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Change interface to subsetting for .notdef

This commit is contained in:
John Whitington 2023-07-06 13:52:13 +01:00
parent a63cbd66b8
commit 344e4d6266
3 changed files with 68 additions and 104 deletions
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4
cpdfembed.ml
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@ -89,6 +89,6 @@ let make_fontpack_hashtable fs =
table table
let embed_truetype pdf ~fontfile ~fontname ~codepoints ~encoding = let embed_truetype pdf ~fontfile ~fontname ~codepoints ~encoding =
let fs = Cpdftruetype.parse ~subset:codepoints fontfile encoding in 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 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) (map snd subsets_and_their_fonts, make_fontpack_hashtable subsets_and_their_fonts)

166
cpdftruetype.ml
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@ -2,16 +2,13 @@
open Pdfutil open Pdfutil
open Pdfio open Pdfio
(* FIXME Missing characters in Bear example *) (* FIXME Add suport for composite glyphs *)
(* FIXME No need for bitstream - everything is byte based, so we can use a normal input *) (* FIXME No need for bitstream - everything is byte based, so we can use a normal input *)
(* FIXME Don't create a second font unless we have to *)
(* FIXME Create third, fourth etc. font when we need to *)
(* FIXME Get rid of double-calling of this code to 1) make font then 2) collect chars then 3) subset it i.e the subset = [] stuff *) (* FIXME Get rid of double-calling of this code to 1) make font then 2) collect chars then 3) subset it i.e the subset = [] stuff *)
(* FIXME Check WinAnsiEncoding actually does the right thing, and covers all possible characters in that set *)
(* FIXME Subset names better than AAAAAB *) (* FIXME Subset names better than AAAAAB *)
(* FIXME Rationalise padding code *)
(* FIXME Document the mechanisms we use *)
(* FIXME Proper table choice mechanism *) (* FIXME Proper table choice mechanism *)
(* FIXME All uses - add text / drawing / texttopdf / table of contents *)
(* FIXME Work across AND? *)
let dbg = ref true let dbg = ref true
let _ = let _ =
@ -86,6 +83,12 @@ 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 padding n =
if n mod 4 = 0 then 0 else 4 - n mod 4
let padding32 n =
i32ofi (padding (i32toi n))
let pdf_unit unitsPerEm x = let pdf_unit unitsPerEm x =
int_of_float (float_of_int x *. 1000. /. float_of_int unitsPerEm +. 0.5) int_of_float (float_of_int x *. 1000. /. float_of_int unitsPerEm +. 0.5)
@ -100,71 +103,38 @@ let read_format_6_encoding_table b =
let firstCode = read_ushort b in let firstCode = read_ushort b in
let entryCount = read_ushort b in let entryCount = read_ushort b in
let t = null_hash () in let t = null_hash () in
try for x = firstCode to firstCode + entryCount - 1 do
for x = firstCode to firstCode + entryCount - 1 do Hashtbl.add t x (read_ushort b)
Hashtbl.add t x (read_ushort b) done;
done; t
t
with
e -> failwith ("bad format 6 table: " ^ Printexc.to_string e ^ "\n")
let read_magic_formula b glyphIndexArrayStart seg segCount ro c sc = let read_magic_formula b glyphIndexArrayStart seg segCount ro c sc =
if !dbg then Printf.printf "read_magic_formula: seg = %i, setCount = %i, ro = %i, c = %i, sc = %i\n" seg segCount ro c sc; b.input.seek_in (glyphIndexArrayStart + (seg - segCount + ro / 2 + (c - sc)) * 2);
let position = seg - segCount + ro / 2 + (c - sc) in b.bit <- 0;
if !dbg then Printf.printf "position is %i\n" position; b.bitsread <- 0;
