89 lines
3.4 KiB
OCaml
89 lines
3.4 KiB
OCaml
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open Pdfutil
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open Pdfio
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open Cpdferror
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let add_xobject_to_page xobjname xobjnum page pdf =
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let resources' =
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let xobjects =
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match Pdf.lookup_direct pdf "/XObject" page.Pdfpage.resources with
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| Some xobjects -> xobjects
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| _ -> Pdf.Dictionary []
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in
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let new_xobjects =
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Pdf.add_dict_entry xobjects xobjname (Pdf.Indirect xobjnum)
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in
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Pdf.add_dict_entry page.Pdfpage.resources "/XObject" new_xobjects
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in
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{page with Pdfpage.resources = resources'}
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let add_page_as_xobject pdf range page name =
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let xobject_data =
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match Pdfops.stream_of_ops (Pdfops.parse_operators pdf page.Pdfpage.resources page.Pdfpage.content) with
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Pdf.Stream {contents = (_, Got b)} -> b
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| _ -> assert false
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in
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let xobject_dict =
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["/Type", Pdf.Name "/XObject";
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"/Subtype", Pdf.Name "/Form";
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"/BBox", page.Pdfpage.mediabox;
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"/Resources", page.Pdfpage.resources;
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"/Length", Pdf.Integer (bytes_size xobject_data)]
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in
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let xobject =
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Pdf.Stream {contents = (Pdf.Dictionary xobject_dict, Pdf.Got xobject_data)}
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in
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let xobject_objnum = Pdf.addobj pdf xobject in
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let pages = Pdfpage.pages_of_pagetree pdf in
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let new_pages =
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List.map2
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(fun page pnum ->
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if mem pnum range
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then add_xobject_to_page name xobject_objnum page pdf
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else page)
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pages
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(indx pages)
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in
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Pdfpage.change_pages true pdf new_pages
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(* n.b the use of change_pages here ensures no inheritable resources in the
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* stamp, therefore creation of xobject from page is as simple as expected. *)
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let stamp_as_xobject pdf range over =
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let prefix = Pdfpage.shortest_unused_prefix pdf in
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Pdfpage.add_prefix over prefix;
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let marks = Pdfmarks.read_bookmarks pdf in
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let marks_refnumbers = Pdf.page_reference_numbers pdf in
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let pdf = Pdfmarks.remove_bookmarks pdf in
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let over = Pdfmarks.remove_bookmarks over in
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let pageseqs = ilist 1 (Pdfpage.endpage pdf) in
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let over_firstpage_pdf =
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match Pdfpage.pages_of_pagetree over with
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| [] -> error "empty PDF"
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| h::_ -> Pdfpage.change_pages ~changes:[(1, 1)] true over [h]
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in
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let merged =
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Pdfmerge.merge_pdfs
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false false ["a"; "b"] [pdf; over_firstpage_pdf] [pageseqs; [1]]
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in
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let merged =
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{merged with Pdf.saved_encryption = pdf.Pdf.saved_encryption}
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in
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let merged = Cpdfmetadata.copy_id true pdf merged in
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let merged_pages = Pdfpage.pages_of_pagetree merged in
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let under_pages, over_page =
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all_but_last merged_pages, last merged_pages
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in
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let new_pages = under_pages in
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let changed =
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let changes =
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map (fun x -> (x, x)) (ilist 1 (length new_pages))
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in
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Pdfpage.change_pages ~changes true merged new_pages
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in
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let new_refnumbers = Pdf.page_reference_numbers changed in
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let changetable = hashtable_of_dictionary (combine marks_refnumbers new_refnumbers) in
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let new_marks = map (Cpdfbookmarks.change_bookmark changetable) marks in
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let pdf = Pdfmarks.add_bookmarks new_marks changed in
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let name = "/" ^ Pdfpage.shortest_unused_prefix pdf ^ "CPDFXObj" in
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(add_page_as_xobject pdf range over_page name, name)
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