cpdf-source/cpdf.ml

(* CPDF Core routines *)
open Pdfutil
open Pdfio

let debug = ref false

let xmp_template =
{|<?xpacket begin='' id='W5M0MpCehiHzreSzNTczkc9d'?>

<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
 xmlns:iX='http://ns.adobe.com/iX/1.0/'>

 <rdf:Description about=''
  xmlns='http://ns.adobe.com/pdf/1.3/'
  xmlns:pdf='http://ns.adobe.com/pdf/1.3/'>
  <pdf:CreationDate>CREATEDATE</pdf:CreationDate>
  <pdf:ModDate>MODDATE</pdf:ModDate>
  <pdf:Producer>PRODUCER</pdf:Producer>
  <pdf:Creator>CREATOR</pdf:Creator>
  <pdf:Title>TITLE</pdf:Title>
  <pdf:Subject>SUBJECT</pdf:Subject>
  <pdf:Author>AUTHOR</pdf:Author>
  <pdf:Keywords>KEYWORDS</pdf:Keywords>
  <pdf:Trapped>TRAPPED</pdf:Trapped>
 </rdf:Description>

 <rdf:Description about=''
  xmlns='http://ns.adobe.com/xap/1.0/'
  xmlns:xap='http://ns.adobe.com/xap/1.0/'>
   <xap:CreateDate>CREATEDATE</xap:CreateDate>
   <xap:CreatorTool>CREATOR</xap:CreatorTool>
   <xap:ModifyDate>MODDATE</xap:ModifyDate>
   <xap:MetadataDate>METADATADATE</xap:MetadataDate>
 </rdf:Description>

 <rdf:Description about=''
  xmlns='http://purl.org/dc/elements/1.1/'
  xmlns:dc='http://purl.org/dc/elements/1.1/'>
   <dc:title>TITLE</dc:title>
 </rdf:Description>

</rdf:RDF>

<?xpacket end='r'?>|}

(* For debugging *)
let report_pdf_size pdf =
  Pdf.remove_unreferenced pdf;
  Pdfwrite.pdf_to_file_options ~preserve_objstm:false ~generate_objstm:false
  ~compress_objstm:false false None false pdf "temp.pdf";
  let fh = open_in_bin "temp.pdf" in
    Printf.printf "Size %i bytes\n" (in_channel_length fh);
    flush stdout;
    close_in fh

(* Prefer a) the one given with -cpdflin b) a local cpdflin, c) otherwise assume
installed at a system place *)
let find_cpdflin provided =
  match provided with
    Some x -> x
  | None ->
      let dotslash = match Sys.os_type with "Win32" -> "" | _ -> "./" in
      if Sys.file_exists "cpdflin" then (dotslash ^ "cpdflin") else
      if Sys.file_exists "cpdflin.exe" then (dotslash ^ "cpdflin.exe") else
        match Sys.os_type with
          "Win32" -> "cpdflin.exe"
        | _ -> "cpdflin"

(* Call cpdflin, given the (temp) input name, the output name, and the location
of the cpdflin binary. Returns the exit code. *)
let call_cpdflin cpdflin temp output best_password =
  let command =
    cpdflin ^ " --linearize " ^ " --password=" ^ best_password ^ " " ^
    Filename.quote temp ^ " " ^ Filename.quote output 
  in
    match Sys.os_type with
      "Win32" ->
        (* On windows, don't use LD_LIBRARY_PATH - it will happen automatically *)
        if !debug then prerr_endline command;
        Sys.command command
    | _ ->
        (* On other platforms, if -cpdflin was provided, or cpdflin was in the
        current folder, set up LD_LIBRARY_PATH: *)
        match cpdflin with
          "cpdflin" ->
            if !debug then prerr_endline command;
            Sys.command command
        | _ ->
            let command = 
              "DYLD_FALLBACK_LIBRARY_PATH=" ^ Filename.dirname cpdflin ^ " " ^
              "LD_LIBRARY_PATH=" ^ Filename.dirname cpdflin ^ " " ^
              command
            in
              if !debug then prerr_endline command;
              Sys.command command

(* Recompress anything which isn't compressed, unless it's metadata. *)
let recompress_stream pdf = function
  (* If there is no compression, compress with /FlateDecode *)
  | Pdf.Stream {contents = (dict, _)} as stream ->
      begin match
        Pdf.lookup_direct pdf "/Filter" dict, 
        Pdf.lookup_direct pdf "/Type" dict
      with
      | _, Some (Pdf.Name "/Metadata") -> ()
      | (None | Some (Pdf.Array [])), _ ->
          Pdfcodec.encode_pdfstream pdf Pdfcodec.Flate stream
      | _ -> ()
      end
  | _ -> assert false

let recompress_pdf pdf =
  if not (Pdfcrypt.is_encrypted pdf) then
    Pdf.iter_stream (recompress_stream pdf) pdf;
    pdf

let decompress_pdf pdf =
  if not (Pdfcrypt.is_encrypted pdf) then
    (Pdf.iter_stream (Pdfcodec.decode_pdfstream_until_unknown pdf) pdf);
    pdf

(* Equality on PDF objects *)
let pdfobjeq pdf x y =
  let x = Pdf.lookup_obj pdf x 
  and y = Pdf.lookup_obj pdf y in
    begin match x with Pdf.Stream _ -> Pdf.getstream x | _ -> () end;
    begin match y with Pdf.Stream _ -> Pdf.getstream y | _ -> () end;
    compare x y

let really_squeeze pdf =
  let objs = ref [] in
    Pdf.objiter (fun objnum _ -> objs := objnum :: !objs) pdf;
    let toprocess =
      keep
        (fun x -> length x > 1)
        (collate (pdfobjeq pdf) (sort (pdfobjeq pdf) !objs))
    in
      (* Remove any pools of objects which are page objects, since Adobe Reader
       * gets confused when there are duplicate page objects. *)
      let toprocess =
        option_map
          (function
             [] -> assert false
           | h::_ as l ->
               match Pdf.lookup_direct pdf "/Type" (Pdf.lookup_obj pdf h) with
                 Some (Pdf.Name "/Page") -> None
               | _ -> Some l)
          toprocess
      in
        let pdfr = ref pdf in
        let changetable = Hashtbl.create 100 in
          iter
            (function [] -> assert false | h::t ->
               iter (fun e -> Hashtbl.add changetable e h) t)
            toprocess;
          (* For a unknown reason, the output file is much smaller if
             Pdf.renumber is run twice. This is bizarre, since Pdf.renumber is
             an old, well-understood function in use for years -- what is
             going on? Furthermore, if we run it 3 times, it gets bigger again! *)
          pdfr := Pdf.renumber changetable !pdfr;
          pdfr := Pdf.renumber changetable !pdfr;
          Pdf.remove_unreferenced !pdfr;
          pdf.Pdf.root <- !pdfr.Pdf.root;
          pdf.Pdf.objects <- !pdfr.Pdf.objects;
          pdf.Pdf.trailerdict <- !pdfr.Pdf.trailerdict

(* Squeeze the form xobject at objnum.

FIXME: For old PDFs (< v1.2) any resources from the page (or its ancestors in
the page tree!) are also needed - we must merge them with the ones from the
xobject itself. However, it it safe for now -- in the unlikely event that the
resources actually need to be available, the parse will fail, the squeeze of
this object will fail, and we bail out. *)
let xobjects_done = ref []

let squeeze_form_xobject pdf objnum =
  if mem objnum !xobjects_done then () else
    xobjects_done := objnum :: !xobjects_done;
    let obj = Pdf.lookup_obj pdf objnum in
      match Pdf.lookup_direct pdf "/Subtype" obj with
        Some (Pdf.Name "/Form") ->
          let resources =
            match Pdf.lookup_direct pdf "/Resources" obj with
              Some d -> d
            | None -> Pdf.Dictionary []
          in
            begin match
              Pdfops.stream_of_ops
                (Pdfops.parse_operators pdf resources [Pdf.Indirect objnum])
            with
              Pdf.Stream {contents = (_, Pdf.Got data)} ->
                (* Put replacement data in original stream, and overwrite /Length *)
                begin match obj with
                  Pdf.Stream ({contents = (d, _)} as str) ->
                    str :=
                      (Pdf.add_dict_entry d "/Length" (Pdf.Integer (bytes_size data)),
                       Pdf.Got data)
                | _ -> failwith "squeeze_form_xobject"
                end
            | _ -> failwith "squeeze_form_xobject"
            end
      | _ -> ()

(* For a list of indirects representing content streams, make sure that none of
them are duplicated in the PDF. This indicates sharing, which parsing and
rewriting the streams might destroy, thus making the file bigger. FIXME: The
correct thing to do is to preserve the multiple content streams. *)
let no_duplicates content_stream_numbers stream_numbers =
  not
    (mem false
       (map
         (fun n -> length (keep (eq n) content_stream_numbers) < 2)
         stream_numbers))

(* Give a list of content stream numbers, given a page reference number *)
let content_streams_of_page pdf refnum =
  match Pdf.direct pdf (Pdf.lookup_obj pdf refnum) with
    Pdf.Dictionary dict ->
      begin match lookup "/Contents" dict with
        Some (Pdf.Indirect i) -> [i]
      | Some (Pdf.Array x) ->
          option_map (function Pdf.Indirect i -> Some i | _ -> None) x
      | _ -> []
      end
  | _ -> []

(* For each object in the PDF marked with /Type /Page, for each /Contents
indirect reference or array of such, decode and recode that content stream. *)
let squeeze_all_content_streams pdf =
  let page_reference_numbers = Pdf.page_reference_numbers pdf in
    let all_content_streams_in_doc =
      flatten (map (content_streams_of_page pdf) page_reference_numbers)
    in
      xobjects_done := [];
      Pdf.objiter
        (fun objnum _ ->
          match Pdf.lookup_obj pdf objnum with
            Pdf.Dictionary dict as d
              when
                Pdf.lookup_direct pdf "/Type" d = Some (Pdf.Name "/Page")
              ->
                let resources =
                  match Pdf.lookup_direct pdf "/Resources" d with
                    Some d -> d
                  | None -> Pdf.Dictionary []
                in
                  begin try
                    let content_streams =
                      match lookup "/Contents" dict with
                        Some (Pdf.Indirect i) ->
                          begin match Pdf.direct pdf (Pdf.Indirect i) with
                            Pdf.Array x -> x
                          | _ -> [Pdf.Indirect i]
                          end
                      | Some (Pdf.Array x) -> x
                      | _ -> raise Not_found
                    in
                      if
                        no_duplicates
                          all_content_streams_in_doc
                          (map (function Pdf.Indirect i -> i | _ -> assert false) content_streams)
                      then
                        let newstream =
                          Pdfops.stream_of_ops
                            (Pdfops.parse_operators pdf resources content_streams)
                        in
                          let newdict =
                            Pdf.add_dict_entry
                              d "/Contents" (Pdf.Indirect (Pdf.addobj pdf newstream))
                          in
                            Pdf.addobj_given_num pdf (objnum, newdict);
                            (* Now process all xobjects related to this page *)
                            begin match Pdf.lookup_direct pdf "/XObject" resources with
                              Some (Pdf.Dictionary xobjs) ->
                                iter
                                  (function
                                     (_, Pdf.Indirect i) -> squeeze_form_xobject pdf i
                                    | _ -> failwith "squeeze_xobject")
                                  xobjs
                            | _ -> ()
                            end
                  with
                    (* No /Contents, which is ok. Or a parsing failure due to
                     uninherited resources. FIXME: Add support for inherited
                     resources. *)
                    Not_found -> ()
                  end
            | _ -> ())
        pdf

(* We run squeeze enough times for the number of objects to not change *)
let squeeze ?logto pdf =
  let log x =
    match logto with
      None -> print_string x; flush stdout
    | Some "nolog" -> ()
    | Some s ->
        let fh = open_out_gen [Open_wronly; Open_creat] 0o666 s in
          seek_out fh (out_channel_length fh);
          output_string fh x;
          close_out fh
  in
    try
      let n = ref (Pdf.objcard pdf) in
      log (Printf.sprintf "Beginning squeeze: %i objects\n" (Pdf.objcard pdf));
      while !n > (ignore (really_squeeze pdf); Pdf.objcard pdf) do
        n := Pdf.objcard pdf;
        log (Printf.sprintf "Squeezing... Down to %i objects\n" (Pdf.objcard pdf));
      done;
      log (Printf.sprintf "Squeezing page data and xobjects\n");
      squeeze_all_content_streams pdf;
      log (Printf.sprintf "Recompressing document\n");
      Pdfcodec.flate_level := 9;
      ignore (recompress_pdf pdf)
    with
      e ->
        raise
          (Pdf.PDFError
             (Printf.sprintf
                "Squeeze failed. No output written.\n Proximate error was:\n %s"
                (Printexc.to_string e)))

type encoding =
  | Raw
  | UTF8
  | Stripped

(* Just strip everything which isn't 7 bit ASCII *)
let crude_de_unicode s =
  implode (map char_of_int (lose (fun x -> x > 127) (Pdftext.codepoints_of_pdfdocstring s)))

let encode_output enc s =
  match enc with
  | Raw -> s
  | UTF8 -> Pdftext.utf8_of_pdfdocstring s
  | Stripped -> crude_de_unicode s

(* Get the number of pages in file. Doesn't need decryption. *)
let endpage_io ?revision i user_pw owner_pw =
  let pdf = Pdfread.pdf_of_input_lazy ?revision user_pw owner_pw i in
    Pdfpage.endpage pdf

(* Raised when syntax is ok, but endpage is too low. Caught by validator.
Caught and reraised as normal failure by parse_pagespec. *)
exception PageSpecUnknownPage of int

(* There would be no pages *)
exception PageSpecWouldBeNoPages

(* Raised when syntax is wrong. Caught and reraised by parse_pagespec and
validator. *)
exception PageSpecBadSyntax

(* Parsing range specifications *)
let rec splitat_commas toks =
  match cleavewhile (neq (Pdfgenlex.LexName ",")) toks with
  | [], [] -> []
  | [], _ -> raise PageSpecBadSyntax
  | some, [] -> [some]
  | _::_ as before, _::rest -> before::splitat_commas rest 

let is_dimension comparison {Pdfpage.mediabox = box} =
  let minx, miny, maxx, maxy = Pdf.parse_rectangle box in
    comparison (maxx -. minx) (maxy -. miny)

let select_dimensions comparison pdf candidates =
  let pages = Pdfpage.pages_of_pagetree pdf in
    let pagenums, kept_pages =
      split
        (option_map
           (fun (index, page) ->
             if mem index candidates then Some (index, page) else None)
           (combine (indx pages) pages))
    in
      option_map2
        (fun pagenum page ->
          if is_dimension comparison page then Some pagenum else None)
        pagenums
        kept_pages

let select_portrait = select_dimensions ( < )

let select_landscape = select_dimensions ( > )

let rec mk_numbers pdf endpage lexemes =
  match lexemes with
  | [Pdfgenlex.LexInt n] -> [n]
  | [Pdfgenlex.LexName "end"] -> [endpage]
  | [Pdfgenlex.LexInt n; Pdfgenlex.LexName "-"; Pdfgenlex.LexInt n'] ->
      if n > n' then rev (ilist n' n) else ilist n n'
  | [Pdfgenlex.LexName "end"; Pdfgenlex.LexName "-"; Pdfgenlex.LexInt n] ->
      if n <= endpage
        then rev (ilist n endpage)
        else raise (PageSpecUnknownPage n)
  | [Pdfgenlex.LexInt n; Pdfgenlex.LexName "-"; Pdfgenlex.LexName "end"] ->
      if n <= endpage
        then ilist n endpage
        else raise (PageSpecUnknownPage n)
  | [Pdfgenlex.LexName "end"; Pdfgenlex.LexName "-"; Pdfgenlex.LexName "end"] ->
       [endpage]
  | [Pdfgenlex.LexName "even"] ->
       drop_odds (ilist 1 endpage)
  | [Pdfgenlex.LexName "portrait"] ->
       select_portrait pdf (ilist 1 endpage)
  | [Pdfgenlex.LexName "landscape"] ->
       select_landscape pdf (ilist 1 endpage)
  | [Pdfgenlex.LexName "odd"] ->
       really_drop_evens (ilist 1 endpage)
  | [Pdfgenlex.LexName "all"] ->
       ilist 1 endpage
  | [Pdfgenlex.LexName "reverse"] ->
       rev (ilist 1 endpage)
  | toks ->
      let ranges = splitat_commas toks in
        if ranges = [toks] then raise PageSpecBadSyntax else
          flatten (map (mk_numbers pdf endpage) ranges)

(* Space dashes and commas *)
let rec add_spaces = function
  | [] -> []
  | ('-' | ',') as h::t -> ' '::h::' '::add_spaces t
  | h::t -> h::add_spaces t

let space_string s =
  implode (add_spaces (explode s))

let fixup_negatives endpage = function
  | Pdfgenlex.LexName s when String.length s > 1 && s.[0] = '~' ->
      Pdfgenlex.LexInt (endpage + 1 + ~-(int_of_string (implode (tl (explode s)))))
  | x -> x

let parse_pagespec_inner endpage pdf spec =
  let spec = space_string spec in
    if endpage < 1 then raise (Pdf.PDFError "This PDF file has no pages and is therefore malformed") else
      let numbers =
        try
          match rev (explode spec) with
          | ['n'; 'e'; 'v'; 'e'] ->
              keep even (ilist 1 endpage)
          | ['d'; 'd'; 'o'] ->
              keep odd (ilist 1 endpage)
          | ['t'; 'i'; 'a'; 'r'; 't'; 'r'; 'o'; 'p'] ->
              select_portrait pdf (ilist 1 endpage)
          | ['e'; 'p'; 'a'; 'c'; 's'; 'd'; 'n'; 'a'; 'l'] ->
              select_landscape pdf (ilist 1 endpage)
          | 't'::'i'::'a'::'r'::'t'::'r'::'o'::'p'::more ->
              select_portrait
                pdf
                (mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string (implode (rev more)))))
          | 'e'::'p'::'a'::'c'::'s'::'d'::'n'::'a'::'l'::more ->
              select_landscape
                pdf
                (mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string (implode (rev more)))))
          | 'd'::'d'::'o'::more ->
              keep
                odd
                (mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string (implode (rev more)))))
          | 'n'::'e'::'v'::'e'::more ->
              keep
                even
                (mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string (implode (rev more)))))
          | _ ->
              mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string spec))
        with
          e -> raise PageSpecBadSyntax
      in
       if numbers = [] then raise PageSpecWouldBeNoPages else
         iter
           (fun n ->
              if n <= 0 || n > endpage then raise (PageSpecUnknownPage n))
           numbers;
         numbers

let parse_pagespec pdf spec =
  try parse_pagespec_inner (Pdfpage.endpage pdf) pdf spec with
  | PageSpecUnknownPage n ->
     raise (Pdf.PDFError ("Page " ^ string_of_int n ^ " does not exist."))
  | PageSpecWouldBeNoPages ->
     raise (Pdf.PDFError ("Page range specifies no pages"))
  | e ->
     raise
       (Pdf.PDFError
         ("Bad page specification " ^ spec ^
          ". Raw error was " ^ Printexc.to_string e ^
          ". Last page was " ^ string_of_int (Pdfpage.endpage pdf)))

(* To validate a pagespec as being syntactically correct without the PDF in
question. This is nasty, since the parser above includes checking based on the
endpage of the PDF (which we don't have). Pass 100 as the endpage, doubling on
page range exception, bailng out above 500000. *)
let rec validate_pagespec_inner n spec =
  try
    ignore (parse_pagespec_inner n (Pdf.empty ()) spec); true
  with
  | PageSpecUnknownPage _ -> if n < 500000 then validate_pagespec_inner (n * 2) spec else false
  | PageSpecBadSyntax | _ -> false

let validate_pagespec spec =
  validate_pagespec_inner 100 spec

let rec parse_pagespec_without_pdf_inner n spec =
  try
    parse_pagespec_inner n (Pdf.empty ()) spec
  with
    PageSpecUnknownPage _ ->
      if n < 500000
        then parse_pagespec_without_pdf_inner (n * 2) spec
        else raise (Pdf.PDFError "PageSpecUnknownPage")

let parse_pagespec_without_pdf spec =
  parse_pagespec_without_pdf_inner 100 spec

