fontinfo 'postscriptBlueScale' and 'float' versus 'integer or float'

[cmyr]

Looking at the docs for fontinfo.plist in UFOv3, most types that can be floating-point numbers are listed as being integer or floats, with one exception: the 'postscriptBlueScale' field is described as a float.

My understanding is that 'integer or float' is essentially a detail of serialization: it allows the implementation to serialize an integer when the fractional part of a number is zero, which saves some space.

Given that understanding, I'm confused by the 'postcriptBlueScale' field. My best guess is that this is an oversight, but I wanted to make sure. Does anyone have any insight? Is there something special about this field?

[LettError]

https://stackoverflow.com/questions/8693290/what-does-bluescale-mean-for-type-1-fonts

[benkiel]

i.e. postscriptBlueScale will always be a float

[cmyr]

so to check my understanding, this value x is expected to be 0 < x < 1?

[benkiel]

Yes. See also https://adobe-type-tools.github.io/font-tech-notes/pdfs/T1_SPEC.pdf section 5.6