100 lines
3.4 KiB
OCaml
100 lines
3.4 KiB
OCaml
(* Embed a font *)
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open Pdfutil
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(* For the first stage of our embedder, we are only allowing Latin, and we don't actually subset.
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a) Get a list of Unicode codepoints;
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b) See which of them are in the glyph list;
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c) See which of those are in (StdEncoding|MacRomanEncoding|WinAnsiEncoding), and get their codes;
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d) Build a font to do just those;
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e) We put missing glyph or similar for any character not in the encoding
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(* FUTURE *)
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1) Actually subset the font to save size
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2) Allow characters not in the standard encodings by builing one or more secondary subsets *)
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(*let () =
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iter
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(fun u ->
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Printf.printf "unicode %i --> " u;
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let glyphname = Hashtbl.find glyphlist_table [u] in
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Printf.printf "glyph name %s --> " glyphname;
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let pdfcode = Hashtbl.find encoding_table glyphname in
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Printf.printf "pdf code %i\n" pdfcode)
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unicodepoints *)
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let pdfcode_of_unicode_codepoint encoding_table glyphlist_table u =
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try
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Some (Hashtbl.find encoding_table (Hashtbl.find glyphlist_table [u]))
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with
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Not_found -> None
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let calc_accepted_unicodepoints encoding_table glyphlist_table codepoints =
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setify
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(option_map
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(fun u ->
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match
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pdfcode_of_unicode_codepoint encoding_table glyphlist_table u
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with
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| Some _ -> Some u
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| None -> None)
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codepoints)
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let fontnum = ref 0
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let basename () =
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incr fontnum;
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"AAAAA" ^ string_of_char (char_of_int (!fontnum + 65))
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let embed_truetype pdf ~fontfile ~fontname ~codepoints ~encoding =
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let glyphlist_table = Pdfglyphlist.reverse_glyph_hashes () in
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let encoding_table = Pdftext.reverse_table_of_encoding encoding in
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let accepted_unicodepoints =
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map
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(fun u ->
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(u, pdfcode_of_unicode_codepoint encoding_table glyphlist_table u))
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(calc_accepted_unicodepoints
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encoding_table glyphlist_table codepoints)
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in
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let f = Cpdftruetype.parse ~subset:accepted_unicodepoints fontfile ~encoding in
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let name_1 = basename () in
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let fontfile =
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let len = Pdfio.bytes_size fontfile in
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Pdf.Stream
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{contents =
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(Pdf.Dictionary
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[("/Length", Pdf.Integer len); ("/Length1", Pdf.Integer len)],
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Pdf.Got fontfile)}
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in
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let fontfile_num = Pdf.addobj pdf fontfile in
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let module TT = Cpdftruetype in
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let open Pdftext in
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let fontmetrics =
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let a = Array.make 256 0. in
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for x = f.TT.firstchar to f.TT.lastchar do
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a.(x) <- float_of_int (f.TT.widths.(x - f.TT.firstchar))
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done;
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a
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in
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SimpleFont
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{fonttype = Truetype;
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basefont = Printf.sprintf "/%s+%s" name_1 fontname;
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fontmetrics = Some fontmetrics;
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firstchar = f.TT.firstchar;
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lastchar = f.TT.lastchar;
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widths = f.TT.widths;
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fontdescriptor = Some
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{ascent = float_of_int f.TT.ascent;
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descent = float_of_int f.TT.descent;
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avgwidth = float_of_int f.TT.avgwidth;
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maxwidth = float_of_int f.TT.maxwidth;
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flags = f.TT.flags;
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italicangle = float_of_int f.TT.italicangle;
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capheight = float_of_int f.TT.capheight;
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xheight = float_of_int f.TT.xheight;
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stemv = float_of_int f.TT.stemv;
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fontbbox = (float_of_int f.TT.minx, float_of_int f.TT.miny,
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float_of_int f.TT.maxx, float_of_int f.TT.maxy);
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fontfile = Some (FontFile2 fontfile_num);
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charset = None;
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tounicode = None};
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encoding}
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