(* Convert an integer list representing a set to a page specification, in order. *)
let string_of_pagespec pdf = function
  | [] -> ""
  | is ->
      let iseven len is =
        drop_odds (ilist 1 len) = is
      in let isodd len is =
        really_drop_evens (ilist 1 len) = is
      in let isall len is =
        ilist 1 len = is
      in let is = sort compare is
      in let len = Pdfpage.endpage pdf in
        let rec mkranges prev = function
        | [] -> map extremes (rev (map rev prev))
        | h::t ->
            match prev with
            | (ph::pht)::pt when h = ph + 1 -> mkranges ((h::ph::pht)::pt) t
            | (_::_)::_ -> mkranges ([h]::prev) t
            | []::_ -> assert false
            | [] -> mkranges [[h]] t
        in
          if iseven len is && len > 3 then "even" else
            if isodd len is && len > 2 then "odd" else
              if isall len is then "all" else
                let ranges = mkranges [] is in
                  let rangestrings =
                    map
                      (function (s, e) ->
                         if s = e
                           then string_of_int s
                           else string_of_int s ^ "-" ^ string_of_int e)
                      ranges
                  in
                    fold_left ( ^ ) "" (interleave "," rangestrings)

let string_of_range r =
  fold_left (fun a b -> a ^ " " ^ b) "" (map string_of_int r)

let print_pdf_objs pdf =
  Printf.printf "Trailerdict: %s\n" (Pdfwrite.string_of_pdf pdf.Pdf.trailerdict);
  Printf.printf "Root: %i\n" pdf.Pdf.root;
  begin match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
  | Some catalog -> 
      Printf.printf "Catalog: %s\n" (Pdfwrite.string_of_pdf catalog);
      begin match Pdf.lookup_direct pdf "/Pages" catalog with
      | Some pages ->
          Printf.printf "Pages: %s\n" (Pdfwrite.string_of_pdf pages)
      | None ->
          flprint "no catalog\n"
      end
  | None ->
       flprint "No catalog!\n"
  end;
  Pdf.objiter
    (fun n obj ->
       Printf.printf "%i 0 obj:\n\n" n;
       Printf.printf "%s\n" (Pdfwrite.string_of_pdf obj))
    pdf

(* Return page label at pdf page num, or page number in arabic if no label *) 
let pagelabel pdf num =
  Pdfpagelabels.pagelabeltext_of_pagenumber
    num
    (Pdfpagelabels.complete (Pdfpagelabels.read pdf))

let rec process_text text m =
  match m with
  | [] -> Cpdfstrftime.strftime text
  | (s, r)::t -> process_text (string_replace_all_lazy s r text) t

let expand_date = function
  | "now" -> Cpdfstrftime.strftime "D:%Y%m%d%H%M%S"
  | x -> x

let process_pages f pdf range =
  let pages = Pdfpage.pages_of_pagetree pdf in
    let pages' =
      map2
        (fun n p -> if mem n range then f n p else p)
        (ilist 1 (length pages))
        pages
    in
      Pdfpage.change_pages true pdf pages'

let iter_pages f pdf range =
  let pages = Pdfpage.pages_of_pagetree pdf in
    iter2
      (fun n p -> if mem n range then f n p)
      (ilist 1 (length pages))
      pages

let map_pages f pdf range =
  let pages = Pdfpage.pages_of_pagetree pdf in
    option_map2
      (fun n p -> if mem n range then Some (f n p) else None)
      (ilist 1 (length pages))
      pages

(* Add stack operators to a content stream to ensure it is composeable. On
-fast, we don't check for Q deficit, assuming PDF is ISO. *)
let protect fast pdf resources content =
  let deficit =
    if fast then 0 else
      let ops = Pdfops.parse_operators pdf resources content in
      let qs = length (keep (eq Pdfops.Op_q) ops) in
      let bigqs = length (keep (eq Pdfops.Op_Q) ops) in
      let deficit = if qs > bigqs then qs - bigqs else 0 in
        if deficit <> 0 then Printf.eprintf "Q Deficit was nonzero. Fixing. %i\n" deficit;
        deficit
  in
    let addstream ops = Pdf.addobj pdf (Pdfops.stream_of_ops ops) in
    let q = addstream [Pdfops.Op_q] in
    let qs = addstream (many Pdfops.Op_Q deficit @ [Pdfops.Op_Q]) in
      [Pdf.Indirect q] @ content @ [Pdf.Indirect qs]

exception SoftError of string

let error s = raise (SoftError s)

exception HardError of string

(* Union two resource dictionaries from the same PDF. *)
let combine_pdf_resources pdf a b =
  let a_entries =
    match a with
    | Pdf.Dictionary entries -> entries
    | _ -> []
  in let b_entries =
    match b with
    | Pdf.Dictionary entries -> entries
    | _ -> []
  in
    let resource_keys =
      ["/Font"; "/ExtGState"; "/ColorSpace"; "/Pattern";
       "/Shading"; "/XObject"; "/Properties"]
    in
      let combine_entries key =
        let a_entries =
          match Pdf.lookup_direct pdf key a with
          | Some (Pdf.Dictionary d) -> d
          | _ -> []
        in let b_entries =
          match Pdf.lookup_direct pdf key b with
          | Some (Pdf.Dictionary d) -> d
          | _ -> []
        in
          if a_entries = [] && b_entries = [] then
            None
          else
            Some (key, Pdf.Dictionary (a_entries @ b_entries))
      in
        let unknown_keys_a = lose (fun (k, _) -> mem k resource_keys) a_entries in
        let unknown_keys_b = lose (fun (k, _) -> mem k resource_keys) b_entries in
        let combined_known_entries = option_map combine_entries resource_keys in
          Pdf.Dictionary (unknown_keys_a @ unknown_keys_b @ combined_known_entries)

(* \section{Build PDF Presentations} *)
let change_page_effect t d horizontal inward direction effect_duration page =
  let checkname = function
    | "Split" | "Blinds" | "Box" | "Wipe" | "Dissolve" | "Glitter" -> ()
    | _ -> error "Unknown presentation type"
  in
    let rest = page.Pdfpage.rest in
      let transdict =
        match t with
        | None ->
            Pdf.Dictionary []
        | Some name ->
            checkname name;
            Pdf.Dictionary [("/S", Pdf.Name ("/" ^ name))]
      in
        let transdict = Pdf.add_dict_entry transdict "/D" (Pdf.Real effect_duration) in
          let transdict =
            match t with
            | Some ("Split" | "Blinds") ->
                Pdf.add_dict_entry
                  transdict "/Dm" (Pdf.Name (if horizontal then "/H" else "/V"))
            | _ -> transdict
          in
           let transdict =
             match t with
             | Some ("Split" | "Box") ->
                 Pdf.add_dict_entry
                   transdict "/M" (Pdf.Name (if inward then "/I" else "/O"))
             | _ -> transdict
           in 
             let transdict =
               match t with
               | Some ("Wipe" | "Glitter") ->
                   Pdf.add_dict_entry transdict "/Di" (Pdf.Integer direction)
               | _ -> transdict
             in
              let rest = Pdf.add_dict_entry rest "/Trans" transdict in
                let rest =
                  match d with
                  | None -> Pdf.remove_dict_entry rest "/Dur"
                  | Some delay -> Pdf.add_dict_entry rest "/Dur" (Pdf.Real delay)
                in
                  {page with Pdfpage.rest = rest}

let presentation range t d h i dir effect_dur pdf =
  let pages = Pdfpage.pages_of_pagetree pdf in
    let pages' =
      map2
        (fun page num ->
          if mem num range
            then change_page_effect t d h i dir effect_dur page
            else page)
        pages
        (indx pages)
    in
      Pdfpage.change_pages true pdf pages'

(* Attaching files *)
let attach_file ?memory keepversion topage pdf file =
  let data =
    match memory with
      Some data -> data
    | None ->
        let ch = open_in_bin file in
        let len = in_channel_length ch in
        let stream = mkbytes len in
        let i = input_of_channel ch in
          setinit i stream 0 len;
          close_in ch;
          stream
  in
    let filestream =
      Pdf.Stream
        (ref (Pdf.Dictionary
               [("/Length", Pdf.Integer (bytes_size data));
                ("/Type", Pdf.Name "/EmbeddedFile");
                ("/Params",
                   Pdf.Dictionary
                     [("/Size", Pdf.Integer (bytes_size data));
                      ("/CheckSum", Pdf.String (Digest.string (string_of_bytes data)))
                     ])],
              Pdf.Got data))
    in
      let filestream_num = Pdf.addobj pdf filestream in
        let filespec =
          Pdf.Dictionary
            [("/EF", Pdf.Dictionary ["/F", Pdf.Indirect filestream_num]);
             ("/F", Pdf.String (Filename.basename file));
             ("/Type", Pdf.Name "/Filespec");
             ("/Desc", Pdf.String "");
             ("/UF", Pdf.String (Filename.basename file))]
        in
          match topage with
          | None ->
              (* Look up /Names and /EmbeddedFiles and /Names. *)
              let rootdict = Pdf.lookup_obj pdf pdf.Pdf.root in
                let namedict =
                  match Pdf.lookup_direct pdf "/Names" rootdict with
                  | None -> Pdf.Dictionary []
                  | Some namedict -> namedict
                in
                  let embeddednamedict =
                    match Pdf.lookup_direct pdf "/EmbeddedFiles" namedict with
                    | None -> Pdf.Dictionary []
                    | Some embeddednamedict -> embeddednamedict
                  in
                    let elts =
                      match Pdf.lookup_direct pdf "/Names" embeddednamedict with
                      | Some (Pdf.Array elts) -> elts
                      | _ -> []
                    in
                      let filespecobj = Pdf.addobj pdf filespec in
                      let names' = Pdf.Array (elts @ [Pdf.String (Filename.basename file); Pdf.Indirect filespecobj]) in
                      let embeddednamedict' = Pdf.add_dict_entry embeddednamedict "/Names" names' in
                      let namedict' = Pdf.add_dict_entry namedict "/EmbeddedFiles" embeddednamedict' in
                      let rootdict' = Pdf.add_dict_entry rootdict "/Names" namedict' in
                      let rootnum = Pdf.addobj pdf rootdict' in
                        {pdf with
                           Pdf.minor = if keepversion then pdf.Pdf.minor else max pdf.Pdf.minor 4;
                           Pdf.root = rootnum;
                           Pdf.trailerdict =
                             Pdf.add_dict_entry
                               pdf.Pdf.trailerdict "/Root" (Pdf.Indirect rootnum)}
          | Some pagenumber ->
              let pages = Pdfpage.pages_of_pagetree pdf in
                if pagenumber < 0 || pagenumber > length pages then error "attach_file: Page not found" else
                  let page = select pagenumber pages in
                    let annots =
                      match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
                      | Some (Pdf.Array annots) -> annots
                      | _ -> []
                    in
                      let rect =
                        let minx, miny, maxx, maxy = Pdf.parse_rectangle page.Pdfpage.mediabox in
                          Pdf.Array [Pdf.Real 18.; Pdf.Real (maxy -. 45.); Pdf.Real 45.; Pdf.Real (maxy -. 18.)]
                      in
                        let filespecobj = Pdf.addobj pdf filespec in
                        let annot =
                          Pdf.Dictionary
                            [("/FS", Pdf.Indirect filespecobj);
                             ("/Subtype", Pdf.Name "/FileAttachment");
                             ("/Contents", Pdf.String (Filename.basename file));
                             ("/Rect", rect)]
                        in
                          let annots' = Pdf.Array (annot::annots) in
                            let page' =
                              {page with Pdfpage.rest = Pdf.add_dict_entry page.Pdfpage.rest "/Annots" annots'}
                            in
                              let pages' = replace_number pagenumber page' pages in
                                let pdf = Pdfpage.change_pages true pdf pages' in
                                  {pdf with
                                     Pdf.minor = if keepversion then pdf.Pdf.minor else max pdf.Pdf.minor 4}

type attachment =
  {name : string;
   pagenumber : int;
   data : unit -> Pdfio.bytes}

let list_attached_files pdf =
  let toplevel =
    match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
    | None -> []
    | Some rootdict ->
        match Pdf.lookup_direct pdf "/Names" rootdict with
        | None -> []
        | Some namedict ->
            match Pdf.lookup_direct pdf "/EmbeddedFiles" namedict with
            | Some nametree ->
                 map
                   (function (x, ef) ->
                      match Pdf.lookup_direct pdf "/EF" ef with
                      | Some ((Pdf.Dictionary _) as d) ->
                          begin match Pdf.lookup_direct pdf "/F" d with
                          | Some stream ->
                              {name = x;
                               pagenumber = 0;
                               data =
                                 (fun () ->
                                   try
                                     Pdf.getstream stream;
                                     Pdfcodec.decode_pdfstream pdf stream;
                                     match stream with
                                       Pdf.Stream {contents = (_, Pdf.Got data)} -> data
                                     | _ -> raise Not_found
                                   with
                                     _ -> raise (Pdf.PDFError "could not retreive attachment data"))}
                          | None -> raise (Pdf.PDFError "/F not found")
                          end
                      | _ -> raise (Pdf.PDFError "/EF not found"))
                   (option_map
                     (function (Pdf.String s, ef) -> Some (s, ef) | _ -> None)
                     (Pdf.contents_of_nametree pdf nametree))
            | _ -> []
  in let pagelevel =
    let pages = Pdfpage.pages_of_pagetree pdf in
      flatten
        (map2
          (fun page pagenumber ->
             option_map
               (function annot ->
                  match Pdf.lookup_direct pdf "/Subtype" annot with
                  | Some (Pdf.Name "/FileAttachment") ->
                      (match Pdf.lookup_direct pdf "/Contents" annot with
                      | Some (Pdf.String s) ->
                          begin match Pdf.lookup_direct pdf "/FS" annot with
                          | Some ((Pdf.Dictionary _) as d) ->
                              Printf.eprintf "%s\n" (Pdfwrite.string_of_pdf d);
                              begin match Pdf.lookup_direct pdf "/EF" d with
                              |  Some ((Pdf.Dictionary _) as d) ->
                                   begin match Pdf.lookup_direct pdf "/F" d with
                                   | Some stream ->
                                       Some
                                        {name = s;
                                         pagenumber = pagenumber;
                                         data =
                                           (fun () ->
                                             try
                                               Pdf.getstream stream;
                                               Pdfcodec.decode_pdfstream pdf stream;
                                               match stream with
                                                 Pdf.Stream {contents = (_, Pdf.Got data)} -> data
                                               | _ -> raise Not_found
                                             with
                                               _ -> raise (Pdf.PDFError "could not retreive attachment data"))}
                                   | _ -> raise (Pdf.PDFError "no /F found in attachment")
                                   end
                              | _ ->
                                  Some
                                    {name = s;
                                     pagenumber = pagenumber;
                                     data = (fun () -> raise (Pdf.PDFError "no attachment data"))}
                              end
                          | _ -> None
                          end
                      | _ -> None)
                  | _ -> None)
               (match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
               | Some (Pdf.Array annots) -> annots
               | _ -> []))
          pages
          (indx pages))
  in
    toplevel @ pagelevel

(* \section{Remove Attached files} *)
let remove_attached_files_on_pages pdf =
  let remove_from_page page =
    {page with Pdfpage.rest =
       Pdf.add_dict_entry page.Pdfpage.rest "/Annots"
         (Pdf.Array
           (option_map
             (function annot ->
                match Pdf.lookup_direct pdf "/Subtype" annot with
                | Some (Pdf.Name "/FileAttachment") -> None
                | _ -> Some annot)
             (match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
             | Some (Pdf.Array annots) -> annots
             | _ -> [])))}
  in
    Pdfpage.change_pages true pdf (map remove_from_page (Pdfpage.pages_of_pagetree pdf))

let remove_attached_files pdf =
  let pdf = remove_attached_files_on_pages pdf in
    match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
    | None -> pdf
    | Some rootdict ->
        match Pdf.lookup_direct pdf "/Names" rootdict with
        | None -> pdf
        | Some namedict ->
            let namedict' = Pdf.remove_dict_entry namedict "/EmbeddedFiles" in
              let rootdict' = Pdf.add_dict_entry rootdict "/Names" namedict' in
                let rootdict'num = Pdf.addobj pdf rootdict' in
                  {pdf with
                     Pdf.root =
                       rootdict'num;
                     Pdf.trailerdict =
                       Pdf.add_dict_entry pdf.Pdf.trailerdict "/Root" (Pdf.Indirect rootdict'num)}

(* \section{Copy an /ID from one file to another} *)
let copy_id keepversion copyfrom copyto =
  match Pdf.lookup_direct copyfrom "/ID" copyfrom.Pdf.trailerdict with
  | None -> copyto (* error "Source PDF file has no /ID entry to copy from" *)
  | Some id ->
      copyto.Pdf.trailerdict <-
        Pdf.add_dict_entry copyto.Pdf.trailerdict "/ID" id;
      copyto.Pdf.minor <-
        if keepversion then copyto.Pdf.minor else max copyto.Pdf.minor 1;
      copyto

(* \section{Remove bookmarks} *)

(* \section{Add bookmarks} *)
let read_lines input =
  let lines = ref [] in
   try
     while true do
       let c = read_line input in
         lines =| c
    done; []
   with
     _ -> rev !lines

(* Verify a list of bookmarks. Positive jumps of > 1 not allowed, no numbers
smaller than 0. *)
let rec verify_bookmarks pdf lastlevel fastrefnums endpage = function
  | [] -> true
  | {Pdfmarks.level = level; Pdfmarks.target = target}::more ->
      let page = Pdfpage.pagenumber_of_target pdf ~fastrefnums target in
        level < lastlevel + 2 &&
        level >= 0 &&
        page <= endpage &&
        page >= 0 &&
        verify_bookmarks pdf level fastrefnums endpage more

let verify_bookmarks pdf lastlevel endpage marks =
  let refnums = Pdf.page_reference_numbers pdf in
  let fastrefnums = hashtable_of_dictionary (combine refnums (indx refnums)) in
    match marks with
    | [] -> true
    | m::more -> m.Pdfmarks.level = 0 && verify_bookmarks pdf lastlevel fastrefnums endpage more

(* Parse a line of the bookmarks file. *)

(* Un-escape things which are escaped. Quotes, newlines and backslashes *)
let rec fixup_characters prev = function
  | [] -> rev prev
  | '\\'::'\\'::t -> fixup_characters ('\\'::prev) t
  | '\\'::'"'::t -> fixup_characters ('"'::prev) t
  | '\\'::'n'::t -> fixup_characters ('\n'::prev) t
  | h::t -> fixup_characters (h::prev) t

let debug_bookmark_string s =
  Printf.printf "STR: %s\n" s

(* If optionaldest = [Pdfgenlex.LexString s], we parse the string, convert the
 * integer to an indirect of the real page target, and then put it in. *)
let bookmark_of_data pdf i s i' isopen optionaldest =
  let target =
    match optionaldest with
    | [Pdfgenlex.LexString s] ->
        let pdfobj =
          Pdfread.parse_single_object s
        in
          (*Printf.printf "Parsed %s\n" (Pdfwrite.string_of_pdf pdfobj);*)
          begin match pdfobj with
            Pdf.Array (Pdf.Integer x::more) ->
              let pageobjnum = Pdfpage.page_object_number pdf i' in
                begin match pageobjnum with
                  None ->
                    raise (Pdf.PDFError "bookmark_of_data: page obj num not found")
                | Some p ->
                    Pdfdest.read_destination pdf (Pdf.Array (Pdf.Indirect p::more))
                end
          (* Need to deal with "null", "(string)", and "<<other thing like action" *) 
          | Pdf.Null -> Pdfdest.NullDestination
          | Pdf.String s -> Pdfdest.read_destination pdf (Pdf.String s)
          | x -> Pdfdest.Action x
          end
    | _ -> Pdfpage.target_of_pagenumber pdf i'
  in
    (*debug_bookmark_string s;
    debug_bookmark_string (implode (fixup_characters [] (explode s)));
    debug_bookmark_string (Pdftext.pdfdocstring_of_utf8 (implode (fixup_characters [] (explode s))));*)
    {Pdfmarks.level = i;
     Pdfmarks.text = Pdftext.pdfdocstring_of_utf8 (implode (fixup_characters [] (explode s)));
     Pdfmarks.target = target;
     Pdfmarks.isopen = isopen}

let parse_bookmark_file verify pdf input =
  let currline = ref 0 in
  try
    let lines = Pdfio.read_lines input in
      let currline = ref 0 in
      let bookmarks = ref [] in
        iter
          (function line ->
             match
               incr currline;
               Pdfgenlex.lex_string line
             with
             | Pdfgenlex.LexInt i::Pdfgenlex.LexString s::Pdfgenlex.LexInt i'::Pdfgenlex.LexName "open"::optionaldest ->
                 bookmarks =| bookmark_of_data pdf i s i' true optionaldest
             | Pdfgenlex.LexInt i::Pdfgenlex.LexString s::Pdfgenlex.LexInt i'::optionaldest ->
                 bookmarks =| bookmark_of_data pdf i s i' false optionaldest
             | [] -> () (* ignore blank lines *)
             | _ ->
                 error ("Bad bookmark file, line " ^ (string_of_int !currline)))
          lines;
        let bookmarks = rev !bookmarks in
          if verify then
            if verify_bookmarks pdf 0 (Pdfpage.endpage pdf) bookmarks
                then bookmarks
                else
                  error
                    "Bad bookmark file (References non-existant pages or is malformed)"
            else
              bookmarks
  with
    e ->
      error
        (Printf.sprintf 
           "Bad bookmark file (syntax) at line %i (error was %s)"
           !currline
           (Printexc.to_string e))


let add_bookmarks verify input pdf =
  let parsed = parse_bookmark_file verify pdf input in
    (*iter (fun b -> flprint (Pdfmarks.string_of_bookmark b); flprint "\n") parsed;*)
    Pdfmarks.add_bookmarks parsed pdf 

