swift - 围绕另一个 CGPoint 旋转一个 CGPoint

Question

好的，我想将 CGPoint(A) 围绕 CGPoint(B) 旋转 50 度，有什么好的方法吗？

CGPoint(A) = CGPoint(x: 50, y: 100)

CGPoint(B) = CGPoint(x: 50, y: 0)

这是我想做的:

Answer 1

这真是一道数学题。在 Swift 中，你想要这样的东西:

func rotatePoint(target: CGPoint, aroundOrigin origin: CGPoint, byDegrees: CGFloat) -> CGPoint {
    let dx = target.x - origin.x
    let dy = target.y - origin.y
    let radius = sqrt(dx * dx + dy * dy)
    let azimuth = atan2(dy, dx) // in radians
    let newAzimuth = azimuth + byDegrees * CGFloat(M_PI / 180.0) // convert it to radians
    let x = origin.x + radius * cos(newAzimuth)
    let y = origin.y + radius * sin(newAzimuth)
    return CGPoint(x: x, y: y)
}

有很多方法可以简化它，它是 CGPoint 扩展的完美案例，但为了清楚起见，我将其保留得很冗长。