如何使照片缩放,设置宽高比,然后缩放在 Swift 中留下白色区域?
How to make a photo zoom, setting aspect ratio and then zooming leaves white area in Swift?
[After scrolling : Problem White Screen]1
After Zooming
[Before Zoom image setted aspect ratio]
我正在实现一个照片查看页面,其中只包含一张照片。功能:缩放。
由于图片尺寸为 1024x510。我已经实现了纵横比并将 imageview 框架设置为屏幕尺寸。我已经使用 Scrollview 和 imageview 概念实现了。
问题是,当我缩放图像时,白屏也被缩放了。问题是缩放时白色 space os imageview。
.
代码
override func viewDidLoad() {
super.viewDidLoad()
print(imageIndex)
self.scrollV.maximumZoomScale = 5.0
self.scrollV.minimumZoomScale = 1.0
self.scrollV.contentSize = self.view.bounds.size;
self.scrollV.delegate = self
let urlStr : NSString = vehicleImages[imageIndex].stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!
url=NSURL(string: urlStr as String)
imageView.kf_setImageWithURL(url,placeholderImage: UIImage(named: "placeholder.png"))
}
func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
return imageView
}
看看这些方法。可能会有帮助。我将滚动视图拉伸到控制器的视图大小。 customizeScrollView()
将计算最小和最大比例选项。 centerImageView()
会将 UIImageView 放在你的 UIScrollView 的中心
fileprivate func customizeScrollView() {
guard let image = imageView?.image else { return }
var minZoom = fmin(self.view.frame.width / image.size.width, self.view.frame.height / image.size.height)
minZoom = fmin(1.0, minZoom)
scrollView?.contentSize = image.size
scrollView?.minimumZoomScale = minZoom
scrollView?.addSubview(self.imageView!)
scrollView?.setZoomScale(minZoom, animated: false)
centerImageView()
}
fileprivate func centerImageView() {
guard let imageView = imageView else { return }
guard let scrollView = scrollView else { return }
let boundsSize = scrollView.bounds.size
var frameToCenter = imageView.frame
// Center horizontally
if frameToCenter.size.width < boundsSize.width {
frameToCenter.origin.x = (boundsSize.width - frameToCenter.size.width) / 2
} else {
frameToCenter.origin.x = 0
}
// Center vertically
if frameToCenter.size.height < boundsSize.height {
frameToCenter.origin.y = (boundsSize.height - frameToCenter.size.height) / 2
} else {
frameToCenter.origin.y = 0
}
imageView.frame = frameToCenter
}
还有 UIScrollViewDelegate 方法:
/// `UIScrollViewDelegate` protocol implementation
extension ImagePreviewController: UIScrollViewDelegate {
public func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return imageView
}
public func scrollViewDidZoom(_ scrollView: UIScrollView) {
centerImageView()
}
}
[After scrolling : Problem White Screen]1
After Zooming
[Before Zoom image setted aspect ratio]
我正在实现一个照片查看页面,其中只包含一张照片。功能:缩放。
由于图片尺寸为 1024x510。我已经实现了纵横比并将 imageview 框架设置为屏幕尺寸。我已经使用 Scrollview 和 imageview 概念实现了。
问题是,当我缩放图像时,白屏也被缩放了。问题是缩放时白色 space os imageview。 . 代码
override func viewDidLoad() {
super.viewDidLoad()
print(imageIndex)
self.scrollV.maximumZoomScale = 5.0
self.scrollV.minimumZoomScale = 1.0
self.scrollV.contentSize = self.view.bounds.size;
self.scrollV.delegate = self
let urlStr : NSString = vehicleImages[imageIndex].stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!
url=NSURL(string: urlStr as String)
imageView.kf_setImageWithURL(url,placeholderImage: UIImage(named: "placeholder.png"))
}
func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
return imageView
}
看看这些方法。可能会有帮助。我将滚动视图拉伸到控制器的视图大小。 customizeScrollView()
将计算最小和最大比例选项。 centerImageView()
会将 UIImageView 放在你的 UIScrollView 的中心
fileprivate func customizeScrollView() {
guard let image = imageView?.image else { return }
var minZoom = fmin(self.view.frame.width / image.size.width, self.view.frame.height / image.size.height)
minZoom = fmin(1.0, minZoom)
scrollView?.contentSize = image.size
scrollView?.minimumZoomScale = minZoom
scrollView?.addSubview(self.imageView!)
scrollView?.setZoomScale(minZoom, animated: false)
centerImageView()
}
fileprivate func centerImageView() {
guard let imageView = imageView else { return }
guard let scrollView = scrollView else { return }
let boundsSize = scrollView.bounds.size
var frameToCenter = imageView.frame
// Center horizontally
if frameToCenter.size.width < boundsSize.width {
frameToCenter.origin.x = (boundsSize.width - frameToCenter.size.width) / 2
} else {
frameToCenter.origin.x = 0
}
// Center vertically
if frameToCenter.size.height < boundsSize.height {
frameToCenter.origin.y = (boundsSize.height - frameToCenter.size.height) / 2
} else {
frameToCenter.origin.y = 0
}
imageView.frame = frameToCenter
}
还有 UIScrollViewDelegate 方法:
/// `UIScrollViewDelegate` protocol implementation
extension ImagePreviewController: UIScrollViewDelegate {
public func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return imageView
}
public func scrollViewDidZoom(_ scrollView: UIScrollView) {
centerImageView()
}
}