b.input.seek_in (glyphIndexArrayStart + position * 2); b.currbyte <- 0;
b.bit <- 0; read_short b
b.bitsread <- 0;
b.currbyte <- 0;
read_short b
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
let segCount = segCountX2 / 2 in let segCount = segCountX2 / 2 in
let searchRange = read_ushort b in let _ (* searchRange *) = read_ushort b in
let entrySelector = read_ushort b in let _ (* entrySelector *) = read_ushort b in
let rangeShift = read_ushort b in let _ (* rangeShift *) = read_ushort b in
let endCodes = Array.init segCount (fun _ -> read_ushort b) in let endCodes = Array.init segCount (fun _ -> read_ushort b) in
let _ (* reservedPad *) = read_ushort b in let _ (* reservedPad *) = read_ushort b in
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 let glyphIndexArrayStart = b.input.pos_in () in
if !dbg then Printf.printf "glyphIndexArrayStart = %i\n" glyphIndexArrayStart;
if !dbg then
begin
Printf.printf "segCount = %i, searchRange = %i, entrySelector = %i, rangeShift = %i\n" segCount searchRange entrySelector rangeShift;
Printf.printf "endCodes\n";
print_ints (Array.to_list endCodes);
Printf.printf "startCodes\n";
print_ints (Array.to_list startCodes);
Printf.printf "idDelta\n";
print_ints (Array.to_list idDelta);
Printf.printf "idRangeOffset\n";
print_ints (Array.to_list idRangeOffset);
end;
for seg = 0 to segCount - 1 do for seg = 0 to segCount - 1 do
if !dbg then Printf.printf "Segment %i\n" seg; let ec, sc, del, ro = endCodes.(seg), startCodes.(seg), idDelta.(seg), idRangeOffset.(seg) in
let ec = endCodes.(seg) in
let sc = startCodes.(seg) in
let del = idDelta.(seg) in
let ro = idRangeOffset.(seg) in
if !dbg then Printf.printf "sc = %i, ec = %i, del = %i, ro = %i\n" sc ec del ro;
for c = sc to ec do for c = sc to ec do
if !dbg then Printf.printf "Code %i\n" c;
if c != 0xFFFF then if c != 0xFFFF then
if ro = 0 then if ro = 0 then Hashtbl.add t c ((c + del) mod 65536) else
Hashtbl.add t c ((c + del) mod 65536)
else
begin
if !dbg then flprint "format 4 magic required\n";
let v = read_magic_formula b glyphIndexArrayStart seg segCount ro c sc in let v = read_magic_formula b glyphIndexArrayStart seg segCount ro c sc in
if !dbg then Printf.printf "Value %i returned\n" v; Hashtbl.add t c (((if v = 0 then c else v) + del) mod 65536)
if v = 0
then Hashtbl.add t c (let r = (c + del) mod 65536 in if !dbg then Printf.printf "into hash %i\n" r; r)
else Hashtbl.add t c (let r = (v + del) mod 65536 in if !dbg then Printf.printf "into hash %i\n" r; r)
end
done done
done; done;
t t
@ -245,25 +215,21 @@ let read_hhea_table b =
read_ushort b (* numOfLongHorMetrics *) read_ushort b (* numOfLongHorMetrics *)
let read_hmtx_table numOfLongHorMetrics b = let read_hmtx_table numOfLongHorMetrics b =
Printf.printf "**** numOfLongHorMetrics = %i\n" numOfLongHorMetrics;
let r =
Array.init Array.init
numOfLongHorMetrics numOfLongHorMetrics
(fun _ -> let r = read_ushort b in ignore (read_short b); r) (fun _ -> let r = read_ushort b in ignore (read_short b); r)
in
for x = 0 to numOfLongHorMetrics - 1 do
Printf.printf "longHorMetrics %i = %i\n" x r.(x)
done;
r
let write_loca_table subset cmap indexToLocFormat bs loca = let write_loca_table subset cmap indexToLocFormat bs loca =
let locnums = null_hash () in let locnums = null_hash () in
Hashtbl.add locnums 0 (); (* .notdef *) Hashtbl.add locnums 0 (); (* .notdef *)
iter iter
(fun u -> (fun u ->
let locnum = Hashtbl.find cmap u in try
let locnum = Hashtbl.find cmap u in
