diff --git a/Makefile b/Makefile
index 45511c8..e971697 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,7 @@ DOC = cpdfunicodedata cpdferror cpdfdebug cpdfjson cpdfstrftime cpdfcoord \
       cpdfembed cpdfaddtext cpdffont cpdftype cpdfpad cpdfocg \
       cpdfsqueeze cpdfdraft cpdfspot cpdfpagelabels cpdfcreate cpdfannot \
       cpdfxobject cpdfimpose cpdftweak cpdftexttopdf cpdftoc cpdfjpeg \
-      cpdfpng cpdfimage cpdfdraw cpdfcommand
+      cpdfpng cpdfimage cpdfdraw cpdfcomposition cpdfcommand
 
 MODS = $(NONDOC) $(DOC)
 
diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index 0b7f579..fb6c724 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -3385,80 +3385,6 @@ let warn_prerotate range pdf =
 let prerotate range pdf =
   Cpdfpage.upright ~fast:args.fast range pdf
 
-let find_composition_images pdf i obj marked =
-  match Pdf.lookup_direct pdf "/Subtype" obj with
-  | Some (Pdf.Name "/Image") ->
-      Hashtbl.add marked i ();
-      String.length (Pdfwrite.string_of_pdf_including_data obj);
-  | _ -> 0
-
-let find_composition_fonts pdf i obj marked = 0
-
-let find_composition_content_streams pdf i obj marked =
-  match Pdf.lookup_direct pdf "/Type" obj with
-  | Some (Pdf.Name "/Page") ->
-      let cs =
-        begin match Pdf.lookup_direct pdf "/Contents" obj with
-        | Some (Pdf.Indirect i) -> [i]
-        | Some (Pdf.Array is) -> option_map (function Pdf.Indirect i -> Some i | _ -> None) is
-        | _ -> []
-        end
-      in
-        let l = ref 0 in
-          iter
-            (fun i ->
-               Hashtbl.add marked i ();
-               l += String.length (Pdfwrite.string_of_pdf_including_data (Pdf.lookup_obj pdf i)))
-            cs;
-          !l
-  | _ -> 0
-
-let find_composition_structure_info pdf i obj marked = 0
-
-let find_composition_link_annotations pdf i obj marked = 0
-
-let find_composition_embedded_files pdf i obj marked = 0
-
-let find_composition pdf =
-  let marked = null_hash () in
-  let images = ref 0 in
-  let fonts = ref 0 in
-  let content_streams = ref 0 in
-  let structure_info = ref 0 in
-  let link_annotations = ref 0 in
-  let embedded_files = ref 0 in
-    Pdf.objiter
-      (fun i obj ->
-         match Hashtbl.find marked i with _ -> () | exception Not_found ->
-           images += find_composition_images pdf i obj marked;
-           fonts += find_composition_fonts pdf i obj marked;
-           content_streams += find_composition_content_streams pdf i obj marked;
-           structure_info += find_composition_structure_info pdf i obj marked;
-           link_annotations += find_composition_link_annotations pdf i obj marked;
-           embedded_files += find_composition_embedded_files pdf i obj marked)
-      pdf;
-    (!images, !fonts, !content_streams, !structure_info, !link_annotations, !embedded_files)
-
-(* First go: images, fonts, content streams, structure info, link annotations, embedded files *)
-let show_composition_json filesize pdf =
-  let perc x = float_of_int x /. float_of_int filesize *. 100. in
-  let images, fonts, content_streams, structure_info, link_annotations, embedded_files =
-    find_composition pdf
-  in
-  let r = images + fonts + content_streams + structure_info + link_annotations + embedded_files in
-    `List [`Tuple [`String "Images"; `Int images; `Float (perc images)];
-           `Tuple [`String "Content streams"; `Int content_streams; `Float (perc content_streams)];
-           `Tuple [`String "Unclassified"; `Int (filesize - r); `Float (perc (filesize - r))]]
-
-let show_composition filesize json pdf =
-  let module J = Cpdfyojson.Safe in
-  let j = show_composition_json filesize pdf in
-  if json then (flprint (J.pretty_to_string j); flprint "\n") else
-    match j with
-    | `List js ->
-        iter (function `Tuple [`String a; `Int b; `Float c] -> Printf.printf "%s: %i bytes (%.1f%%)\n" a b c | _ -> ()) js
-    | _ -> ()
-
 let embed_font () =
   match args.font with
   | StandardFont f ->
@@ -4429,7 +4355,7 @@ let go () =
         | (InFile inname, _, _, _, _, _)::_ -> filesize inname
         | _ -> 0
       in
-        show_composition filesize json pdf
+        Cpdfcomposition.show_composition filesize json pdf
 