(* \section{Set page mode} *)
let set_page_mode pdf s =
  match s with
  | "UseNone" | "UseOutlines" | "UseThumbs"
  | "FullScreen" | "UseOC" | "UseAttachments" ->
      begin match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
      | Some catalog ->
          let catalog' =
            Pdf.add_dict_entry catalog "/PageMode" (Pdf.Name ("/" ^ s))
          in
            let catalognum = Pdf.addobj pdf catalog' in
              let trailerdict' =
                Pdf.add_dict_entry pdf.Pdf.trailerdict "/Root" (Pdf.Indirect catalognum)
              in
                {pdf with
                  Pdf.root = catalognum;
                  Pdf.trailerdict = trailerdict'}
      | None -> error "bad root"
      end
  | _ -> error "Unknown page mode"

(* Set open action *)
let set_open_action pdf fit pagenumber =
  if pagenumber > Pdfpage.endpage pdf || pagenumber < 0 then
    raise (error "set_open_action: invalid page number")
  else
    let pageobjectnumber = select pagenumber (Pdf.page_reference_numbers pdf) in
      let destination =
        if fit then
          Pdf.Array [Pdf.Indirect pageobjectnumber; Pdf.Name "/Fit"]
        else
          Pdf.Array [Pdf.Indirect pageobjectnumber; Pdf.Name "/XYZ"; Pdf.Null; Pdf.Null; Pdf.Null]
      in
        let open_action =
          Pdf.Dictionary [("/D", destination); ("/S", Pdf.Name "/GoTo")]
        in
          match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
          | Some catalog ->
              let catalog' =
                Pdf.add_dict_entry catalog "/OpenAction" open_action
              in
                let catalognum = Pdf.addobj pdf catalog' in
                  let trailerdict' =
                    Pdf.add_dict_entry pdf.Pdf.trailerdict "/Root" (Pdf.Indirect catalognum)
                  in
                    {pdf with Pdf.root = catalognum; Pdf.trailerdict = trailerdict'}
          | None -> error "bad root"

(* \section{Set viewer preferences} *)
let set_viewer_preference (key, value, version) pdf =
  match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
  | Some catalog ->
      let viewer_preferences =
        match Pdf.lookup_direct pdf "/ViewerPreferences" catalog with
        | Some d -> d
        | None -> Pdf.Dictionary []
      in
        let viewer_preferences' =
          Pdf.add_dict_entry viewer_preferences key value
        in
          let catalog' =
            Pdf.add_dict_entry catalog "/ViewerPreferences" viewer_preferences'
          in
            let catalognum = Pdf.addobj pdf catalog' in
              let trailerdict' =
                Pdf.add_dict_entry pdf.Pdf.trailerdict "/Root" (Pdf.Indirect catalognum)
              in
                {pdf with
                  Pdf.minor = max pdf.Pdf.minor version;
                  Pdf.root = catalognum;
                  Pdf.trailerdict = trailerdict'}
  | None -> error "bad root"



(* \section{Set page layout} *)
let set_page_layout pdf s =
  match s with
  | "SinglePage" | "OneColumn" | "TwoColumnLeft"
  | "TwoColumnRight" | "TwoPageLeft" | "TwoPageRight" ->
      begin match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
      | Some catalog ->
          let catalog' =
            Pdf.add_dict_entry catalog "/PageLayout" (Pdf.Name ("/" ^ s))
          in
            let catalognum = Pdf.addobj pdf catalog' in
              let trailerdict' =
                Pdf.add_dict_entry pdf.Pdf.trailerdict "/Root" (Pdf.Indirect catalognum)
              in
                {pdf with
                  Pdf.root = catalognum;
                  Pdf.trailerdict = trailerdict'}
      | None -> error "bad root"
      end
  | _ -> error "Unknown page layout"

(* \section{Set or replace metadata} *)
let set_metadata_from_bytes keepversion data pdf =
  let metadata_stream =
    Pdf.Stream
      {contents =
        (Pdf.Dictionary
         ["/Length", Pdf.Integer (bytes_size data);
          "/Type", Pdf.Name "/Metadata";
          "/Subtype", Pdf.Name "/XML"],
         Pdf.Got data)}
  in
    let objnum = Pdf.addobj pdf metadata_stream in 
      let document_catalog =
        match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
        | Some s -> s
        | None -> error "Malformed PDF: No root."
      in
        let document_catalog' =
          Pdf.add_dict_entry document_catalog "/Metadata" (Pdf.Indirect objnum)
        in
          let rootnum = Pdf.addobj pdf document_catalog' in
            let trailerdict =
              Pdf.add_dict_entry pdf.Pdf.trailerdict "/Root" (Pdf.Indirect rootnum)
            in
            {pdf with
               Pdf.trailerdict = trailerdict;
               Pdf.root = rootnum;
               Pdf.minor =
                 if keepversion then pdf.Pdf.minor else max 4 pdf.Pdf.minor}

let set_metadata keepversion filename pdf =
  let ch = open_in_bin filename in
    let data = mkbytes (in_channel_length ch) in
      for x = 0 to bytes_size data - 1 do
        bset data x (input_byte ch)
      done;
      set_metadata_from_bytes keepversion data pdf



(* \section{Remove metadata} *)
let remove_metadata pdf =
  match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
  | None -> error "malformed file" 
  | Some root ->
      let root' = Pdf.remove_dict_entry root "/Metadata" in
        let rootnum = Pdf.addobj pdf root' in
          {pdf with
             Pdf.trailerdict =
               Pdf.add_dict_entry pdf.Pdf.trailerdict "/Root" (Pdf.Indirect rootnum);
             Pdf.root =
               rootnum}

(* List bookmarks *)
let output_string_of_target pdf fastrefnums x =
  match Pdfdest.pdfobject_of_destination x with
  | Pdf.Array (_::more) ->
      let a =
        Pdf.Array (Pdf.Integer (Pdfpage.pagenumber_of_target ~fastrefnums pdf x)::more)
      in
        "\"" ^ Pdfwrite.string_of_pdf a ^ "\"" 
  | x -> "\"" ^ Pdfwrite.string_of_pdf x ^ "\""

(* List the bookmarks, optionally deunicoding the text, in the given range to the given output *)
let list_bookmarks encoding range pdf output =
  let process_stripped escaped =
    let b = Buffer.create 200 in
      List.iter
        (fun x ->
           if x <= 127 then Buffer.add_char b (char_of_int x))
        escaped;
      Buffer.contents b
  in
  let process_string s =
    let rec replace c x y = function
    | [] -> []
    | h::t when h = c -> x::y::replace c x y t
    | h::t -> h::replace c x y t
    in
      (* Convert to UTF8, raw, or stripped, and escape backslashed and quotation marks *)
      let codepoints = Pdftext.codepoints_of_pdfdocstring s in
        let escaped =
          let bs = int_of_char '\\'
          and nl = int_of_char '\n'
          and n = int_of_char 'n'
          and q = int_of_char '\"' in
            replace q bs q (replace nl bs n (replace bs bs bs codepoints))
        in
          match encoding with
          | UTF8 -> Pdftext.utf8_of_codepoints escaped
          | Stripped -> process_stripped escaped
          | Raw -> s
    in
      let bookmarks = Pdfmarks.read_bookmarks pdf in
      let refnums = Pdf.page_reference_numbers pdf in
      let rangetable = hashset_of_list range in
      let range_is_all = range = ilist 1 (Pdfpage.endpage pdf) in
      let fastrefnums = hashtable_of_dictionary (combine refnums (indx refnums)) in
        (* Find the pagenumber of each bookmark target. If it is in the range,
         * keep that bookmark. Also keep the bookmark if its target is the null
         * destination. *)
        let inrange =
          keep
            (function x ->
               range_is_all || 
               x.Pdfmarks.target = Pdfdest.NullDestination ||
               (match x.Pdfmarks.target with Pdfdest.NamedDestinationElsewhere _ -> true | _ -> false) ||
               Hashtbl.mem rangetable (Pdfpage.pagenumber_of_target ~fastrefnums pdf x.Pdfmarks.target)) bookmarks
        in
          let calculate_page_number mark =
            (* Some buggy PDFs use integers for page numbers instead of page
             * object references. Adobe Reader and Preview seem to support
             * this, for presumably historical reasons. So if we see a
             * OtherDocPageNumber (which is what Pdfdest parses these as,
             * because that's what they are legitimately, we use this as the
             * page number. It is zero based, though, and we are one-based, so
             * we add one. Pdfpage.pagenumber_of_target has been modified to support this.*)
            Pdfpage.pagenumber_of_target ~fastrefnums pdf mark.Pdfmarks.target
          in
            iter
              (function mark ->
                 output.Pdfio.output_string
                   (Printf.sprintf "%i \"%s\" %i%s %s\n"
                     mark.Pdfmarks.level
                     (process_string mark.Pdfmarks.text)
                     (calculate_page_number mark)
                     (if mark.Pdfmarks.isopen then " open" else "")
                     (output_string_of_target pdf fastrefnums mark.Pdfmarks.target)))
              inrange

(* o is the stamp, u is the main pdf page *)

(* \section{Split at bookmarks} *)

(* Returns empty string on failure. Should only be used in conjunction with
split at bookmarks code, so should never fail, by definiton. *)
let remove_unsafe_characters s =
  let chars =
    lose
      (function x ->
         match x with
         '/' | '?' | '<' | '>' | '\\' | ':' | '*' | '|' | '\"' | '^' | '+' | '=' -> true
         | x when int_of_char x < 32 || int_of_char x > 126 -> true
         | _ -> false)
      (explode s)
  in
    match chars with
    | '.'::more -> implode more
    | chars -> implode chars

let get_bookmark_name pdf marks splitlevel n _ =
  let refnums = Pdf.page_reference_numbers pdf in
  let fastrefnums = hashtable_of_dictionary (combine refnums (indx refnums)) in
  match keep (function m -> n = Pdfpage.pagenumber_of_target ~fastrefnums pdf m.Pdfmarks.target && m.Pdfmarks.level <= splitlevel) marks with
  | {Pdfmarks.text = title}::_ -> remove_unsafe_characters title
  | _ -> ""

(* Find the stem of a filename *)
let stem s =
  implode (rev (tail_no_fail (dropwhile (neq '.') (rev (explode (Filename.basename s))))))

(* Return list, in order, a *set* of page numbers of bookmarks at a given level *)
let bookmark_pages level pdf =
  let refnums = Pdf.page_reference_numbers pdf in
  let fastrefnums = hashtable_of_dictionary (combine refnums (indx refnums)) in
  setify_preserving_order
    (option_map
      (function l when l.Pdfmarks.level = level -> Some (Pdfpage.pagenumber_of_target ~fastrefnums pdf l.Pdfmarks.target) | _ -> None)
      (Pdfmarks.read_bookmarks pdf))

(* Called from cpdflib.ml - different from above *)
let split_on_bookmarks pdf level =
  let points = lose (eq 0) (map pred (bookmark_pages level pdf))
  in let pdf_pages = Pdfpage.pages_of_pagetree pdf in
    let ranges = splitat points (indx pdf_pages) in
      map (fun rs -> Pdfpage.pdf_of_pages pdf rs) ranges

(* Output information for each page *)
let output_page_info pdf range =
  let pages = Pdfpage.pages_of_pagetree pdf
  and labels = Pdfpagelabels.read pdf in
    let getbox page box =
      if box = "/MediaBox" then
        match page.Pdfpage.mediabox with
        | Pdf.Array [a; b; c; d] ->
           Printf.sprintf "%f %f %f %f"
             (Pdf.getnum a) (Pdf.getnum b) (Pdf.getnum c) (Pdf.getnum d)
        | _ -> ""
      else
        match Pdf.lookup_direct pdf box page.Pdfpage.rest with
        | Some (Pdf.Array [a; b; c; d]) ->
           Printf.sprintf "%f %f %f %f"
             (Pdf.getnum a) (Pdf.getnum b) (Pdf.getnum c) (Pdf.getnum d)
        | _ -> ""
    and rotation page =
      Pdfpage.int_of_rotation page.Pdfpage.rotate
    in
      List.iter
        (fun pnum ->
           let page = select pnum pages in
             Printf.printf "Page %i:\n" pnum;
             Printf.printf "Label: %s\n"
               (try Pdfpagelabels.pagelabeltext_of_pagenumber pnum labels with Not_found -> "");
             Printf.printf "MediaBox: %s\n" (getbox page "/MediaBox");
             Printf.printf "CropBox: %s\n" (getbox page "/CropBox");
             Printf.printf "BleedBox: %s\n" (getbox page "/BleedBox");
             Printf.printf "TrimBox: %s\n" (getbox page "/TrimBox");
             Printf.printf "ArtBox: %s\n" (getbox page "/ArtBox");
             Printf.printf "Rotation: %i\n" (rotation page))
        range

(* Does the page have a defined box e.g "/CropBox" *)
let hasbox pdf page boxname =
  let pages = Pdfpage.pages_of_pagetree pdf in
    if page > length pages || page < 1 then raise (Failure "hasbox: bad page") else
      let p = select page pages in
        match Pdf.lookup_direct pdf boxname p.Pdfpage.rest with
        | Some _ -> true
        | _ -> false


(* Print metadata *)
let get_metadata pdf =
  match Pdf.lookup_direct pdf "/Root" pdf.Pdf.trailerdict with
  | None -> error "malformed file"
  | Some root ->
      match Pdf.lookup_direct pdf "/Metadata" root with
      | Some ((Pdf.Stream _) as s) ->
          Pdfcodec.decode_pdfstream pdf s;
          begin match s with
          | Pdf.Stream {contents = (_, Pdf.Got data)} -> Some data 
          | _ -> assert false
          end
      | _ -> None

let print_metadata pdf =
  match get_metadata pdf with
    None -> ()
  | Some data ->
      for x = 0 to bytes_size data - 1 do
        Printf.printf "%c" (char_of_int (bget data x))
      done



(* \section{Print font data} *)
let list_font pdf page (name, dict) =
  let subtype =
    match Pdf.lookup_direct pdf "/Subtype" dict with
    | Some (Pdf.Name n) -> n
    | _ -> ""
  in let basefont =
    match Pdf.lookup_direct pdf "/BaseFont" dict with
    | Some (Pdf.Name n) -> n
    | _ -> ""
  in let encoding =
   match Pdf.lookup_direct pdf "/Encoding" dict with
    | Some (Pdf.Name n) -> n
    | _ -> ""
  in 
    (*i Printf.printf
      "%i %s %s %s %s\n" i*)
      page, name, subtype, basefont, encoding

let list_fonts pdf =
  let pages = Pdfpage.pages_of_pagetree pdf in
    flatten
      (map
        (fun (num, page) ->
           match Pdf.lookup_direct pdf "/Font" page.Pdfpage.resources with
           | Some (Pdf.Dictionary fontdict) ->
               map (list_font pdf num) fontdict
           | _ -> [])
        (combine (ilist 1 (length pages)) pages))

let string_of_font (p, n, s, b, e) =
  Printf.sprintf "%i %s %s %s %s\n" p n s b e

let print_fonts pdf =
  flprint
    (fold_left ( ^ ) "" (map string_of_font (list_fonts pdf)))


(* \section{Superimpose text, page numbers etc.} *)

type position =
  | PosCentre of float * float
  | PosLeft of float * float
  | PosRight of float * float
  | Top of float
  | TopLeft of float
  | TopRight of float
  | Left of float
  | BottomLeft of float
  | Bottom of float
  | BottomRight of float
  | Right of float
  | Diagonal
  | ReverseDiagonal
  | Centre

let string_of_position = function
  | PosCentre (a, b) -> Printf.sprintf "PosCentre %f %f" a b
  | PosLeft (a, b) -> Printf.sprintf "PosLeft %f %f" a b
  | PosRight (a, b) -> Printf.sprintf "PosRight %f %f" a b
  | Top a -> Printf.sprintf "Top %f" a
  | TopLeft a -> Printf.sprintf "TopLeft %f" a
  | TopRight a -> Printf.sprintf "TopRight %f" a
  | Left a -> Printf.sprintf "Left %f" a
  | BottomLeft a -> Printf.sprintf "BottomLeft %f" a
  | Bottom a -> Printf.sprintf "Bottom %f" a
  | BottomRight a -> Printf.sprintf "BottomRight %f" a
  | Right a -> Printf.sprintf "Right %f" a
  | Diagonal -> "Diagonal"
  | ReverseDiagonal -> "Reverse Diagonal"
  | Centre -> "Centre"

type orientation =
  | Horizontal
  | Vertical
  | VerticalDown

type justification = LeftJustify | CentreJustify | RightJustify

(* Given the mediabox, calculate an absolute position for the text. *)
let calculate_position ignore_d w (xmin, ymin, xmax, ymax) orientation pos =
  let rot = if orientation = VerticalDown then rad_of_deg 270. else 0. in
    match pos with
    | Centre ->
        (xmin +. xmax) /. 2. -. w /. 2.,
        (ymin +. ymax) /. 2.,
        rot
    | Diagonal ->
        let angle = atan ((ymax -. ymin) /. (xmax -. xmin))
        in let cx, cy = (xmax +. xmin) /. 2., (ymax +. ymin) /. 2. in
          let dl = w /. 2. in
            let dx = dl *. cos angle
            in let dy = dl *. sin angle in
              cx -. dx, cy -. dy, angle
    | ReverseDiagonal ->
        let angle = atan ((ymax -. ymin) /. (xmax -. xmin))
        in let cx, cy = (xmax +. xmin) /. 2., (ymax +. ymin) /. 2. in
          let dl = w /. 2. in
            let dx = dl *. cos angle
            in let dy = dl *. sin angle in
              cx -. dx, (ymax +. ymin) -. (cy -. dy), angle -. ((2. *. pi) -. ((pi -. (2. *. angle)) *. 2.) /. 2.) +. pi
    | PosLeft (x, y) -> xmin +. x, ymin +. y, rot
    | PosCentre (x, y) -> xmin +. x -. (w /. 2.), ymin +. y, rot
    | PosRight (x, y) -> xmin +. x -. w, ymin +. y, rot
    | Top d ->
        let d = if ignore_d then 0. else d in
          (xmin +. xmax) /. 2. -. w /. 2., ymax -. d, rot
    | TopLeft d ->
        let d = if ignore_d then 0. else d in
          xmin +. d, ymax -. d, rot
    | TopRight d ->
        let d = if ignore_d then 0. else d in
        xmax -. d -. w, ymax -. d, rot
    | Left d ->
        let d = if ignore_d then 0. else d in
          xmin +. d, (ymax +. ymin) /. 2., rot
    | BottomLeft d ->
        let d = if ignore_d then 0. else d in
          xmin +. d, ymin +. d, rot
    | Bottom d ->
        let d = if ignore_d then 0. else d in
          (xmin +. xmax) /. 2. -. w /. 2., ymin +. d, rot
    | BottomRight d ->
        let d = if ignore_d then 0. else d in
          xmax -. d -. w, ymin +. d, rot
    | Right d ->
        let d = if ignore_d then 0. else d in
          xmax -. d -. w, (ymax +. ymin) /. 2., rot

