Category: Linux

This will be a fairly technical post, so if you’re not in the mood or don’t know what a bash script or Ubuntu is, this might not be the post for you.

Useful Ubuntu packages: fontforge (install with apt-get install fontforge)
Useful PERL Libraries: Mac::AppleSingleDouble (install with cpan install Mac::AppleSingleDouble)

First; Mac OS X stores the actual font data as a secondary data stream / file that’s attached to the actual font that the user can see. This requires the user sending the font to zip the contents before sending, so that both files can be included. The interesting files will be located in the __MACOSX folder and not in the actual folder containing the font (this folder will only contain the files with a 0 byte size). These files in __MACOSX will be the ones we’re going to town with.

Doing “file” on any file from this directory will probably yield “AppleDouble encoded Macintosh file”.

You can extract the actual contents of these files with the following awesome PERL snippet from a post at superuser:

perl -MMac::AppleSingleDouble -e 'for(@ARGV) {
    $a = new Mac::AppleSingleDouble($_);
    if(open $f, ">", $_.".rsrc") {
        binmode $f;
        print $f $a->get_entry(2);
        close $f;
    }
}' FILENAME_HERE

This will create a FILENAME_HERE.rsrc file in the current directory. This is the actual file that were stored as side channel data, without the other metadata associated with it.

In my case the resulting file was indicated to be a “Mac OSX datafork font, PostScript” by “file”, and after this I tried two things – one worked, one failed.

The first that failed:
In the archive there was also two other small datafiles. I tried extracting these and renaming the files to .pfb and .pfm (to use them as PostScript Type 1 fonts on Windows). This did not work. I’m not really sure where this failed at the moment, as I didn’t really feel like digging myself further down into the Windows Font subsystem. I also tried running the files through fondu, but didn’t get anywhere (it seems I really should run this under Mac OS X to be able to generate the proper .pfb and .afm files).

The second that worked (sort of):
fontforge is able to import a PostScript/dfont file without the associated metadata file. This might break kerning and a few other issues (fontforge will guess, so it won’t be half-bad), but will give you a resulting TTF file that actually works and can be used for most of the things that you’d use the font for. It was good enough for our use. Simply start fontforge, open the file and select file -> Generate Font afterwards.

Hopefully I won’t have to do this any time soon again. Fonts. Prrffftttt.