Merge pull request #57 from gfngfn/gfngfn/temp-debug-subset

Fix how to subset fonts and how to encode fractions
gfngfn · Sep 30, 2023 · e1d49bd · e1d49bd
2 parents f3df372 + 860ca27
commit e1d49bd
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Showing 7 changed files with 177 additions and 103 deletions.
diff --git a/bin/main.ml b/bin/main.ml
@@ -394,6 +394,12 @@ let print_cff_lex (source : D.source) (gid : V.glyph_id) =
   | D.Cff(cff) ->
       let empty = D.Cff.LexicalSubroutineIndex.empty in
       D.Cff.fdindex cff gid |> inj >>= fun fdindex_opt ->
+      let global_bias = D.Cff.get_global_bias cff in
+      let local_bias =
+        match D.Cff.get_local_bias cff fdindex_opt with
+        | Some(local_bias) -> local_bias
+        | None             -> assert false
+      in
       D.Cff.lexical_charstring cff ~gsubrs:empty ~lsubrs:empty gid |> inj >>= function
       | None ->
           Format.printf "  not defined@,";
@@ -402,17 +408,17 @@ let print_cff_lex (source : D.source) (gid : V.glyph_id) =
       | Some((gsubrs, lsubrs, lcharstring)) ->
           Format.printf "  %a@," I.Cff.pp_lexical_charstring lcharstring;
           Format.printf "  dependent gsubrs:@,";
-          D.Cff.LexicalSubroutineIndex.fold (fun i lcs () ->
-            Format.printf "  - non-biased number: %d:@," i;
+          D.Cff.LexicalSubroutineIndex.fold (fun i_biased lcs () ->
+            Format.printf "  - biased: %d / non-biased: %d:@," i_biased (i_biased + global_bias);
             Format.printf "    %a@," I.Cff.pp_lexical_charstring lcs
           ) gsubrs ();
           begin
             match fdindex_opt with
             | None          -> Format.printf "  dependent lsubrs (non-CID):@,"
             | Some(fdindex) -> Format.printf "  dependent lsubrs (CID, fdindex: %d):@," fdindex
           end;
-          D.Cff.LexicalSubroutineIndex.fold (fun i lcs () ->
-            Format.printf "  - non-biased number: %d:@," i;
+          D.Cff.LexicalSubroutineIndex.fold (fun i_biased lcs () ->
+            Format.printf "  - biased: %d / non-biased: %d:@," i_biased (i_biased + local_bias);
             Format.printf "    %a@," I.Cff.pp_lexical_charstring lcs
           ) lsubrs ();
           return ()

diff --git a/src/decodeCff.ml b/src/decodeCff.ml
@@ -634,10 +634,9 @@ let d_charstring_token (lstate : charstring_lexing_state) : (charstring_lexing_s
       return_argument (2, ArgumentInteger(- (b0 - 251) * 256 - b1 - 108))
 
   | 255 ->
-      d_twoscompl2 >>= fun ret1 ->
-      d_twoscompl2 >>= fun ret2 ->
-      let ret = float_of_int ret1 +. (float_of_int ret2) /. (float_of_int (1 lsl 16)) in
-      return_argument (5, ArgumentReal(ret))
+      d_twoscompl4 >>= fun n ->
+      let r = float_of_int n /. (float_of_int (1 lsl 16)) in
+      return_argument (5, ArgumentReal(r))
 
   | n ->
       err @@ Error.UnknownCharstringToken(n)
@@ -1133,8 +1132,8 @@ let rec d_lexical_charstring ~(depth : int) (cconst : charstring_constant) (lcst
             | None ->
                 err Error.NoSubroutineIndexArgument
 
-            | Some(i) ->
-                d_lexical_subroutine ~depth ~local:true cconst lcstate i
+            | Some(i_biased) ->
+                d_lexical_subroutine ~depth ~local:true cconst lcstate i_biased
           end
 
       | OpCallGSubr ->
@@ -1143,8 +1142,8 @@ let rec d_lexical_charstring ~(depth : int) (cconst : charstring_constant) (lcst
             | None ->
                 err Error.NoSubroutineIndexArgument
 
-            | Some(i) ->
-                d_lexical_subroutine ~depth ~local:false cconst lcstate i
+            | Some(i_biased) ->
+                d_lexical_subroutine ~depth ~local:false cconst lcstate i_biased
           end
 
       | ArgumentInteger(n) ->
@@ -1165,7 +1164,7 @@ let rec d_lexical_charstring ~(depth : int) (cconst : charstring_constant) (lcst
   aux lcstate Alist.empty
 
