如何自定义相机视图并捕获叠加中的零件？

Question

我需要构建类似于以下内容的自定义相机视图： 示例图像

我使用了AVFoundation并将UIImageView放在AVCaptureVideoPreviewLayer上，它看起来几乎是相同的（尽管我不确定这是否正确，这就是我这样写标题的方式）。 我正在捕获图像并将其保存到图库，但是我只需要中间矩形区域中的图像即可。

有什么建议怎么做吗？

提前致谢！

Answer 1

您需要在叠加图像视图的上下文中裁剪图像。在下面的功能中传递捕获的图像可能会有所帮助。

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
}

Answer 2

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

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
}