ChangeWeight produces weird results on italic fonts

[tobiasBora]

Thanks for this useful software. So if I load a font like the NimbusSanL-ReguItal.ttf:

NimbusSanL-ReguItal.zip

and open it + go to Element > Style > Change:

then most fonts are really weird, like:

I would for instance expect the lines caps not to be curved, the t to have a more regular shape… For instance, if I use LuaLaTeX with:

\newfontface\mySemibold{NimbusSanL-ReguItal.ttf}[
  FakeBold=2.5
]

I get a much better result:

Is it a bug, or am I missing something?

When reporting a bug/issue:

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[skef]

The ChangeWeight function has a set of heuristics that will sometimes more or less work and sometimes won't. You should think of it as something that might make changes that are close to what you need, which can be cleaned up by hand after. And even setting that general discouragement aside:

1. Most of the testing of ChangeWeight was done with cubics, and this is a TrueType font with quadratic curves.
2. It's known to be pretty dubious when it comes to italics, as well as any other "unusual" sort of font.

Still, as it turns out the font you're working with isn't an italic font, it's just a boring old san-serif font that's been slanted. So I tried the following:

1. Select some letters you want to modify (I tried the lower case Latin glyphs)
2. Open the Element -> Transformations ... -> Transform dialog and apply a 12 degree Withershins skew on those glyphs
3. Run ChangeWeight on those glyphs
4. Open the Element -> Transformations ... -> Transform dialog and apply a 12 degree Clockwise skew on those glyphs

And that result isn't too bad. Some of the needed cleanup is strange, like the lines that turn into curves -- those might have to do with the quadratics. But that's easy enough to deal with. The "e" closed up and needs some help. But overall the results are OKish.