SpriteKit: unwanted stretching of sprite when resizing/scaling - swift

Question

I've seen similar questions before but seems that no clear solution is provided. Currently I have a SKScene with child, contained by a SKView. Note: I'm not using a Game project; instead, I'm using the SKView in a normal UIView, and just add SKView as the subview of the UIView. The sprite itself is a small image, and it only occupies a certain portion in the middle-bottom part of the whole frame. The code looks something like this:
let imageView = SKView()
imageView.frame = CGRect(x: ..., y: ..., width: ..., height: ...) //all are predefined constants
let sprite = SKSpriteNode(texture: SKTexture(imageNamed: "image"))
sprite.position = CGPoint(x: imageView.frame.width * 0.5, y: imageView.frame.height * 0.5) // so it's positioned in the center
let scene = SKScene(size: imageView.frame.size) // also tried with sprite.size, but not working
scene.addChild(sprite)
scene.scaleMode = .aspectFit
imageView.presentScene(scene)
self.frame.addSubview(imageView)
Now the problem is the sprite is not in its original shape; it's stretched along the vertical axis. I tried changing the scaleMode with all 5 choices: .fill / .aspectFill / .aspectFit / .resizeFill / none, but none of them give the sprite its original shape/ratio. I've also tried changing the constants for the imageView's frame, but that only cuts the sprite (if imageView.frame.height is decreased). So may I know how to address this issue?

Answer 1

Your code works fine as written, so the problem is likely elsewhere. I modified it a little bit so you can test it out in a Playground. Just make a new Playground and copy and paste. You'll also have to drag in an image for your sprite.
import SpriteKit
import PlaygroundSupport
// create the outer UIView and show it on the playground
let outerView = UIView(frame: CGRect(x: 0, y: 0, width: 300, height: 300))
PlaygroundPage.current.liveView = outerView
// create the SKView and add it to the outer view
let imageView = SKView(frame: CGRect(x: 25, y: 25, width: 250, height: 250))
outerView.addSubview(imageView)
// create the scene and present it
var scene = SKScene(size: imageView.frame.size)
imageView.presentScene(scene)
// create the sprite, position it, add it to the scene
let sprite = SKSpriteNode(texture: SKTexture(imageNamed: "worf.jpg"))
sprite.position = CGPoint(x: imageView.frame.width * 0.5, y: imageView.frame.height * 0.5)
scene.scaleMode = .aspectFit
scene.addChild(sprite)
Here's the result:
No stretching! So your issue is probably related to the UIView you're placing it in. For example if you add:
outerView.transform = CGAffineTransform(scaleX: 1, y: 2)
Now the image is stretched as you describe. Take a look at your containing view and everything above it.