ios - swift 在 ScrollView 内缩放 UIImageView

Question

我在 ScrollView 中有一个 ImageView。我可以缩放。但是每当我释放光标时，整个图像都会适合屏幕。我只想显示图像的缩放部分。这是我的代码。

  func centerScrollViewContents(){
    let boundsSize = scrollView.bounds.size
    var contentsFrame = imageView.frame

    if contentsFrame.size.width < boundsSize.width{
        contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2
    }else{
        contentsFrame.origin.x = 0
    }

    if contentsFrame.size.height < boundsSize.height {

        contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2
    }else{
        contentsFrame.origin.y = 0
    }

    imageView.frame = contentsFrame

}

func scrollViewDidZoom(scrollView: UIScrollView) {
    centerScrollViewContents()
}

func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
    return imageView
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()

    // Dispose of any resources that can be recreated.
}
override func viewDidAppear(animated: Bool) {

    scrollView.delegate = self
    imageView.frame = CGRectMake(16, 16, scrollView.frame.size.width, scrollView.frame.size.height)
    imageView.contentMode = UIViewContentMode.ScaleToFill
    imageView.image = UIImage(named: imgstr)
    var imagee = UIImage(named: imgstr)
    let size = imagee?.size
    //imageView.contentMode  = UIViewContentMode.ScaleAspectFit
    imageView.userInteractionEnabled = true
    scrollView.addSubview(imageView)
    scrollView.contentSize = size!
    let scrollViewFrame = scrollView.frame
    let scaleWidth = scrollViewFrame.size.width / scrollView.contentSize.width
    let scaleHeight = scrollViewFrame.size.height / scrollView.contentSize.height
    let minScale = min(scaleHeight, scaleWidth)

    scrollView.minimumZoomScale = minScale
    scrollView.maximumZoomScale = 1
    scrollView.zoomScale = minScale

   centerScrollViewContents()


}

我删除了 centerScrollViewContents() 但我得到了相同的结果

Answer 1

你试过在 layoutSubView 中调用 centerScrollViewContents 吗？像下面的开源一样:https://github.com/huynguyencong/ImageScrollView