cpdf-source/cpdfannot.ml

189 lines
6.7 KiB
OCaml

open Pdfutil
(* For uses of process_pages which don't need to deal with matrices, this
function transforms into one which returns the identity matrix *)
let ppstub f n p = (f n p, n, Pdftransform.i_matrix)
(* \section{List annotations} *)
let get_annotation_string encoding pdf annot =
match Pdf.lookup_direct pdf "/Contents" annot with
| Some (Pdf.String s) -> Cpdfmetadata.encode_output encoding s
| _ -> ""
let print_annotation encoding pdf num s =
let s = get_annotation_string encoding pdf s in
match s with
| "" -> ()
| s ->
flprint (Printf.sprintf "Page %d: " num);
flprint s;
flprint "\n"
let list_page_annotations encoding pdf num page =
match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
| Some (Pdf.Array annots) ->
iter (print_annotation encoding pdf num) (map (Pdf.direct pdf) annots)
| _ -> ()
let annotations_json_page pdf page pagenum =
match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
| Some (Pdf.Array annots) ->
map
(fun annot ->
`List [`Int pagenum; Cpdfjson.json_of_object pdf (fun _ -> ()) false false annot])
(map (Pdf.direct pdf) annots)
| _ -> []
let list_annotations_json pdf =
let module J = Cpdfyojson.Safe in
let pages = Pdfpage.pages_of_pagetree pdf in
let pagenums = indx pages in
let json = `List (flatten (map2 (annotations_json_page pdf) pages pagenums)) in
J.pretty_to_channel stdout json
let list_annotations ~json encoding pdf =
let range = Cpdfpagespec.parse_pagespec pdf "all" in
if json
then list_annotations_json pdf
else Cpdfpage.iter_pages (list_page_annotations encoding pdf) pdf range
let get_annotations encoding pdf =
let pages = Pdfpage.pages_of_pagetree pdf in
flatten
(map2
(fun page pagenumber ->
match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
| Some (Pdf.Array annots) ->
let strings =
map (get_annotation_string encoding pdf) (map (Pdf.direct pdf) annots)
in
combine (many pagenumber (length strings)) strings
| _ -> [])
pages
(ilist 1 (length pages)))
(* Equalise the page lengths of two PDFs by chopping or extending the first one.
*)
let equalise_lengths a b =
let a' =
if Pdfpage.endpage a < Pdfpage.endpage b then
Pdfpage.change_pages false a
(Pdfpage.pages_of_pagetree a @
many (Pdfpage.blankpage Pdfpaper.a4) (Pdfpage.endpage b - Pdfpage.endpage a))
else if Pdfpage.endpage a > Pdfpage.endpage b then
Pdfpage.change_pages false a
(take (Pdfpage.pages_of_pagetree a) (Pdfpage.endpage b))
else a
in
a', b
(* Copy annotations *)
(* FIXME: Why does this chop the files to the same length? Should be able to
apply annotations from a longer file to a shorter? *)
(* Rewrite any annotation destinations to point to pages in the
destination file. This prevents pages being copied, and ensures the links are
correct Any Indirect link inside a /Dest is rewritten if in the table. If not
inside a /Dest, nothing is rewritten. *)
let rec renumber_in_dest table indest = function
Pdf.Indirect i ->
begin
try Pdf.Indirect (Hashtbl.find table i) with _ -> Pdf.Indirect i
end
| Pdf.Array a ->
Pdf.recurse_array (renumber_in_dest table indest) a
| Pdf.Dictionary d ->
Pdf.Dictionary
(map
(function
("/Dest", v) -> ("/Dest", renumber_in_dest table true v)
| (k, v) -> (k, renumber_in_dest table indest v))
d)
| x -> x
let renumber_in_object pdf objnum table =
Pdf.addobj_given_num
pdf (objnum, (renumber_in_dest table false (Pdf.lookup_obj pdf objnum)))
let copy_annotations_page topdf frompdf frompage topage =
match Pdf.lookup_direct frompdf "/Annots" frompage.Pdfpage.rest with
Some (Pdf.Array frompage_annots as annots) ->
let table =
hashtable_of_dictionary
(combine
(Pdf.page_reference_numbers frompdf)
(Pdf.page_reference_numbers topdf))
in
iter
(function
(* FIXME: We assume they are indirects. Must also do direct, though rare.*)
Pdf.Indirect x ->
(*Printf.printf "Copying annotation %s which is\n%s\n"
(Pdfwrite.string_of_pdf (Pdf.Indirect x))
(Pdfwrite.string_of_pdf (Pdf.direct frompdf (Pdf.Indirect
x)));*)
renumber_in_object frompdf x table
| _ -> ())
frompage_annots;
let objects_to_copy = Pdf.objects_referenced [] [] frompdf annots in
iter
(fun n ->
ignore (Pdf.addobj_given_num topdf (n, Pdf.lookup_obj frompdf n)))
objects_to_copy;
let topage_annots =
match Pdf.lookup_direct frompdf "/Annots" topage.Pdfpage.rest with
| Some (Pdf.Array annots) -> annots
| _ -> []
in
let merged_dict = Pdf.Array (frompage_annots @ topage_annots) in
let topage' =
{topage with Pdfpage.rest =
Pdf.add_dict_entry topage.Pdfpage.rest "/Annots" merged_dict}
in
topdf, topage'
| Some x -> topdf, topage
| None -> topdf, topage
let copy_annotations range frompdf topdf =
let frompdf, topdf = equalise_lengths frompdf topdf in
match Pdf.renumber_pdfs [frompdf; topdf] with
| [frompdf; topdf] ->
let frompdf_pages = Pdfpage.pages_of_pagetree frompdf in
let topdf_pages = Pdfpage.pages_of_pagetree topdf in
let pdf = ref topdf
and pages = ref []
and pnum = ref 1
and frompdf_pages = ref frompdf_pages
and topdf_pages = ref topdf_pages in
(* Go through, updating pdf and collecting new pages. *)
while not (isnull !frompdf_pages) do
let frompdf_page = hd !frompdf_pages
and topdf_page = hd !topdf_pages in
let pdf', page =
if mem !pnum range
then copy_annotations_page !pdf frompdf frompdf_page topdf_page
else !pdf, topdf_page
in
pdf := pdf';
pages =| page;
incr pnum;
frompdf_pages := tl !frompdf_pages;
topdf_pages := tl !topdf_pages
done;
Pdfpage.change_pages true !pdf (rev !pages)
| _ -> assert false
(* \section{Remove annotations} *)
let remove_annotations range pdf =
let remove_annotations_page pagenum page =
if mem pagenum range then
let rest' =
Pdf.remove_dict_entry page.Pdfpage.rest "/Annots"
in
{page with Pdfpage.rest = rest'}
else
page
in
Cpdfpage.process_pages (ppstub remove_annotations_page) pdf range