 (* Advise the user if a combination of command line flags makes little sense,
 or error out if it make no sense at all. *)
diff --git a/cpdfcomposition.ml b/cpdfcomposition.ml
new file mode 100644
index 0000000..7eff76f
--- /dev/null
+++ b/cpdfcomposition.ml
@@ -0,0 +1,80 @@
+open Pdfutil
+
+let find_composition_images pdf i obj marked =
+  match Pdf.lookup_direct pdf "/Subtype" obj with
+  | Some (Pdf.Name "/Image") ->
+      Hashtbl.add marked i ();
+      String.length (Pdfwrite.string_of_pdf_including_data obj);
+  | _ -> 0
+
+let find_composition_fonts pdf i obj marked = 0
+
+(* Also includes xobjects *)
+let find_composition_content_streams pdf i obj marked =
+  match Pdf.lookup_direct pdf "/Type" obj with
+  | Some (Pdf.Name "/Page") ->
+      let cs =
+        begin match Pdf.lookup_direct pdf "/Contents" obj with
+        | Some (Pdf.Indirect i) -> [i]
+        | Some (Pdf.Array is) -> option_map (function Pdf.Indirect i -> Some i | _ -> None) is
+        | _ -> []
+        end
+      in
+        let l = ref 0 in
+          iter
+            (fun i ->
+               Hashtbl.add marked i ();
+               l += String.length (Pdfwrite.string_of_pdf_including_data (Pdf.lookup_obj pdf i)))
+            cs;
+          !l
+  | _ -> 0
+
+let find_composition_structure_info pdf i obj marked = 0
+
+let find_composition_link_annotations pdf i obj marked = 0
+
+let find_composition_embedded_files pdf i obj marked = 0
+
+let find_composition pdf =
+  let marked = null_hash () in
+  let images = ref 0 in
+  let fonts = ref 0 in
+  let content_streams = ref 0 in
+  let structure_info = ref 0 in
+  let link_annotations = ref 0 in
+  let embedded_files = ref 0 in
+    Pdf.objiter
+      (fun i obj ->
+         match Hashtbl.find marked i with _ -> () | exception Not_found ->
+           images += find_composition_images pdf i obj marked;
+           fonts += find_composition_fonts pdf i obj marked;
+           content_streams += find_composition_content_streams pdf i obj marked;
+           structure_info += find_composition_structure_info pdf i obj marked;
+           link_annotations += find_composition_link_annotations pdf i obj marked;
+           embedded_files += find_composition_embedded_files pdf i obj marked)
+      pdf;
+    (!images, !fonts, !content_streams, !structure_info, !link_annotations, !embedded_files)
+
+(* First go: images, fonts, content streams, structure info, link annotations, embedded files *)
+let show_composition_json filesize pdf =
+  let perc x = float_of_int x /. float_of_int filesize *. 100. in
+  let images, fonts, content_streams, structure_info, link_annotations, embedded_files =
+    find_composition pdf
+  in
+  let r = images + fonts + content_streams + structure_info + link_annotations + embedded_files in
+    `List [`Tuple [`String "Images"; `Int images; `Float (perc images)];
+           `Tuple [`String "Fonts"; `Int fonts; `Float (perc fonts)];
+           `Tuple [`String "Content streams"; `Int content_streams; `Float (perc content_streams)];
+           `Tuple [`String "Structure Info"; `Int structure_info; `Float (perc structure_info)];
+           `Tuple [`String "Link Annotations"; `Int link_annotations; `Float (perc link_annotations)];
+           `Tuple [`String "Embedded Files"; `Int embedded_files; `Float (perc embedded_files)];
+           `Tuple [`String "Unclassified"; `Int (filesize - r); `Float (perc (filesize - r))]]
+
+let show_composition filesize json pdf =
+  let module J = Cpdfyojson.Safe in
+  let j = show_composition_json filesize pdf in
+  if json then (flprint (J.pretty_to_string j); flprint "\n") else
+    match j with
+    | `List js ->
+        iter (function `Tuple [`String a; `Int b; `Float c] -> Printf.printf "%s: %i bytes (%.2f%%)\n" a b c | _ -> ()) js
+    | _ -> ()
diff --git a/cpdfcomposition.mli b/cpdfcomposition.mli
new file mode 100644
index 0000000..b380998
--- /dev/null
+++ b/cpdfcomposition.mli
@@ -0,0 +1 @@
+val show_composition : int -> bool -> Pdf.t -> unit