cpdf-source/cpdfimage.ml

128 lines
5.1 KiB
OCaml

open Pdfutil
open Pdfio
(* Extract Images. *)
let pnm_to_channel_24 channel w h s =
let white () = output_char channel ' '
and newline () = output_char channel '\n'
and output_string = Pervasives.output_string channel in
output_string "P6";
white ();
output_string (string_of_int w);
white ();
output_string (string_of_int h);
white ();
output_string "255";
newline ();
let pos = ref 0 in
for y = 1 to h do
for x = 1 to w * 3 do
output_byte channel (bget s !pos);
incr pos
done
done
let write_stream name stream =
let fh = open_out_bin name in
for x = 0 to bytes_size stream - 1 do
output_byte fh (bget stream x)
done;
close_out fh
let write_image path_to_p2p path_to_im pdf resources name image =
match Pdfimage.get_image_24bpp pdf resources image with
| Pdfimage.JPEG (stream, _) -> write_stream (name ^ ".jpg") stream
| Pdfimage.JPEG2000 (stream, _) -> write_stream (name ^ ".jpx") stream
| Pdfimage.JBIG2 (stream, _) -> write_stream (name ^ ".jbig2") stream
| Pdfimage.Raw (w, h, Pdfimage.BPP24, stream) ->
let pnm = name ^ ".pnm" in
let png = name ^ ".png" in
let fh = open_out_bin pnm in
pnm_to_channel_24 fh w h stream;
close_out fh;
begin match path_to_p2p with
| "" ->
begin match path_to_im with
"" -> Printf.eprintf "Neither pnm2png nor imagemagick found. Specify with -p2p or -im\n%!"
| _ ->
begin match
Sys.command (Filename.quote_command path_to_im [pnm; png])
with
0 -> Sys.remove pnm
| _ ->
Printf.eprintf "Call to imagemagick failed: did you specify -p2p correctly?\n%!";
Sys.remove pnm
end
end
| _ ->
begin match
Sys.command (Filename.quote_command path_to_p2p ~stdout:png ["-gamma"; "0.45"; "-quiet"; pnm])
with
| 0 -> Sys.remove pnm
| _ ->
Printf.eprintf "Call to pnmtopng failed: did you specify -p2p correctly?\n%!";
Sys.remove pnm
end
end
| _ ->
Printf.eprintf "Unsupported image type when extracting image %s %!" name
let written = ref []
let extract_images_inner path_to_p2p path_to_im encoding serial pdf resources stem pnum images =
let names = map
(fun _ ->
Cpdfbookmarks.name_of_spec
encoding [] pdf 0 (stem ^ "-p" ^ string_of_int pnum)
(let r = !serial in serial := !serial + 1; r) "" 0 0) (indx images)
in
iter2 (write_image path_to_p2p path_to_im pdf resources) names images
let rec extract_images_form_xobject path_to_p2p path_to_im encoding dedup dedup_per_page pdf serial stem pnum form =
let resources =
match Pdf.lookup_direct pdf "/Resources" form with
Some (Pdf.Dictionary d) -> Pdf.Dictionary d
| _ -> Pdf.Dictionary []
in
let images =
let xobjects =
match Pdf.lookup_direct pdf "/XObject" resources with
| Some (Pdf.Dictionary elts) -> map snd elts
| _ -> []
in
(* Remove any already in !written. Add any remaining to !written, if !args.dedup or !args.dedup_page *)
let images = keep (fun o -> Pdf.lookup_direct pdf "/Subtype" o = Some (Pdf.Name "/Image")) xobjects in
let already_written, images = List.partition (function Pdf.Indirect n -> mem n !written | _ -> false) images in
if dedup || dedup_per_page then
written := (option_map (function Pdf.Indirect n -> Some n | _ -> None) images) @ !written;
images
in
extract_images_inner path_to_p2p path_to_im encoding serial pdf resources stem pnum images
let extract_images path_to_p2p path_to_im encoding dedup dedup_per_page pdf range stem =
if dedup || dedup_per_page then written := [];
let pdf_pages = Pdfpage.pages_of_pagetree pdf in
let pages =
option_map
(function (i, pdf_pages) -> if mem i range then Some pdf_pages else None)
(combine (indx pdf_pages) pdf_pages)
in
let serial = ref 0 in
iter2
(fun page pnum ->
if dedup_per_page then written := [];
let xobjects =
match Pdf.lookup_direct pdf "/XObject" page.Pdfpage.resources with
| Some (Pdf.Dictionary elts) -> map snd elts
| _ -> []
in
let images = keep (fun o -> Pdf.lookup_direct pdf "/Subtype" o = Some (Pdf.Name "/Image")) xobjects in
let already_written, images = List.partition (function Pdf.Indirect n -> mem n !written | _ -> false) images in
if dedup || dedup_per_page then
written := (option_map (function Pdf.Indirect n -> Some n | _ -> None) images) @ !written;
let forms = keep (fun o -> Pdf.lookup_direct pdf "/Subtype" o = Some (Pdf.Name "/Form")) xobjects in
extract_images_inner path_to_p2p path_to_im encoding serial pdf page.Pdfpage.resources stem pnum images;
iter (extract_images_form_xobject path_to_p2p path_to_im encoding dedup dedup_per_page pdf serial stem pnum) forms)
pages
(indx pages)