PngWriter: When fancy = True, some threads don't show up

[gemini133]

Thanks for your great work on pyembroidery. It'd be helpful for my latest project to generate previews for embroidery files.

here is the pattern file I use https://embroideres.com/free-embroidery-designs/individual/phrases-and-words-free-embroidery-designs/hope-christmas-inscription/

Archive.zip

I tried with dst and pes, they both generate the unexpected results.

the red part is the most obvious one.

here is the correct one from the website above where I downloaded the emb files.

Thanks in advance!

[tatarize]

I'll have to maybe check the PR, you posted but I think it's just that that section is entirely dark colored and doesn't get a proper gradient without it. Seems like it's certainly worth looking at.