使用 UIPinchGestureRecognizer 进行捏合缩小

Question

奇怪的是，我的应用程序的

UIPinchGestureRecognizer

使得将我的手指移动到一起可以放大 in，而将手指分开则可以放大 out——这与 iOS 正常工作方式的相反。

我认为这不相关，但是：我在

SpriteKit

应用程序中使用它。

我做错了什么？如何使

UIPinchGestureRecognizer

启用正常的 iOS 捏拉放大 和 捏捏缩小 行为？

let pinch = UIPinchGestureRecognizer(target: self, action: #selector(GameScene.pinchZoom))

self.thisView?.addGestureRecognizer(pinch)

var normalCameraScale: CGFloat?
var accumulatedCameraScale: CGFloat = 1.0
    
@objc func pinchZoom(_ gesture: UIPinchGestureRecognizer) {
    if self.normalCameraScale == nil {
        self.normalCameraScale = self.camera?.xScale ?? 1.0
        self.accumulatedCameraScale = self.normalCameraScale!
    }
    
    let maxScale: CGFloat = 10.0
        
    
    let newScale = gesture.scale * self.accumulatedCameraScale
        
    if newScale <= maxScale && newScale >= self.normalCameraScale! {
        self.camera?.setScale(newScale)
    }
        
    if gesture.state == .ended {
        self.accumulatedCameraScale = self.camera?.xScale ?? 1.0
    }
        
        
}

谢谢

Answer 1

正如这里所述，这个公式解决了这个问题：

self.accumulatedCameraScale * 1 / gesture.scale

功能齐全：

var normalCameraScale: CGFloat?
var accumulatedCameraScale: CGFloat = 1.0
    
@objc func pinchZoom(_ gesture: UIPinchGestureRecognizer) {
  if self.normalCameraScale == nil {
       self.normalCameraScale = self.camera?.xScale ?? 1.0
       self.accumulatedCameraScale = self.normalCameraScale!
  }
    
  let maxScale: CGFloat = 10.0
        
  //This formula makes it work correctly:
  let newScale = self.accumulatedCameraScale * 1 / gesture.scale
        
  if newScale <= maxScale && newScale >= self.normalCameraScale! {
     self.camera?.setScale(newScale)
  }
        
  if gesture.state == .ended {
     self.accumulatedCameraScale = self.camera?.xScale ?? 1.0
  }
        
}