How do I adjust the pages of annotations in a FDF file?

Question:

Before merging annotations in a FDF object into a PDF object, I want to adjust the pages that some annotations are on. How do I check the annotations type and possibly change the page?

Answer:

The following code will get you started with this. Note that in a FDF document, the pages start at index zero, while for a PDFDoc the index is one.

//given FDFDoc fdfdoc instance Obj fdfroot = fdfdoc.GetRoot(); Obj fdfdict = fdfroot.FindObj("FDF"); Obj annotsarray = fdfdict.FindObj("Annots"); if(annotsarray == null || !annotsarray.IsArray()) return; int annots_sz = annotsarray.Size(); for(int i = 0; i < annots_sz; ++i) { Obj annotobj = annotsarray.GetAt(i); Annot annot = new Annot(annotobj); Annot.Type annotType = annot.GetType(); int page_index = annotobj.FindObj("Page").GetNumber(); // change the page number to page 10 for example annotobj.PutNumber("Page", 9)' // zero indexed, so index 9 is the tenth page in the PDF }