 
-and d_lexical_subroutine ~(depth : int) ~(local : bool) (cconst : charstring_constant) (lcstate : lexical_charstring_state) (i : int) =
+and d_lexical_subroutine ~(depth : int) ~(local : bool) (cconst : charstring_constant) (lcstate : lexical_charstring_state) (i_biased : int) =
   let open DecodeOperation in
 
   if depth > max_depth_limit then
@@ -1175,8 +1174,7 @@ and d_lexical_subroutine ~(depth : int) ~(local : bool) (cconst : charstring_con
     let remaining = lcstate.lexical_lexing.remaining in
 
     let subrs = if local then cconst.lsubr_index else cconst.gsubr_index in
-
-    transform_result @@ access_subroutine subrs i >>= fun (offset, length, _biased_number) ->
+    transform_result @@ access_subroutine subrs i_biased >>= fun (offset, length, _biased_number) ->
     let lcstate = { lcstate with lexical_lexing = { lcstate.lexical_lexing with remaining = length } } in
     pick offset (d_lexical_charstring ~depth:(depth + 1) cconst lcstate) >>= fun (lcstate, acc) ->
     let lcs = Alist.to_list acc in
@@ -1185,12 +1183,12 @@ and d_lexical_subroutine ~(depth : int) ~(local : bool) (cconst : charstring_con
     let lcstate =
       if local then
         { lcstate with
-          lexical_lsubrs = lcstate.lexical_lsubrs |> LexicalSubroutineIndex.add i lcs;
+          lexical_lsubrs = lcstate.lexical_lsubrs |> LexicalSubroutineIndex.add i_biased lcs;
           lexical_lexing = { lcstate.lexical_lexing with remaining = remaining };
         }
       else
         { lcstate with
-          lexical_gsubrs = lcstate.lexical_gsubrs |> LexicalSubroutineIndex.add i lcs;
+          lexical_gsubrs = lcstate.lexical_gsubrs |> LexicalSubroutineIndex.add i_biased lcs;
           lexical_lexing = { lcstate.lexical_lexing with remaining = remaining };
         }
     in
@@ -1509,3 +1507,23 @@ let path_of_charstring (ops : Intermediate.Cff.charstring) : (cubic_path list) o
     | (_, Middle(middle)) ->
         let path = (middle.start, Alist.to_list middle.elems) in
         return @@ Alist.to_list (Alist.extend middle.paths path)
+
+
+(* For experimental use. *)
+let get_global_bias (cff : cff_source) : int =
+  convert_subroutine_number cff.cff_specific.charstring_info.gsubr_index 0
+
+
+(* For experimental use. *)
+let get_local_bias (cff : cff_source) (fdindex_opt : fdindex option) : int option =
+  let private_info = cff.cff_specific.charstring_info.private_info in
+  match (private_info, fdindex_opt) with
+  | (SinglePrivate{ local_subr_index; _ }, None) ->
+      Some(convert_subroutine_number local_subr_index 0)
+
+  | (FontDicts(fdarray, _fdselect), Some(fdindex)) ->
+      let single_private = fdarray.(fdindex) in
+      Some(convert_subroutine_number single_private.local_subr_index 0)
+
+  | (SinglePrivate(_), Some(_)) | (FontDicts(_, _), None) ->
+      None
diff --git a/src/decodeCff.mli b/src/decodeCff.mli
@@ -52,3 +52,9 @@ val fdindex : cff_source -> Value.glyph_id -> (Intermediate.Cff.fdindex option)
 val lexical_charstring : cff_source -> gsubrs:LexicalSubroutineIndex.t -> lsubrs:LexicalSubroutineIndex.t -> Value.glyph_id -> ((LexicalSubroutineIndex.t * LexicalSubroutineIndex.t * Intermediate.Cff.lexical_charstring) option) ok
 
 val path_of_charstring : Intermediate.Cff.charstring -> (Value.cubic_path list) ok
+
+(** Gets the bias for Global Subrs (for experimental use). *)
+val get_global_bias : cff_source -> int
+
+(** Gets the bias for Local Subrs (for experimental use). *)
+val get_local_bias : cff_source -> Intermediate.Cff.fdindex option -> int option
diff --git a/src/encodeCff.ml b/src/encodeCff.ml
@@ -237,11 +237,22 @@ let e_dict (dict : dict) =
   e_list e_dict_entry entries
 
 
+let e_charstring_integer =
+  e_integer_value
+
+
+let e_charstring_real (r : float) : unit encoder =
+  let open EncodeOperation in
+  let n = int_of_float (r *. (float_of_int (1 lsl 16))) in
+  e_uint8 255 >>= fun () ->
+  e_twoscompl4 n
+
+
 let e_charstring_token (ctoken : charstring_token) : unit encoder =
   let open EncodeOperation in
   match ctoken with
-  | ArgumentInteger(n) -> e_integer_value n
-  | ArgumentReal(r)    -> e_real_value r
+  | ArgumentInteger(n) -> e_charstring_integer n
+  | ArgumentReal(r)    -> e_charstring_real r
 
   | OpHStem   -> e_short_key 1
   | OpVStem   -> e_short_key 3

diff --git a/src/otfed.mli b/src/otfed.mli
@@ -1443,6 +1443,12 @@ module Decode : sig
 
     (** Converts a CharString into a cubic Bézier path. *)
     val path_of_charstring : Intermediate.Cff.charstring -> (Value.cubic_path list) ok
+
+    (** Gets the bias for Global Subrs (for experimental use). *)
+    val get_global_bias : cff_source -> int
+
+    (** Gets the bias for Local Subrs (for experimental use). *)
+    val get_local_bias : cff_source -> Intermediate.Cff.fdindex option -> int option
   end
 end
 
@@ -1586,6 +1592,7 @@ module Subset : sig
       | DecodeError                 of Decode.Error.t
       | EncodeError                 of Encode.Error.t
       | NonexplicitSubroutineNumber
+      | CallSubrInGlobalSubr        of { old_biased : int }
     [@@deriving show]
   end