如何自定义相机视图并捕获叠加层中的部分？

Question

我需要构建一个类似这样的自定义相机视图：example image

我使用了 AVFoundation 并在 AVCaptureVideoPreviewLayer 上放置了一个 UIImageView，它看起来几乎相同（虽然我不确定这是否是正确的方法，我就是这样写标题的）。我正在捕获图像并将其保存到画廊，但我只需要中间矩形中的图像。

有什么建议吗？

提前致谢！

Answer 1

实际上，来自 Nishant Bhindi 的答案需要一些更正。下面的代码将完成这项工作：

func cropToBounds(image: UIImage) -> UIImage
{
    let contextImage: UIImage = UIImage(cgImage: image.cgImage!)
    let contextSize: CGSize = contextImage.size
    let widthRatio = contextSize.height/UIScreen.main.bounds.size.height
    let heightRatio = contextSize.width/UIScreen.main.bounds.size.width

    let width = (self.imgOverlay?.frame.size.width)!*widthRatio
    let height = (self.imgOverlay?.frame.size.height)!*heightRatio
    let x = (contextSize.width/2) - width/2
    let y = (contextSize.height/2) - height/2
    let rect = CGRect(x: x, y: y, width: width, height: height)

    let imageRef: CGImage = contextImage.cgImage!.cropping(to: rect)!
    let image: UIImage = UIImage(cgImage: imageRef, scale: 0, orientation: image.imageOrientation)
    return image
}

Answer 2

您需要在覆盖 imageView 的上下文中裁剪图像。将捕获的图像传递到下面的函数中，这可能会对您有所帮助。

func cropToBounds(image: UIImage) -> UIImage
{
        let contextImage: UIImage = UIImage(cgImage: image.cgImage!)
        let contextSize: CGSize = contextImage.size
        let widthRatio = contextSize.height/UIScreen.main.bounds.size.width
        let heightRatio = contextSize.width/UIScreen.main.bounds.size.height

        let width = (self.imgOverlay?.frame.size.width)!*widthRatio
        let height = (self.imgOverlay?.frame.size.height)!*heightRatio
        let x = ((self.imgOverlay?.frame.origin.x)!)*widthRatio
        let y = (self.imgOverlay?.frame.origin.y)!*heightRatio
        let rect = CGRect(x: x, y: y, width: height, height: width)

        let imageRef: CGImage = contextImage.cgImage!.cropping(to: rect)!
        let image: UIImage = UIImage(cgImage: imageRef, scale: image.scale, orientation: image.imageOrientation)
        return image
}