效果图.gif

实现方式:

1. 新建一个ViewController,在其中使用AVFoundation框架中AVCaptureSession,AVCaptureVideoPreviewLayer,AVCaptureDevice实现前置相机功能.

2. 绘制自定义蒙层View,实现页面效果.

3. 遵循AVCaptureVideoDataOutputSampleBufferDelegate.实现拍照功能.

4. 新建ViewController实现photo预览

5. 使用protocol实现相片回调.

---

1.实现前置相机功能.

    private func drawCamera() {
        /// SessionPreset,用于设置output输出流的bitrate或者说画面质量
        captureSession.sessionPreset = AVCaptureSession.Preset.photo
        /// 获取输入设备,builtInWideAngleCamera是通用相机,AVMediaType.video代表视频媒体,front表示前置摄像头,如果需要后置摄像头修改为back
        let availableDevices = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .front).devices
        /// 获取前置摄像头
        captureDevice = availableDevices.first
        beginSession()
    }
/// 开始相机功能
    private func beginSession() {
        captureSession.beginConfiguration()
        do {
            /// 将前置摄像头作为session的input输入流
            let captureDeviceInput = try AVCaptureDeviceInput(device: captureDevice)
            captureSession.addInput(captureDeviceInput)
        }catch {
            print(error.localizedDescription)
        }
        /// 设定视频预览层,也就是相机预览layer
        let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        self.previewLayer = previewLayer
        self.view.layer.addSublayer(self.previewLayer)
        self.previewLayer.frame = self.view.layer.frame
        /// 相机页面展现形式
        self.previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill /// 拉伸充满frame
        /// 设定输出流
        let dataOutput = AVCaptureVideoDataOutput()
        /// 指定像素格式
        dataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString):NSNumber(value:kCVPixelFormatType_32BGRA)] as [String : Any]
        /// 是否直接丢弃处理旧帧时捕获的新帧,默认为True,如果改为false会大幅提高内存使用
        dataOutput.alwaysDiscardsLateVideoFrames = true
        /// 将输出流加入session
        if captureSession.canAddOutput(dataOutput) {
            captureSession.addOutput(dataOutput)
        }
        /// beginConfiguration()和commitConfiguration()方法中的修改将在commit时同时提交
        captureSession.commitConfiguration()
        captureSession.startRunning()
        /// 开新线程进行输出流代理方法调用
        let queue = DispatchQueue(label: "com.brianadvent.captureQueue")
        dataOutput.setSampleBufferDelegate(self, queue: queue)
    }

2.绘制自定义蒙层View,实现页面效果.

    private func drawCoverView() {
        self.view.addSubview(overlayView)
        self.view.addSubview(clearView)
        let maskLayer = CAShapeLayer()
        let path = CGMutablePath()
        // 裁切View左侧side
        path.addRect(CGRect(x: 0, y: 0, width: self.clearView.frame.origin.x, height: self.overlayView.frame.size.height))
        // 裁切View右侧side
        path.addRect(CGRect(
            x: self.clearView.frame.origin.x + self.clearView.frame.size.width, y: 0, width: self.overlayView.frame.size.width - self.clearView.frame.origin.x - self.clearView.frame.size.width, height: self.overlayView.frame.size.height))
        // 裁切View上方side
        path.addRect(CGRect(x: 0, y: 0, width: self.overlayView.frame.size.width, height: self.clearView.frame.origin.y))
        // 裁切View下方side
        path.addRect(CGRect(x: 0, y: self.clearView.frame.origin.y + self.clearView.frame.size.height, width: self.overlayView.frame.size.width, height: self.overlayView.frame.size.height - self.clearView.frame.origin.y + self.clearView.frame.size.height))
        maskLayer.path = path
        /// 修改overlayView.将裁切View区域空白出来
        self.overlayView.layer.mask = maskLayer
        path.closeSubpath()
    }

3.遵循AVCaptureVideoDataOutputSampleBufferDelegate.实现拍照功能.

/// 相册输出流代理
extension EWPhotoPickerViewController: AVCaptureVideoDataOutputSampleBufferDelegate{
    /// 输出流代理方法,实时调用
    func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
        /// 判断takePhoto状态,如果为True代表执行拍照动作
        if takePhoto {
            takePhoto = false
            /// 获取预览photo并将其传到相片预览页
            if let image = self.getImageFromSampleBuffer(buffer: sampleBuffer) {
                DispatchQueue.main.async {
                    let photoShowVC = EWPhotoShowViewController()
                    photoShowVC.photoShowImageView.image = image
                    photoShowVC.delegate = self.delegate
                    self.navigationController?.pushViewController(photoShowVC, animated: true)
                    self.stopCaptureSession()
                }
            }
        }
    }
}

4. 新建ViewController实现photo预览

open class EWPhotoShowViewController: UIViewController {
    public var delegate: EWPhotoFinishDelegate?
    public let photoShowImageView: UIImageView = {
        let imageView = UIImageView(frame: UIScreen.main.bounds)
        imageView.contentMode = .center
        return imageView
    }()

    override open func viewDidLoad() {
        super.viewDidLoad()
        self.view.addSubview(photoShowImageView)
        self.view.backgroundColor = UIColor.black
        self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "完成", style: .plain, target: self, action: #selector(onClickCompleteButton))
    }
    @objc private func onClickCompleteButton(){
        if delegate != nil{
            if self.delegate!.responds(to: #selector(EWPhotoFinishDelegate.photo(_:didFinished:))) {
                self.delegate!.photo(self, didFinished: self.photoShowImageView.image!)
            }
        }
    }
}

5. 使用protocol实现相片回调.

/// 预览后照片返回协议
@objc public protocol EWPhotoFinishDelegate : NSObjectProtocol {
    func photo(_ viewController: EWPhotoShowViewController, didFinished photo: UIImage)
}
extension ViewController: EWPhotoFinishDelegate{
    func photo(_ viewController: EWPhotoShowViewController, didFinished photo: UIImage) {
        viewController.navigationController?.dismiss(animated: true, completion: {
            self.showImageView.image = photo
        })
    }
}

---

总结:

主要运用了AVFoundation中AVCaptureSession相关知识,以这种方式调用本机硬件设备,可以实现自定义相机界面,还是有很多情景需要类似功能的.

还有很多属性可以添加,例如闪光灯效果,点击聚焦,点击切换镜头等功能,在这里没有实现,如果有需要的朋友可以私密我给加上.

---

demo地址: EWPhotoPicker

有问题欢迎探讨.