if !dbg then Printf.printf "write_loca_table: Unicode U+%04X is at location number %i\n" u locnum; if !dbg then Printf.printf "write_loca_table: Unicode U+%04X is at location number %i\n" u locnum;
Hashtbl.add locnums locnum ()) Hashtbl.add locnums locnum ()
with
Not_found -> ())
subset; subset;
let len = ref 0 in let len = ref 0 in
let write_entry loc position = let write_entry loc position =
@ -294,8 +260,7 @@ let write_loca_table subset cmap indexToLocFormat bs loca =
else else
write_entry loc off) write_entry loc off)
pairs; pairs;
let padding = if !len mod 4 = 0 then 0 else 4 - !len mod 4 in for x = 1 to padding !len do putval bs 8 0l done
for x = 1 to padding do putval bs 8 0l done
(* Write the notdef glyf, and any others in the subset *) (* Write the notdef glyf, and any others in the subset *)
let write_glyf_table subset cmap bs mk_b glyfoffset loca = let write_glyf_table subset cmap bs mk_b glyfoffset loca =
@ -304,9 +269,12 @@ let write_glyf_table subset cmap bs mk_b glyfoffset loca =
Hashtbl.add locnums 0 (); (* .notdef *) Hashtbl.add locnums 0 (); (* .notdef *)
iter iter
(fun u -> (fun u ->
let locnum = Hashtbl.find cmap u in try
if !dbg then Printf.printf "write_glyf_table: Unicode U+%04X is at location number %i\n" u locnum; let locnum = Hashtbl.find cmap u in
Hashtbl.add locnums locnum ()) if !dbg then Printf.printf "write_glyf_table: Unicode U+%04X is at location number %i\n" u locnum;
Hashtbl.add locnums locnum ()
with
Not_found -> ())
subset; subset;
let locnums = sort compare (map fst (list_of_hashtbl locnums)) in let locnums = sort compare (map fst (list_of_hashtbl locnums)) in
if !dbg then (Printf.printf "We want glyfs for locations: "; iter (Printf.printf "%i ") locnums; Printf.printf "\n"); if !dbg then (Printf.printf "We want glyfs for locations: "; iter (Printf.printf "%i ") locnums; Printf.printf "\n");
@ -319,14 +287,13 @@ let write_glyf_table subset cmap bs mk_b glyfoffset loca =
for x = 1 to i32toi l do putval bs 8 (getval_32 b 8) done for x = 1 to i32toi l do putval bs 8 (getval_32 b 8) done
in in
iter (fun (a, b) -> write_bytes bs a (i32sub b a)) byteranges; iter (fun (a, b) -> write_bytes bs a (i32sub b a)) byteranges;
let padding = if i32toi len mod 4 = 0 then 0 else 4 - i32toi len mod 4 in for x = 1 to padding (i32toi len) do putval bs 8 0l done;
for x = 1 to padding do putval bs 8 0l done;
len len
let write_cmap_table subset cmap bs = let write_cmap_table subset cmap bs =
if !dbg then Printf.printf "***write_cmap_table\n"; if !dbg then Printf.printf "***write_cmap_table\n";
let glyphindexes = let glyphindexes =
map (Hashtbl.find cmap) subset map (fun code -> try Hashtbl.find cmap code with Not_found -> 0) subset
in in
putval bs 16 0l; (* table version number *) putval bs 16 0l; (* table version number *)
putval bs 16 1l; (* number of encoding tables *) putval bs 16 1l; (* number of encoding tables *)
@ -340,8 +307,7 @@ let write_cmap_table subset cmap bs =
putval bs 16 (i32ofi (length glyphindexes)); (* number of character codes *) putval bs 16 (i32ofi (length glyphindexes)); (* number of character codes *)
iter (fun gi -> putval bs 16 (i32ofi gi)) glyphindexes; (* glyph indexes *) iter (fun gi -> putval bs 16 (i32ofi gi)) glyphindexes; (* glyph indexes *)
let len = i32ofi (22 + 2 * length glyphindexes) in let len = i32ofi (22 + 2 * length glyphindexes) in
let padding = if i32toi len mod 4 = 0 then 0 else 4 - i32toi len mod 4 in for x = 1 to padding (i32toi len) do putval bs 8 0l done;
