README.md

VectorArithmetic

Overview

Extending CGPoint, CGSize and CGVector with the protocols VectorOperatable & VectorArithmetic

Handles some of the Swift bugs related to architecture differences.

Just want to point out that Apple themselves uses CGPoint throughout UIKit for velocity and other vectors. So remember that when you see myPoint + myOtherPoint * 2

Dependency

To get better interoperability between different numerical types use

• ScalarArithmetic

Usage

Math Functions

let vector = CGVector(20, 5.5)
let point = CGPoint(x: 5, y: 5)

vector.angleInRadians // -1.30243011588899
vector.magnitude // 20.7424685126915
vector.length // synonym to magnitude
vector.lengthSquared // 430.25
vector.dotProduct(point) // 127.5
vector.crossProduct(point) // -72.5
vector.distanceTo(point) // 15.0083310198036
vector.reversed  // {dx -20.0, dy -5.5}
vector.normalized  // {dx 0.96420539280379, dy 0.265156483021042} 
vector.limited(20) // {dx 19.2841078560758, dy 5.30312966042085}
vector.scaled(20) // synonym to limited()
vector.angled(90) // {dx -9.29415287392715, dy 18.5436976451859}

Operators

var point:CGPoint = CGPoint(x: 2.0, y: 2.0)
var vector:CGVector = CGVector(horizontal: 2.0, vertical: 2.0)

point = point + vector
point += vector

point = point - vector
point -= vector

point = point * vector
point *= vector

point = point / vector
point /= vector

vector = vector * 4.5
vector *= 20.5

vector = vector / 2.0
vector /= 2.0

Equatable and Comparable

point == vector
point != vector
point < vector
point <= vector
point > vector
point >= vector

Generic initializer

let point = CGPoint(horizontal:2.0,vertical:2.0)
let vector = CGVector(horizontal:2.0,vertical:2.0)
let yourStruct = YourStruct(horizontal:2.0,vertical:2.0)

Type constraints

class Boid<T:VectorOperatable, U:VectorOperatable> {
  var position = T(horizontal: 2.0, vertical: 2.5)
  var velocity = U(horizontal: 2.0, vertical: 2.5)
}

let boid = Boid<CGPoint, CGVector>()
boid.position = CGPointZero
boid.velocity = CGVectorMake(20, 20)
boid.velocity > boid.position // True

Extending

Equatable and Comparable

protocol VectorOperatable  {
  init(horizontal:Double,vertical:Double)
  var horizontal:Double { get set }
  var vertical:Double { get set }
}

Math Functions

protocol VectorArithmetic : VectorOperatable {
  var angleInRadians:Double {get}
  var magnitude:Double {get}
  var length:Double {get}
  var lengthSquared:Double {get}
  func dotProduct <T : VectorArithmetic>(vector:T) -> Double
  func distanceTo <T : VectorArithmetic>(vector:T) -> Double
  var reversed:Self {get}
  var normalized:Self {get}
  func limited(scalar:Double) -> Self
  func scaled(scalar:Double) -> Self
  func angled(scalar:Double) -> Self 
}

###Contact

If you end up using VectorArithmetic in a project, I'd love to hear about it.

email: [email protected]
twitter: @seivanheidari

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License

VectorArithmetic is © 2014 Seivan and may be freely distributed under the MIT license. See the LICENSE.md file.

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