decurried.swift

public func projectFunctionToCoordinateSystem(function f: FunctionType) -> (p0: CGPoint, p1: CGPoint) -> (x: CGFloat) -> CGPoint {
    return { p0, p1 in
        return { x in
            let (dx, dy) = (p1.x - p0.x, p1.y - p0.y)
            let (magnitude, theta) = (hypot(dy, dx), atan2(dy, dx)) // Thanks loooop
            var outPoint = CGPoint(x: x * magnitude, y: f(x) * magnitude)
            outPoint = CGPointApplyAffineTransform(outPoint, CGAffineTransformMakeRotation(theta))
            outPoint = CGPointApplyAffineTransform(outPoint, CGAffineTransformMakeTranslation(p0.x, p0.y))
            return CGPoint(x: outPoint.x, y: outPoint.y)
        }
    }
}