UIScrollView缩放和contentInset
UIScrollView缩放和contentInset
提问于 2016-09-13 07:39:30
类似于iOS照片应用程序，用户可以通过收缩来放大和缩小图像：
UIView > UIScrollView > UIImageView > UIImage
最初，我遇到了缩放比例1以下的问题:图像偏离中心。我通过这样做解决了这个问题：
func scrollViewDidZoom(scrollView: UIScrollView) {
let offsetX = max((scrollView.bounds.width - scrollView.contentSize.width) * 0.5, 0)
let offsetY = max((scrollView.bounds.height - scrollView.contentSize.height) * 0.5, 0)
scrollView.contentInset = UIEdgeInsetsMake(offsetY, offsetX, 0, 0)
}这在缩小时效果很好。
UIImage内容模式为aspectFit
问题
当I ZOOM IN时，当zoomScale大于1时，滚动视图插入需要拥抱滚动视图所包含的UIImage的周围。这将移除UIImage周围的死区。即，照片应用程序放大时，通过挤压或双击。
已尝试
func scrollViewDidZoom(scrollView: UIScrollView) {
if scrollView.zoomScale > 1 {
let imageScale = (self.imageView.bounds.width/self.imageView.image!.size.width)
let imageWidth = self.imageView.image!.size.width * imageScale
let imageHeight = self.imageView.image!.size.height * imageScale
scrollView.contentInset = UIEdgeInsetsMake(((scrollView.frame.height - imageHeight) * 0.5), (scrollView.frame.width - imageWidth) * 0.5 , 0, 0)
print (scrollView.contentInset.top)
}
else {
let offsetX = max((scrollView.bounds.width - scrollView.contentSize.width) * 0.5, 0)
let offsetY = max((scrollView.bounds.height - scrollView.contentSize.height) * 0.5, 0)
scrollView.contentInset = UIEdgeInsetsMake(offsetY, offsetX, 0, 0)
}
}上面的加法似乎仍然改变了嵌入量。
更新(添加图像)
第一个图像显示了默认布局。放大时的Rest显示.....
回答 3
Stack Overflow用户
回答已采纳
发布于 2016-11-08 14:47:55
你的方法看起来是正确的。您需要更新代码，如下所示。
func scrollViewDidZoom(scrollView: UIScrollView) {
if scrollView.zoomScale > 1 {
if let image = imageView.image {
let ratioW = imageView.frame.width / image.size.width
let ratioH = imageView.frame.height / image.size.height
let ratio = ratioW < ratioH ? ratioW:ratioH
let newWidth = image.size.width*ratio
let newHeight = image.size.height*ratio
let left = 0.5 * (newWidth * scrollView.zoomScale > imageView.frame.width ? (newWidth - imageView.frame.width) : (scrollView.frame.width - scrollView.contentSize.width))
let top = 0.5 * (newHeight * scrollView.zoomScale > imageView.frame.height ? (newHeight - imageView.frame.height) : (scrollView.frame.height - scrollView.contentSize.height))
scrollView.contentInset = UIEdgeInsetsMake(top, left, top, left)
}
} else {
scrollView.contentInset = UIEdgeInsetsZero
}
}Swift 5
func scrollViewDidZoom(scrollView: UIScrollView) {
if scrollView.zoomScale > 1 {
if let image = imageView.image {
let ratioW = imageView.frame.width / image.size.width
let ratioH = imageView.frame.height / image.size.height
let ratio = ratioW < ratioH ? ratioW:ratioH
let newWidth = image.size.width*ratio
let newHeight = image.size.height*ratio
let left = 0.5 * (newWidth * scrollView.zoomScale > imageView.frame.width ? (newWidth - imageView.frame.width) : (scrollView.frame.width - scrollView.contentSize.width))
let top = 0.5 * (newHeight * scrollView.zoomScale > imageView.frame.height ? (newHeight - imageView.frame.height) : (scrollView.frame.height - scrollView.contentSize.height))
scrollView.contentInset = UIEdgeInsets(top: top, left: left, bottom: top, right: left)
}
} else {
scrollView.contentInset = .zero
}
}Stack Overflow用户
发布于 2019-06-26 01:55:40
Swift 5
func scrollViewDidZoom(_ scrollView: UIScrollView) {
if scrollView.zoomScale > 1 {
if let image = imageView.image {
let ratioW = imageView.frame.width / image.size.width
let ratioH = imageView.frame.height / image.size.height
let ratio = ratioW < ratioH ? ratioW : ratioH
let newWidth = image.size.width * ratio
let newHeight = image.size.height * ratio
let left = 0.5 * (newWidth * scrollView.zoomScale > imageView.frame.width ? (newWidth - imageView.frame.width) : (scrollView.frame.width - scrollView.contentSize.width))
let top = 0.5 * (newHeight * scrollView.zoomScale > imageView.frame.height ? (newHeight - imageView.frame.height) : (scrollView.frame.height - scrollView.contentSize.height))
scrollView.contentInset = UIEdgeInsets(top: top, left: left, bottom: top, right: left)
}
} else {
scrollView.contentInset = UIEdgeInsets.zero
}
}Stack Overflow用户
发布于 2018-05-31 17:17:07
对于swift 4
func scrollViewDidZoom(_ scrollView: UIScrollView) {
if scrollView.zoomScale > 1 {
if let image = self.imageViewZoom.image {
let ratioW = self.imageViewZoom.frame.width / image.size.width
let ratioH = self.imageViewZoom.frame.height / image.size.height
let ratio = ratioW < ratioH ? ratioW:ratioH
let newWidth = image.size.width*ratio
let newHeight = image.size.height*ratio
let left = 0.5 * (newWidth * scrollView.zoomScale > self.imageViewZoom.frame.width ? (newWidth - self.imageViewZoom.frame.width) : (scrollView.frame.width - scrollView.contentSize.width))
let top = 0.5 * (newHeight * scrollView.zoomScale > self.imageViewZoom.frame.height ? (newHeight - self.imageViewZoom.frame.height) : (scrollView.frame.height - scrollView.contentSize.height))
scrollView.contentInset = UIEdgeInsetsMake(top, left, top, left)
}
} else {
scrollView.contentInset = UIEdgeInsets.zero
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/39460256
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