||r/w||numeric part of the length|
||r/w||unit part of the length|
This is equivalent to CSS lengths.
It is up to the calling application to convert lengths in non-pixel units (i.e. those where the unit field is not
Rsvg.Unit.PX) into something meaningful to the application. For example, if your application knows the dots-per-inch (DPI) it is using, it can convert lengths with unit in
Rsvg.Unit.INor other physical units.