(* Process UTF8 text to /WinAnsiEncoding string. *)
let winansi_of_utf8 s =
  (*flprint "winansi_of_utf8:";
  iter (Printf.printf "%C ") (explode s);
  flprint "\n";*)
  let extractor = Pdftext.charcode_extractor_of_encoding Pdftext.WinAnsiEncoding
  and codepoints = Pdftext.codepoints_of_utf8 s in
    (*flprint "codepoints after Pdftext.codepoints_of_utf8\n";
    iter (Printf.printf "%i ") codepoints;
    flprint "\ndone\n";*)
    implode (map char_of_int (option_map extractor codepoints))

(* Process codepoints back to UTF8, assuming it came from UTF8 to start with *)
let utf8_of_winansi s =
  let text_extractor =
    Pdftext.text_extractor_of_font
      (Pdf.empty ())
      (Pdf.Dictionary
        [("/BaseFont", Pdf.Name "/TimesRoman");
         ("/Subtype", Pdf.Name "/Type1");
         ("/Encoding", Pdf.Name "/WinAnsiEncoding")]) 
  in
    let codepoints = Pdftext.codepoints_of_text text_extractor s in
      Pdftext.utf8_of_codepoints codepoints

(* Get the width of some text in the given font *)
let width_of_text font text =
  match font with
  | Pdftext.SimpleFont {Pdftext.fontmetrics = Some fontmetrics} ->
       begin try
         fold_left ( +. ) 0. (map (fun c -> fontmetrics.(int_of_char c)) (explode text))
       with
         _ -> 0.
       end
  | _ -> 0.

type ops_metrics =
  {metrics_text : string;
   metrics_x : float;
   metrics_y : float;
   metrics_rot : float}
   
let ops_metrics : ops_metrics list ref = ref []

let ops_baseline_adjustment = ref 0.

let metrics_howmany () = length !ops_metrics

let metrics_text n =
  utf8_of_winansi (select n !ops_metrics).metrics_text

let metrics_x n =
  (select n !ops_metrics).metrics_x

let metrics_y n =
  (select n !ops_metrics).metrics_y

let metrics_rot n =
  (select n !ops_metrics).metrics_rot

let metrics_baseline_adjustment () = !ops_baseline_adjustment

let ops longest_w metrics x y rotate hoffset voffset outline linewidth unique_fontname unique_extgstatename colour fontsize text =
  if metrics then
    ops_metrics :=
      {metrics_text = text; metrics_x = x -. hoffset; metrics_y = y -. voffset; metrics_rot = rotate}
      ::!ops_metrics;
  [Pdfops.Op_q;
  Pdfops.Op_BMC "/CPDFSTAMP";
   Pdfops.Op_cm
     (Pdftransform.matrix_of_transform
       [Pdftransform.Translate (x -. hoffset, y -. voffset);
        Pdftransform.Rotate ((0., 0.), rotate)]);
   Pdfops.Op_BT;
   ] @
   (if outline then [Pdfops.Op_w linewidth; Pdfops.Op_Tr 1] else [Pdfops.Op_Tr 0]) @
   [
   (match colour with (r, g, b) -> Pdfops.Op_rg (r, g, b));
   (match colour with (r, g, b) -> Pdfops.Op_RG (r, g, b))]
   @
   (match unique_extgstatename with None -> [] | Some n -> [Pdfops.Op_gs n])
   @
   [Pdfops.Op_Tf (unique_fontname, fontsize);
   Pdfops.Op_Tj text;
   Pdfops.Op_ET;
   Pdfops.Op_EMC;
   Pdfops.Op_Q]

(* Find the h-offset for justification based on the longest width, the current
width, the justification and the position. *)
let find_justification_offsets longest_w w position = function
  | LeftJustify ->
      begin match position with
      | TopLeft _ | Left _ | PosLeft _ | BottomLeft _ -> 0.
      | Top _ | PosCentre _ | Bottom _ | Centre -> (longest_w -. w) /. 2.
      | TopRight _ | BottomRight _ | PosRight _ | Right _ -> longest_w -. w
      | Diagonal -> 0.
      | ReverseDiagonal -> 0.
      end
  | RightJustify ->
      begin match position with
      | TopLeft _ | Left _ | PosLeft _ | BottomLeft _ -> ~-.(longest_w -. w)
      | Top _ | PosCentre _ | Bottom _ | Centre -> ~-.((longest_w -. w) /. 2.)
      | TopRight _ | BottomRight _ | PosRight _ | Right _ -> 0.
      | Diagonal -> 0.
      | ReverseDiagonal -> 0.
      end
  | CentreJustify ->
      begin match position with
      | TopLeft _ | Left _ | PosLeft _ | BottomLeft _ -> ~-.((longest_w -. w) /. 2.)
      | Top _ | PosCentre _ | Bottom _ | Centre -> 0.
      | TopRight _ | BottomRight _ | PosRight _ | Right _ -> (longest_w -. w) /. 2.
      | Diagonal -> 0.
      | ReverseDiagonal -> 0.
      end

(* Lex an integer from the table *)
let extract_num header s =
  match Pdfgenlex.lex_string (Hashtbl.find header s) with
    [Pdfgenlex.LexInt i] -> Pdf.Integer i
  | [Pdfgenlex.LexReal f] -> Pdf.Real f
  | _ -> raise (Failure ("extract_num: " ^ s))

let extract_fontbbox header s =
  let num = function
      Pdfgenlex.LexInt i -> Pdf.Integer i
    | Pdfgenlex.LexReal f -> Pdf.Real f
    | _ -> raise (Failure "extract_fontbbox")
  in
    match Pdfgenlex.lex_string (Hashtbl.find header s) with
      [a; b; c; d] -> [num a; num b; num c; num d] 
    | _ -> raise (Failure "extract_fontbbox")

let remove_slash s =
  match explode s with
   '/'::x -> implode x
  | _ -> raise (Failure "remove_slash")

let extract_widths chars_and_widths =
  let win_to_name = List.map (fun (x, y) -> (y, x)) Pdfglyphlist.name_to_win in
    List.map
      (fun x ->
          try
            let name = List.assoc x win_to_name in
              let width = List.assoc (remove_slash name) chars_and_widths in
                width
          with
            _ -> 0)
      (ilist 0 255)

let make_font embed fontname =
  let font = unopt (Pdftext.standard_font_of_name ("/" ^ fontname)) in
  let header, width_data, _, chars_and_widths = Pdfstandard14.afm_data font in
    let widths = extract_widths (list_of_hashtbl chars_and_widths) in
    let flags = Pdfstandard14.flags_of_standard_font font in
    let fontbbox = extract_fontbbox header "FontBBox" in
    let italicangle = extract_num header "ItalicAngle" in
    let ascent = try extract_num header "Ascender" with _ -> Pdf.Integer 0 in
    let descent = try extract_num header "Descender" with _ -> Pdf.Integer 0 in
    let capheight = try extract_num header "CapHeight" with _ -> Pdf.Integer 0 in
    let stemv = Pdfstandard14.stemv_of_standard_font font in
      let fontdescriptor =
        Pdf.Dictionary
          [("/Type", Pdf.Name "/FontDescriptor");
           ("/FontName", Pdf.Name ("/" ^ fontname));
           ("/Flags", Pdf.Integer flags);
           ("/FontBBox", Pdf.Array fontbbox);
           ("/ItalicAngle", italicangle);
           ("/Ascent", ascent);
           ("/Descent", descent);
           ("/CapHeight", capheight);
           ("/StemV", Pdf.Integer stemv)]
      in
        (* With -no-embed-font, we use the standard encoding, and just the
         * minimal stuff. Without -no-embed-font, we switch to WinAnsiEncoding,
         * and fill out everything except the font file instead *)
        if embed then
          Pdf.Dictionary
            [("/Type", Pdf.Name "/Font");
             ("/Subtype", Pdf.Name "/Type1");
             ("/BaseFont", Pdf.Name ("/" ^ fontname));          
             ("/Encoding", Pdf.Name "/WinAnsiEncoding");
             ("/FirstChar", Pdf.Integer 0);
             ("/LastChar", Pdf.Integer 255);
             ("/Widths", Pdf.Array (map (fun x -> Pdf.Integer x) widths));
             ("/FontDescriptor", fontdescriptor)]
        else
          Pdf.Dictionary
            [("/Type", Pdf.Name "/Font");
             ("/Subtype", Pdf.Name "/Type1");
             ("/Encoding", Pdf.Name "/WinAnsiEncoding");
             ("/BaseFont", Pdf.Name ("/" ^ fontname))]

let extract_page_text only_fontsize pdf _ page =
  let text_extractor = ref None in
  let right_font_size = ref false in
    fold_left ( ^ ) ""
      (map
        (function
         | Pdfops.Op_Tf (fontname, fontsize) ->
             right_font_size :=
               begin match only_fontsize with
                 Some x -> x = fontsize
               | _ -> false
               end;
             let fontdict =
               match Pdf.lookup_direct pdf "/Font" page.Pdfpage.resources with
               | None -> raise (Pdf.PDFError "Missing /Font in text extraction")
               | Some d ->
                   match Pdf.lookup_direct pdf fontname d with
                   | None -> raise (Pdf.PDFError "Missing font in text extraction")
                   | Some d -> d
             in
               text_extractor := Some (Pdftext.text_extractor_of_font pdf fontdict);
               ""
         | Pdfops.Op_Tj text when !text_extractor <> None ->
             if not !right_font_size then
               ""
             else
               Pdftext.utf8_of_codepoints
                 (Pdftext.codepoints_of_text (unopt !text_extractor) text)
         | Pdfops.Op_TJ (Pdf.Array objs) when !text_extractor <> None ->
             if not !right_font_size then
               ""
             else
               fold_left ( ^ ) ""
                 (option_map
                    (function
                     | Pdf.String text ->
                         Some
                           (Pdftext.utf8_of_codepoints
                             (Pdftext.codepoints_of_text (unopt !text_extractor) text))
                     | _ -> None)
                    objs)
         | _ -> "")
        (Pdfops.parse_operators pdf page.Pdfpage.resources page.Pdfpage.content))

(* For each page, extract all the ops with text in them, and concatenate it all together *)
let extract_text extract_text_font_size pdf range =
  fold_left (fun x y -> x ^ (if x <> "" && y <> "" then "\n" else "") ^ y) ""
    (map_pages (extract_page_text extract_text_font_size pdf) pdf range)

let addtext
  metrics lines linewidth outline fast colour fontname embed bates batespad fontsize font
  underneath position hoffset voffset text pages orientation cropbox opacity
  justification filename extract_text_font_size pdf
=
  let endpage = Pdfpage.endpage pdf in
  let replace_pairs pdf filename bates batespad num page =
      [
       "%PageDiv2", (fun () -> string_of_int ((num + 1) / 2));
       "%Page", (fun () -> string_of_int num);
       "%Roman", (fun () -> roman_upper num);
       "%roman", (fun () -> roman_lower num);
       "%filename", (fun () -> filename);
       "%Label", (fun () -> pagelabel pdf num);
       "%EndPage", (fun () -> string_of_int endpage);
       "%EndLabel", (fun () -> pagelabel pdf endpage);
       "%ExtractedText", (fun () -> extract_page_text extract_text_font_size pdf num page);
       "%Bates",
          (fun () ->
            (let numstring = string_of_int (bates + num - 1) in
             match batespad with
               None -> numstring
             | Some w ->
                 if String.length numstring >= w
                   then numstring
                   else implode (many '0' (w - String.length numstring)) ^ numstring))]
  in
  let addtext_page num page =
    let resources', unique_extgstatename =
      if opacity < 1.0 then
        let dict =
          match Pdf.lookup_direct pdf "/ExtGState" page.Pdfpage.resources with
          | Some d -> d
          | None -> Pdf.Dictionary []
        in
          let unique_extgstatename = Pdf.unique_key "gs" dict in
            let dict' =
              Pdf.add_dict_entry dict unique_extgstatename
                (Pdf.Dictionary [("/ca", Pdf.Real opacity); ("/CA", Pdf.Real opacity)])
            in
              Pdf.add_dict_entry page.Pdfpage.resources "/ExtGState" dict', Some unique_extgstatename
      else
        page.Pdfpage.resources, None
    in
      let fontdict =
        match Pdf.lookup_direct pdf "/Font" page.Pdfpage.resources with
        | None -> Pdf.Dictionary []
        | Some d -> d
      in
        let unique_fontname = Pdf.unique_key "F" fontdict in
          let ops =
            let text = process_text text (replace_pairs pdf filename bates batespad num page) in
              let calc_textwidth text =
                match font with
                | Some f ->
                    let rawwidth =
                      Pdfstandard14.textwidth
                        false
                        (if embed then Pdftext.WinAnsiEncoding else Pdftext.StandardEncoding)
                        f
                        text
                    in
                      (float rawwidth *. fontsize) /. 1000.
                | None -> 
                    let font =
                      match Pdf.lookup_direct pdf "/Font" page.Pdfpage.resources with
                      | Some fontdict ->
                          begin match Pdf.lookup_direct pdf fontname fontdict with
                          | Some font -> font
                          | _ -> failwith "addtext: bad font A"
                          end
                      | _ -> failwith "addtext: bad font B"
                    in
                      let rawwidth = width_of_text (Pdftext.read_font pdf font) text in
                        (rawwidth *. fontsize) /. 1000.
              in
                let expanded_lines =
                  map
                    (function text ->
                       process_text text (replace_pairs pdf filename bates batespad num page))
                    lines
                in
                let textwidth = calc_textwidth text
                and allwidths = map calc_textwidth expanded_lines in
                  let longest_w = last (sort compare allwidths) in
                  let joffset = find_justification_offsets longest_w textwidth position justification in
                  let mediabox =
                    if cropbox then
                      match Pdf.lookup_direct pdf "/CropBox" page.Pdfpage.rest with
                      | Some pdfobject -> Pdf.parse_rectangle (Pdf.direct pdf pdfobject)
                      | None -> Pdf.parse_rectangle page.Pdfpage.mediabox
                    else
                      Pdf.parse_rectangle page.Pdfpage.mediabox
                  in
                    let x, y, rotate = calculate_position false textwidth mediabox orientation position in
                      let hoffset, voffset =
                        if position = Diagonal || position = ReverseDiagonal
                          then -. (cos ((pi /. 2.) -. rotate) *. voffset), sin ((pi /. 2.) -. rotate) *. voffset
                          else hoffset, voffset 
                      in
                        match font with
                        | Some f ->
                            ops longest_w metrics x y rotate (hoffset +. joffset) voffset outline linewidth
                            unique_fontname unique_extgstatename colour fontsize text
                        | None ->
                            ops longest_w metrics x y rotate (hoffset +. joffset) voffset outline linewidth
                            fontname None colour fontsize text 
          in
            let newresources =
              match font with
              | Some _ ->
                  let newfontdict =
                    Pdf.add_dict_entry fontdict unique_fontname (make_font embed fontname)
                  in
                    Pdf.add_dict_entry resources' "/Font" newfontdict
              | None -> page.Pdfpage.resources
          in
            let page = {page with Pdfpage.resources = newresources} in
              if underneath
                then Pdfpage.prepend_operators pdf ops ~fast:fast page
                else Pdfpage.postpend_operators pdf ops ~fast:fast page
  in
    if metrics then
      (ignore (iter_pages (fun a b -> ignore (addtext_page a b)) pdf pages); pdf)
    else
      process_pages addtext_page pdf pages

(* Prev is a list of lists of characters *)
let split_at_newline t =
  let rec split_at_newline_inner prev = function
    | [] -> rev (map implode (map rev prev))
    | '\\'::'\\'::'n'::t -> split_at_newline_inner (('n'::'\\'::'\\'::hd prev)::tl prev) t
    | '\\'::'n'::t -> split_at_newline_inner ([]::prev) t
    | h::t -> split_at_newline_inner ((h::hd prev)::tl prev) t
  in
    split_at_newline_inner [[]] (explode t)

let rec unescape_chars prev = function
  | [] -> rev prev
  | '\\'::('0'..'7' as a)::('0'..'7' as b)::('0'..'7' as c)::t ->
       let chr = char_of_int (int_of_string ("0o" ^ implode [a;b;c])) in
         unescape_chars (chr::prev) t
  | '\\'::'\\'::t -> unescape_chars ('\\'::prev) t
  | '\\'::c::t when c <> 'n' -> unescape_chars (c::prev) t
  | h::t -> unescape_chars (h::prev) t

let unescape_string s =
  implode (unescape_chars [] (explode s))

let
  addtexts metrics linewidth outline fast fontname font embed bates batespad colour position linespacing
  fontsize underneath text pages orientation cropbox opacity justification
  midline topline filename extract_text_font_size pdf
=
  (*flprint "addtexts:\n";
  iter (Printf.printf "%C ") (explode text);
  flprint "\n";
  Printf.printf "\nCpdf.addtexts: metrics = %b" metrics;
  flprint "\n";*)
  (*Printf.printf "linewidth = %f\n" linewidth;
  Printf.printf "outline = %b\n" outline;
  Printf.printf "fast = %b\n" fast;
  Printf.printf "fontname = %s\n" fontname;
  Printf.printf "winansi text = %s\n" text;
  Printf.printf "position = %s\n" (string_of_position position);
  Printf.printf "bates = %i\n" bates;
  Printf.printf "linespacing = %f\n" linespacing;
  Printf.printf "fontsize = %f\n" fontsize;
  Printf.printf "underneath = %b\n" underneath;
  Printf.printf "font = %s\n" begin match font with None -> "None" | Some x -> Pdftext.string_of_standard_font x end;
  Printf.printf "justification = %s\n"
  begin match justification with LeftJustify -> "left" | RightJustify -> "right" | CentreJustify -> "centre" end;
  Printf.printf "midline = %b\n" midline;
  begin match colour with r, g, b -> Printf.printf "%f, %f, %f\n" r g b end;
  Printf.printf "opacity = %f\n" opacity;
  flprint "\n";
  Printf.printf "relative-to-cropbox = %b" cropbox;
  flprint "\n";*)
  ops_metrics := [];
  let text = winansi_of_utf8 text in
    let lines = map unescape_string (split_at_newline text) in
      let pdf = ref pdf in
        let voffset =
          match position with
          | Bottom _ | BottomLeft _ | BottomRight _ ->
              ref (0. -. (linespacing *. fontsize *. (float (length lines) -. 1.)))
          | Left _ | Right _ ->
              (* Vertically align *)
              ref (0. -. (linespacing *. ((fontsize *. (float (length lines) -. 1.)) /. 2.)))
          | Diagonal | ReverseDiagonal ->
              (* Change so that the whole paragraph sits on the centre... *)
              ref (0. -. ((linespacing *. fontsize *. (float (length lines) -. 1.)) /. 2.))
          | _ -> ref 0.
        in
          if midline then
            begin match font with
              | Some font ->
                  let baseline_adjustment =
                    (fontsize *. float (Pdfstandard14.baseline_adjustment font)) /. 1000.
                  in
                    ops_baseline_adjustment := baseline_adjustment;
                    voffset := !voffset +. baseline_adjustment
              | _ ->
                 ops_baseline_adjustment := 0.
            end
          else
          if topline then
            begin match font with
              | Some font ->
                  let baseline_adjustment =
                    (fontsize *. float (Pdfstandard14.baseline_adjustment font) *. 2.0) /. 1000.
                  in
                    ops_baseline_adjustment := baseline_adjustment;
                    voffset := !voffset +. baseline_adjustment
              | _ ->
                 ops_baseline_adjustment := 0.
            end
          else
            ops_baseline_adjustment := 0.;
          iter
            (fun line ->
               let voff, hoff =
                 if orientation = Vertical then 0., -.(!voffset) else !voffset, 0.
               in
                 pdf :=
                   addtext metrics lines linewidth outline fast colour fontname
                   embed bates batespad fontsize font underneath position hoff voff line
                   pages orientation cropbox opacity justification filename
                   extract_text_font_size
                   !pdf;
                 voffset := !voffset +. (linespacing *. fontsize))
            lines;
            ops_metrics := rev !ops_metrics;
            !pdf

let removetext range pdf =
  (* Could fail on nesting, or other marked content inside our marked content.*)
  let rec remove_until_last_EMC level = function
    | [] -> []
    | Pdfops.Op_BMC "/CPDFSTAMP"::more ->
        remove_until_last_EMC (level + 1) more
    | Pdfops.Op_EMC::more ->
        if level = 1
          then more
          else remove_until_last_EMC (level - 1) more
    | _::more ->
        remove_until_last_EMC level more
  in
    let rec remove_stamps prev = function
      | [] -> rev prev
      | Pdfops.Op_BMC "/CPDFSTAMP"::more ->
          let rest = remove_until_last_EMC 1 more in
            remove_stamps prev rest
      | h::t -> remove_stamps (h::prev) t
    in
      let removetext_page _ page =
        {page with
           Pdfpage.content =
             let ops = Pdfops.parse_operators pdf page.Pdfpage.resources page.Pdfpage.content in
               [Pdfops.stream_of_ops (remove_stamps [] ops)]}
      in
        process_pages removetext_page pdf range

