Wraps FPDFPage_GetAnnotIndex, FPDFPage_RemoveAnnot and
FPDFPage_CloseAnnot. The handle's annotation is located on the
page when the call is made, so it is the one removed even after
other annotations on the page were deleted. The annotation leaves
the page's /Annots array, PDFium's annotation context is
released together with any page-objects of its appearance stream,
and the handle is closed: further pdf_annot_* calls on it, and
on page-objects read from it with pdf_annot_objects(), on their
clip paths (pdf_obj_clip_path()) and on the objects of forms among
them (pdf_form_objects()), error cleanly.
Value
Invisibly returns the parent pdfium_doc. Errors, changing
nothing, when the annotation is no longer on its page, for
example because it was deleted through another handle.
Details
Later annotations on the page move down one position. Other handles
still print the position they had when they were made;
pdf_annot_index() gives the current one.