Scaffolding for tags

cpdfcommand.ml

@@ -2804,6 +2804,12 @@ let specs =
      " Find width of a line of text");
    ("-draw", Arg.Unit setdraw, " Begin drawing");
    ("-draw-struct-tree", Arg.Unit setdrawstructtree, " Build structure trees when drawing.");
+   ("-tag", Arg.String Cpdfdrawcontrol.addtag, " Begin structure item");
+   ("-stag", Arg.String Cpdfdrawcontrol.addstag, " Begin struture branch");
+   ("-end-tag", Arg.Unit Cpdfdrawcontrol.endtag, " End structure item");
+   ("-end-stag", Arg.Unit Cpdfdrawcontrol.endstag, " End structure branch");
+   ("-auto-tags", Arg.Unit (fun _ -> Cpdfdrawcontrol.autotags true), " Auto-tag paragraphs and figures");
+   ("-no-auto-tags", Arg.Unit (fun _ -> Cpdfdrawcontrol.autotags false), " Don't auto-tag paragraphs and figures");
    ("-rect", Arg.String Cpdfdrawcontrol.addrect, " Draw rectangle");
    ("-to", Arg.String Cpdfdrawcontrol.addto, " Move to");
    ("-line", Arg.String Cpdfdrawcontrol.addline, " Add line to");

cpdfdrawcontrol.ml

@@ -95,6 +95,12 @@ let setstroke s =
 let setfill s =
   addop (Cpdfdraw.SetFill (col_of_string s))
 
+let addtag t = ()
+let addstag t = ()
+let endtag () = ()
+let endstag () = ()
+let autotags b = ()
+
 let addrect s =
   let x, y, w, h = Cpdfcoord.parse_rectangle (Pdf.empty ()) s in
     addop (Cpdfdraw.Rect (x, y, w, h))

cpdfdrawcontrol.mli

@@ -14,6 +14,11 @@ val fontpack_initialised : bool ref
 val drawops : (string * Cpdfdraw.drawops list) list ref
 val addop : Cpdfdraw.drawops -> unit
 val parse_colour : string -> Cpdfaddtext.colour
+val addtag : string -> unit
+val addstag : string -> unit
+val endtag : unit -> unit
+val endstag : unit -> unit
+val autotags : bool -> unit
 val addrect : string -> unit
 val addto : string -> unit
 val addline : string -> unit