cpdf-source/cpdfembed.ml

95 lines
3.1 KiB
OCaml

(* Embed a font *)
open Pdfutil
type t = Pdftext.font list * (int, int * int) Hashtbl.t (* Table returns font number and charcode for given unicode codepoint *)
type cpdffont =
PreMadeFontPack of t
| EmbedInfo of {fontfile : Pdfio.bytes; fontname : string; encoding : Pdftext.encoding}
| ExistingNamedFont
let fontpack_of_standardfont sf =
let te = Pdftext.text_extractor_of_font_real sf in
let table = null_hash () in
for x = 0 to 255 do
let u = hd (Pdftext.codepoints_of_text te (string_of_char (char_of_int x))) in
Hashtbl.add table u (0, x)
done;
([sf], table)
let get_char (fonts, table) u =
match Hashtbl.find table u with
| (n, charcode) -> Some (charcode, n, List.nth fonts n)
| exception Not_found -> None
let fontnum = ref 0
let basename () =
incr fontnum;
"AAAAA" ^ string_of_char (char_of_int (!fontnum + 65))
let make_single_font ~fontname ~encoding pdf f =
let name_1 = basename () in
let module TT = Cpdftruetype in
let fontfile =
let len = Pdfio.bytes_size f.TT.subset_fontfile in
Pdf.Stream
{contents =
(Pdf.Dictionary
[("/Length", Pdf.Integer len); ("/Length1", Pdf.Integer len)],
Pdf.Got f.TT.subset_fontfile)}
in
let fontfile_num = Pdf.addobj pdf fontfile in
let open Pdftext in
let fontmetrics =
let a = Array.make 256 0. in
for x = f.TT.firstchar to f.TT.lastchar do
a.(x) <- float_of_int (f.TT.widths.(x - f.TT.firstchar))
done;
a
in
(f.TT.subset,
SimpleFont
{fonttype = Truetype;
basefont = Printf.sprintf "/%s+%s" name_1 fontname;
fontmetrics = Some fontmetrics;
firstchar = f.TT.firstchar;
lastchar = f.TT.lastchar;
widths = f.TT.widths;
fontdescriptor = Some
{ascent = float_of_int f.TT.ascent;
descent = float_of_int f.TT.descent;
avgwidth = float_of_int f.TT.avgwidth;
maxwidth = float_of_int f.TT.maxwidth;
flags = f.TT.flags;
italicangle = float_of_int f.TT.italicangle;
capheight = float_of_int f.TT.capheight;
xheight = float_of_int f.TT.xheight;
stemv = float_of_int f.TT.stemv;
fontbbox = (float_of_int f.TT.minx, float_of_int f.TT.miny,
float_of_int f.TT.maxx, float_of_int f.TT.maxy);
fontfile = Some (FontFile2 fontfile_num);
charset = None;
tounicode = f.TT.tounicode};
encoding})
let make_fontpack_hashtable fs =
let indexes = indx0 fs in
let table = null_hash () in
iter2
(fun i (subset, f) ->
let charcode_extractor = Pdftext.charcode_extractor_of_font_real f in
iter
(fun u ->
match charcode_extractor u with
| Some x -> Hashtbl.add table u (i, x)
| None -> Printf.printf "charcode_extractor could not find char in make_fontpack_hashtable\n")
subset)
indexes fs;
table
let embed_truetype pdf ~fontfile ~fontname ~codepoints ~encoding =
let found_codepoints, fs = Cpdftruetype.parse ~subset:codepoints fontfile encoding in
let subsets_and_their_fonts = map (make_single_font ~fontname ~encoding pdf) fs in
(map snd subsets_and_their_fonts, make_fontpack_hashtable subsets_and_their_fonts)