swift3.0实现图片放大缩小动画效果

1. LJPhotoGroupView：图片浏览管理类，用于展示图片

import Foundation 
import UIKit 
 
class LJPhotoGroupView: UIView { 
   
  let baseIndex = 1000 
   
  var originFrame : CGRect? // 图片的源尺寸 
  var currentIndex : NSInteger = 0 //当前选中的图片index 
  var ljPhotoArray : [Any] = [Any]()//存储多组需要加载的图片原始信息 
   
  lazy var ljScrollView : UIScrollView = { 
    let view = UIScrollView.init(frame: CGRect(x: 0, y: 0, width: AppWidth, height: AppHeight)) 
    view.delegate = self 
    view.isPagingEnabled = true 
    view.backgroundColor = UIColor.yellow 
    return view 
  }() 
   
  override init(frame: CGRect) { 
    super.init(frame: frame) 
    self.addSubview(self.ljScrollView) 
  } 
 
  func setData(_ photoArray : Array<Any>, selectedIndex : NSInteger) { 
    self.ljScrollView.contentSize = CGSize(width: floor(AppWidth) * CGFloat(photoArray.count), height: AppHeight) 
    self.currentIndex = selectedIndex 
    self.ljPhotoArray = photoArray 
  } 
   
  required init?(coder aDecoder: NSCoder) { 
    fatalError("init(coder:) has not been implemented") 
  } 
} 
 
extension LJPhotoGroupView { 
 
// MARK: -- 图片cell复用 
  func dequeueReusableCell() -> LJPhotoView { 
     
    var cell = self.viewWithTag(baseIndex + self.currentIndex) as? LJPhotoView 
     
    if ljPhotoArray.count > currentIndex { 
      let info = ljPhotoArray[currentIndex] as? LJPhotoInfo 
      let tempImageView = info?.thumbImageview 
 
      if cell != nil{ 
        self.originFrame = tempImageView?.convert((tempImageView?.bounds)!, to: self) 
        return cell! 
      } 
       
      cell = LJPhotoView.init(frame: CGRect(x: floor(AppWidth)*CGFloat(currentIndex), y: 0, width: AppWidth, height: AppHeight)) 
      self.originFrame = tempImageView?.convert((tempImageView?.bounds)!, to: self) 
    } 
    return cell! 
  } 
  
// MARK: -- 展示图片 
  func showPhotoView(){ 
     
    UIApplication.shared.keyWindow?.rootViewController?.view.addSubview(self) 
    self.backgroundColor = UIColor.black 
   
    let cell1 = self.dequeueReusableCell() 
    cell1.tag = self.baseIndex + self.currentIndex 
     
    var ljTempImage : UIImage? 
    if ljPhotoArray.count > currentIndex { 
      let info = ljPhotoArray[currentIndex] as? LJPhotoInfo 
      ljTempImage = info?.thumbImageview?.image 
    } 
     
    ljTempImage = (ljTempImage != nil) ? ljTempImage : UIImage.init(named: "pic_broadcast_gray_square") 
     
    let tfImageView = UIImageView.init(image: ljTempImage) 
    tfImageView.frame = self.originFrame ?? CGRect.zero 
    tfImageView.clipsToBounds = true 
    tfImageView.backgroundColor = UIColor.red 
    tfImageView.contentMode = .scaleAspectFit 
    self.addSubview(tfImageView) 
     
    //添加页面消失的手势 
    let tap = UITapGestureRecognizer.init(target: self, action: #selector(hideImageView)) 
    self.addGestureRecognizer(tap) 
     
    UIView.animate(withDuration: 0.25, animations: { 
      let y : CGFloat? = (AppHeight - (ljTempImage?.size.height)! * AppWidth / (ljTempImage?.size.width)!)/2.0 
      let height : CGFloat? = (ljTempImage?.size.height)! * AppWidth / (ljTempImage?.size.width)! 
      tfImageView.frame = CGRect(x: 0, y: y!, width: AppWidth, height: height!) 
    }) { (finish) in 
      //根据选中第几张图片直接展示出来 
      let cell = self.dequeueReusableCell() 
      cell.tag = self.baseIndex + self.currentIndex 
      cell.backgroundColor = UIColor.gray 
       
      if self.ljPhotoArray.count > self.currentIndex{ 
        cell.setCurrentImageview(self.ljPhotoArray[self.currentIndex] as! LJPhotoInfo) 
      } 
      let x : CGFloat = CGFloat(self.currentIndex) * floor(AppWidth); 
      self.ljScrollView.setContentOffset(CGPoint.init(x: x, y: 0), animated: false) 
      self.ljScrollView.addSubview(cell) 
       
       
      tfImageView.removeFromSuperview() 
    } 
  } 
   
// MARK: -- 移除图片 
  func hideImageView(){ 
    let cell = self.viewWithTag(baseIndex + currentIndex) as? LJPhotoView 
    UIView.animate(withDuration: 0.25, animations: { 
      cell?.ljImageView.frame = self.originFrame! 
    }) { (finish) in 
      self.backgroundColor = UIColor.white 
      self.removeFromSuperview() 
    } 
  } 
} 
 
extension LJPhotoGroupView : UIScrollViewDelegate{ 
   
  func scrollViewDidScroll(_ scrollView: UIScrollView) { 
    //滑动时，会调用多次 
  } 
   
  func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) { 
   //滑动完毕时，只会调用一次 
    let page = self.ljScrollView.contentOffset.x / self.frame.size.width; 
    self.currentIndex = NSInteger(page); 
    print("scrollViewDidEndDecelerating当前页数----(page)") 
     
    let cell = self.dequeueReusableCell() 
    cell.tag = self.baseIndex + Int(page) 
    if self.ljPhotoArray.count > self.currentIndex{ 
      cell.setCurrentImageview(self.ljPhotoArray[self.currentIndex] as! LJPhotoInfo) 
    } 
    self.ljScrollView.addSubview(cell) 
  } 
} 
								 
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