Beginning implementation of -pad-with

cpdf.ml

@@ -2063,38 +2063,45 @@ let rec insert_after_many_changes isbefore padsize offset range = function
 let print_changes =
   List.iter (fun (f, t) -> Printf.printf "%i --> %i\n" f t)
 
-let pad range pdf isbefore =
-  let i = if isbefore then 1 else 0 in
-  let pages = Pdfpage.pages_of_pagetree pdf in
-    let blankpages =
-      map
-        (fun n ->
-           {Pdfpage.content = [];
-            Pdfpage.mediabox = (select (n + i) pages).Pdfpage.mediabox;
-            Pdfpage.resources = Pdf.Dictionary [];
-            Pdfpage.rotate = (select (n + i) pages).Pdfpage.rotate;
-            Pdfpage.rest = (select (n + i) pages).Pdfpage.rest})
-        range
-    in
-      let pages' = insert_after_many pages (combine range blankpages) in
-      let changes =
-        insert_after_many_changes
-          isbefore 1 0 (List.map (fun x -> x + i) range) (ilist 1 (length pages))
-      in
-        (*print_changes changes;*)
-        Pdfpage.change_pages ~changes true pdf pages'
+let pad_with_pdf range pdf isbefore padfile =
+  (* 1. Split the input pdf around the range, taking account of isbefore *)
+  (* 2. Build a merge after "a p b p c p" or before "p a p b p c" *)
+  pdf
 
-let padafter range pdf =
+let pad padwith range pdf isbefore =
+  match padwith with
+    Some padfile -> pad_with_pdf range pdf isbefore padfile
+  | None ->
+      let i = if isbefore then 1 else 0 in
+      let pages = Pdfpage.pages_of_pagetree pdf in
+        let blankpages =
+          map
+            (fun n ->
+               {Pdfpage.content = [];
+                Pdfpage.mediabox = (select (n + i) pages).Pdfpage.mediabox;
+                Pdfpage.resources = Pdf.Dictionary [];
+                Pdfpage.rotate = (select (n + i) pages).Pdfpage.rotate;
+                Pdfpage.rest = (select (n + i) pages).Pdfpage.rest})
+            range
+        in
+          let pages' = insert_after_many pages (combine range blankpages) in
+          let changes =
+            insert_after_many_changes
+              isbefore 1 0 (List.map (fun x -> x + i) range) (ilist 1 (length pages))
+          in
+            Pdfpage.change_pages ~changes true pdf pages'
+
+let padafter ?padwith range pdf =
   let isinpdf n = mem n (ilist 1 (Pdfpage.endpage pdf)) in
     if not (fold_left ( && ) true (map isinpdf range)) then
       raise (Failure "padafter: range contains pages not present in pdf");
-    pad range pdf false
+    pad padwith range pdf false
 
-let padbefore range pdf =
+let padbefore ?padwith range pdf =
   let isinpdf n = mem n (ilist 1 (Pdfpage.endpage pdf)) in
     if not (fold_left ( && ) true (map isinpdf range)) then
       raise (Failure "padbefore: range contains pages not present in pdf");
-    pad (map pred range) pdf true
+    pad padwith (map pred range) pdf true
 
 let padmultiple n pdf =
   let pages = Pdfpage.pages_of_pagetree pdf in

cpdf.mli

@@ -364,10 +364,10 @@ val scale_contents : ?fast:bool -> position -> float -> Pdf.t -> int list -> Pdf
 (** {2 Padding} *)
 
 (** Put blank pages before the given page numbers *)
-val padbefore : int list -> Pdf.t -> Pdf.t
+val padbefore : ?padwith:Pdf.t -> int list -> Pdf.t -> Pdf.t
 
 (** Put blank pages after the given page numbers *)
-val padafter : int list -> Pdf.t -> Pdf.t
+val padafter : ?padwith:Pdf.t -> int list -> Pdf.t -> Pdf.t
 
 (** Pad to a multiple of n pages *)
 val padmultiple : int -> Pdf.t -> Pdf.t

cpdfcommand.ml

@@ -381,7 +381,8 @@ type args =
    mutable creator : string option;
    mutable producer : string option;
    mutable embedfonts : bool;
-   mutable extract_text_font_size : float option}
+   mutable extract_text_font_size : float option;
+   mutable padwith : string option}
 
 let args =
   {op = None;
@@ -465,7 +466,8 @@ let args =
    producer = None;
    creator = None;
    embedfonts = true;
-   extract_text_font_size = None}
+   extract_text_font_size = None;
+   padwith = None}
 
 let reset_arguments () =
   args.op <- None;
@@ -546,7 +548,8 @@ let reset_arguments () =
   args.embedfonts <- true;
   args.creator <- None;
   args.producer <- None;
-  args.extract_text_font_size <- None
+  args.extract_text_font_size <- None;
+  args.padwith <- None
   (* Do not reset original_filename or cpdflin or was_encrypted or
    * was_decrypted_with_owner or recrypt, since we want these to work across ANDs. *)
 
@@ -1378,6 +1381,9 @@ let setpadevery i =
   else
     error "PadEvery: must be > 0"
 
+let setpadwith filename =
+  args.padwith <- Some filename
+
 let setpadmultiple i =
   args.op <- Some (PadMultiple i)
 
@@ -1874,6 +1880,9 @@ and specs =
    ("-pad-every",
       Arg.Int setpadevery,
       " Add a blank page after every n pages");
+   ("-pad-with",
+      Arg.String setpadwith,
+      " Use a given PDF instead of a blank page");
    ("-pad-multiple",
       Arg.Int setpadmultiple,
       " Pad the document to a multiple of n pages");
@@ -3756,11 +3765,21 @@ let go () =
   | Some PadBefore ->
       let pdf = get_single_pdf args.op false in
         let range = parse_pagespec pdf (get_pagespec ()) in
-          write_pdf false (Cpdf.padbefore range pdf)
+          let padwith =
+            match args.padwith with
+              None -> None
+            | Some filename -> Some (pdfread_pdf_of_file None None filename)
+          in
+            write_pdf false (Cpdf.padbefore ?padwith range pdf)
   | Some PadAfter ->
       let pdf = get_single_pdf args.op false in
         let range = parse_pagespec pdf (get_pagespec ()) in
-          write_pdf false (Cpdf.padafter range pdf)
+          let padwith =
+            match args.padwith with
+              None -> None
+            | Some filename -> Some (pdfread_pdf_of_file None None filename)
+          in
+            write_pdf false (Cpdf.padafter ?padwith range pdf)
   | Some (PadEvery n) ->
       let pdf = get_single_pdf args.op false in
         let range =