(* \section{Padding with blank pages.} *)
let insert_after pos page pages =
  let before, after = cleave pages pos in
    before @ [page] @ after

(* Insert many. *)
let rec insert_after_many pages = function
  | [] -> pages
  | (pos, page)::more ->
      let pages' = insert_after pos page pages in
        insert_after_many pages' (map (fun (p, pa) -> p + 1, pa) more)

(* For each pagenum in the range, increment the count by padsize, and carry on. e.g
insert_after_many_changes 1 0 [2] [1; 2; 3] --> [(1, 1); (2, 2); (3, 4)] *)
let rec insert_after_many_changes isbefore padsize offset range = function
  [] -> []
| h::t ->
    let item = (h, h + offset + if isbefore && mem h range then 1 else 0) in
      if mem h range then
        item::insert_after_many_changes isbefore padsize (offset + padsize) range t
      else
        item::insert_after_many_changes isbefore padsize offset range t

let print_changes =
  List.iter (fun (f, t) -> Printf.printf "%i --> %i\n" f t)

let pad_with_pdf (range : int list) (pdf : Pdf.t) (isbefore : bool) (padfile : Pdf.t) =
  let range = List.sort compare (setify range) in
  let merged =
    Pdfmerge.merge_pdfs
      false false ["a"; "b"] [pdf; padfile] [ilist 1 (Pdfpage.endpage pdf); ilist 1 (Pdfpage.endpage padfile)]
  in
  let original_pages, padpages =
    cleave (Pdfpage.pages_of_pagetree merged) (Pdfpage.endpage pdf) 
  in
    let newpages =
      List.map
        (fun (pagenum, page) ->
           if mem pagenum range then
             (if isbefore then padpages @ [page] else [page] @ padpages)
           else
             [page])
        (combine (indx original_pages) original_pages)
    in
      (* FIXME Provide ~changes here? *)
      Pdfpage.change_pages false merged (flatten newpages)

let pad padwith range pdf isbefore =
  match padwith with
    Some padfile -> pad_with_pdf range pdf isbefore padfile
  | None ->
      let i = if isbefore then 1 else 0 in
      let pages = Pdfpage.pages_of_pagetree pdf in
        let blankpages =
          map
            (fun n ->
               {Pdfpage.content = [];
                Pdfpage.mediabox = (select (n + i) pages).Pdfpage.mediabox;
                Pdfpage.resources = Pdf.Dictionary [];
                Pdfpage.rotate = (select (n + i) pages).Pdfpage.rotate;
                Pdfpage.rest = (select (n + i) pages).Pdfpage.rest})
            range
        in
          let pages' = insert_after_many pages (combine range blankpages) in
          let changes =
            insert_after_many_changes
              isbefore 1 0 (List.map (fun x -> x + i) range) (ilist 1 (length pages))
          in
            Pdfpage.change_pages ~changes true pdf pages'

let padafter ?padwith range pdf =
  let isinpdf n = mem n (ilist 1 (Pdfpage.endpage pdf)) in
    if not (fold_left ( && ) true (map isinpdf range)) then
      raise (Failure "padafter: range contains pages not present in pdf");
    pad padwith range pdf false

let padbefore ?padwith range pdf =
  let isinpdf n = mem n (ilist 1 (Pdfpage.endpage pdf)) in
    if not (fold_left ( && ) true (map isinpdf range)) then
      raise (Failure "padbefore: range contains pages not present in pdf");
    pad padwith (map pred range) pdf true

let padmultiple n pdf =
  let neg, n = n < 0, if n < 0 then -n else n in
  let pages = Pdfpage.pages_of_pagetree pdf in
    let len = length pages in
      let pages_to_add = if len / n * n = len then 0 else n - (len mod n) in
        if pages_to_add > 0 then
          let blankpages =
            many
              {Pdfpage.content = [];
               Pdfpage.mediabox = (select len pages).Pdfpage.mediabox;
               Pdfpage.resources = Pdf.Dictionary [];
               Pdfpage.rotate = (select len pages).Pdfpage.rotate;
               Pdfpage.rest = Pdf.Dictionary []}
              pages_to_add
          in
            let changes = map (fun x -> (x, x)) (ilist 1 (length pages)) in
              Pdfpage.change_pages ~changes true pdf (if neg then blankpages @ pages else pages @ blankpages)
        else
          pdf

(* \section{Shift page data} *)
let make_mediabox (xmin, ymin, xmax, ymax) =
  Pdf.Array
    [Pdf.Real xmin; Pdf.Real ymin; Pdf.Real xmax; Pdf.Real ymax]

(* Change the media box and other known boxes by the function [f] which takes
xmin, xmax, ymin, ymax as input. *)
let change_boxes f pdf page =
  let names = ["/TrimBox"; "/ArtBox"; "/CropBox"; "/BleedBox"]
  in let getbox n =
    Pdf.lookup_direct pdf n page.Pdfpage.rest
  in
    let boxes = combine names (map getbox names) in
      let toreplace = lose (function (_, None) -> true | _ -> false) boxes in
        let toreplace =
          map
            (function (name, Some value) -> (name, value) | _ -> assert false)
            toreplace
        in
          let rest' =
            fold_left
              (fun e (k, v) ->
                 let v =
                   make_mediabox (f (Pdf.parse_rectangle v))
                 in
                   Pdf.replace_dict_entry e k v)
              page.Pdfpage.rest
              toreplace
          in
            {page with
               Pdfpage.mediabox =
                 make_mediabox (f (Pdf.parse_rectangle page.Pdfpage.mediabox));
               Pdfpage.rest = rest'}

(* The content is flipped by altering any use of [Op_cm]. But we must also
alter any /Matrix entries in pattern dictionaries for tiled and shading
patterns. In addition, shadings used by Op_sh in the main page content and in
xobjects must be altered. *)
(*let rec change_shadings pdf tr resources =
  let transform_shading s =
    s
  in
    try
      let resources =
        begin match Pdf.lookup_direct pdf "/Shading" resources with
        | Some (Pdf.Dictionary shadings) ->
            let names, nums =
              split
                (map
                   (fun (name, shading) ->
                      Printf.printf "Fixing up shading %s\n" name;
                      name, Pdf.addobj pdf (transform_shading shading))
                   shadings)
            in
              let entries =
                map2 (fun name num -> name, Pdf.Indirect num) names nums
              in
                Pdf.add_dict_entry resources "/Shading" (Pdf.Dictionary entries)
        | _ -> resources
        end
      in
        let process_xobject xobject =
          change_shadings pdf tr xobject
        in
          begin match Pdf.lookup_direct pdf "/XObject" resources with
          | Some (Pdf.Dictionary xobjects) ->
              let names, nums =
                split
                  (map
                     (fun (name, xobject) ->
                        Printf.printf "Looking for shadings in xobject %s\n" name;
                        name, Pdf.addobj pdf (process_xobject xobject))
                     xobjects)
              in
                let entries =
                  map2 (fun name num -> name, Pdf.Indirect num) names nums
                in
                  Pdf.add_dict_entry resources "/XObject" (Pdf.Dictionary entries)
          | _ -> resources
          end
    with
      _ -> resources*)

let change_pattern_matrices pdf tr resources =
  try
    (*let resources = change_shadings pdf tr resources in*)
      begin match Pdf.lookup_direct pdf "/Pattern" resources with
      | Some (Pdf.Dictionary patterns) ->
          let names, nums =
            split
              (map
                (fun (name, p) ->
                  let old_pattern = Pdf.direct pdf p in
                    let new_pattern =
                      let existing_tr = Pdf.parse_matrix pdf "/Matrix" old_pattern in
                        let new_tr = Pdftransform.matrix_compose (Pdftransform.matrix_invert tr) existing_tr in
                          Pdf.add_dict_entry old_pattern "/Matrix" (Pdf.make_matrix new_tr)
                    in
                      name, Pdf.addobj pdf new_pattern)
                patterns)
          in
            let entries =
              map2 (fun name num -> name, Pdf.Indirect num) names nums
            in
              Pdf.add_dict_entry resources "/Pattern" (Pdf.Dictionary entries)
      | _ -> resources
    end
  with
    Pdftransform.NonInvertable -> resources

(* Apply transformations to any annotations in /Annots (i.e their /Rect entries) *)
let transform_annotations pdf transform rest =
  match Pdf.lookup_direct pdf "/Annots" rest with
  | Some (Pdf.Array annots) ->
      (* Always indirect references, so alter in place *)
      List.iter
        (function
         | Pdf.Indirect i ->
             let annot = Pdf.lookup_obj pdf i in
               let rect' =
                 match Pdf.lookup_direct pdf "/Rect" annot with
                   Some rect ->
                     let minx, miny, maxx, maxy = Pdf.parse_rectangle rect in
                       let (x0, y0) = Pdftransform.transform_matrix transform (minx, miny) in
                       let (x1, y1) = Pdftransform.transform_matrix transform (maxx, maxy) in
                       let (x2, y2) = Pdftransform.transform_matrix transform (minx, maxy) in
                       let (x3, y3) = Pdftransform.transform_matrix transform (maxx, miny) in
                         let minx = fmin (fmin x0 x1) (fmin x2 x3) in
                         let miny = fmin (fmin y0 y1) (fmin y2 y3) in
                         let maxx = fmax (fmax x0 x1) (fmax x2 x3) in
                         let maxy = fmax (fmax y0 y1) (fmax y2 y3) in
                           Pdf.Array [Pdf.Real minx; Pdf.Real miny; Pdf.Real maxx; Pdf.Real maxy]
                 | None -> raise (Pdf.PDFError "transform_annotations: no rect")
               in
                 let annot' = Pdf.add_dict_entry annot "/Rect" rect' in 
                 Pdf.addobj_given_num pdf (i, annot')
         | _ -> Printf.eprintf "transform_annotations: not indirect")
        annots
   | _ -> ()

let shift_page ?(fast=false) dxdylist pdf pnum page =
  let dx, dy = List.nth dxdylist (pnum - 1) in
    let transform_op =
      Pdfops.Op_cm (Pdftransform.matrix_of_op (Pdftransform.Translate (dx, dy)))
    in
      let resources' =
        change_pattern_matrices pdf (Pdftransform.mktranslate ~-.dx ~-.dy) page.Pdfpage.resources
      in
        transform_annotations pdf (Pdftransform.mktranslate ~-.dx ~-.dy) page.Pdfpage.rest;
        Pdfpage.prepend_operators pdf [transform_op] ~fast {page with Pdfpage.resources = resources'}

let shift_pdf ?(fast=false) dxdylist pdf range =
  process_pages (shift_page ~fast dxdylist pdf) pdf range

(* Change a page's media box so its minimum x and y are 0, making other
operations simpler to think about. Any shift that is done is reflected in
other boxes (clip etc.) *)
let rectify_boxes ?(fast=false) pdf page =
  let minx, miny, _, _ =
    Pdf.parse_rectangle page.Pdfpage.mediabox
  in
    let f (iminx, iminy, imaxx, imaxy) =
      iminx -. minx, iminy -. miny, imaxx -. minx, imaxy -. miny
    in
      let page = change_boxes f pdf page in
        if minx <> 0. || miny <> 0.
          then shift_page ~fast [(-.minx),(-.miny)] pdf 1 page
          else page

(* \section{Flip pages} *)
let flip_page ?(fast=false) transform_op pdf _ page =
  let minx, miny, maxx, maxy =
    Pdf.parse_rectangle page.Pdfpage.mediabox
  in
    let tr = transform_op minx miny maxx maxy in
      let resources =
        change_pattern_matrices pdf tr page.Pdfpage.resources
      in
        transform_annotations pdf tr page.Pdfpage.rest;
        Pdfpage.prepend_operators pdf [Pdfops.Op_cm tr] ~fast {page with Pdfpage.resources = resources}

let vflip_pdf ?(fast=false) pdf range =
  let transform_op _ miny _ maxy =
    Pdftransform.matrix_of_op
      (Pdftransform.Scale ((0., ((miny +. maxy) /. 2.)), 1., -.1.))
  in
    process_pages (flip_page ~fast transform_op pdf) pdf range

let hflip_pdf ?(fast=false) pdf range =
  let transform_op minx _ maxx _ =
    Pdftransform.matrix_of_op
      (Pdftransform.Scale (((minx +. maxx) /. 2., 0.), -.1., 1.))
  in
    process_pages (flip_page ~fast transform_op pdf) pdf range

let stamp_shift_of_position topline midline sw sh w h p =
  let half x = x /. 2.
  and dy =
    if midline then sh /. 2.
    else if topline then sh
    else 0.
  in
    match p with
    | PosCentre (ox, oy) -> ox -. half sw, oy -. dy
    | PosLeft (ox, oy) -> ox, oy -. dy
    | PosRight (ox, oy) -> ox -. sw, oy -. dy
    | Top o -> half w -. half sw, h -. o -. sh -. dy
    | TopLeft o -> o, h -. sh -. o -. dy
    | TopRight o -> w -. sw -. o, h -. sh -. o -. dy
    | Left o -> o, half h -. half sh -. dy
    | BottomLeft o -> o, o -. dy
    | Bottom o -> half w -. half sw, o -. dy
    | BottomRight o -> w -. sw -. o, o -. dy
    | Right o -> w -. sw -. o, half h -. half sh -. dy
    | Diagonal | ReverseDiagonal | Centre ->
        half w -. half sw, half h -. half sh -. dy

(* Combine Pdfpage.rest items for two PDFs. For now, we combine /Annots, and
 * copy everything else from adict. What else should we combine? *)
let combine_page_items pdf adict bdict =
  let getannots dict =
    begin match dict with
      Pdf.Dictionary d ->
        begin match lookup "/Annots" d with
          Some (Pdf.Array items) -> items
        | _ -> []
        end
    | _ -> []
    end
  in
    let a_annots = getannots adict in
    let b_annots = getannots bdict in
      match a_annots @ b_annots with
        [] -> adict
      | annots -> Pdf.add_dict_entry adict "/Annots" (Pdf.Array annots)

let do_stamp relative_to_cropbox fast position topline midline scale_to_fit isover pdf o u opdf =
  (* Scale page stamp o to fit page u *)
  let sxmin, symin, sxmax, symax =
    Pdf.parse_rectangle
      (match Pdf.lookup_direct pdf "/CropBox" o.Pdfpage.rest with | Some r -> r | None -> o.Pdfpage.mediabox)
  in let txmin, tymin, txmax, tymax =
    Pdf.parse_rectangle
      (match Pdf.lookup_direct pdf "/CropBox" u.Pdfpage.rest with | Some r -> r | None -> u.Pdfpage.mediabox)
  in
    let o =
      if scale_to_fit then
        let xmag = (txmax -. txmin) /. (sxmax -. sxmin) in
          let ymag = (tymax -. tymin) /. (symax -. symin) in
            let scale =
              if xmag < 0.999 && ymag < 0.999 then
                if xmag > ymag then xmag else ymag
              else if xmag >= 1.001 && ymag >= 1.001 then
                if xmag > ymag then ymag else xmag
              else if xmag >= 1.001 then ymag
              else xmag
            in
              let dx = txmin +. ((txmax -. txmin) -. (sxmax -. sxmin) *. scale) /. 2. in
                let dy = tymin +. ((tymax -. tymin) -. (symax -. symin) *. scale) /. 2. in
                  let matrix = 
                    (Pdftransform.matrix_of_transform
                         ([Pdftransform.Translate (dx, dy)] @
                          (if relative_to_cropbox then [Pdftransform.Translate (txmin, tymin)] else []) @
                          [Pdftransform.Scale ((sxmin, symin), scale, scale)]))
                  in
                    transform_annotations pdf matrix o.Pdfpage.rest;
                    let r = Pdfpage.prepend_operators pdf [Pdfops.Op_cm matrix] ~fast o in
                      {r with Pdfpage.resources = 
                        change_pattern_matrices pdf matrix r.Pdfpage.resources}
      else
        let sw = sxmax -. sxmin and sh = symax -. symin
        and w = txmax -. txmin and h = tymax -. tymin in
          let dx, dy = stamp_shift_of_position topline midline sw sh w h position in
            let matrix =
              (Pdftransform.matrix_of_transform
                ((if relative_to_cropbox then [Pdftransform.Translate (txmin, tymin)] else []) @
                [Pdftransform.Translate (dx, dy)]))
            in
              transform_annotations pdf matrix o.Pdfpage.rest;
              let r = Pdfpage.prepend_operators pdf [Pdfops.Op_cm matrix] ~fast o in
                {r with Pdfpage.resources = 
                   change_pattern_matrices pdf matrix r.Pdfpage.resources}
    in
      {u with
         Pdfpage.content =
           (if isover then ( @ ) else ( @@ ))
           (protect fast pdf u.Pdfpage.resources u.Pdfpage.content)
           (protect fast pdf o.Pdfpage.resources o.Pdfpage.content);
         Pdfpage.rest =
           combine_page_items pdf u.Pdfpage.rest o.Pdfpage.rest; 
         Pdfpage.resources =
           combine_pdf_resources pdf u.Pdfpage.resources o.Pdfpage.resources}

(* Alter bookmark destinations given a hash table of (old page reference
 * number, new page reference number) pairings *)
let change_destination t = function
   Pdfdest.XYZ (Pdfdest.PageObject p, a, b, c) ->
     Pdfdest.XYZ (Pdfdest.PageObject (Hashtbl.find t p), a, b, c)
 | Pdfdest.Fit (Pdfdest.PageObject p) ->
     Pdfdest.Fit (Pdfdest.PageObject (Hashtbl.find t p))
 | Pdfdest.FitH (Pdfdest.PageObject p, x) ->
     Pdfdest.FitH (Pdfdest.PageObject (Hashtbl.find t p), x)
 | Pdfdest.FitV (Pdfdest.PageObject p, x) ->
     Pdfdest.FitV (Pdfdest.PageObject (Hashtbl.find t p), x)
 | Pdfdest.FitR (Pdfdest.PageObject p, a, b, c, d) ->
     Pdfdest.FitR (Pdfdest.PageObject (Hashtbl.find t p), a, b, c, d)
 | Pdfdest.FitB (Pdfdest.PageObject p) ->
     Pdfdest.Fit (Pdfdest.PageObject (Hashtbl.find t p))
 | Pdfdest.FitBH (Pdfdest.PageObject p, x) ->
     Pdfdest.FitBH (Pdfdest.PageObject (Hashtbl.find t p), x)
 | Pdfdest.FitBV (Pdfdest.PageObject p, x) ->
     Pdfdest.FitBV (Pdfdest.PageObject (Hashtbl.find t p), x)
 | x -> x

let change_bookmark t m =
  {m with Pdfmarks.target =
    try change_destination t m.Pdfmarks.target with Not_found -> m.Pdfmarks.target}

let stamp relative_to_cropbox position topline midline fast scale_to_fit isover range over pdf =
  let prefix = Pdfpage.shortest_unused_prefix pdf in
  Pdfpage.add_prefix over prefix;
  let marks = Pdfmarks.read_bookmarks pdf in
  let marks_refnumbers = Pdf.page_reference_numbers pdf in
  let pdf = Pdfmarks.remove_bookmarks pdf in
  let over = Pdfmarks.remove_bookmarks over in
  let pageseqs = ilist 1 (Pdfpage.endpage pdf) in
    let over_firstpage_pdf =
      match Pdfpage.pages_of_pagetree over with
      | [] -> error "empty PDF"
      | h::_ -> Pdfpage.change_pages ~changes:[(1, 1)] true over [h]
    in
      let merged =
        Pdfmerge.merge_pdfs
          false false ["a"; "b"] [pdf; over_firstpage_pdf] [pageseqs; [1]]
      in
        let merged =
          {merged with Pdf.saved_encryption = pdf.Pdf.saved_encryption}
        in
          let merged = copy_id true pdf merged in
            let merged_pages = Pdfpage.pages_of_pagetree merged in
              let under_pages, over_page =
                all_but_last merged_pages, last merged_pages
              in
                let new_pages =
                  map2
                    (fun pageseq under_page ->
                      do_stamp relative_to_cropbox fast position topline midline scale_to_fit isover merged
                      (if mem pageseq range then over_page else
                        Pdfpage.blankpage Pdfpaper.a4)
                      under_page over)
                    pageseqs
                    under_pages 
                in
                  let changed =
                    let changes =
                      List.map (fun x -> (x, x)) (ilist 1 (length new_pages))
                    in
                      Pdfpage.change_pages ~changes true merged new_pages
                  in
                    let new_refnumbers = Pdf.page_reference_numbers changed in
                    let changetable = hashtable_of_dictionary (List.combine marks_refnumbers new_refnumbers) in
                    let new_marks = map (change_bookmark changetable) marks in
                      Pdfmarks.add_bookmarks new_marks changed

