xkcd-Script: generate with FontForge official package

[dummy-index]

Hello.
I try to generate xkcd-script without installing any compiler, and it seems to almost succesful in sense of binary reproduction. But a mystery appears.

Procedure

pt1, pt2: run with Anaconda python (python 3.6)

• install numpy, scipy, skimage by conda
• install parse.py by pip

pt3, pt4, pt5: run with ffpython.exe in FontForgeBuilds (Windows Installer)

• FontForgeBuilds bundle ffpython and potrace
• install parse.py by hand (copy it into FontForgeBuilds/lib/python*.*/site-packages/)
• I tested with FontForge-2016-10-04-Windows.exe, FontForge-2017-07-31-Windows-r2.exe, FontForge-2019-04-13-Windows.exe, FontForge-2020-03-14-Windows.exe

code fix needed: #35

Mystery

I generate fonts with 4 versions of FontForgeBuilds.
xkcd-script-withffpython.zip
Here *.otf are generated by pt5_gen_reprod_font.py with changes:

- ttf = os.path.join(base, 'xkcd-script.ttf')
+ ttf = os.path.join(base, 'xkcd-script.otf')

And I checked these fonts with ttx (fonttools), I found that most similar to the latest xkcd-script.ttf is xkcd-script-ff20161014.otf. ...Somehow the latest xkcd-script.ttf has CFF table (cubic outline), every ffpython output the ttf with glyf table (quadratic outline).
I was convinced that font.generate('foobar.ttf') always makes outline quadratic... but why?

2020/10/25
To get ttf with CFF table, I want a modify:
- font.generate(ttf)
+ otf = os.path.join(base, 'xkcd-script-ttf.otf')
+ font.generate(otf)
+ shutil.move(otf, ttf)

2020/12/5
Sorry, probably I had compared to xkcd-script.woff mistakenly.
xkcd-script.ttf has quadratic outline.