Swift：如何获得SKShapeNode的位置？

Question

我在SKShapeNode的位置上遇到了麻烦。我存储了用户触摸屏幕的路径。然后我创建一个多边形并将其放入pathOfShape变量。我创建了该路径的SKShapeNode，一切正常。我在屏幕上整齐地绘制了用户绘制的多边形。

但是我想在多边形上添加更多东西。出于某种原因，我无法获得SKShapeNode的位置。相反，如果我尝试使用position属性，它会指向x：0.0，y：0.0，如下所示。这里有什么？如何获得SKShapeNode的实际position？

var pathOfShape = CGPathCreateMutable()                       
//path of polygon added here to pathOfShape
var shapeNode = SKShapeNode()
shapeNode.path = pathOfShape 
shapeNode.name = "shape"
self.addChild(shapeNode)

let node1 = self.childNodeWithName("shape")
print(node1?.position)

结果为Optional((0.0, 0.0))

Answer 1

实际上，如果你制作一个CGPath，例如一个三角形：

var pathOfShape = CGPathCreateMutable()
let center = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
CGPathMoveToPoint(pathOfShape, nil, center.x, center.y)
CGPathAddLineToPoint(pathOfShape, nil, center.x + 50, center.y + 50)
CGPathMoveToPoint(pathOfShape, nil, center.x + 50, center.y + 50)
CGPathAddLineToPoint(pathOfShape, nil, center.x - 50, center.y + 50)
CGPathMoveToPoint(pathOfShape, nil, center.x - 50, center.y + 50)
CGPathAddLineToPoint(pathOfShape, nil, center.x - 50, center.y - 50)
CGPathMoveToPoint(pathOfShape, nil, center.x - 50, center.y - 50)
CGPathAddLineToPoint(pathOfShape, nil, center.x, center.y)
CGPathCloseSubpath(pathOfShape)

您决定根据此路径创建SKShapeNode：

let shape = SKShapeNode(path: pathOfShape)

你可以要求获得这种形状的中心：

let center = CGPointMake(CGRectGetMidX(shape.frame),CGRectGetMidY(shape.frame))

正确的位置总是（0.0,0.0），但几乎你知道你的形状在哪里。