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First bash at annotation BBox transforms

This commit is contained in:
John Whitington 2020-07-23 15:17:27 +01:00
parent 1305853bd8
commit 405540d9fb
1 changed files with 40 additions and 16 deletions
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64
cpdf.ml
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@ -2287,24 +2287,7 @@ let change_pattern_matrices_page pdf tr page =
page
| _ -> page
(* test *)
let transform_xobject_in_place pdf transform i =
Printf.printf "transforming xobject %i as part of annotation\n" i
(* Apply transformations to any annotations in /Annots (i.e their /Rect entries) *)
let transform_annotations pdf transform rest =
(*Printf.printf "in transform_annotations\n";*)
match Pdf.lookup_direct pdf "/Annots" rest with
| Some (Pdf.Array annots) ->
(* Always indirect references, so alter in place *)
iter
(function
| Pdf.Indirect i ->
(*Printf.printf "Found an annotation to modify...\n";*)
let annot = Pdf.lookup_obj pdf i in
let rect' =
match Pdf.lookup_direct pdf "/Rect" annot with
Some rect ->
let transform_rect transform 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
@ -2315,6 +2298,33 @@ let transform_annotations pdf transform rest =
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]
(* This is used to transform the BBox inside a form xobject representing an
* annotation appearance.*)
let transform_xobject_in_place pdf transform i =
Printf.printf "transforming xobject %i as part of annotation\n" i;
let obj = Pdf.lookup_obj pdf i in
match Pdf.lookup_direct pdf "/BBox" obj with
| Some bbox ->
Printf.printf "Found bbox %s\n" (Pdfwrite.string_of_pdf bbox);
let obj = Pdf.add_dict_entry obj "/BBox" (transform_rect transform bbox) in
Pdf.addobj_given_num pdf (i, obj)
| None -> ()
(* Apply transformations to any annotations in /Annots (i.e their /Rect entries) *)
let transform_annotations pdf transform rest =
Printf.printf "in transform_annotations with transform %s\n" (Pdftransform.string_of_matrix transform);
match Pdf.lookup_direct pdf "/Annots" rest with
| Some (Pdf.Array annots) ->
(* Always indirect references, so alter in place *)
iter
(function
| Pdf.Indirect i ->
(*Printf.printf "Found an annotation to modify...\n";*)
let annot = Pdf.lookup_obj pdf i in
let rect' =
match Pdf.lookup_direct pdf "/Rect" annot with
Some rect -> transform_rect transform rect
| None -> raise (Pdf.PDFError "transform_annotations: no rect")
in
let ap' =
@ -2331,16 +2341,30 @@ let transform_annotations pdf transform rest =
* b) a direct or indirect dictionary with some entries,
* each of which is an indirect reference to a stream. *)
(* We do this in place. *)
(* Make sure we never do an object more than once -- is this possible in a valid PDF anyway? *)
let seen_nums = Hashtbl.create 128 in
List.iter
(fun (k, v) ->
match v with
Pdf.Indirect i -> transform_xobject_in_place pdf transform i
Pdf.Indirect i ->
if Hashtbl.find_opt seen_nums i = None then
begin
Printf.printf "%i not in hash table\n" i;
Hashtbl.add seen_nums i ();
transform_xobject_in_place pdf transform i
end
| _ -> let dict = Pdf.lookup_direct pdf k (Pdf.Dictionary dict) in
match dict with Some (Pdf.Dictionary dict) ->
List.iter
(fun (_, v) ->
match v with
Pdf.Indirect i -> transform_xobject_in_place pdf transform i
Pdf.Indirect i ->
if Hashtbl.find_opt seen_nums i = None then
begin
Printf.printf "%i not in hash table\n" i;
Hashtbl.add seen_nums i ();
transform_xobject_in_place pdf transform i
end
| _ -> Printf.eprintf "Malformed /AP structure b"; ())
dict
| _ -> Printf.eprintf "Malformed /AP structure c"; ())