UIView.transition 动画只用一次，第二次就没了

Question

如何让动画保持一致？

func addBlurTo(_ image: UIImage) -> UIImage? {

    guard let ciImg = CIImage(image: image) else { return nil }
    let blur = CIFilter(name: "CIGaussianBlur")
    blur?.setValue(ciImg, forKey: kCIInputImageKey)
    blur?.setValue(1 , forKey: kCIInputRadiusKey)
    if let outputImg = blur?.outputImage {
        return UIImage(ciImage: outputImg)
    }
    return nil
}

对于按钮：

@IBAction func Button7(_ sender: UIButton) {

        UIView.transition(with: imageView, duration: 1, options: .transitionCrossDissolve, animations: {
            guard let testImage = self.imageView.image else {return}
            self.imageView.image = self.addBlurTo(testImage)
        }, completion: nil)
}

Answer 1

您需要将函数稍微更改为以下内容，它应该可以工作。问题是在不使用上下文的情况下从 ciImage 转换为 UIImage。看这里：

If the UIImage object was initialized using a CIImage object, the value of the property is NULL.

这里：

func addBlurTo(_ image: UIImage) -> UIImage? {

            guard let ciImg = CIImage(image: image) else { return nil }
            let blur = CIFilter(name: "CIGaussianBlur")
            blur?.setValue(ciImg, forKey: kCIInputImageKey)
            blur?.setValue(1 , forKey: kCIInputRadiusKey)
            if let outputImg = blur?.outputImage {
                let context = CIContext()
                guard let cgOutput = context.createCGImage(outputImg, from: outputImg.extent) else { return nil }
                return UIImage(cgImage: cgOutput)
            }
            return nil
        }

UIView.transition 动画只用一次，第二次就没了

UIView.transition animation It only works once, a second time the picture just disappears

uiviewanimationtransition

ios

swift

UIView.transition 动画 只用一次，第二次就没了

UIView.transition animation It only works once, a second time the picture just disappears

uiviewanimationtransition

ios

swift

UIView.transition 动画只用一次，第二次就没了