An Angle type already exists in Foundation; see Measurement<UnitAngle>. You
could add some convenience methods in an extension pretty easily.
import Foundation
typealias Angle = Measurement<UnitAngle>
extension Measurement where UnitType == UnitAngle {
var sine: Double {
let radians = self.converted(to: .radians).value
return sin(radians)
}
static var threeQuarterTurn: Angle {
return Angle(value: 0.75, unit: .revolutions)
}
}
let x = Angle.threeQuarterTurn
x.sine // -1
-BJ
> On Jan 13, 2018, at 9:31 PM, Erica Sadun via swift-evolution
> <[email protected]> wrote:
>
> I would like to see a full Geometry implementation but I don't think it
> should be part of the standard library.
>
> I've kicked around some ideas here:
>
> * https://gist.github.com/erica/8cb4b21cf0c429828fad1d8ad459b71b
> <https://gist.github.com/erica/8cb4b21cf0c429828fad1d8ad459b71b>
> * https://gist.github.com/erica/ee06008202c9fed699bfa6254c42c721
> <https://gist.github.com/erica/ee06008202c9fed699bfa6254c42c721>
>
> and
>
> * https://github.com/erica/SwiftGeometry
> <https://github.com/erica/SwiftGeometry>
>
>> On Jan 13, 2018, at 7:49 PM, Jonathan Hull via swift-evolution
>> <[email protected] <mailto:[email protected]>> wrote:
>>
>> Hi Evolution,
>>
>> I would really like to see Swift gain an Angle type in the standard library.
>> Every time I have to deal with an angle in an api, I have to go figure out
>> the conventions for that call. Is it in degrees? Is it in radians? What if
>> it is in radians, but I want to think about it in degrees?
>>
>> I ended up writing an Angle type for my own code a few years back, and I
>> have to say it is really wonderful. It has greatly simplified my graphics
>> work. It takes a lot of mental load off of my brain when dealing with
>> Angles.
>>
>> I can of course initialize it either as degrees or radians (or revolutions),
>> but I can also just say things like ‘.threeQuarterTurn’, and then I can get
>> the value back out in whatever format I like. There are also useful
>> additions that let me normalize the angle to different ranges and which let
>> me snap to the nearest multiple of an angle. Both of these are enormously
>> useful for user facing features. I can also do math on angles in a way that
>> makes geometric sense for angles. It is also really useful for interacting
>> with CGVectors in intelligent ways.
>>
>> Using Doubles or CGFloats to represent angles everywhere is just
>> semantically wrong IMHO, and it stops us from adding all of these
>> angle-specific niceties.
>>
>> Happy to provide code if there is interest…
>>
>> Thanks,
>> Jon
>> _______________________________________________
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>> [email protected] <mailto:[email protected]>
>> https://lists.swift.org/mailman/listinfo/swift-evolution
>
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