From b27c97a50ac5da8fda1b9a42756dff53866e8d75 Mon Sep 17 00:00:00 2001
From: John Whitington <john@coherentgraphics.co.uk>
Date: Wed, 11 Sep 2024 15:15:35 +0100
Subject: [PATCH] Marking artifacts

---
 cpdfcommand.ml |  4 ++--
 cpdfdraw.ml    | 26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index 601a178..3992981 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -2828,8 +2828,8 @@ let specs =
    ("-use", Arg.String Cpdfdrawcontrol.usexobj, " Use a saved sequence of graphics operators");
    ("-draw-jpeg", Arg.String Cpdfdrawcontrol.addjpeg, " Load a JPEG from file and name it");
    ("-draw-png", Arg.String Cpdfdrawcontrol.addpng, " Load a PNG from file and name it");
-   ("-image", Arg.String (fun s -> Cpdfdrawcontrol.addimage ?title:args.image_title s), " Draw an image which has already been loaded");
-   ("-image-title", Arg.String (fun s -> args.image_title <- Some s), " Give title for future images");
+   ("-image", Arg.String (fun s -> Cpdfdrawcontrol.addimage ?title:args.image_title s; args.image_title <- None), " Draw an image which has already been loaded");
+   ("-image-title", Arg.String (fun s -> args.image_title <- Some s), " Give title for the next -image");
    ("-fill-opacity", Arg.Float Cpdfdrawcontrol.addopacity, " Set opacity");
    ("-stroke-opacity", Arg.Float Cpdfdrawcontrol.addsopacity, " Set stroke opacity");
    ("-bt", Arg.Unit Cpdfdrawcontrol.addbt, " Begin text");
diff --git a/cpdfdraw.ml b/cpdfdraw.ml
index e512e0b..6dc81bb 100644
--- a/cpdfdraw.ml
+++ b/cpdfdraw.ml
@@ -395,6 +395,31 @@ let save_whole_stack () =
 let restore_whole_stack r =
   resstack := r
 
+(* Mark as an artifact anything not already marked. *)
+let add_artifacts ops =
+  let content = ref false in
+  let artifact = ref false in
+  let rec loop a = function
+  | [] ->
+      (* The end. Must end artifact if in artifact. *)
+      if !artifact then rev (Pdfops.Op_EMC::a) else rev a
+  | Pdfops.Op_BDC _ as h::t -> 
+      (* Entering content. If in artifact, must end artifact. *)
+      let a' = if !artifact then h::Pdfops.Op_EMC::a else h::a in
+        set content; clear artifact; loop a' t
+  | Pdfops.Op_EMC as h::t ->
+      (* Exiting content. *)
+      clear content;
+      loop (h::a) t
+  | h::t -> 
+      (* A normal operation. If not in content or artifact must start artifact. *)
+      let a' =
+        if not (!content || !artifact) then (set artifact; h::Pdfops.Op_BMC "/Artifact"::a) else h::a
+      in
+        loop a' t
+  in
+    loop [] ops
+
 let draw_single ~fast ~underneath ~filename ~bates ~batespad range pdf drawops =
   (res ()).num <- max (res ()).num (minimum_resource_number pdf range);
   let endpage = Pdfpage.endpage pdf in
@@ -420,6 +445,7 @@ let draw_single ~fast ~underneath ~filename ~bates ~batespad range pdf drawops =
     map3
       (fun n p ops ->
         if not (mem n range) then p else
+          let ops = add_artifacts ops in
           let page = {p with Pdfpage.resources = update_resources pdf p.Pdfpage.resources} in
             (if underneath then Pdfpage.prepend_operators else Pdfpage.postpend_operators) pdf ops ~fast page)
       (ilist 1 endpage)