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cpdf-source
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This commit is contained in:
John Whitington 2022-09-26 19:12:44 +01:00
parent 1b4cbf3080
commit 96062b9fe7
1 changed files with 33 additions and 32 deletions
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65
cpdftruetype.ml
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@ -54,6 +54,9 @@ let read_f2dot14 b =
let discard_bytes b n = let discard_bytes b n =
for x = 1 to n do ignore (getval_31 b 8) done for x = 1 to n do ignore (getval_31 b 8) done
let pdf_unit unitsPerEm x =
int_of_float (float_of_int x *. 1000. /. float_of_int unitsPerEm)
let string_of_tag t = let string_of_tag t =
Printf.sprintf "%c%c%c%c" Printf.sprintf "%c%c%c%c"
(char_of_int (i32toi (Int32.shift_right t 24))) (char_of_int (i32toi (Int32.shift_right t 24)))
@ -139,20 +142,20 @@ let read_loca_table indexToLocFormat numGlyphs b =
fix_empties arr; arr fix_empties arr; arr
| _ -> raise (Pdf.PDFError "Unknown indexToLocFormat in read_loca_table") | _ -> raise (Pdf.PDFError "Unknown indexToLocFormat in read_loca_table")
let read_os2_table b blength = let read_os2_table unitsPerEm b blength =
let version = read_ushort b in let version = read_ushort b in
if !dbg then Printf.printf "OS/2 table blength = %i bytes, version number = %i\n" blength version; if !dbg then Printf.printf "OS/2 table blength = %i bytes, version number = %i\n" blength version;
let xAvgCharWidth = read_short b in let xAvgCharWidth = pdf_unit unitsPerEm (read_short b) in
discard_bytes b 64; (* discard 14 entries usWeightClass...fsLastCharIndex *) discard_bytes b 64; (* discard 14 entries usWeightClass...fsLastCharIndex *)
(* -- end of original OS/2 Version 0 Truetype table. Must check length before reading now. *) (* -- end of original OS/2 Version 0 Truetype table. Must check length before reading now. *)
let sTypoAscender = if blength > 68 then read_short b else 0 in let sTypoAscender = if blength > 68 then pdf_unit unitsPerEm (read_short b) else 0 in
let sTypoDescender = if blength > 68 then read_short b else 0 in let sTypoDescender = if blength > 68 then pdf_unit unitsPerEm (read_short b) else 0 in
discard_bytes b 6; (* discard sTypoLineGap...usWinDescent *) discard_bytes b 6; (* discard sTypoLineGap...usWinDescent *)
(* -- end of OpenType version 0 table *) (* -- end of OpenType version 0 table *)
discard_bytes b 8; (* discard ulCodePageRange1, ulCodePageRange2 *) discard_bytes b 8; (* discard ulCodePageRange1, ulCodePageRange2 *)
(* -- end of OpenType version 1 table *) (* -- end of OpenType version 1 table *)
let sxHeight = if version < 2 then 0 else read_short b in let sxHeight = if version < 2 then 0 else pdf_unit unitsPerEm (read_short b) in
let sCapHeight = if version < 2 then 0 else read_short b in let sCapHeight = if version < 2 then 0 else pdf_unit unitsPerEm (read_short b) in
(sTypoAscender, sTypoDescender, sCapHeight, sxHeight, xAvgCharWidth) (sTypoAscender, sTypoDescender, sCapHeight, sxHeight, xAvgCharWidth)
let read_post_table b = let read_post_table b =
@ -173,7 +176,7 @@ let calculate_limits subset =
if subset = [] then (0, 255) else if subset = [] then (0, 255) else
extremes (sort compare subset) extremes (sort compare subset)
let calculate_stemv () = 80 let calculate_stemv () = 0
let read_hhea_table b = let read_hhea_table b =
discard_bytes b 34; discard_bytes b 34;
@ -191,9 +194,6 @@ let unicode_codepoint_of_pdfcode encoding_table glyphlist_table p =
with with
Not_found -> 0 Not_found -> 0
let pdf_unit unitsPerEm x =
int_of_float (float_of_int x *. 1000. /. float_of_int unitsPerEm)
let calculate_widths unitsPerEm encoding firstchar lastchar subset (cmapdata : (int, int) Hashtbl.t) (hmtxdata : int array) = let calculate_widths unitsPerEm encoding firstchar lastchar subset (cmapdata : (int, int) Hashtbl.t) (hmtxdata : int array) =
if lastchar < firstchar then failwith "lastchar < firschar" else if lastchar < firstchar then failwith "lastchar < firschar" else
if !dbg then List.iter (fun (a, b) -> Printf.printf "%i -> %i\n" a b) (sort compare (list_of_hashtbl cmapdata)); if !dbg then List.iter (fun (a, b) -> Printf.printf "%i -> %i\n" a b) (sort compare (list_of_hashtbl cmapdata));
@ -215,8 +215,8 @@ let calculate_widths unitsPerEm encoding firstchar lastchar subset (cmapdata : (
pdf_unit unitsPerEm width pdf_unit unitsPerEm width
with e -> if !dbg then Printf.printf "no width for %i\n" code; 0) with e -> if !dbg then Printf.printf "no width for %i\n" code; 0)
