the high-level Document class' showTextAligned() method.
You start counting at 1 + pdfDoc.getNumberOfPages() which is weird. Your code sample is not a SSCCE. No one but you can run it because no one but you knows what variables such as k and gs1 are about. Not providing a SSCCE is often interpreted as "I am asking a question, but I'm not interested in getting an answer."
You are defining a value in degrees where a value in radians is expected, see the API docs: showTextAligned(Paragraph p, float x, float y, int pageNumber, TextAlignment textAlign, VerticalAlignment vertAlign, float radAngle)
I have taken the iText 7 Jump-Start Tutorial, and I have added a vertical watermark to the left of the page:
This was the code I used:
PdfReader reader = new PdfReader(src);
PdfWriter writer = new PdfWriter(dest);
PdfDocument pdf = new PdfDocument(reader, writer);
Document document = new Document(pdf);
Paragraph p = new Paragraph("My vertical watermark");
for (int i = 1; i <= pdf.getNumberOfPages(); i++) {
document.showTextAligned(
p, 36, 72, i, TextAlignment.LEFT, VerticalAlignment.BOTTOM,
(float)Math.PI / 2);
}
document.close();
As you can see: there's no need for a PdfCanvas and it's Math.PI / 2 radians instead of 90 degrees.