Question

我想捕捉屏幕的一小部分区域的快照并对其应用模糊 - 尽管速度为60fps - 这对于此代码是不可能的：

let rectangle = CGRect(x: -37, y: -153, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)

captureSnapShotWithGaussianBlur(rect: rectangle)

public func captureSnapShotWithGaussianBlur(rect: CGRect) -> UIImage {

      let SCREEN_SIZE_SCALE_FACTOR = UIScreen.main.scale
      let CROPPING_RECT = CGRect(x: 0, y: 0, width: 118*SCREEN_SIZE_SCALE_FACTOR, height: 66*SCREEN_SIZE_SCALE_FACTOR)

      UIGraphicsBeginImageContextWithOptions(CGSize(width: 118, height: 66), true, 0.0)

      backgroundView!.drawHierarchy(in: rect, afterScreenUpdates: true)

      let capturedImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
      let ciimage: CIImage = CIImage(image: capturedImage)!

      UIGraphicsEndImageContext()

      let gaussianfilter: CIFilter = CIFilter(name:"CIGaussianBlur")!
      gaussianfilter.setDefaults()
      gaussianfilter.setValue(ciimage, forKey: kCIInputImageKey)
      gaussianfilter.setValue(10, forKey: kCIInputRadiusKey)

      let outputImage: CIImage = gaussianfilter.outputImage!
      let finalImage: UIImage = UIImage(ciImage: outputImage.cropping(to: CROPPING_RECT), scale: SCREEN_SIZE_SCALE_FACTOR, orientation: UIImageOrientation.up)

      return finalImage

}

我在代码中看到的一个问题是我认为高斯模糊应用于整个图像（因为用于drawHierarchy矩形的UIScreen.main.bounds）。

我希望有一种方法可以执行屏幕的resizableSnapshotView（），然后在该视图中执行drawHierarchy并提取图像 - 唉，这不起作用（虽然它似乎在模拟器中，但不是在电话，它只是呈现黑色）。

有关如何制作更高效的捕捉和模糊方法的任何建议？

干杯！

Answer 1

尝试使用此扩展程序对视图进行快照并将其模糊，它似乎适用于模拟器和设备：

extenstion UIView {
    /// A more efficient way to snapshot a UIView other than UIView.snapshot
///
/// - Returns: UIImage representing the snapshot of the UIView
public func snapshotImage() -> UIImage? {
    UIGraphicsBeginImageContextWithOptions(bounds.size, isOpaque, 0)
    drawHierarchy(in: bounds, afterScreenUpdates: false)
    let snapshotImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return snapshotImage
}

public func snapshotView() -> UIView? {
    if let snapshotImage = snapshotImage() {
        return UIImageView(image: snapshotImage)
    } else {
        return nil
    }
}
}

模糊UIView的一小部分的更有效方法？

1 个答案: