designspacelib: axis minimum and maximum values in designspace coordinate?

[LettError]

Is there a recommended way to get the extreme values of an axis in designspace coordinates?
Usecase: I need to clip designspace coordinates to axis extremes.
@madig

[justvanrossum]

Axes have a map_forward() method, which maps values from user space to designspace. So feed it the axis.minimum and axis.maximum and Bob's your uncle:

from fontTools.designspaceLib import DesignSpaceDocument

p = "path/to/Font.designspace"

doc = DesignSpaceDocument.fromfile(p)
for axis in doc.axes:
    print(axis.name)
    print(axis.minimum, axis.map_forward(axis.minimum))
    print(axis.maximum, axis.map_forward(axis.maximum))

[LettError]

One follow up: are there known use cases for mapping applied to discrete axis values?