From e6afa6e8f2daee03b8509a396a8c0ad73befb370 Mon Sep 17 00:00:00 2001
From: John Whitington <john@coherentgraphics.co.uk>
Date: Thu, 19 Mar 2020 16:23:16 +0000
Subject: [PATCH] More apparatus for -stamp-as-xobject

---
 cpdf.ml        | 21 +++++++++++++++++----
 cpdf.mli       |  2 +-
 cpdfcommand.ml |  3 ++-
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/cpdf.ml b/cpdf.ml
index 31e0285..81dff9c 100644
--- a/cpdf.ml
+++ b/cpdf.ml
@@ -2533,10 +2533,23 @@ let stamp relative_to_cropbox position topline midline fast scale_to_fit isover
                     let new_marks = map (change_bookmark changetable) marks in
                       Pdfmarks.add_bookmarks new_marks changed
 
-let add_page_as_xobject pdf page name =
-  pdf
+let add_page_as_xobject pdf range page name =
+  let xobject_data = bytes_of_string "0 0 m 0 100 l 100 100 l 100 0 l f" in
+  let xobject_dict =
+     ["/Type", Pdf.Name "/XObject";
+     "/Subtype", Pdf.Name "/Form";
+     "/BBox", Pdf.Array [Pdf.Real 0.; Pdf.Real 0.; Pdf.Real 1000.; Pdf.Real 1000.];
+     "/Resources", Pdf.Dictionary [];
+     "/Length", Pdf.Integer (bytes_size xobject_data);
+    ]
+  in
+    let xobject =
+      Pdf.Stream {contents = (Pdf.Dictionary xobject_dict, Pdf.Got xobject_data)}
+    in
+      let xobject_objnum = Pdf.addobj pdf xobject in
+      pdf
 
-let stamp_as_xobject pdf over =
+let stamp_as_xobject pdf range over =
   let prefix = Pdfpage.shortest_unused_prefix pdf in
   Pdfpage.add_prefix over prefix;
   let marks = Pdfmarks.read_bookmarks pdf in
@@ -2573,7 +2586,7 @@ let stamp_as_xobject pdf over =
                     let new_marks = map (change_bookmark changetable) marks in
                     let pdf = Pdfmarks.add_bookmarks new_marks changed in
                     let name = "/X0" in
-                      (add_page_as_xobject pdf over_page name, name)
+                      (add_page_as_xobject pdf range over_page name, name)
 
 (* Combine pages from two PDFs. For now, assume equal length. *)
 
diff --git a/cpdf.mli b/cpdf.mli
index 0e47fcd..34217cc 100644
--- a/cpdf.mli
+++ b/cpdf.mli
@@ -458,5 +458,5 @@ val ocg_rename : string -> string -> Pdf.t -> unit
 
 val ocg_order_all : Pdf.t -> unit
 
-val stamp_as_xobject : Pdf.t -> Pdf.t -> Pdf.t * string
+val stamp_as_xobject : Pdf.t -> int list -> Pdf.t -> Pdf.t * string
 
diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index 266c67f..80dce5f 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -4504,8 +4504,9 @@ let go () =
         | x -> pdfread_pdf_of_file None None x
       in
         let pdf = get_single_pdf args.op false in
+        let range = parse_pagespec pdf (get_pagespec ()) in
           let pdf, xobj_name =
-            Cpdf.stamp_as_xobject pdf stamp_pdf
+            Cpdf.stamp_as_xobject pdf range stamp_pdf
           in
             Printf.printf "%s\n" xobj_name;
             flush stdout;