for x = 1 to padding do putval bs 8 0l done;
len len
let calculate_widths unitsPerEm encoding firstchar lastchar subset cmapdata hmtxdata = let calculate_widths unitsPerEm encoding firstchar lastchar subset cmapdata hmtxdata =
@ -352,7 +318,7 @@ let calculate_widths unitsPerEm encoding firstchar lastchar subset cmapdata hmtx
with with
Not_found -> 0 Not_found -> 0
in in
if lastchar < firstchar then failwith "lastchar < firstchar" else if lastchar < firstchar then Cpdferror.error "lastchar < firstchar" 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));*)
let encoding_table = Pdftext.table_of_encoding encoding in let encoding_table = Pdftext.table_of_encoding encoding in
let glyphlist_table = Pdfglyphlist.glyph_hashes () in let glyphlist_table = Pdfglyphlist.glyph_hashes () in
@ -378,21 +344,19 @@ let calculate_width_higher unitsPerEm firstchar lastchar subset cmapdata hmtxdat
Array.init Array.init
(lastchar - firstchar + 1) (lastchar - firstchar + 1)
(fun pos -> (fun pos ->
let glyphnum = Hashtbl.find cmapdata subset.(pos) in try
if !dbg then Printf.printf "glyph number %i --> " glyphnum; let glyphnum = Hashtbl.find cmapdata subset.(pos) in
Printf.printf "hmtxdata length = %i\n" (Array.length hmtxdata); if !dbg then Printf.printf "glyph number %i --> " glyphnum;
(* If it fails, we are a monospaced font. Pick the last hmtxdata entry. *) (* If it fails, we are a monospaced font. Pick the last hmtxdata entry. *)
let width = try hmtxdata.(glyphnum) with _ -> hmtxdata.(Array.length hmtxdata - 1) in let width = try hmtxdata.(glyphnum) with _ -> hmtxdata.(Array.length hmtxdata - 1) in
if !dbg then Printf.printf "width %i\n" width; if !dbg then Printf.printf "width %i\n" width;
pdf_unit unitsPerEm width) pdf_unit unitsPerEm width
with
Not_found -> 0)
let calculate_maxwidth unitsPerEm hmtxdata = let calculate_maxwidth unitsPerEm hmtxdata =
pdf_unit unitsPerEm (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 padword n =
let n = i32toi n in
let r = n + (if n mod 4 = 0 then 0 else 4 - n mod 4) in
i32ofi r
let fonumr = ref (-1) let fonumr = ref (-1)
@ -425,14 +389,14 @@ let subset_font major minor tables indexToLocFormat subset encoding cmap loca mk
let newlen = write_glyf_table subset cmap bs mk_b glyfoffset loca in let newlen = write_glyf_table subset cmap bs mk_b glyfoffset loca in
let paddedlen = i32ofi (bytes_size (bytes_of_write_bitstream bs)) in let paddedlen = i32ofi (bytes_size (bytes_of_write_bitstream bs)) in
if !dbg then Printf.printf "new glyf table length = %li\n" newlen; if !dbg then Printf.printf "new glyf table length = %li\n" newlen;
glyf_table_size_reduction := i32sub (padword ttlength) paddedlen; glyf_table_size_reduction := i32sub (i32add ttlength (padding32 ttlength)) paddedlen;
newlen newlen
else if string_of_tag tag = "cmap" && subset <> [] && encoding = Pdftext.ImplicitInFontFile then else if string_of_tag tag = "cmap" && subset <> [] && encoding = Pdftext.ImplicitInFontFile then
let bs = make_write_bitstream () in let bs = make_write_bitstream () in~/Dropbox/cpdfwork/ttf/10000fonts/AEROPLAN.TTF
let newlen = write_cmap_table subset cmap bs in let newlen = write_cmap_table subset cmap bs in
let paddedlen = i32ofi (bytes_size (bytes_of_write_bitstream bs)) in let paddedlen = i32ofi (bytes_size (bytes_of_write_bitstream bs)) in
if !dbg then Printf.printf "new cmap table length = %li\n" newlen; if !dbg then Printf.printf "new cmap table length = %li\n" newlen;