(* Combine pages from two PDFs. For now, assume equal length. *)

(* If [over] has more pages than [under], chop the excess. If the converse, pad
[over] to the same length *)
let equalize_pages under over =
  let length_under = Pdfpage.endpage under in
  let length_over = Pdfpage.endpage over in
    if length_over > length_under then
      let changes =
        List.map (fun x -> (x, x)) (ilist 1 length_under)
      in
        (under,
         (Pdfpage.change_pages
            ~changes true over (take (Pdfpage.pages_of_pagetree over) length_under)))
    else if length_under > length_over then
      let changes =
        List.map (fun x -> (x, x)) (ilist 1 length_over)
      in
        (under,
         Pdfpage.change_pages
           ~changes true over
           (Pdfpage.pages_of_pagetree over @
              (many (Pdfpage.blankpage Pdfpaper.a4) (length_under - length_over))))
    else
      under, over

let combine_pages fast under over scaletofit swap equalize =
  let debug_combine_pages = false in
  let debug_pdf pdf n =
    if debug_combine_pages then
      begin Pdf.remove_unreferenced pdf; Pdfwrite.pdf_to_file pdf n end
  in
  Pdfpage.add_prefix over (Pdfpage.shortest_unused_prefix under);
  let marks_under, marks_over = Pdfmarks.read_bookmarks under, Pdfmarks.read_bookmarks over in
  let under, over = if equalize then equalize_pages under over else under, over in
  let under_length, over_length = Pdfpage.endpage under, Pdfpage.endpage over in
    if under_length <> over_length then
      raise (Pdf.PDFError "combine_pages: not of equal length")
    else
      let pageseqs_under = ilist 1 (Pdfpage.endpage under) in
      let pageseqs_over = ilist 1 (Pdfpage.endpage over) in
      let merged =
        Pdfmerge.merge_pdfs
          false false ["a"; "b"] [under; over] [pageseqs_under; pageseqs_over]
      in
        debug_pdf merged "merged.pdf";
        let under_pages, over_pages =
          cleave (Pdfpage.pages_of_pagetree merged) under_length
        in
          let new_pages =
            map2
              (fun o u ->
                 do_stamp
                   false fast (BottomLeft 0.) false false scaletofit (not swap) merged o u over)
              over_pages under_pages
          in
            (* Build the changes. 123456 -> 123123 *)
            let changes =
              let len = List.length new_pages in
                combine (ilist 1 (len * 2)) (let x = ilist 1 len in x @ x)
            in
              let changed = Pdfpage.change_pages ~changes true merged new_pages in
                let r = Pdfmarks.add_bookmarks (marks_under @ marks_over) changed in
                   debug_pdf r "final.pdf";
                   r

let nobble_page pdf _ page =
  let minx, miny, maxx, maxy =
    (* Use cropbox if available *)
    Pdf.parse_rectangle
      (match Pdf.lookup_direct pdf "/CropBox" page.Pdfpage.rest with
       | Some r -> r
       | None -> page.Pdfpage.mediabox)
  in
    let fontdict =
      match Pdf.lookup_direct pdf "/Font" page.Pdfpage.resources with
      | None -> Pdf.Dictionary []
      | Some d -> d
    in
      let fontname = Pdf.unique_key "F" fontdict in
    let width = maxx -. minx in let height = maxy -. miny in
      let scalex =
        (width *. 1000.) /. float (Pdfstandard14.textwidth false Pdftext.StandardEncoding Pdftext.Helvetica "DEMO")
      in
        let page' =
          let font =
            Pdf.Dictionary
              [("/Type", Pdf.Name "/Font");
               ("/Subtype", Pdf.Name "/Type1");
               ("/BaseFont", Pdf.Name "/Helvetica")]
          in let ops =
            [Pdfops.Op_BMC "/CPDFSTAMP";
             Pdfops.Op_cm
               (Pdftransform.matrix_of_transform
                  [Pdftransform.Translate (minx, miny +. height /. 2.)]);
             Pdfops.Op_gs "/gs0";
             Pdfops.Op_BT;
             Pdfops.Op_Tf (fontname, scalex);
             Pdfops.Op_Tj "DEMO";
             Pdfops.Op_ET;
             Pdfops.Op_EMC]
          in
            {(Pdfpage.blankpage Pdfpaper.a4) with
                Pdfpage.mediabox = page.Pdfpage.mediabox;
                Pdfpage.content = [Pdfops.stream_of_ops ops];
                Pdfpage.resources =
                  Pdf.Dictionary
                    [("/Font", Pdf.Dictionary [(fontname, font)]);
                     ("/ExtGState", Pdf.Dictionary
                        ["/gs0",
                        Pdf.Dictionary["/Type", Pdf.Name "/ExtGState"; "/ca", Pdf.Real 0.2]]);
                    ]
            }
        in
          do_stamp false false (BottomLeft 0.) false false false true pdf page' page (Pdf.empty ())

(* \section{Set media box} *)
let set_mediabox xywhlist pdf range =
  let crop_page pnum page =
    let x, y, w, h = List.nth xywhlist (pnum - 1) in
    {page with
       Pdfpage.mediabox =
        (Pdf.Array
           [Pdf.Real x; Pdf.Real y;
            Pdf.Real (x +.  w); Pdf.Real (y +. h)])}
  in
    process_pages crop_page pdf range

(*let setBox box minx maxx miny maxy pdf range =
  let set_box_page _ page =
    {page with
       Pdfpage.rest =
         Pdf.add_dict_entry
           page.Pdfpage.rest box
           (Pdf.Array [Pdf.Real minx; Pdf.Real miny; Pdf.Real maxx; Pdf.Real maxy])}
  in
    process_pages set_box_page pdf range*)

(* \section{Cropping} *)
let crop_pdf ?(box="/CropBox") xywhlist pdf range =
  let crop_page pagenum page =
    {page with
       Pdfpage.rest =
         (Pdf.add_dict_entry
            page.Pdfpage.rest
            box
            (let x, y, w, h = List.nth xywhlist (pagenum - 1) in
              (Pdf.Array
                 [Pdf.Real x; Pdf.Real y;
                  Pdf.Real (x +.  w); Pdf.Real (y +. h)])))}
  in
    process_pages crop_page pdf range

(* Clip a page to one of its boxes, or the media box if that box is not
 * present. This is a hard clip, done by using a clipping rectangle, so that
 * the page may then be used as a stamp without extraneous material reapearing.
 * *)
let hard_box pdf range boxname mediabox_if_missing fast =
  process_pages
    (fun pagenum page ->
       let minx, miny, maxx, maxy =
         if boxname = "/MediaBox" then
           Pdf.parse_rectangle page.Pdfpage.mediabox
         else
           match Pdf.lookup_direct pdf boxname page.Pdfpage.rest with
           | Some a -> Pdf.parse_rectangle a
           | _ ->
               if mediabox_if_missing
                 then Pdf.parse_rectangle page.Pdfpage.mediabox
                 else error "hard_box: Box not found"
       in
         let ops = [Pdfops.Op_re (minx, miny, maxx -. minx, maxy -. miny); Pdfops.Op_W; Pdfops.Op_n] in
           Pdfpage.prepend_operators pdf ops ~fast:fast page)
    pdf
    range

let remove_cropping_pdf pdf range =
  let remove_cropping_page _ page =
    {page with
       Pdfpage.rest =
         (Pdf.remove_dict_entry page.Pdfpage.rest "/CropBox")}
  in
    process_pages remove_cropping_page pdf range

let remove_trim_pdf pdf range =
  let remove_trim_page _ page =
    {page with
       Pdfpage.rest =
         (Pdf.remove_dict_entry page.Pdfpage.rest "/TrimBox")}
  in
    process_pages remove_trim_page pdf range

let remove_art_pdf pdf range =
  let remove_art_page _ page =
    {page with
       Pdfpage.rest =
         (Pdf.remove_dict_entry page.Pdfpage.rest "/ArtBox")}
  in
    process_pages remove_art_page pdf range

let remove_bleed_pdf pdf range =
  let remove_bleed_page _ page =
    {page with
       Pdfpage.rest =
         (Pdf.remove_dict_entry page.Pdfpage.rest "/BleedBox")}
  in
    process_pages remove_bleed_page pdf range

(* \section{Rotating pages} *)
let rotate_pdf r pdf range =
  let rotate_page _ page =
    {page with Pdfpage.rotate =
       Pdfpage.rotation_of_int r}
  in
    process_pages rotate_page pdf range

let rotate_pdf_by r pdf range =
  let rotate_page_by _ page =
    {page with Pdfpage.rotate =
       Pdfpage.rotation_of_int ((Pdfpage.int_of_rotation page.Pdfpage.rotate + r) mod 360)}
  in
    process_pages rotate_page_by pdf range

let rotate_page_contents ~fast rotpoint r pdf _ page =
  let rotation_point =
    match rotpoint with
    | None ->
        let minx, miny, maxx, maxy = Pdf.parse_rectangle page.Pdfpage.mediabox in
          (minx +. maxx) /. 2.,  (miny +. maxy) /. 2.
    | Some point -> point
  in
    let tr =
      Pdftransform.matrix_of_op
        (Pdftransform.Rotate (rotation_point, -.(rad_of_deg r)))
    in let tr2 =
      Pdftransform.matrix_of_op
        (Pdftransform.Rotate (rotation_point, rad_of_deg r))
    in    
      let transform_op = Pdfops.Op_cm tr in
        let resources' = change_pattern_matrices pdf tr2 page.Pdfpage.resources in
          transform_annotations pdf tr page.Pdfpage.rest;
          Pdfpage.prepend_operators pdf [transform_op] ~fast {page with Pdfpage.resources = resources'}

let rotate_contents ?(fast=false) r pdf range =
  process_pages (rotate_page_contents ~fast None r pdf) pdf range

(* Return the pages from the pdf in the range, unordered. *)
let select_pages range pdf =
  let pages = Pdfpage.pages_of_pagetree pdf in
    option_map (function n -> try Some (select n pages) with _ -> None) range


(* Upright functionality *)

(* If all pages are already upright, and the mediabox is (0,0)-based, do nothing
to save time. *)
let allupright range pdf =
  let page_is_upright page =
    page.Pdfpage.rotate = Pdfpage.Rotate0 &&
      (let (minx, miny, _, _) = Pdf.parse_rectangle page.Pdfpage.mediabox in
         minx < 0.001 && miny < 0.001 && minx > ~-.0.001 && miny > ~-.0.001)
  in
    not (mem false (map page_is_upright (select_pages range pdf)))

let upright_transform page =
  let rotate =
    Pdfpage.int_of_rotation page.Pdfpage.rotate
  and cx, cy =
    let minx, miny, maxx, maxy = Pdf.parse_rectangle page.Pdfpage.mediabox in
      (minx +. maxx) /. 2., (miny +. maxy) /. 2.
  in
    Pdftransform.mkrotate (cx, cy) (rad_of_deg (~-.(float rotate)))

let transform_boxes tr pdf page =
  let f (minx, miny, maxx, maxy) =
    let minx, miny = Pdftransform.transform_matrix tr (minx, miny)
    and maxx, maxy = Pdftransform.transform_matrix tr (maxx, maxy) in
      (minx, miny, maxx, maxy)
  in
    change_boxes f pdf page

let transform_contents ?(fast=false) tr pdf page =
  let transform_op = Pdfops.Op_cm tr in
    let resources' = change_pattern_matrices pdf (Pdftransform.matrix_invert tr) page.Pdfpage.resources in
      transform_annotations pdf tr page.Pdfpage.rest;
      Pdfpage.prepend_operators pdf [transform_op] ~fast {page with Pdfpage.resources = resources'}

let upright ?(fast=false) range pdf =
  if allupright range pdf then pdf else
    let upright_page _ _ page =
      let tr = upright_transform page in
        let page = transform_boxes tr pdf page in
          let page = transform_contents ~fast tr pdf page in
            rectify_boxes ~fast pdf {page with Pdfpage.rotate = Pdfpage.Rotate0}
    in
      process_pages (upright_page pdf) pdf range

(* \section{Scale page data} *)
let scale_pdf ?(fast=false) sxsylist pdf range =
  let scale_page pnum page =
    let sx, sy = List.nth sxsylist (pnum - 1) in
      let f (xmin, ymin, xmax, ymax) =
        xmin *. sx, ymin *. sy, xmax *. sx, ymax *. sy
      in
        let page = change_boxes f pdf page
        and matrix = Pdftransform.matrix_of_op (Pdftransform.Scale ((0., 0.), sx, sy)) in
          let transform_op =
            Pdfops.Op_cm matrix
          and resources' =
            change_pattern_matrices pdf (Pdftransform.matrix_invert matrix) page.Pdfpage.resources
          in
           transform_annotations pdf matrix page.Pdfpage.rest;
           Pdfpage.prepend_operators pdf ~fast [transform_op] {page with Pdfpage.resources = resources'} 
      in
        process_pages scale_page pdf range

(* Scale to fit page of size x * y *)
let scale_to_fit_pdf ?(fast=false) position input_scale xylist op pdf range =
  let scale_page_to_fit pnum page =
    let x, y = List.nth xylist (pnum - 1) in
    let matrix =
      let (minx, miny, maxx, maxy) =
        (* Use cropbox if available *)
        Pdf.parse_rectangle
          (match Pdf.lookup_direct pdf "/CropBox" page.Pdfpage.rest with
          | Some r -> r
          | None -> page.Pdfpage.mediabox)
      in
        if maxx <= 0. || maxy <= 0. then failwith "Zero-sized pages are invalid" else
          let fx = x /. maxx in let fy = y /. maxy in
            let scale = fmin fx fy *. input_scale in
              let trans_x =
                match position with
                  Left _ -> 0.
                | Right _ -> (x -. (maxx *. scale))
                | _ -> (x -. (maxx *. scale)) /. 2.
              and trans_y =
                match position with
                | Top _ -> (y -. (maxy *. scale))
                | Bottom _ -> 0.
                | _ -> (y -. (maxy *. scale)) /. 2.
              in
                (Pdftransform.matrix_of_transform
                   [Pdftransform.Translate (trans_x, trans_y);
                    Pdftransform.Scale ((0., 0.), scale, scale)])
    in
      let page =
        change_boxes
          (function (minx, miny, maxx, maxy) -> 0., 0., x, y)
          pdf page
      in
        transform_annotations pdf matrix page.Pdfpage.rest;
        Pdfpage.prepend_operators pdf [Pdfops.Op_cm matrix] ~fast
        {page with Pdfpage.resources = change_pattern_matrices pdf (Pdftransform.matrix_invert matrix) page.Pdfpage.resources}
  in
    process_pages scale_page_to_fit pdf range


(* Scale contents *)
let scale_page_contents ?(fast=false) scale position pdf _ page =
  let (minx, miny, maxx, maxy) as box =
    (* Use cropbox if available *)
    Pdf.parse_rectangle
      (match Pdf.lookup_direct pdf "/CropBox" page.Pdfpage.rest with
       | Some r -> r
       | None -> page.Pdfpage.mediabox)
  in
    let sx, sy, _ = calculate_position true 0. box Horizontal position in
      let tx, ty =
        match position with
        | Top t -> 0., -.t
        | TopLeft t -> t, -.t
        | TopRight t -> 0., -.t
        | Left t -> t, 0.
        | BottomLeft t -> t, t
        | Bottom t -> 0., t
        | BottomRight t -> -.t, -.t
        | Right t -> -.t, 0.
        | _ -> 0., 0. (* centre it... FIXME: We will add a center position, eventually, for text and this... *)
    in
      let transform =
        Pdftransform.matrix_of_transform
          [Pdftransform.Translate (tx, ty);
           Pdftransform.Scale ((sx, sy), scale, scale)]
      in
        let transform_op = Pdfops.Op_cm transform in
          let resources' = change_pattern_matrices pdf transform page.Pdfpage.resources in
          transform_annotations pdf transform page.Pdfpage.rest;
          Pdfpage.prepend_operators pdf [transform_op] ~fast
            {page with Pdfpage.resources = resources'}

let scale_contents ?(fast=false) position scale pdf range =
  process_pages (scale_page_contents ~fast scale position pdf) pdf range

(* \section{List annotations} *)
let get_annotation_string encoding pdf annot =
  match Pdf.lookup_direct pdf "/Contents" annot with
  | Some (Pdf.String s) -> 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 list_annotations encoding pdf =
  let range = parse_pagespec pdf "all" in
  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))) 

let list_annotations_more pdf =
  let pages = Pdfpage.pages_of_pagetree pdf in
    iter2
      (fun page pagenumber ->
         iter
           (function annot ->
              let print_annot annot =
                let annot_type_string =
                  match annot.Pdfannot.subtype with
                  | Pdfannot.Stamp -> "Stamp"
                  | Pdfannot.Text -> "Text"
                  | Pdfannot.Link -> "Link"
                  | Pdfannot.FreeText -> "FreeText"
                  | Pdfannot.Line -> "Line"
                  | Pdfannot.Square -> "Square"
                  | Pdfannot.Circle -> "Circle"
                  | Pdfannot.Polygon -> "Polygon"
                  | Pdfannot.PolyLine -> "PolyLine"
                  | Pdfannot.Highlight -> "Highlight"
                  | Pdfannot.Underline -> "Underline"
                  | Pdfannot.Squiggly -> "Squiggly"
                  | Pdfannot.StrikeOut -> "StrikeOut"
                  | Pdfannot.Caret -> "Caret"
                  | Pdfannot.Ink -> "Ink"
                  | Pdfannot.Popup _ -> "Popup"
                  | Pdfannot.FileAttachment -> "FileAttachment"
                  | Pdfannot.Sound -> "Sound"
                  | Pdfannot.Movie -> "Movie"
                  | Pdfannot.Widget -> "Widget"
                  | Pdfannot.Screen -> "Screen"
                  | Pdfannot.PrinterMark -> "PrinterMark"
                  | Pdfannot.TrapNet -> "TrapNet"
                  | Pdfannot.Watermark -> "Watermark"
                  | Pdfannot.ThreeDee -> "ThreeDee"
                  | Pdfannot.Unknown -> "Unknown"
                in let subject =
                  match annot.Pdfannot.subject with
                  | Some s -> s
                  | None -> ""
                in let contents =
                  match annot.Pdfannot.annot_contents with
                  | Some s -> s
                  | None -> ""
                in
                  Printf.printf "Page: %i\n" pagenumber;
                  Printf.printf "Subtype: %s\n" annot_type_string;
                  Printf.printf "Subject: %s\n" subject;
                  Printf.printf "Contents: %s\n" contents;
              in
                match annot.Pdfannot.subtype with
                | Pdfannot.Popup annot -> print_annot annot
                | _ -> print_annot annot
           )
           (Pdfannot.annotations_of_page pdf page))
      pages
      (ilist 1 (length pages));
      flprint "" (* flush *)

(* 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
        (List.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
        List.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{N-up} *)

