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First attempt at Truetype format 4 cmap magic formula

This commit is contained in:
John Whitington 2023-06-12 13:55:15 +01:00
parent 0c9a5e0101
commit 09986b5198
1 changed files with 15 additions and 5 deletions
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20
cpdftruetype.ml
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@ -79,7 +79,14 @@ let read_format_6_encoding_table b =
with with
e -> failwith ("bad format 6 table: " ^ Printexc.to_string e ^ "\n") e -> failwith ("bad format 6 table: " ^ Printexc.to_string e ^ "\n")
(* fixme might need indexToLocFormat here, to undo the "clever" formula. *) let read_magic_formula b glyphIndexArrayStart seg segCount ro c sc =
let position = seg - segCount + ro / 2 + (c - sc) in
let saved = b.pos_in () in
b.seek_in (glyphIndexArrayStart + position);
let result = b.input_byte () in
b.seek_in saved;
result
let read_format_4_encoding_table b = let read_format_4_encoding_table b =
let t = null_hash () in let t = null_hash () in
let segCountX2 = read_ushort b in let segCountX2 = read_ushort b in
@ -92,6 +99,7 @@ let read_format_4_encoding_table b =
let startCodes = Array.init segCount (fun _ -> read_ushort b) in let startCodes = Array.init segCount (fun _ -> read_ushort b) in
let idDelta = Array.init segCount (fun _ -> read_ushort b) in let idDelta = Array.init segCount (fun _ -> read_ushort b) in
let idRangeOffset = Array.init segCount (fun _ -> read_ushort b) in let idRangeOffset = Array.init segCount (fun _ -> read_ushort b) in
let glyphIndexArrayStart = b.input.pos_in () in
if !dbg then if !dbg then
begin begin
Printf.printf "segCount = %i, searchRange = %i, entrySelector = %i, rangeShift = %i\n" segCount searchRange entrySelector rangeShift; Printf.printf "segCount = %i, searchRange = %i, entrySelector = %i, rangeShift = %i\n" segCount searchRange entrySelector rangeShift;
@ -113,8 +121,10 @@ let read_format_4_encoding_table b =
if ro = 0 then if ro = 0 then
Hashtbl.add t c ((c + del) mod 65536) Hashtbl.add t c ((c + del) mod 65536)
else else
let sum = (c - sc) + del in let v = read_magic_formula b.input glyphIndexArrayStart seg segCount ro c sc in
() if v = 0
then Hashtbl.add t c ((c + del) mod 65536)
else Hashtbl.add t c ((v + del) mod 65536)
done done
done; done;
t t
@ -127,12 +137,12 @@ let print_encoding_table (table : (int, int) Hashtbl.t) =
Hashtbl.add unicodetable x.Cpdfunicodedata.code_value x.Cpdfunicodedata.character_name) Hashtbl.add unicodetable x.Cpdfunicodedata.code_value x.Cpdfunicodedata.character_name)
unicodedata; unicodedata;
let l = sort compare (list_of_hashtbl table) in let l = sort compare (list_of_hashtbl table) in
Printf.printf "There are %i characters in this font\n" (length l); Printf.printf "There are %i characters in this font\n" (length l)(*;
iter iter
(fun (c, gi) -> (fun (c, gi) ->
let str = Printf.sprintf "%04X" c in let str = Printf.sprintf "%04X" c in
Printf.printf "Char %s (%s) is at glyph index %i\n" str (Hashtbl.find unicodetable str) gi) Printf.printf "Char %s (%s) is at glyph index %i\n" str (Hashtbl.find unicodetable str) gi)
l l*)
let read_encoding_table fmt length version b = let read_encoding_table fmt length version b =
Printf.printf "********** format %i table has length, version %i, %i\n" fmt length version; Printf.printf "********** format %i table has length, version %i, %i\n" fmt length version;