let calculate_maxwidth hmtxdata = let calculate_maxwidth unitsPerEm hmtxdata =
hd (sort (fun a b -> compare b a) (Array.to_list hmtxdata)) pdf_unit unitsPerEm (hd (sort (fun a b -> compare b a) (Array.to_list hmtxdata)))
let parse ?(subset=[]) data ~encoding = let parse ?(subset=[]) data ~encoding =
let subset = map fst subset in let subset = map fst subset in
@ -240,6 +240,24 @@ let parse ?(subset=[]) data ~encoding =
tag (string_of_tag tag) checkSum offset ttlength; tag (string_of_tag tag) checkSum offset ttlength;
tables =| (tag, checkSum, offset, ttlength); tables =| (tag, checkSum, offset, ttlength);
done; done;
let headoffset, headlength =
match keep (function (t, _, _, _) -> string_of_tag t = "head") !tables with
| (_, _, o, l)::_ -> o, l
| [] -> raise (Pdf.PDFError "No maxp table found in TrueType font")
in
let b = mk_b (i32toi headoffset) in
discard_bytes b 18;
let unitsPerEm = read_ushort b in
discard_bytes b 16;
let minx = pdf_unit unitsPerEm (read_fword b) in
let miny = pdf_unit unitsPerEm (read_fword b) in
let maxx = pdf_unit unitsPerEm (read_fword b) in
let maxy = pdf_unit unitsPerEm (read_fword b) in
discard_bytes b 6;
let indexToLocFormat = read_short b in
let _ (*glyphDataFormat*) = read_short b in
if !dbg then Printf.printf "head table: indexToLocFormat is %i\n" indexToLocFormat;
if !dbg then Printf.printf "box %i %i %i %i\n" minx miny maxx maxy;
let os2 = let os2 =
match keep (function (t, _, _, _) -> string_of_tag t = "OS/2") !tables with match keep (function (t, _, _, _) -> string_of_tag t = "OS/2") !tables with
| (_, _, o, l)::_ -> Some (o, l) | (_, _, o, l)::_ -> Some (o, l)
@ -248,7 +266,7 @@ let parse ?(subset=[]) data ~encoding =
let ascent, descent, capheight, xheight, avgwidth = let ascent, descent, capheight, xheight, avgwidth =
match os2 with match os2 with
| None -> raise (Pdf.PDFError "No os/2 table found in truetype font") | None -> raise (Pdf.PDFError "No os/2 table found in truetype font")
| Some (o, l) -> let b = mk_b (i32toi o) in read_os2_table b (i32toi l) | Some (o, l) -> let b = mk_b (i32toi o) in read_os2_table unitsPerEm b (i32toi l)
in in
let italicangle = let italicangle =
match keep (function (t, _, _, _) -> string_of_tag t = "post") !tables with match keep (function (t, _, _, _) -> string_of_tag t = "post") !tables with
@ -299,24 +317,7 @@ let parse ?(subset=[]) data ~encoding =
let major, minor = read_fixed b in let major, minor = read_fixed b in
let numGlyphs = read_ushort b in let numGlyphs = read_ushort b in
if !dbg then Printf.printf "maxp table version %i.%i: This font has %i glyphs\n" major minor numGlyphs; if !dbg then Printf.printf "maxp table version %i.%i: This font has %i glyphs\n" major minor numGlyphs;
let headoffset, headlength =
match keep (function (t, _, _, _) -> string_of_tag t = "head") !tables with
| (_, _, o, l)::_ -> o, l
| [] -> raise (Pdf.PDFError "No maxp table found in TrueType font")
in
let b = mk_b (i32toi headoffset) in
discard_bytes b 18;
let unitsPerEm = read_ushort b in
discard_bytes b 16;
let minx = read_fword b in
let miny = read_fword b in
let maxx = read_fword b in
let maxy = read_fword b in
discard_bytes b 6;
let indexToLocFormat = read_short b in
let _ (*glyphDataFormat*) = read_short b in
if !dbg then Printf.printf "head table: indexToLocFormat is %i\n" indexToLocFormat;
if !dbg then Printf.printf "box %i %i %i %i\n" minx miny maxx maxy;
let locaoffset, localength = let locaoffset, localength =
match keep (function (t, _, _, _) -> string_of_tag t = "loca") !tables with match keep (function (t, _, _, _) -> string_of_tag t = "loca") !tables with
| (_, _, o, l)::_ -> o, l | (_, _, o, l)::_ -> o, l
@ -335,7 +336,7 @@ let parse ?(subset=[]) data ~encoding =
| [] -> raise (Pdf.PDFError "No hmtx table found in TrueType font") | [] -> raise (Pdf.PDFError "No hmtx table found in TrueType font")
in in
let widths = calculate_widths unitsPerEm encoding firstchar lastchar subset !glyphcodes hmtxdata in let widths = calculate_widths unitsPerEm encoding firstchar lastchar subset !glyphcodes hmtxdata in
let maxwidth = calculate_maxwidth hmtxdata in let maxwidth = calculate_maxwidth unitsPerEm hmtxdata in
let stemv = calculate_stemv () in let stemv = calculate_stemv () in
let b = mk_b (i32toi locaoffset) in let b = mk_b (i32toi locaoffset) in
let offsets = read_loca_table indexToLocFormat numGlyphs b in let offsets = read_loca_table indexToLocFormat numGlyphs b in