Rotating PDF 90 degrees using iTextSharp in C#
The Rotate90Degrees example uses PdfReader
to get an instance of the document then changes the /Rotate
value in every page dictionary. If there is no such entry, a /Rotate
entry with value 90
is added:
final PdfReader reader = new PdfReader(source);
final int pagesCount = reader.getNumberOfPages();
for (int n = 1; n <= pagesCount; n++) {
final PdfDictionary page = reader.getPageN(n);
final PdfNumber rotate = page.getAsNumber(PdfName.ROTATE);
final int rotation =
rotate == null ? 90 : (rotate.intValue() + 90) % 360;
page.put(PdfName.ROTATE, new PdfNumber(rotation));
}
Once this is done, we use a PdfStamper
to persist the change:
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
stamper.close();
reader.close();
This is for iText Java. For iTextSharp, porting Java to C# is easy as the terminology is identical. Change some lower cases into upper cases like this:
PdfDictionary page = reader.GetPageN(1);
page.Put(PdfName.ROTATE, new PdfNumber(90));
There's a more or less identical code snippet in the question part of this post: How to rotate PDF page with iTextSharp without causing error in ghostscript?