cmap_table_size_reduction := i32sub (padword ttlength) paddedlen; cmap_table_size_reduction := i32sub (i32add ttlength (padding32 ttlength)) paddedlen;
newlen newlen
else else
ttlength ttlength
@ -485,7 +449,7 @@ let subset_font major minor tables indexToLocFormat subset encoding cmap loca mk
raise Exit raise Exit
end end
done; done;
failwith "failed to find table" Cpdferror.error "failed to find table"
with with
Exit -> (!off, !len) Exit -> (!off, !len)
end end
@ -533,7 +497,7 @@ let find_main encoding subset =
(fun u -> try ignore (Hashtbl.find encoding_table u); true with Not_found -> false) (fun u -> try ignore (Hashtbl.find encoding_table u); true with Not_found -> false)
subset*) subset*)
let parse ?(subset=[]) data encoding = let parse ~subset data encoding =
if !dbg then if !dbg then
begin begin
Printf.printf "********Cpdftruetype.parse SUBSET is "; Printf.printf "********Cpdftruetype.parse SUBSET is ";
@ -617,14 +581,14 @@ let parse ?(subset=[]) data encoding =
let subtable_offset = read_ulong b in let subtable_offset = read_ulong b in
if !dbg then Printf.printf "subtable %i. platform_id = %i, encoding_id = %i, subtable_offset = %li\n" if !dbg then Printf.printf "subtable %i. platform_id = %i, encoding_id = %i, subtable_offset = %li\n"
x platform_id encoding_id subtable_offset; x platform_id encoding_id subtable_offset;
let b = mk_b (i32toi cmapoffset + i32toi subtable_offset) in let b = mk_b (i32toi cmapoffset + i32toi subtable_offset) in
let fmt = read_ushort b in let fmt = read_ushort b in
let lngth = read_ushort b in let lngth = read_ushort b in
let version = read_ushort b in let version = read_ushort b in
if !dbg then Printf.printf "subtable has format %i, length %i, version %i\n" fmt lngth version; if !dbg then Printf.printf "subtable has format %i, length %i, version %i\n" fmt lngth version;
let got_glyphcodes = read_encoding_table fmt lngth version b in let got_glyphcodes = read_encoding_table fmt lngth version b in
if fmt = 4 then print_encoding_table 4 got_glyphcodes; (*if fmt = 4 then print_encoding_table 4 got_glyphcodes;*)
if fmt = 4 then Hashtbl.iter (Hashtbl.add !glyphcodes) got_glyphcodes if fmt = 4 then Hashtbl.iter (Hashtbl.add !glyphcodes) got_glyphcodes
done; done;
end; end;
let maxpoffset, maxplength = let maxpoffset, maxplength =
@ -715,8 +679,8 @@ let parse ?(subset=[]) data encoding =
Printf.printf "\nHigher subset:\n"; Printf.printf "\nHigher subset:\n";
debug_t two; debug_t two;
write_font "two.ttf" two.subset_fontfile;*) write_font "two.ttf" two.subset_fontfile;*)
[one; two] (subset, [one; two])
let parse ?(subset=[]) data encoding = (*let parse ~subset data encoding =
try parse ~subset data encoding with try parse ~subset data encoding with
e -> raise (Cpdferror.error ("Failed to parse TrueType font: " ^ Printexc.to_string e)) e -> raise (Cpdferror.error ("Failed to parse TrueType font: " ^ Printexc.to_string e))*)

2
cpdftruetype.mli
View File

@ -27,4 +27,4 @@ type t =
additional characters in the font. For subsetting, or to return a full additional characters in the font. For subsetting, or to return a full
font-pack, you should supply a subset (a list of unicode codepoints whose font-pack, you should supply a subset (a list of unicode codepoints whose
corresponding glyphs are required). *) corresponding glyphs are required). *)
val parse : ?subset:int list -> Pdfio.bytes -> Pdftext.encoding -> t list val parse : subset:int list -> Pdfio.bytes -> Pdftext.encoding -> int list * t list