Unable to load AP-OTF fonts (DecodingError NotARealInDict)

[ghaaj]

Environment: WSL2 Ubuntu 24.04

When trying to load Morisawa's AP-OTF-*.otf fonts, otfedcli throws the following error:

$ dune exec otfedcli ~/.satysfi/dist/fonts/MorisawaFonts/AP-OTF-RyuminPr6N-Regular.otf tables
(DecodingError NotARealInDict)

~/.satysfi/dist/fonts/MorisawaFonts is a symlink to %LOCALAPPDATA%\Microsoft\Windows\Fonts\MorisawaFonts in the mounted Windows file system.

Given the contents of dictmap, it appears that this error is thrown in get_real_with_default due to the value for LongKey(31) being [Integer(1)].

otfed/src/decodeCff.ml

Lines 62 to 67 in c11304c

	let get_real_with_default dictmap key default =
	let open ResultMonad in
	match DictMap.find_opt key dictmap with
	| Some(Real(r) :: []) -> return r
	| Some(_) -> err Error.NotARealInDict
	| None -> return default

I'm not sure why cid_font_version needs to be a float. From reading the spec it seems to me that CIDFontVersion is defined as an integer. Page 22 of the document says:

The %%Version comment provides the version number of this CIDFont file.
This number is an integer; Adobe recommends that it be the same number that is defined for /CIDFontVersion later in the file.
%%Version: 1

Please note that I'm a layman in terms of typography. Thank you.

[gfngfn]

Thank you for the report! This is a great catch.

The referenced spec is actually “Technical Note #5176: The Compact Font Format Specification, Version 1.0”.

I haven't encountered that error so far, but it seems that this was by chance; according to Table 10 on page 16, CIDFontVersion must be a number, i.e., it can be an integer as well as a (decimally encoded) real number:

I should thereby fix this so that otfed can decode versions encoded as integers.

[gfngfn]

Side note: I can access RyuminPr6N-Light via Adobe CC, so I checked the CIDFontVersion of the font file. It was 1.2:

$ otfedcli 26143.otf cff_top 
CFF Top DICT:
  { font_name = "RyuminPr6N-Light"; version = None;
    notice =
    (Some "(c) Copyright 1989-2007 Adobe Systems Incorporated. All rights reserved. Ryumin Light is a trademark of Morisawa Inc.");
    copyright =
    (Some "Font (c) Copyright 2007 Morisawa Inc. All rights reserved.");
    full_name = (Some "Ryumin Pr6N OpenType Light");
    family_name = (Some "Ryumin Pr6N OpenType"); weight = (Some "Light");
    is_fixed_pitch = false; italic_angle = 0; underline_position = -100;
    underline_thickness = 50; paint_type = 0;
    font_bbox = { x_min = -280; y_min = -294; x_max = 1134; y_max = 1160 };
    stroke_width = 0;
    cid_info =
    (Some { registry = "Adobe"; ordering = "Japan1"; supplement = 6;
            cid_font_version = 1.2; cid_font_revision = 0; cid_font_type = 0;
            cid_count = 23058 });
    number_of_glyphs = 23058 }

[gfngfn]

The PR #62 will remedy this issue. Thank you!

[gfngfn]

I've reflected the change above in the master branch of SATySFi: gfngfn/SATySFi#466

[ghaaj]

Thank you for your prompt action!