Apple 是否有办法将一个视图的外观（即您在屏幕上实际看到的内容）复制到图像缓冲区中？

Question

我们有一个 UIView，当点击时，我们希望 'copy' 屏幕上显示的内容同时向上移动、增大和淡出，作为用户点击该特定项目的视觉提示。将其视为类似于网站上的 'liking' 内容，以赋予它一点视觉效果。 Apple 是否有任何内置方法可以将屏幕上显示的内容的副本检索到图像中？

Answer 1

简化更新

这是 animateUserReaction 扩展的一个版本，它使用 UIView 的内置 snapshotView 函数，无需 makeImageSnapshot 辅助函数。

func animateUserReaction() {

    guard let containerView = superview,
          let snapshotView  = snapshotView(afterScreenUpdates:true)
    else {
        return
    }

    // Make sure to match the frame to the current frame
    snapshotView.frame = frame

    containerView.addSubview(snapshotView)

    UIView.animate(
        withDuration : 0.5,
        delay        : 0,
        options      : [.beginFromCurrentState, .curveEaseOut],
        animations: {
            snapshotView.transform       = CGAffineTransform(scaleX: 2, y: 2)
            snapshotView.frame.origin.y -= snapshotView.frame.size.height * 1.5
            snapshotView.alpha           = 0
        },
        completion: { _ in
            snapshotView.removeFromSuperview()
        }
    )
}

原答案...

知道了！它来自一个没有 Whosebug 帐户的同事 (??!!!) 但它就在这里！完美的！谢谢，乔恩！现在获取一个帐户!!!

复制 UIView 并存储在 UIImage 中

extension UIView {

    func makeImageSnapshot() -> UIImage? {
        // NOTE: 0.0 scale is to respect retina (prevents pixelation)
        UIGraphicsBeginImageContextWithOptions(bounds.size, false, 0.0)
        defer {
            UIGraphicsEndImageContext()
        }

        guard let context = UIGraphicsGetCurrentContext() else {
            return nil
        }

        layer.render(in: context)

        return UIGraphicsGetImageFromCurrentImageContext()
    }
}

为该副本制作动画...

extension UIView {

    func animateSnapshotOfSelf() {

        guard let containerView = superview,
              let snapshot      = makeImageSnapshot()
        else {
            return
        }

        let imageView = UIImageView(frame: frame)
        imageView.image = snapshot
        containerView.addSubview(imageView)

        UIView.animate(withDuration: 0.75, delay: 0, options: [.beginFromCurrentState, .curveEaseOut], animations: {
            imageView.transform = CGAffineTransform(scaleX: 2, y: 2)
            imageView.frame.origin.y += -100
            imageView.alpha = 0
        }, completion: { _ in
            imageView.removeFromSuperview()
        })
    }
}

Answer 2

是的，它叫做快照视图。

https://developer.apple.com/documentation/uikit/uiview/1622531-snapshotview

Apple 是否有办法将一个视图的外观（即您在屏幕上实际看到的内容）复制到图像缓冲区中？

Does Apple have a way to copy one view's appearance (i.e. what you physically see on screen) into an image buffer?

calayer

uiview

uiimage

swift