83 lines
3.0 KiB
OCaml
83 lines
3.0 KiB
OCaml
open Pdfutil
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open Cpdferror
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(* Chop a single page into pieces. We prefer the cropbox when available. We set
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mediabox only, and delete any other boxes. We delete /Annots, since
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duplicate annotations are not allowed. *)
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let get_box pdf page =
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match Pdf.lookup_direct pdf "/CropBox" page.Pdfpage.rest with
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| Some r -> Pdf.parse_rectangle pdf r
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| None -> Pdf.parse_rectangle pdf page.Pdfpage.mediabox
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let erase_boxes d =
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let f = Pdf.remove_dict_entry in
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f (f (f (f (f d "/CropBox") "/BleedBox") "/TrimBox") "/ArtBox") "/Annots"
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let make_pages x y columns btt rtl w h ps move_page =
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if columns then
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let column tx =
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if btt then
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for ty = 0 to y - 1 do ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty) done
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else
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for ty = y - 1 downto 0 do ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty) done
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in
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if rtl then for tx = x - 1 downto 0 do column tx done else for tx = 0 to x - 1 do column tx done
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else
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let row ty =
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if rtl then
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for tx = x - 1 downto 0 do ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty) done
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else
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for tx = 0 to x - 1 do ps =| move_page (w *. float_of_int tx) (h *. float_of_int ty) done
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in
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if btt then for ty = 0 to y - 1 do row ty done else for ty = y - 1 downto 0 do row ty done
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let chop_boxes line pdf x y columns btt rtl p =
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let move_page mx my p w h dx dy =
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let nminx, nminy, nmaxx, nmaxy = (mx +. dx, my +. dy, mx +. w +. dx, my +. h +. dy) in
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{p with
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Pdfpage.mediabox = Pdf.Array [Pdf.Real nminx; Pdf.Real nminy; Pdf.Real nmaxx; Pdf.Real nmaxy];
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Pdfpage.rest = erase_boxes p.Pdfpage.rest}
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in
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if x = 0 then
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(* horizontal split at line *)
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[]
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else
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if y = 0 then
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(* vertical split at line *)
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[]
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else
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let minx, miny, maxx, maxy = get_box pdf p in
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let w, h = (maxx -. minx) /. float_of_int x, (maxy -. miny) /. float_of_int y in
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let ps = ref [] in
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make_pages x y columns btt rtl w h ps (move_page minx miny p w h);
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rev !ps
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let chop_inner ~line ~x ~y ~columns ~btt ~rtl pdf range =
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let pages = Pdfpage.pages_of_pagetree pdf in
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let pages_out =
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flatten
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(map2
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(fun n p -> if mem n range then chop_boxes line pdf x y columns btt rtl p else [p])
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(ilist 1 (Pdfpage.endpage pdf))
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pages)
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in
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let changes =
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let q = ref 0 in
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flatten
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(map2
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(fun n p ->
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if mem n range
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then (q += 1; let r = combine (many n (x * y)) (ilist !q (!q + x * y - 1)) in q += (x * y - 1); r)
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else (q += 1; [(n, !q)]))
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(ilist 1 (Pdfpage.endpage pdf))
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pages)
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in
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Pdfpage.change_pages ~changes true pdf pages_out
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let chop ~x ~y ~columns ~btt ~rtl pdf range =
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chop_inner ~line:0. ~x ~y ~columns ~btt ~rtl pdf range
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let chop_hv ~is_h ~line ~columns pdf range =
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chop_inner ~line ~x:(if is_h then 0 else 1) ~y:(if is_h then 1 else 0) ~columns ~btt:false ~rtl:false pdf range
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