(* Given a number to fit and a mediabox, return a list of transforms for the
2 pages. *)
let twoup_transforms mediabox =
  let width, height =
    match Pdf.parse_rectangle mediabox with
      xmin, ymin, xmax, ymax -> xmax -. xmin, ymax -. ymin
  in
    let width_exceeds_height = width > height in
      let rotate = Pdftransform.Rotate ((0., 0.), rad_of_deg 90.) 
      in let sc =
        if width_exceeds_height
          then fmin (height /. width) ((width /. 2.) /. height)
          else fmin (width /. height) ((height /. 2.) /. width)
      in
        let scale = Pdftransform.Scale ((0., 0.), sc, sc) in
          let tr0, tr1 =
            if width_exceeds_height then
              Pdftransform.Translate (height *. sc, 0.),
              Pdftransform.Translate (height *. sc *. 2., 0.)
            else
              Pdftransform.Translate (height *. sc, 0.),
              Pdftransform.Translate (height *. sc, width *. sc)
          in
            let t0 = Pdftransform.matrix_of_transform [tr0; rotate; scale]
            in let t1 = Pdftransform.matrix_of_transform [tr1; rotate; scale] in
              [t0; t1]

let twoup_stack_transforms mediabox =
  let width, height =
    match Pdf.parse_rectangle mediabox with
      xmin, ymin, xmax, ymax -> xmax -. xmin, ymax -. ymin
  in
    let rotate = Pdftransform.Rotate ((0., 0.), rad_of_deg 90.) 
    in let tr0 = Pdftransform.Translate (height, 0.)
    in let tr1 = Pdftransform.Translate (height, width) in
      let t0 = Pdftransform.matrix_of_transform [tr0; rotate]
      in let t1 = Pdftransform.matrix_of_transform [tr1; rotate] in
        [t0; t1]

(* Combine two pages into one throughout the document. The pages have already
had their objects renumbered so as not to clash.*)
let twoup_pages_inner isstack fast pdf = function
  | [] -> assert false
  | (h::_) as pages ->
     let resources' =
       pair_reduce
         (combine_pdf_resources pdf)
         (map (fun p -> p.Pdfpage.resources) pages)
     in
       let content' =
          let transform_stream clipbox contents transform =
            let clipops =
              let minx, miny, maxx, maxy = Pdf.parse_rectangle clipbox in
              [Pdfops.Op_re (minx, miny, maxx -. minx, maxy -. miny);
               Pdfops.Op_W;
               Pdfops.Op_n]
            in
              (* If fast, no q/Q protection and no parsing of operators. *)
              if fast then
                let before = Pdfops.stream_of_ops (Pdfops.Op_q::Pdfops.Op_cm transform::clipops) in
                let after = Pdfops.stream_of_ops [Pdfops.Op_Q] in
                [before] @ contents @ [after]
              else
              (* If slow, use protect from Pdfpage. *)
              let ops = Pdfpage.protect pdf resources' contents @ Pdfops.parse_operators pdf resources' contents in
                [Pdfops.stream_of_ops
                  ([Pdfops.Op_q] @ [Pdfops.Op_cm transform] @ clipops @ ops @ [Pdfops.Op_Q])]
          in
            List.flatten
              (map2
              (fun p ->
                 transform_stream
                   (match Pdf.lookup_direct pdf "/CropBox" p.Pdfpage.rest with
                      None -> p.Pdfpage.mediabox
                    | Some box -> box)
                   p.Pdfpage.content)
              pages
              (take (((if isstack then twoup_stack_transforms else twoup_transforms) h.Pdfpage.mediabox)) (length pages)))
       in
         {Pdfpage.mediabox =
           if isstack then
            let width, height =
              match Pdf.parse_rectangle h.Pdfpage.mediabox with
                xmin, ymin, xmax, ymax -> xmax -. xmin, ymax -. ymin
            in
              Pdf.Array [Pdf.Real 0.; Pdf.Real 0.; Pdf.Real height; Pdf.Real (width *. 2.)]
           else
             h.Pdfpage.mediabox;
          Pdfpage.rotate = h.Pdfpage.rotate;
          Pdfpage.content = content';
          Pdfpage.resources = resources';
          Pdfpage.rest = if isstack then Pdf.remove_dict_entry h.Pdfpage.rest "/CropBox" else h.Pdfpage.rest}

let f_twoup f_pages pdf =
  let pagenums = ilist 1 (Pdfpage.endpage pdf) in
  let pdf = upright pagenums pdf in
    let pages = Pdfpage.pages_of_pagetree pdf in
      let pagesets = splitinto 2 pages in
        let renumbered = map (Pdfpage.renumber_pages pdf) pagesets in
          let pages' = map (f_pages pdf) renumbered in
            let changes = List.map (fun x -> (x, (x + 1) / 2)) pagenums in
              (*print_changes changes;*)
              Pdfpage.change_pages ~changes true pdf pages'

let twoup fast pdf = f_twoup (twoup_pages_inner false fast) pdf

let twoup_stack fast pdf = f_twoup (twoup_pages_inner true fast) pdf

(* \section{Output info} *)
let get_info raw pdf =
  let infodict =
    match Pdf.lookup_direct pdf "/Info" pdf.Pdf.trailerdict with
    | Some infodict -> infodict
    | _ -> Pdf.Dictionary []
  in
    let getstring name =
      match Pdf.lookup_direct pdf name infodict with
      | Some (Pdf.String s) ->
          if raw then s else crude_de_unicode s
      | Some (Pdf.Boolean false) -> "False"
      | Some (Pdf.Boolean true) -> "True"
      | _ -> if name = "/Trapped" then "False" else ""
    in
      getstring
       
let get_info_utf8 pdf =
  let infodict =
    match Pdf.lookup_direct pdf "/Info" pdf.Pdf.trailerdict with
    | Some infodict -> infodict
    | _ -> Pdf.Dictionary []
  in
    (function name ->
      match Pdf.lookup_direct pdf name infodict with
      | Some (Pdf.String s) -> Pdftext.utf8_of_pdfdocstring s
      | Some (Pdf.Boolean false) -> "False"
      | Some (Pdf.Boolean true) -> "True"
      | _ -> if name = "/Trapped" then "False" else "")

let getstring encoding pdf =
  match encoding with
  | Raw -> get_info true pdf
  | Stripped -> get_info false pdf
  | UTF8 -> get_info_utf8 pdf

let output_info encoding pdf =
  let getstring = getstring encoding pdf in
    Printf.printf "Version: %i.%i\n" pdf.Pdf.major pdf.Pdf.minor;
    Printf.printf "Pages: %i\n" (Pdfpage.endpage pdf);
    Printf.printf "Title: %s\n" (getstring "/Title");
    Printf.printf "Author: %s\n" (getstring "/Author");
    Printf.printf "Subject: %s\n" (getstring "/Subject");
    Printf.printf "Keywords: %s\n" (getstring "/Keywords");
    Printf.printf "Creator: %s\n" (getstring "/Creator");
    Printf.printf "Producer: %s\n" (getstring "/Producer");
    Printf.printf "Created: %s\n" (getstring "/CreationDate");
    Printf.printf "Modified: %s\n" (getstring "/ModDate");
    Printf.printf "Trapped: %s\n" (getstring "/Trapped")

type xmltree =
    E of Xmlm.tag * xmltree list
  | D of string

let xmltree_of_bytes b =
  let i = Xmlm.make_input (`String (0, string_of_bytes b)) in
    let el tag childs = E (tag, childs)
    and data d = D d in
      Xmlm.input_doc_tree ~el ~data i

let bytes_of_xmltree t =
  let buf = Buffer.create 1024 in
  let o = Xmlm.make_output (`Buffer buf) in
  let frag = function
      E (tag, childs) -> `El (tag, childs)
    | D d -> `Data d
  in
    Xmlm.output_doc_tree frag o t;
    bytes_of_string (Buffer.contents buf)

let rec string_of_xmltree = function
   D d ->
     Printf.sprintf "DATA {%s}" d
 | E (tag, trees) ->
     Printf.sprintf "ELT (%s, %s)"
       (string_of_tag tag)
       (string_of_xmltrees trees)

and string_of_tag ((n, n'), attributes) =
  Printf.sprintf
    "NAME |%s| |%s|, ATTRIBUTES {%s}" n n'
    (string_of_attributes attributes)

and string_of_attribute ((n, n'), str) =
  Printf.sprintf "ATTRNAME |%s| |%s|, STR {%s}" n n' str

and string_of_attributes attrs =
  fold_left
    (fun a b -> a ^ " " ^ b) "" (map string_of_attribute attrs)

and string_of_xmltrees trees =
  fold_left
    (fun a b -> a ^ " " ^ b) "" (map string_of_xmltree trees)

let adobe = "http://ns.adobe.com/pdf/1.3/"

let xmp = "http://ns.adobe.com/xap/1.0/"

let dc = "http://purl.org/dc/elements/1.1/"

let rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"

(* For OCaml < 4.00 *)
let string_trim s =
  implode
    (rev (dropwhile
       Pdf.is_whitespace (rev (dropwhile Pdf.is_whitespace (explode s)))))

let combine_with_spaces strs =
  string_trim
    (fold_left (fun x y -> x ^ (if x <> "" then ", " else "") ^ y) "" strs)

(* Collect all <li> elements inside a seq, bag, or alt. Combine with commas. If
none found, return empty string instead. *)
let collect_list_items = function
   E (((n, n'), _), elts) when
     n = rdf && (n' = "Alt" || n' = "Seq" || n' = "Bag")
   ->
     combine_with_spaces
       (option_map
         (function
             E (((n, n'), _), [D d]) when n = rdf && n' = "li" ->
               Some d
           | _ -> None)
         elts)
 | _ -> ""

let collect_list_items_all all =
  match keep (function E _ -> true | _ -> false) all with
    h::_ -> Some (collect_list_items h)
  | [] -> None

let rec get_data_for namespace name = function
   D _ -> None
 | E (((n, n'), _), [D d]) when n = namespace && n' = name ->
     Some d
 | E (((n, n'), _), e) when n = namespace && n' = name ->
     collect_list_items_all e
 | E (_, l) ->
     match option_map (get_data_for namespace name) l with
       x :: _ -> Some x
     | _ -> None

let output_xmp_info encoding pdf =
  let print_out tree title namespace name =
    match get_data_for namespace name tree with
      None -> ()
    | Some data ->
        Printf.printf "%s: " title;
        print_endline data
  in
    match get_metadata pdf with
      None -> ()
    | Some metadata ->
        try
          let dtd, tree = xmltree_of_bytes metadata in
            print_out tree "XMP pdf:Keywords" adobe "Keywords";
            print_out tree "XMP pdf:Producer" adobe "Producer";
            print_out tree "XMP pdf:Trapped" adobe "Trapped";
            print_out tree "XMP pdf:Title" adobe "Title";
            print_out tree "XMP pdf:Creator" adobe "Creator";
            print_out tree "XMP pdf:Subject" adobe "Subject";
            print_out tree "XMP pdf:Author" adobe "Author";
            print_out tree "XMP pdf:CreationDate" adobe "CreationDate";
            print_out tree "XMP pdf:ModDate" adobe "ModDate";
            print_out tree "XMP xmp:CreateDate" xmp "CreateDate";
            print_out tree "XMP xmp:CreatorTool" xmp "CreatorTool";
            print_out tree "XMP xmp:MetadataDate" xmp "MetadataDate";
            print_out tree "XMP xmp:ModifyDate" xmp "ModifyDate";
            print_out tree "XMP dc:title" dc "title";
            print_out tree "XMP dc:creator" dc "creator";
            print_out tree "XMP dc:subject" dc "subject"
        with
          _ -> ()

(* Get XMP info equivalent of an old metadata field e.g Title. For now just title, used by Cpdfcommand.add_bookmark_title *)
let check = function
  "/Title" -> [(adobe, "Title"); (dc, "title")]
| _ -> failwith "Cpdf.check_name not /Title"

let get_xmp_info pdf name =
  let tocheck = check name in
  match get_metadata pdf with
    None -> ""
  | Some metadata ->
      try
        let _, tree = xmltree_of_bytes metadata in
          let results = List.map (fun (kind, key) -> match get_data_for kind key tree with Some x -> x | None -> "") tocheck in
            match lose (eq "") results with
             x::_ -> x
           | [] -> ""
      with
        _ -> ""

(* Set XMP info *)
let rec set_xml_field kind fieldname value = function
  D data -> D data
| E (((n, n'), m), [D _]) when n = kind && n' = fieldname ->
    E (((n, n'), m), [D value])
| E (x, ts) -> E (x, List.map (set_xml_field kind fieldname value) ts)

let set_pdf_info_xml kind fieldname value xmldata pdf =
  let dtd, tree = xmltree_of_bytes xmldata in
  let str =
    match value with
      Pdf.String s -> s
    | Pdf.Boolean true -> "True"
    | Pdf.Boolean false -> "False"
    | _ -> failwith "set_pdf_info_xml: not a string"
  in
  let newtree = set_xml_field kind fieldname str tree in
    bytes_of_xmltree (dtd, newtree)

let set_pdf_info_xml_many changes value xmldata pdf =
  let xmldata = ref xmldata in
    List.iter
      (fun (kind, fieldname) ->
         xmldata := set_pdf_info_xml kind fieldname value !xmldata pdf)
      changes;
    !xmldata


(* \section{Set an entry in the /Info dictionary} *)

(* We must parse the date to get its components, then use strftime to build the
 * new string in XMP format *)

type date =
  {mutable year : int;
   mutable month : int; (* 1 - 12 *)
   mutable day : int; (* 1 - 31 *)
   mutable hour : int; (* 0 - 23 *)
   mutable minute : int; (* 0 - 59 *)
   mutable second : int; (* 0 - 59 *)
   mutable ut_relationship : int; (* -1, 0, +1 *)
   mutable offset_hours : int; (* 0 - 59 *)
   mutable offset_minutes : int (* 0 - 59 *)}

let default_date () =
  {year = 0;
   month = 1;
   day = 1;
   hour = 0;
   minute = 0;
   second = 0;
   ut_relationship = 0;
   offset_hours = 0;
   offset_minutes = 0}

(* XMP date format is YYYY-MM-DDThh:mm:ssTZD *)
let make_xmp_date_from_components d =
  let tzd =
    if d.ut_relationship = 0 && d.offset_hours = 0 && d.offset_minutes = 0 then "Z" else
    (if d.ut_relationship >=0 then "+" else "-") ^
    Printf.sprintf "%02i" d.offset_hours ^
    ":" ^
    Printf.sprintf "%02i" d.offset_minutes
  in 
    Cpdfstrftime.strftime
      ~time:{Unix.tm_sec = d.second;
             Unix.tm_min = d.minute;
             Unix.tm_hour = d.hour;
             Unix.tm_mday = d.day;
             Unix.tm_mon = d.month - 1;
             Unix.tm_year = d.year - 1900;
             Unix.tm_wday = 0;
             Unix.tm_yday = 0;
             Unix.tm_isdst = false}
      "%Y-%m-%dT%H:%M:%S"
  ^
    tzd

let xmp_date date =
  let d = default_date () in
  try
    match explode date with
      'D'::':'::r ->
        begin match r with
          y1::y2::y3::y4::r ->
            d.year <- int_of_string (implode [y1; y2; y3; y4]);
            begin match r with
              m1::m2::r ->
                d.month <- int_of_string (implode [m1; m2]);
                begin match r with
                  d1::d2::r ->
                  d.day <- int_of_string (implode [d1; d2]);
                  begin match r with
                    h1::h2::r ->
                    d.hour <- int_of_string (implode [h1; h2]);
                    begin match r with
                      m1::m2::r ->
                      d.minute <- int_of_string (implode [m1; m2]);
                      begin match r with
                       s1::s2::r ->
                       d.second <- int_of_string (implode [s1; s2]);
                         begin match r with
                           o::r ->
                           d.ut_relationship <-
                             if o = '+' then 1 else
                             if o = '-' then -1 else
                             0;
                           begin match r with
                             h1::h2::'\''::r ->
                             d.offset_hours <- int_of_string (implode [h1; h2]);
                             begin match r with
                               m1::m2::_ ->
                               d.offset_minutes <- int_of_string (implode [m1; m2]);
                               raise Exit
                             | _ -> raise Exit
                             end
                           | _ -> raise Exit
                           end
                         | _ -> raise Exit
                         end
                      | _ -> raise Exit
                      end
                    | _ -> raise Exit
                    end
                  | _ -> raise Exit
                  end
                | _ -> raise Exit
                end
            | _ -> raise Exit  
            end
        | _ -> failwith "xmp_date: Malformed date string (no year)"
        end
    | _ -> failwith "xmp_date: Malformed date string (no prefix)"
  with
    Exit -> make_xmp_date_from_components d

let set_pdf_info ?(xmp_also=false) ?(xmp_just_set=false) (key, value, version) pdf =
  let infodict =
    match Pdf.lookup_direct pdf "/Info" pdf.Pdf.trailerdict with
    | Some d -> d
    | None -> Pdf.Dictionary []
  in
    let infodict' = Pdf.add_dict_entry infodict key value in
      let objnum = Pdf.addobj pdf infodict' in
        if not xmp_just_set then
          begin
            pdf.Pdf.trailerdict <-
              Pdf.add_dict_entry pdf.Pdf.trailerdict "/Info" (Pdf.Indirect objnum);
            pdf.Pdf.minor <-
              max pdf.Pdf.minor version
          end;
        if xmp_also then
          begin match get_metadata pdf with
            None -> pdf
          | Some xmldata ->
              let xmp_date = function Pdf.String s -> Pdf.String (xmp_date s) | _ -> failwith "xmp_date not a string" in
              let changes, value =
                match key with
                | "/Producer" -> [(adobe, "Producer")], value
                | "/Creator" -> [(adobe, "Creator"); (xmp, "CreatorTool"); (dc, "creator")], value
                | "/Author" -> [(adobe, "Author")], value
                | "/Title" -> [(adobe, "Title"); (dc, "title")], value
                | "/Subject" -> [(adobe, "Subject"); (dc, "subject")], value
                | "/Keywords" -> [(adobe, "Keywords")], value
                | "/CreationDate" -> [(adobe, "CreationDate"); (xmp, "CreateDate")], xmp_date value
                | "/ModDate" -> [(adobe, "ModDate"); (xmp, "ModifyDate")], xmp_date value
                | "/Trapped" -> [(adobe, "Trapped")], value
                | _ -> failwith "Unknown call to set_pdf_info"
              in
                set_metadata_from_bytes
                  true
                  (set_pdf_info_xml_many changes value xmldata pdf)
                  pdf
          end
       else
         pdf

(* Set metadata date *)
let set_metadata_date pdf date =
  match get_metadata pdf with
    None -> pdf
  | Some xmldata ->
      let changes= [(xmp, "MetadataDate")] in
      let value = match date with "now" -> xmp_date (expand_date "now") | x -> x in
        set_metadata_from_bytes
          true
          (set_pdf_info_xml_many changes (Pdf.String value) xmldata pdf)
          pdf

let replacements pdf =
  let info = get_info_utf8 pdf in
    [("CREATEDATE", xmp_date (info "/CreationDate"));
     ("MODDATE", xmp_date (info "/ModDate"));
     ("PRODUCER", info "/Producer");
     ("CREATOR", info "/Creator");
     ("TITLE", info "/Title");
     ("SUBJECT", info "/Subject");
     ("AUTHOR", info "/Author");
     ("KEYWORDS", info "/Keywords");
     ("TRAPPED", info "/Trapped");
     ("METADATADATE", xmp_date (expand_date "now"))]

let create_metadata pdf =
  let xmp = ref xmp_template in
  List.iter
    (fun (s, r) -> xmp := string_replace_all s r !xmp)
    (replacements pdf);
  set_metadata_from_bytes false (bytes_of_string !xmp) pdf

(* \section{Blacken text} *)

(*
   \begin{verbatim}
    Algorithm: Change
     BT
     <ops>
    ET
 
    ...to...
 
