From e33120bf940cbd6e7e04a105bd2dfef409d1946a Mon Sep 17 00:00:00 2001
From: John Whitington <john@coherentgraphics.co.uk>
Date: Wed, 18 Sep 2024 16:32:29 +0100
Subject: [PATCH] Namespaces
---
cpdfdraw.ml | 56 +++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 44 insertions(+), 12 deletions(-)
diff --git a/cpdfdraw.ml b/cpdfdraw.ml
index 6466196..6d7ecd0 100644
--- a/cpdfdraw.ml
+++ b/cpdfdraw.ml
@@ -242,7 +242,17 @@ let mcpage = ref ~-1
let standard_namespace = "http://iso.org/pdf/ssn"
let pdf2_namespace = "http://iso.org/pdf2/ssn"
-let namespace = ref standard_namespace
+(* namespace, object number pair. *)
+let namespaces = null_hash ()
+
+(* Add the object, add its number and this namespace to the hash. *)
+let add_namespace pdf s =
+ if s = standard_namespace then () else
+ match Hashtbl.find_opt namespaces s with
+ | Some _ -> ()
+ | None ->
+ let objnum = Pdf.addobj pdf (Pdf.Dictionary [("/NS", Pdf.String s)]) in
+ Hashtbl.add namespaces s objnum
(* The structure data, as it is created, in flat form. Later on, this will be
reconstructed into a structure tree. *)
@@ -251,6 +261,7 @@ type structdata =
| StDataEndTree
| StDataMCID of string * int * string option
| StDataPage of int
+ | StDataNamespace of string
let structdata = ref []
@@ -435,7 +446,13 @@ let rec ops_of_drawop struct_tree dryrun pdf endpage filename bates batespad num
| EndSTag -> if not dryrun then structdata =| StDataEndTree; []
| BeginArtifact -> [Pdfops.Op_BMC "/BeginArtifact"]
| EndArtifact -> [Pdfops.Op_BMC "/EndArtifact"]
- | Namespace s -> if not dryrun then namespace := s; []
+ | Namespace s ->
+ if not dryrun then
+ begin
+ add_namespace pdf s;
+ structdata =| StDataNamespace s
+ end;
+ []
and ops_of_drawops struct_tree dryrun pdf endpage filename bates batespad num page drawops =
flatten (map (ops_of_drawop struct_tree dryrun pdf endpage filename bates batespad num page) drawops)
@@ -585,7 +602,7 @@ let dryrun ~struct_tree ~filename ~bates ~batespad range pdf chunks =
type st =
StMCID of int
- | StItem of {kind : string; pageobjnum : int option; alt : string option; children : st list}
+ | StItem of {kind : string; namespace : string; pageobjnum : int option; alt : string option; children : st list}
(* Build a tree from the MCIDs and structure tree instructions gathered *)
let rec find_tree_contents a level = function
@@ -596,16 +613,19 @@ let rec find_tree_contents a level = function
if level = 1 then (rev a, t) else find_tree_contents a (level - 1) t
| h::t -> find_tree_contents (h::a) level t
-let rec make_structure_tree pageobjnums pdf pagenum = function
+let rec make_structure_tree pageobjnums pdf pagenum namespace = function
| [] -> []
| StDataMCID (n, mcid, alt)::t ->
- StItem {kind = n; alt; pageobjnum = lookup !pagenum pageobjnums; children = [StMCID mcid]}::make_structure_tree pageobjnums pdf pagenum t
+ StItem {kind = n; namespace = !namespace; alt; pageobjnum = lookup !pagenum pageobjnums; children = [StMCID mcid]}::make_structure_tree pageobjnums pdf pagenum namespace t
| StDataPage n::t ->
pagenum := n;
- make_structure_tree pageobjnums pdf pagenum t
+ make_structure_tree pageobjnums pdf pagenum namespace t
+ | StDataNamespace s::t ->
+ namespace := s;
+ make_structure_tree pageobjnums pdf pagenum namespace t
| StDataBeginTree s::t ->
let tree_contents, rest = find_tree_contents [] 1 t in
- [StItem {kind = s; alt = None; pageobjnum = None; children = make_structure_tree pageobjnums pdf pagenum rest}]
+ [StItem {kind = s; namespace = !namespace; alt = None; pageobjnum = None; children = make_structure_tree pageobjnums pdf pagenum namespace rest}]
| StDataEndTree::t ->
error "Too many -end-tags"
@@ -614,7 +634,7 @@ let make_structure_tree pdf items =
let objnums = Pdf.page_reference_numbers pdf in
combine (indx objnums) objnums
in
- make_structure_tree pageobjnums pdf (ref 0) items
+ make_structure_tree pageobjnums pdf (ref 0) (ref standard_namespace) items
(* Write such a structure tree to a PDF. *)
let write_structure_tree pdf st =
@@ -626,7 +646,7 @@ let write_structure_tree pdf st =
in
let struct_tree_root = Pdf.addobj pdf Pdf.Null in
let rec mktree struct_tree_parent = function
- | StItem {kind; pageobjnum; alt; children} ->
+ | StItem {kind; namespace; pageobjnum; alt; children} ->
let this_objnum = Pdf.addobj pdf Pdf.Null in
begin match pageobjnum with
| Some p -> add_parentmap p this_objnum
@@ -642,10 +662,15 @@ let write_structure_tree pdf st =
| Some i -> [("/Pg", Pdf.Indirect i)]
| None -> []
in
+ let namespace =
+ if namespace = standard_namespace then [] else
+ [("/NS", Pdf.Indirect (Hashtbl.find namespaces namespace))]
+ in
let this_obj =
Pdf.Dictionary
(alt
@ page
+ @ namespace
@ [("/S", Pdf.Name kind);
("/P", Pdf.Indirect struct_tree_parent);
("/K", Pdf.Array (map (mktree this_objnum) children))])
@@ -664,9 +689,16 @@ let write_structure_tree pdf st =
map (fun (pon, items) -> (string_of_int pon, Pdf.Array (map (fun x -> Pdf.Indirect x) (rev items)))) !parentmap
in
let st =
- Pdf.Dictionary [("/Type", Pdf.Name "/StructTreeRoot");
- ("/ParentTree", Pdf.Indirect (Pdf.addobj pdf (Pdftree.build_name_tree true pdf parentmap)));
- ("/K", Pdf.Array items)]
+ let namespaces =
+ match list_of_hashtbl namespaces with
+ | [] -> []
+ | ns -> [("/Namespaces", Pdf.Array (map (function (_, objnum) -> Pdf.Indirect objnum) ns))]
+ in
+ Pdf.Dictionary
+ (namespaces @
+ [("/Type", Pdf.Name "/StructTreeRoot");
+ ("/ParentTree", Pdf.Indirect (Pdf.addobj pdf (Pdftree.build_name_tree true pdf parentmap)));
+ ("/K", Pdf.Array items)])
in
Pdf.addobj_given_num pdf (struct_tree_root, st);
Pdf.replace_chain pdf ["/Root"] ("/StructTreeRoot", (Pdf.Indirect struct_tree_root))