cpdf-source/cpdfannot.ml

304 lines
11 KiB
OCaml

open Pdfutil
open Cpdferror
(* 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 rewrite_destination f d =
match d with
| Pdf.Array (Pdf.Indirect i::r) ->
Pdf.Array (Pdf.Integer (f i)::r)
| x -> x
let rewrite_destinations f pdf annot =
(* Deal with /P in annotation *)
let annot =
match Pdf.indirect_number pdf "/P" annot with
| Some i -> Pdf.add_dict_entry annot "/P" (Pdf.Integer (f i))
| None -> annot
in
(* Deal with /Dest in annotation *)
match Pdf.lookup_direct pdf "/Dest" annot with
| Some d -> Pdf.add_dict_entry annot "/Dest" (rewrite_destination f d)
| None ->
(* Deal with /A --> /D dest when /A --> /S = /GoTo *)
match Pdf.lookup_direct pdf "/A" annot with
| Some action ->
begin match Pdf.lookup_direct pdf "/D" action with
| Some d ->
Pdf.add_dict_entry
annot "/A" (Pdf.add_dict_entry action "/D" (rewrite_destination f d))
| None -> annot
end
| None -> annot
let extra = ref []
let annotations_json_page calculate_pagenumber pdf page pagenum =
match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
| Some (Pdf.Array annots) ->
option_map
(fun annot ->
begin match annot with
| Pdf.Indirect objnum ->
let annot = Pdf.direct pdf annot in
let annot =
rewrite_destinations
(fun i -> calculate_pagenumber (Pdfdest.Fit (Pdfdest.PageObject i)))
pdf annot
in
extra := annot::!extra;
Some (`List
[`Int pagenum;
`Int objnum;
Cpdfjson.json_of_object ~utf8:true ~clean_strings:true pdf (fun _ -> ())
~no_stream_data:false ~parse_content:false annot])
| _ -> Printf.eprintf "Warning: annotations must be indirect\n"; None
end)
annots
| _ -> []
let list_annotations_json range pdf =
let refnums = Pdf.page_reference_numbers pdf in
let fastrefnums = hashtable_of_dictionary (combine refnums (indx refnums)) in
let calculate_pagenumber = Pdfpage.pagenumber_of_target ~fastrefnums pdf in
extra := [];
let module J = Cpdfyojson.Safe in
let pages = Pdfpage.pages_of_pagetree pdf in
let pagenums = indx pages in
let pairs = combine pages pagenums in
let pairs = option_map (fun (p, n) -> if mem n range then Some (p, n) else None) pairs in
let pages, pagenums = split pairs in
let json = flatten (map2 (annotations_json_page calculate_pagenumber pdf) pages pagenums) in
(*Printf.printf "%i extra roots to explore\n" (length extra);
iter (fun x -> Printf.eprintf "%s\n\n" (Pdfwrite.string_of_pdf x)) extra;*)
let extra =
map
(fun n ->
`List
[`Int n;
Cpdfjson.json_of_object ~utf8:true ~clean_strings:true pdf (fun _ -> ())
~no_stream_data:false ~parse_content:false (Pdf.lookup_obj pdf n)])
(setify
(flatten
(map
(fun x ->
let r = Pdf.objects_referenced [] [] pdf x in
(*Printf.printf "%i extra for annot %s\n" (length r)
(Pdfwrite.string_of_pdf x);*) r)
!extra)))
in
let header =
`List
[`Int 0;
Cpdfjson.json_of_object ~utf8:true ~clean_strings:true pdf (fun _ -> ())
~no_stream_data:false ~parse_content:false
(Pdf.Dictionary ["/CPDFJSONannotformatversion", Pdf.Integer 1])]
in
let json = `List ([header] @ json @ extra) in
J.pretty_to_channel stdout json
let list_annotations ~json range encoding pdf =
if json
then list_annotations_json range pdf
else Cpdfpage.iter_pages (list_page_annotations encoding pdf) pdf range
(* Return annotations *)
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)))
let get_annotations_json pdf =
let refnums = Pdf.page_reference_numbers pdf in
let fastrefnums = hashtable_of_dictionary (combine refnums (indx refnums)) in
let calculate_pagenumber = Pdfpage.pagenumber_of_target ~fastrefnums pdf in
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 calculate_pagenumber pdf) pages pagenums)) in
Pdfio.bytes_of_string (J.to_string json)
(** Set annotations from JSON, keeping any existing ones. *)
let set_annotations_json pdf i =
let module J = Cpdfyojson.Safe in
let content = Pdfio.string_of_bytes (Pdfio.bytes_of_input i 0 i.Pdfio.in_channel_length) in
let json = J.from_string content in
(* Find largest negative objnumber. Then add number of annot objects. *)
match json with
| `List entries ->
(* Renumber the PDF so everything has bigger object numbers than that. *)
let maxobjnum =
fold_left max min_int
(map
(function
| `List [_; `Int i; _] -> i
| `List [`Int i; _] -> abs i
| _ -> error "Bad annots entry")
entries)
in
let pdf_objnums = map fst (list_of_hashtbl pdf.Pdf.objects.Pdf.pdfobjects) in
let change_table =
hashtable_of_dictionary (map2 (fun f t -> (f, t)) pdf_objnums (ilist (maxobjnum + 1) (maxobjnum + length pdf_objnums)))
in
let pdf = Pdf.renumber change_table pdf in
(* 1. Rewrite all serial numbers in all places (annots and extra objects?) *)
(* 2. Add all the negative numbered objects straight to the file *)
(* 3. Add all the actual annotations to the /Annots array on each page *)
()
| _ -> error "Bad Annotations JSON file"
(* 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: This code is deprecated in favour of extracting annotations to JSON
and then re-adding. *)
(* 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
(* 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 (Pdfpage.ppstub remove_annotations_page) pdf range