230 lines
8.5 KiB
OCaml
230 lines
8.5 KiB
OCaml
open Pdfutil
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(* List annotations *)
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let get_annotation_string encoding pdf annot =
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match Pdf.lookup_direct pdf "/Contents" annot with
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| Some (Pdf.String s) -> Cpdfmetadata.encode_output encoding s
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| _ -> ""
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let print_annotation encoding pdf num s =
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let s = get_annotation_string encoding pdf s in
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match s with
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| "" -> ()
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| s ->
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flprint (Printf.sprintf "Page %d: " num);
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flprint s;
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flprint "\n"
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let list_page_annotations encoding pdf num page =
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match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
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| Some (Pdf.Array annots) ->
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iter (print_annotation encoding pdf num) (map (Pdf.direct pdf) annots)
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| _ -> ()
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(* In the future, we will allow round-tripping of JSON annotations, but this
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will be complicated. For now, we just turn some indirect things into direct
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things, so that the output contains all the pertinent information, not for
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round-tripping, but for mere extraction. *)
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let make_direct pdf annot =
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match Pdf.lookup_direct pdf "/A" annot with
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| None -> annot
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| Some d -> Pdf.add_dict_entry annot "/A" d
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let rewrite_destination calculate_pagenumber d =
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match d with
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| Pdf.Array (Pdf.Indirect i::r) ->
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Pdf.Array (Pdf.Indirect (calculate_pagenumber (Pdfdest.Fit (Pdfdest.PageObject i)))::r)
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| x -> x
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let rewrite_destinations pdf annot =
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let refnums = Pdf.page_reference_numbers pdf in
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let fastrefnums = hashtable_of_dictionary (combine refnums (indx refnums)) in
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let calculate_pagenumber = Pdfpage.pagenumber_of_target ~fastrefnums pdf in
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(* Deal with /Dest in annotation *)
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match Pdf.lookup_direct pdf "/Dest" annot with
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| Some d -> Pdf.add_dict_entry annot "/Dest" (rewrite_destination calculate_pagenumber d)
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| None ->
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(* Deal with /A --> /D dest when /A --> /S = /GoTo *)
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match Pdf.lookup_direct pdf "/A" annot with
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| Some action ->
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begin match Pdf.lookup_direct pdf "/D" action with
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| Some d ->
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Pdf.add_dict_entry
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annot "/A" (Pdf.add_dict_entry action "/D" (rewrite_destination calculate_pagenumber d))
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| None -> annot
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end
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| None -> annot
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let annotations_json_page pdf page pagenum =
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match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
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| Some (Pdf.Array annots) ->
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map
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(fun annot ->
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let annot = make_direct pdf annot in
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`List [`Int pagenum; Cpdfjson.json_of_object ~clean_strings:true pdf (fun _ -> ()) false false annot])
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(map (Pdf.direct pdf) annots)
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| _ -> []
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let list_annotations_json range pdf =
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let module J = Cpdfyojson.Safe in
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let pages = Pdfpage.pages_of_pagetree pdf in
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let pagenums = indx pages in
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let pairs = combine pages pagenums in
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let pairs = option_map (fun (p, n) -> if mem n range then Some (p, n) else None) pairs in
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let pages, pagenums = split pairs in
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let json = `List (flatten (map2 (annotations_json_page pdf) pages pagenums)) in
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J.pretty_to_channel stdout json
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let list_annotations ~json range encoding pdf =
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if json
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then list_annotations_json range pdf
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else Cpdfpage.iter_pages (list_page_annotations encoding pdf) pdf range
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(* Return annotations *)
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let get_annotations encoding pdf =
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let pages = Pdfpage.pages_of_pagetree pdf in
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flatten
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(map2
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(fun page pagenumber ->
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match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
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| Some (Pdf.Array annots) ->
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let strings =
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map (get_annotation_string encoding pdf) (map (Pdf.direct pdf) annots)
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in
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combine (many pagenumber (length strings)) strings
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| _ -> [])
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pages
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(ilist 1 (length pages)))
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let get_annotations_json pdf =
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let module J = Cpdfyojson.Safe in
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let pages = Pdfpage.pages_of_pagetree pdf in
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let pagenums = indx pages in
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let json = `List (flatten (map2 (annotations_json_page pdf) pages pagenums)) in
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Pdfio.bytes_of_string (J.to_string json)
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(* Equalise the page lengths of two PDFs by chopping or extending the first one.