    BT
    Op_g 0.
    <ops minus any color, shading or gs operators>
    ET
    <ops minus any text positioning or text rendering ones>
    \end{verbatim}
*)
let blacktext_ops (r, g, b) pdf resources content =
  let not_text = function
    | Pdfops.Op_Tj _ | Pdfops.Op_TJ _
    | Pdfops.Op_' _ | Pdfops.Op_'' (_, _, _)
    | Pdfops.Op_Td (_, _) | Pdfops.Op_TD (_, _)
    | Pdfops.Op_Tm _ | Pdfops.Op_T'
    | Pdfops.Op_Tc _
    | Pdfops.Op_Tw _
    | Pdfops.Op_Tz _
    | Pdfops.Op_TL _
    | Pdfops.Op_Tf (_, _)
    | Pdfops.Op_Tr _
    | Pdfops.Op_Ts _ -> false
    | _ -> true
  in let textlevel = ref 0
  in let removed = ref []
  in let operators =
    Pdfops.parse_operators pdf resources content
  in
    let rec remove_colourops prev = function
      | [] -> rev prev
      | Pdfops.Op_BT::more ->
          incr textlevel;
          remove_colourops
            (Pdfops.Op_rg (r, g, b)::Pdfops.Op_BT::prev)
            more
      | Pdfops.Op_ET::more ->
          decr textlevel;
          let prev' = !removed @ Pdfops.Op_ET::prev in
            removed := [];
            remove_colourops prev' more
      | (Pdfops.Op_G _
         | Pdfops.Op_g _ 
         | Pdfops.Op_RG (_, _, _)
         | Pdfops.Op_rg (_, _, _)
         | Pdfops.Op_k (_, _, _, _)
         | Pdfops.Op_K (_, _, _, _)
         | Pdfops.Op_SCN _
         | Pdfops.Op_SC _
         | Pdfops.Op_scn _
         | Pdfops.Op_sc _
         | Pdfops.Op_SCNName (_, _)
         | Pdfops.Op_scnName (_, _)
         | Pdfops.Op_CS _
         | Pdfops.Op_cs _
         | Pdfops.Op_sh _
         | Pdfops.Op_gs _)
        as op::more ->
          if !textlevel > 0
            then
              begin
                removed =| op;
                remove_colourops prev more
              end
            else remove_colourops (op::prev) more
      | op::more ->
          if !textlevel > 0 && not_text op then removed =| op;
          remove_colourops (op::prev) more
    in
      let operators' = remove_colourops [] operators in
        [Pdfops.stream_of_ops operators']

(* Blacken a form xobject, writing it to the same object. *)
let process_xobject f pdf resources i =
  let xobj = Pdf.lookup_obj pdf i in
    match Pdf.lookup_direct pdf "/Subtype" xobj with
    | None -> raise (Pdf.PDFError "No /Subtype in Xobject") 
    | Some (Pdf.Name "/Form") ->
        Pdf.getstream xobj;
        begin match xobj with
        | Pdf.Stream ({contents = Pdf.Dictionary dict, Pdf.Got bytes} as rf) ->
            begin match f pdf resources [Pdf.Stream rf] with
            | [Pdf.Stream {contents = (Pdf.Dictionary dict', data)}] ->
                let dict' =
                  Pdf.remove_dict_entry
                    (Pdf.Dictionary (mergedict dict dict'))
                    "/Filter"
                in
                  rf := (dict', data)
            | _ -> assert false
            end
        | _ -> assert false (* getstream would have complained already *)
        end
    | Some _ -> ()

let process_xobjects pdf page f =
  match Pdf.lookup_direct pdf "/XObject" page.Pdfpage.resources with
  | Some (Pdf.Dictionary elts) ->
      iter
        (fun (k, v) ->
          match v with
          | Pdf.Indirect i -> process_xobject f pdf page.Pdfpage.resources i
          | _ -> raise (Pdf.PDFError "process_xobject"))
        elts
  | _ -> ()

let blacktext (r, g, b) range pdf =
  let blacktext_page _ page =
    let content' =
      blacktext_ops (r, g, b) pdf page.Pdfpage.resources page.Pdfpage.content
    in
      process_xobjects pdf page (blacktext_ops (r, g, b));
      {page with Pdfpage.content = content'}
  in
    process_pages blacktext_page pdf range

(* \section{Blacken lines} *)
let blacklines_ops (r, g, b) pdf resources content =
  let rec blacken_strokeops prev = function
    | [] -> rev prev
    | Pdfops.Op_CS _::t ->
        blacken_strokeops (Pdfops.Op_CS "/DeviceRGB"::prev) t
    | (Pdfops.Op_SC _ | Pdfops.Op_SCN _ | Pdfops.Op_SCNName _ | Pdfops.Op_G _
       | Pdfops.Op_RG _ | Pdfops.Op_K _)::t ->
           blacken_strokeops (Pdfops.Op_RG (r, g, b)::prev) t
    | h::t -> blacken_strokeops (h::prev) t
  and operators =
    Pdfops.parse_operators pdf resources content
  in
    let operators' = blacken_strokeops [] operators in
      [Pdfops.stream_of_ops operators']

let blacklines (r, g, b) range pdf =
  let blacklines_page _ page =
    let content' =
      blacklines_ops (r, g, b) pdf page.Pdfpage.resources page.Pdfpage.content
    in
      process_xobjects pdf page (blacklines_ops (r, g, b));
      {page with Pdfpage.content = content'}
  in
    process_pages blacklines_page pdf range

(* \section{Blacken Fills} *)
let blackfills_ops (r, g, b) pdf resources content =
  let rec blacken_fillops prev = function
    | [] -> rev prev
    | Pdfops.Op_cs _::t ->
        blacken_fillops (Pdfops.Op_cs "/DeviceRGB"::prev) t
    | (Pdfops.Op_sc _ | Pdfops.Op_scn _ | Pdfops.Op_scnName _ | Pdfops.Op_g _
       | Pdfops.Op_rg _ | Pdfops.Op_k _)::t ->
           blacken_fillops (Pdfops.Op_rg (r, g, b)::prev) t
    | h::t -> blacken_fillops (h::prev) t
  and operators =
    Pdfops.parse_operators pdf resources content
  in
    let operators' = blacken_fillops [] operators in
      [Pdfops.stream_of_ops operators']

let blackfills (r, g, b) range pdf =
  let blackfills_page _ page =
    let content' =
      blackfills_ops (r, g, b) pdf page.Pdfpage.resources page.Pdfpage.content
    in
      process_xobjects pdf page (blackfills_ops (r, g, b));
      {page with Pdfpage.content = content'}
  in
    process_pages blackfills_page pdf range

(* \section{Set a minimum line width to avoid dropout} *)
let thinlines range width pdf =
  let thinpage _ page =
    let operators =
      Pdfops.parse_operators pdf page.Pdfpage.resources page.Pdfpage.content
    in
      let ctmstack = ref [ref Pdftransform.i_matrix] in
        let scaleof_ctm () =
          try
            match Pdftransform.decompose (!(hd !ctmstack)) with
              (scale, _, _, _, _, _) ->
                 scale
          with
            Failure _ (*"hd"*) -> 1.
        in
          let rec replace_operators prev = function
            | [] -> rev prev
            | (Pdfops.Op_w w)::more ->
              (* Alter width. *)
              let width' = width /. scaleof_ctm () in
                let w' =
                  if w >= width' then Pdfops.Op_w w else Pdfops.Op_w width'
                in
                  replace_operators (w'::prev) more
            | (Pdfops.Op_cm m)::more ->
                (* Update CTM *)
                begin try 
                  let top = hd !ctmstack in
                    top := Pdftransform.matrix_compose !top m
                with
                  Failure _ (*"hd"*) -> error "Malformed file."
                end;
                replace_operators ((Pdfops.Op_cm m)::prev) more
            | Pdfops.Op_q::more ->
                (* Push stack *)
                begin try
                  ctmstack =| ref (!(hd !ctmstack))
                with
                  Failure _ (*"hd"*) -> error "Malformed file"
                end;
                replace_operators (Pdfops.Op_q::prev) more
            | Pdfops.Op_Q::more ->
                (* Pop stack *)
                begin try
                  ctmstack := tl !ctmstack
                with
                  Failure _ (*"tl"*) -> error "Malformed file"
                end;
                replace_operators (Pdfops.Op_Q::prev) more
            | (Pdfops.Op_gs gsname)::more ->
                (* Perhaps insert [Op_w]. *)
                let opw =
                  match Pdf.lookup_direct pdf "/ExtGState" page.Pdfpage.resources with
                  | None -> []
                  | Some ext_state_dict ->
                      match Pdf.lookup_direct pdf gsname ext_state_dict with
                      | None -> []
                      | Some gdict ->
                          match Pdf.lookup_direct pdf "/LW" gdict with
                          | Some s -> (try [Pdfops.Op_w (Pdf.getnum s)] with _ -> [])
                          | None -> []
                in
                  replace_operators (opw @ ((Pdfops.Op_gs gsname)::prev)) more
            | x::more -> replace_operators (x::prev) more
          in
            let operators = replace_operators [] operators in
              (* 2. Add an initial 'w' if width more than default width *)
              let operators =
                if width > 1. then (Pdfops.Op_w width)::operators else operators
              in
                let content' = [Pdfops.stream_of_ops operators] in
                  {page with Pdfpage.content = content'} 
  in
    process_pages thinpage pdf range

(* \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
    process_pages remove_annotations_page pdf range

(* \section{Making draft documents} *)

(* Predicate on an xobject: true if an image xobject. *)
let isimage pdf (_, xobj) =
  match Pdf.lookup_direct pdf "/Subtype" xobj with 
  | Some (Pdf.Name "/Image") -> true
  | _ -> false

(* Given a set of resources for a page, and the name of a resource, determine if
that name refers to an image xobject. *)
let xobject_isimage pdf resources name =
  match resources with
  | Pdf.Dictionary _ ->
      begin match Pdf.lookup_direct pdf "/XObject" resources with
      | Some xobjects ->
          isimage pdf ("", Pdf.lookup_fail "xobject not there" pdf name xobjects)
      | _ -> false
      end
  | _ -> failwith "bad resources"

(* The subsitute for an image. *)
let substitute boxes =
  if boxes then
    rev
      [Pdfops.Op_q;
       Pdfops.Op_w 0.;
       Pdfops.Op_G 0.;
       Pdfops.Op_re (0., 0., 1., 1.);
       Pdfops.Op_m (0., 0.);
       Pdfops.Op_l (1., 1.);
       Pdfops.Op_m (0., 1.);
       Pdfops.Op_l (1., 0.);
       Pdfops.Op_S;
       Pdfops.Op_Q]
  else
    []

(* Remove references to images from a graphics stream. *)
let rec remove_images_stream onlyremove boxes pdf resources prev = function
  | [] -> rev prev
  | (Pdfops.Op_Do name) as h::t ->
      if xobject_isimage pdf resources name && (match onlyremove with None -> true | Some x -> x = name)
      then remove_images_stream onlyremove boxes pdf resources (substitute boxes @ prev) t
      else remove_images_stream onlyremove boxes pdf resources (h::prev) t
  | Pdfops.InlineImage _ as h::t ->
      if onlyremove <> None
        then remove_images_stream onlyremove boxes pdf resources (h::prev) t
        else remove_images_stream onlyremove boxes pdf resources (substitute boxes @ prev) t
  | h::t ->
      remove_images_stream onlyremove boxes pdf resources (h::prev) t

let rec process_form_xobject onlyremove boxes pdf form =
  let form = Pdf.direct pdf form in
    let page =
      {Pdfpage.content = [form];
       Pdfpage.mediabox = Pdf.Null;
       Pdfpage.resources =
         begin match Pdf.lookup_direct pdf "/Resources" form with
         | Some r -> r
         | None -> Pdf.Dictionary []
         end;
       Pdfpage.rotate = Pdfpage.Rotate0;
       Pdfpage.rest = Pdf.Dictionary []}
    in
      let page', pdf =
        remove_images_page onlyremove boxes pdf page
      in
        let form' =
          match form with
          | Pdf.Stream {contents = (dict, _)} ->
              begin match 
                Pdfops.stream_of_ops
                  (Pdfops.parse_operators pdf (Pdf.Dictionary []) page'.Pdfpage.content)
              with
              | Pdf.Stream {contents = (_, Pdf.Got data)} ->
                  let dict' =
                    Pdf.add_dict_entry dict "/Length" (Pdf.Integer (bytes_size data))
                  in
                    Pdf.Stream {contents = (dict', Pdf.Got data)}
              | _ -> assert false
              end
          | _ -> raise (Pdf.PDFError "not a stream")
        in
          form', pdf

(* Remove images from a page. *)
and remove_images_page onlyremove boxes pdf page =
  let isform pdf xobj =
    match Pdf.lookup_direct pdf "/Subtype" xobj with Some (Pdf.Name "/Form") -> true | _ -> false
  in
  let isimage pdf xobj =
    match Pdf.lookup_direct pdf "/Subtype" xobj with Some (Pdf.Name "/Image") -> true | _ -> false
  in
  (* Remove image xobjects and look into form ones *)
  let form_xobjects, image_xobjects =
    match Pdf.lookup_direct pdf "/XObject" page.Pdfpage.resources with
    | Some (Pdf.Dictionary elts) ->
        keep (function (_, p) -> isform pdf p) elts,
        keep (function (_, p) -> isimage pdf p) elts
    | _ -> [], []
  in
  let resources', pdf =
    let names, pointers = split form_xobjects in
      let form_xobjects', pdf =
        let pdf = ref pdf
        in let outputs = ref [] in
          iter
            (fun p ->
              let p', pdf' = process_form_xobject onlyremove boxes !pdf p in
                pdf := pdf';
                outputs =| p')
            pointers;
          rev !outputs, !pdf
      in
        let nums = ref [] in
          iter
            (fun xobj ->
               let objnum = Pdf.addobj pdf xobj in
                 nums =| objnum)
            form_xobjects';
        let image_xobjects' =
          match onlyremove with
            None -> image_xobjects
          | Some n -> option_map (function (n', _) as xobj -> if n = n' then None else Some xobj) image_xobjects
        in
            let newdict =
              Pdf.Dictionary (image_xobjects' @ combine names (map (fun x -> Pdf.Indirect x) (rev !nums)))
            in
              Pdf.add_dict_entry page.Pdfpage.resources "/XObject" newdict, pdf
    in
      let content' =
        remove_images_stream onlyremove boxes pdf page.Pdfpage.resources []
           (Pdfops.parse_operators pdf page.Pdfpage.resources page.Pdfpage.content)
      in
        {page with
          Pdfpage.content =
            (let stream = Pdfops.stream_of_ops content' in
              Pdfcodec.encode_pdfstream pdf Pdfcodec.Flate stream;
              [stream]);
          Pdfpage.resources = resources'}, pdf

(* Remove images from all pages in a document. *)
let draft onlyremove boxes range pdf =
  let pages = Pdfpage.pages_of_pagetree pdf in
    let pagenums = indx pages in
    let pdf = ref pdf
    in let pages' = ref [] in
      iter2 
       (fun p pagenum ->
         let p', pdf' =
           if mem pagenum range
             then remove_images_page onlyremove boxes !pdf p
             else p, !pdf
         in
           pdf := pdf';
           pages' =| p')
       pages
       pagenums;
      Pdfpage.change_pages true !pdf (rev !pages')

let set_version v pdf =
  pdf.Pdf.minor <- v
        
(* Custom Code: CSP1 - four up duplication. Alter media box and crop-box. 4-up the data. *)
let custom_csp1_page pdf _ page =
  let minx, miny, maxx, maxy =
    match Pdf.lookup_direct pdf "/CropBox" page.Pdfpage.rest with
    | Some r -> Pdf.parse_rectangle r
    | None -> Pdf.parse_rectangle page.Pdfpage.mediabox
  in
    let mx0 = -.minx
    in let my0 = -.miny
    in let dx = maxx -. minx
    in let dy = maxy -. miny in
      let content =
        let ops = 
          Pdfops.parse_operators pdf page.Pdfpage.resources page.Pdfpage.content
        in
          [Pdfops.Op_q;
           Pdfops.Op_cm (Pdftransform.matrix_of_transform [Pdftransform.Translate (mx0, my0)])] @ ops @ [Pdfops.Op_Q] @
          [Pdfops.Op_q;
           Pdfops.Op_cm (Pdftransform.matrix_of_transform [Pdftransform.Translate (mx0 +. dx, my0 +. dy)])] @ ops @ [Pdfops.Op_Q] @
          [Pdfops.Op_q;
           Pdfops.Op_cm (Pdftransform.matrix_of_transform [Pdftransform.Translate (mx0, my0 +. dy)])] @ ops @ [Pdfops.Op_Q] @
          [Pdfops.Op_q;
           Pdfops.Op_cm (Pdftransform.matrix_of_transform [Pdftransform.Translate (mx0 +. dx, my0)])] @ ops @ [Pdfops.Op_Q]
      in
        let new_mediabox =
          Pdf.Array
            [Pdf.Real 0.;
             Pdf.Real 0.;
             Pdf.Real ((maxx -. minx) *. 2.);
             Pdf.Real ((maxy -. miny) *. 2.)]
        in
          {page with
             Pdfpage.content = [Pdfops.stream_of_ops content];
             Pdfpage.mediabox = new_mediabox;
             Pdfpage.rest = Pdf.add_dict_entry page.Pdfpage.rest "/CropBox" new_mediabox}

let custom_csp1 pdf =
  process_pages (custom_csp1_page pdf) pdf (ilist 1 (Pdfpage.endpage pdf))

let custom_csp2 f pdf =
  let page = hd (Pdfpage.pages_of_pagetree pdf) in
    let m_minx, m_miny, m_maxx, m_maxy =
      match page.Pdfpage.mediabox with
      | Pdf.Array [a; b; c; d] ->
          Pdf.getnum a, Pdf.getnum b, Pdf.getnum c, Pdf.getnum d
      | _ -> 0., 0., 0., 0.
    in
      let c_minx, c_miny, c_maxx, c_maxy =
        match Pdf.lookup_direct pdf "/CropBox" page.Pdfpage.rest with
        | Some (Pdf.Array [a; b; c; d]) ->
            Pdf.getnum a, Pdf.getnum b, Pdf.getnum c, Pdf.getnum d
        | _ -> m_minx, m_miny, m_maxx, m_maxy
      in
        let x = (c_minx +. c_maxx) /. 2.
        in let y = (c_miny +. c_maxy) /. 2. in
          scale_contents (PosCentre (x, y)) (f /. 100.) pdf (ilist 1 (Pdfpage.endpage pdf))

let blank_document width height pages =
  let pdf_pages =
    map (fun () -> Pdfpage.blankpage (Pdfpaper.make Pdfunits.PdfPoint width height)) (many () pages)
  in
    let pdf, pageroot = Pdfpage.add_pagetree pdf_pages (Pdf.empty ()) in
      Pdfpage.add_root pageroot [] pdf

let blank_document_paper papersize pages =
  let pdf_pages =
    map (fun () -> Pdfpage.blankpage papersize) (many () pages)
  in
    let pdf, pageroot = Pdfpage.add_pagetree pdf_pages (Pdf.empty ()) in
      Pdfpage.add_root pageroot [] pdf

(* Split the given range (which is in order) into multiple contiguous ones. *)
let rec ranges_of_range curr prev = function
  | [] -> begin match curr with [] -> rev prev | _ -> rev (rev curr::prev) end
  | x::xs ->
      match curr with
      | [] -> ranges_of_range [x] prev xs
      | c::cs when x = c + 1 -> ranges_of_range (x::curr) prev xs
      | cs -> ranges_of_range [x] (rev cs::prev) xs

(* Predicate which is true if at least one page range starts at page 1 *)
let page1 labels =
  mem true (map (function l -> l.Pdfpagelabels.startpage = 1) labels)

let add_page_labels pdf style prefix startval range =
  let ranges = map extremes (ranges_of_range [] [] range)
  and labels = Pdfpagelabels.read pdf in
    let labels =
      if not (page1 labels) then
        ref
          ({Pdfpagelabels.labelstyle = Pdfpagelabels.DecimalArabic;
            Pdfpagelabels.labelprefix = None;
            Pdfpagelabels.startpage = 1;
            Pdfpagelabels.startvalue = 1}::labels)
      else
        ref labels
    in
      iter
        (function (s, e) ->
           let label =
             {Pdfpagelabels.labelstyle = style;
              Pdfpagelabels.labelprefix = prefix;
              Pdfpagelabels.startpage = s;
              Pdfpagelabels.startvalue = startval}
           in
             labels := Pdfpagelabels.add_label (Pdfpage.endpage pdf) !labels label e)
        ranges;
        Pdfpagelabels.write pdf !labels