用Swift封裝圖片摺疊效果
談到封裝,那麼就要從使用者的角度出發,提供外界使用的方法
- 1.新建一個類繼承UIView
class XWFoldImageView: UIView {}
- 2.外界想實現這個效果只需要給我圖片名和控件顯示的frame就夠了,那麼提供使用者遍歷構造方法
convenience init(imageName:String ,frame:CGRect){
self.init()
self.frame = frame
//1.在初始化做的操作
self.setupDoubleImageViewLayer(imageName)
self.setupGestureRecognizer()
}
- 3那麼外界使用就是非常方便,如:
override func viewDidLoad() {
super.viewDidLoad()
let foldImageView = XWFoldImageView(imageName: "image", frame: CGRectMake(50, 100, 300, 200))
self.view.addSubview(foldImageView)
}
談談如何具體實現
- 大體思想
1.利用兩張一模一樣的圖片,放在同一個UIView上面分了頂部和底部
具體代碼
//MARK: 成員屬性
private var imageTopView:UIImageView!
private var imageBottomView:UIImageView!
private var gradientLayer:CAGradientLayer = CAGradientLayer()
//MARK: 便利構造
convenience init(imageName:String ,frame:CGRect){
self.init()
self.frame = frame
self.setupDoubleImageViewLayer(imageName)
self.setupGestureRecognizer()
}
//MARK: 設置圖片圖層的描點和 postion
private func setupDoubleImageViewLayer(imageName:String){
//1添加到父控件
let imageBottomView = UIImageView(image: UIImage(named: imageName))
imageBottomView.frame = self.bounds
imageBottomView.contentMode = UIViewContentMode.ScaleAspectFit
self.addSubview(imageBottomView)
self.imageBottomView = imageBottomView
let imageTopView = UIImageView(image: UIImage(named: imageName))
imageTopView.frame = self.bounds
imageTopView.contentMode = UIViewContentMode.ScaleAspectFit
self.addSubview(imageTopView)
self.imageTopView = imageTopView
//2.設置contents顯示比例
self.imageTopView.layer.contentsRect = CGRectMake(0, 0, 1, 0.5)
self.imageBottomView.layer.contentsRect = CGRectMake(0, 0.5, 1, 0.5)
//2.1設置錨點
/** 兩張圖,各顯示一半,讓描點爲中間的點,這樣纔可以用tranfrom */
self.imageTopView.layer.anchorPoint = CGPointMake(0.5, 1)
self.imageBottomView.layer.anchorPoint = CGPointMake(0.5, 0)
//3.修改圖層座標點,修改postion 其實就是center,改了之後center也跟着改了
self.imageTopView.layer.position = CGPointMake(self.imageTopView.center.x, self.imageTopView.center.y + self.imageTopView.height * 0.5)
//3.1 雖然修改了圖層的contentsRect 但是本身的高度並沒有修改,導致旋轉的時候,高度變高
self.imageTopView.height = self.height * 0.5
self.imageBottomView.height = self.height * 0.5
//4 給圖層增加一個陰影層
self.gradientLayer.frame = self.imageBottomView.bounds
//4.1漸變的顏色
self.gradientLayer.colors = [UIColor .clearColor().CGColor, UIColor.blackColor().CGColor]
//不透明度
self.gradientLayer.opacity = 0
//4.2加入到底部ImageView的圖層
self.imageBottomView.layer.addSublayer(self.gradientLayer)
}
2.給父控件添加手勢,來改變子控件圖層的形變
具體代碼
//MARK: 添加手勢拖拽
private func setupGestureRecognizer(){
//1.
let pan = UIPanGestureRecognizer(target: self, action: "panFunc:")
self.addGestureRecognizer(pan)
}
//MARK: 手勢執行
func panFunc(pan:UIPanGestureRecognizer){
//1.得到偏移量,就是x,y座標與 左上角CGPointZero 的差距
let offSet = pan.translationInView(pan.view)
//2.得到旋轉的角度
var angle = -kAngle2Radian(offSet.y) * 5
//3.如果大於角度就固定最剛好遮蓋值,這個值可以更具調試得到
if fabs(angle) >= kAngle2Radian(340) * 5 {
angle = angle / angle * kAngle2Radian(340) * 5
}
//增強立體感
var transfrom:CATransform3D = CATransform3DIdentity
// d:人的眼睛和屏幕的垂直距離
let d:CGFloat = 300
// 設置形變的m34就可以增加立體感,立體感(近大遠小)
transfrom.m34 = -1 / d
//2.根據 y 值的大小進行旋轉X軸的角度
transfrom = CATransform3DRotate(transfrom, angle, 1, 0, 0)
self.imageTopView.layer.transform = transfrom
//2.1設置陰影
self.gradientLayer.opacity = Float(fabs(angle) / (kAngle2Radian(346) * 4.0))
//3.檢查用戶擡起手勢
if pan.state == UIGestureRecognizerState.Ended {
UIView.animateWithDuration(0.5, delay: 0, usingSpringWithDamping: 0.1, initialSpringVelocity: 0, options: UIViewAnimationOptions.CurveEaseInOut, animations: { () -> Void in
self.imageTopView.layer.transform = CATransform3DIdentity
self.gradientLayer.opacity = 0;
}, completion: { (Bool) -> Void in
})
}
}