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*)
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let equalise_lengths a b =
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let a' =
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if Pdfpage.endpage a < Pdfpage.endpage b then
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Pdfpage.change_pages false a
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(Pdfpage.pages_of_pagetree a @
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many (Pdfpage.blankpage Pdfpaper.a4) (Pdfpage.endpage b - Pdfpage.endpage a))
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else if Pdfpage.endpage a > Pdfpage.endpage b then
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Pdfpage.change_pages false a
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(take (Pdfpage.pages_of_pagetree a) (Pdfpage.endpage b))
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else a
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in
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a', b
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(* Copy annotations *)
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(* FIXME: Why does this chop the files to the same length? Should be able to
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apply annotations from a longer file to a shorter? *)
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(* Rewrite any annotation destinations to point to pages in the
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destination file. This prevents pages being copied, and ensures the links are
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correct Any Indirect link inside a /Dest is rewritten if in the table. If not
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inside a /Dest, nothing is rewritten. *)
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let rec renumber_in_dest table indest = function
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Pdf.Indirect i ->
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begin
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try Pdf.Indirect (Hashtbl.find table i) with _ -> Pdf.Indirect i
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end
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| Pdf.Array a ->
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Pdf.recurse_array (renumber_in_dest table indest) a
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| Pdf.Dictionary d ->
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Pdf.Dictionary
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(map
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(function
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("/Dest", v) -> ("/Dest", renumber_in_dest table true v)
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| (k, v) -> (k, renumber_in_dest table indest v))
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d)
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| x -> x
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let renumber_in_object pdf objnum table =
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Pdf.addobj_given_num
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pdf (objnum, (renumber_in_dest table false (Pdf.lookup_obj pdf objnum)))
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let copy_annotations_page topdf frompdf frompage topage =
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match Pdf.lookup_direct frompdf "/Annots" frompage.Pdfpage.rest with
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Some (Pdf.Array frompage_annots as annots) ->
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let table =
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hashtable_of_dictionary
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(combine
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(Pdf.page_reference_numbers frompdf)
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(Pdf.page_reference_numbers topdf))
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in
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iter
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(function
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(* FIXME: We assume they are indirects. Must also do direct, though rare.*)
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Pdf.Indirect x ->
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(*Printf.printf "Copying annotation %s which is\n%s\n"
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(Pdfwrite.string_of_pdf (Pdf.Indirect x))
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(Pdfwrite.string_of_pdf (Pdf.direct frompdf (Pdf.Indirect
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x)));*)
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renumber_in_object frompdf x table
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| _ -> ())
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frompage_annots;
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let objects_to_copy = Pdf.objects_referenced [] [] frompdf annots in
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iter
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(fun n ->
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ignore (Pdf.addobj_given_num topdf (n, Pdf.lookup_obj frompdf n)))
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objects_to_copy;
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let topage_annots =
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match Pdf.lookup_direct frompdf "/Annots" topage.Pdfpage.rest with
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| Some (Pdf.Array annots) -> annots
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| _ -> []
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in
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let merged_dict = Pdf.Array (frompage_annots @ topage_annots) in
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let topage' =
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{topage with Pdfpage.rest =
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Pdf.add_dict_entry topage.Pdfpage.rest "/Annots" merged_dict}
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in
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topdf, topage'
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| Some x -> topdf, topage
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| None -> topdf, topage
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let copy_annotations range frompdf topdf =
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let frompdf, topdf = equalise_lengths frompdf topdf in
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match Pdf.renumber_pdfs [frompdf; topdf] with
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| [frompdf; topdf] ->
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let frompdf_pages = Pdfpage.pages_of_pagetree frompdf in
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let topdf_pages = Pdfpage.pages_of_pagetree topdf in
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let pdf = ref topdf
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and pages = ref []
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and pnum = ref 1
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and frompdf_pages = ref frompdf_pages
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and topdf_pages = ref topdf_pages in
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(* Go through, updating pdf and collecting new pages. *)
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while not (isnull !frompdf_pages) do
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let frompdf_page = hd !frompdf_pages
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and topdf_page = hd !topdf_pages in
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let pdf', page =
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if mem !pnum range
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then copy_annotations_page !pdf frompdf frompdf_page topdf_page
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else !pdf, topdf_page
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in
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pdf := pdf';
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pages =| page;
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incr pnum;
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frompdf_pages := tl !frompdf_pages;
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topdf_pages := tl !topdf_pages
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done;
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Pdfpage.change_pages true !pdf (rev !pages)
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| _ -> assert false
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(* Remove annotations *)
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let remove_annotations range pdf =
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let remove_annotations_page pagenum page =
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if mem pagenum range then
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let rest' =
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Pdf.remove_dict_entry page.Pdfpage.rest "/Annots"
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in
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{page with Pdfpage.rest = rest'}
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else
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page
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in
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Cpdfpage.process_pages (Cpdfutil.ppstub remove_annotations_page) pdf range
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