CGPoint編

CGPoint（NSPointでも可）の演算を円滑にするための便利な演算子と拡張の定義

//オリジナルの演算子ではないためinfix operatorはいらない

func + (left: CGPoint, right: CGPoint) -> CGPoint {
    return CGPoint(x: left.x + right.x, y: left.y + right.y)
}

func += (left: inout CGPoint, right: CGPoint) {
    left = left + right
}

func - (left: CGPoint, right: CGPoint) -> CGPoint {
    return CGPoint(x: left.x - right.x, y: left.y - right.y)
}

func -= (left: inout CGPoint, right: CGPoint) {
    left = left - right
}

func * (left: CGFloat, right: CGPoint) -> CGPoint {
    return CGPoint(x: left * right.x, y: left * right.y)
}

func * (left: CGPoint, right: CGFloat) -> CGPoint {
    return CGPoint(x: right * left.x, y: right * left.y)
}

func *= (left: inout CGPoint, right: CGFloat) {
    left = left * right
}

func / (left: CGPoint, right: CGFloat) -> CGPoint {
    assert(right != 0, "divide by zero")
    return CGPoint(x: left.x / right, y: left.y / right)
}

func /= (left: inout CGPoint, right: CGFloat) {
    assert(right != 0, "divide by zero")
    left = left / right
}

extension CGPoint {
    // xとyが同じ時の初期化
    init(_ scalar: CGFloat) {
        self.init(x: scalar, y: scalar)
    }
    // 二点間の距離を返す
    func length(from: CGPoint) -> CGFloat {
        return sqrt(pow(self.x - from.x, 2.0) + pow(self.y - from.y, 2.0))
    }
    // 二点を結んだ線分の角度（ラジアン）を返す
    func radian(from: CGPoint) -> CGFloat {
        return atan2(self.y - from.y, self.x - from.x)
    }
    // 二点を結んだ線分の角度（度）を返す    
    func degree(from: CGPoint) -> CGFloat {
        return atan2(self.y - from.y, self.x - from.x) * 180 / CGFloat.pi
    }
}

演算子の評価順序は基本的なものと変わらない．

取得できる角度はx軸を基準にした反時計回り(macOSの場合y軸が上向きなのでそれにあわせた）

CGSize編

CGSize（NSSizeでも可）の演算を円滑にするための便利な演算子と拡張の定義

func + (left: CGSize, right: CGSize) -> CGSize {
    return CGSize(width: left.width + right.width, height: left.height + right.height)
}

func += (left: inout CGSize, right: CGSize) {
    left = left + right
}

func - (left: CGSize, right: CGSize) -> CGSize {
    return CGSize(width: left.width - right.width, height: left.height - right.height)
}

func -= (left: inout CGSize, right: CGSize) {
    left = left - right
}

func * (left: CGFloat, right: CGSize) -> CGSize {
    return CGSize(width: left * right.width, height: left * right.height)
}

func * (left: CGSize, right: CGFloat) -> CGSize {
    return CGSize(width: right * left.width, height: right * left.height)
}

func *= (left: inout CGSize, right: CGFloat) {
    left = left * right
}

func / (left: CGSize, right: CGFloat) -> CGSize {
    assert(right != 0, "divide by zero")
    return CGSize(width: left.width / right, height: left.height / right)
}

func /= (left: inout CGSize, right: CGFloat) {
    assert(right != 0, "divide by zero")
    left = left / right
}

extension CGSize {
    // widthとheightの大きさが同じ時の初期化
    init(_ side: CGFloat) {
        self.init(width: side, height: side)
    }
}

だいたいはCGPointと同じ

蛇足

NSPoint，NSSize，NSRectはそれぞれCGPoint，CGSize，CGRectのエイリアス．