swift - 从特定点缩放SpriteNode

将spriteNode缩放为较小（或较大）大小时，默认情况下，spriteNode从中心缩放，通常很好。但是，我需要将精灵从其身体的最左侧缩放。有什么方法可以改变spriteNode的中心点，以便实现这一目标？

我尝试调整了spriteNode的锚点（如下），该锚点确实从主体的左侧开始缩放，但是它也重新定位了spriteNode，我不想这样做。

import SpriteKit

var mySprite: SKSpriteNode!

class GameScene: SKScene {

    override func didMoveToView(view: SKView) {

        anchorPoint = CGPointMake(0.5, 0.5)
        backgroundColor = UIColor.greenColor()

        mySprite = SKSpriteNode(color: UIColor.redColor(), size: CGSizeMake(100, 50))
        mySprite.anchorPoint = CGPointMake(0.0, 0.5)
        addChild(mySprite)

    }

    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

        mySprite.runAction(SKAction.scaleTo(0.5, duration: 1))

    }

我希望获得类似以下的内容（不存在）：

mySprite.centerPoint.x = -mySprite.size.width/2

另外，下面的代码可以得到我想要的结果，但是我真的不想每次调整anchorPoint时都必须调整spriteNode的位置：

var mySprite: SKSpriteNode!

class GameScene: SKScene {
    override func didMoveToView(view: SKView) {

        anchorPoint = CGPointMake(0.5, 0.5)
        backgroundColor = UIColor.greenColor()

        mySprite = SKSpriteNode(color: UIColor.redColor(), size: CGSizeMake(100, 50))
        mySprite.anchorPoint = CGPointMake(0.0, 0.5)
        mySprite.position.x = -mySprite.size.width/2
        addChild(mySprite)

    }

    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

        mySprite.runAction(SKAction.scaleTo(0.5, duration: 1))

    }

最佳答案

尝试删除mySprite.anchorPoint = CGPointMake(0.0, 0.5)和didload中的touchesBegan：

mySprite.anchorPoint = CGPointMake(0.0, 0.5)
func repositionAncorPoint() {
    mySprite.anchorPoint = CGPointMake(0.5, 0.5)
}
let resetAncor = SKAction.runBlock({ repositionAncorPoint() })
let rescale = SKAction.scaleTo(0.5, duration: 1)
let sequence = [rescale,resetAncor]
mySprite.runAction(SKAction.sequence(sequence))

我没有测试... :)