Returns the variation specification dictionary for a font.
- iOS 2.0+
- macOS 10.4+
- tvOS 9.0+
- watchOS 2.0+
- Core Graphics
A font object.
The variation specification dictionary for the font. Returns
NULL if the font doesn't support variations.
The variation specification dictionary contains keys that correspond to the variation axis names of the font. Each key is a variation axis name. The value for each key is the value specified for that particular variation axis represented as a CFNumber object.