在Swift中使用AVFoundation捕獲照片

Question

我正在迅速構建一個實時濾鏡相機應用程序。

我從AVCaptureVideoDataOutput（）更改為AVCaptureStillImageOutput（）以執行拍攝照片功能。 更改后，打開應用程序時將沒有預覽視圖。

拍攝照片功能正在運行，單擊主組區域時可以聽到拍攝聲音“ Ka”。 這里沒有風景。

這是我的完整代碼

import Foundation
import UIKit
import AVFoundation
import CoreMedia

let CIHueAdjust = "CIHueAdjust"
let CIHueAdjustFilter = CIFilter(name: "CIHueAdjust", withInputParameters: ["inputAngle" : 1.24])

let Filters = [CIHueAdjust: CIHueAdjustFilter]

let FilterNames = [String](Filters.keys).sort()

class LiveCamViewController :       UIViewController,AVCaptureVideoDataOutputSampleBufferDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate{
let mainGroup = UIStackView()
let imageView = UIImageView(frame: CGRectZero)
let filtersControl = UISegmentedControl(items: FilterNames)
var videoOutput = AVCaptureStillImageOutput()

override func viewDidLoad()
{
    super.viewDidLoad()

    view.addSubview(mainGroup)
    mainGroup.axis = UILayoutConstraintAxis.Vertical
    mainGroup.distribution = UIStackViewDistribution.Fill

    mainGroup.addArrangedSubview(imageView)
    mainGroup.addArrangedSubview(filtersControl)
    mainGroup.addGestureRecognizer(UITapGestureRecognizer(target: self, action:#selector(LiveCamViewController.saveToCamera(_:))))

    imageView.contentMode = UIViewContentMode.ScaleAspectFit

    filtersControl.selectedSegmentIndex = 0

    let captureSession = AVCaptureSession()
    captureSession.sessionPreset = AVCaptureSessionPresetPhoto

    let backCamera = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)

    do
    {
        let input = try AVCaptureDeviceInput(device: backCamera)

        captureSession.addInput(input)
    }
    catch
    {
        print("can't access camera")
        return
    }

    //get captureOutput invoked
    let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    view.layer.addSublayer(previewLayer)

    videoOutput.outputSettings = [AVVideoCodecKey:AVVideoCodecJPEG]

    if captureSession.canAddOutput(videoOutput)
    {
        captureSession.addOutput(videoOutput)
    }

    captureSession.startRunning()
}

func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!)
{
    guard let filter = Filters[FilterNames[filtersControl.selectedSegmentIndex]] else
    {
        return
    }

    let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
    let cameraImage = CIImage(CVPixelBuffer: pixelBuffer!)

    filter!.setValue(cameraImage, forKey: kCIInputImageKey)

    let filteredImage = UIImage(CIImage: filter!.valueForKey(kCIOutputImageKey) as! CIImage!)
    let fixedImage = correctlyOrientedImage(filteredImage)

    dispatch_async(dispatch_get_main_queue())
    {
        self.imageView.image = fixedImage
    }

}

func correctlyOrientedImage(image: UIImage) -> UIImage {

    UIGraphicsBeginImageContextWithOptions(image.size, false, image.scale)
    image.drawInRect(CGRectMake(0, 0, image.size.width, image.size.height))
    let normalizedImage:UIImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    let imageRef: CGImageRef = normalizedImage.CGImage!
    let rotatedImage: UIImage = UIImage(CGImage: imageRef, scale: 1.0, orientation: .Right)

    return rotatedImage
}

override func viewDidLayoutSubviews()
{
    mainGroup.frame = CGRect(x: 37, y: 115, width: 301, height: 481)
}

func saveToCamera(sender: UITapGestureRecognizer) {

    videoOutput.outputSettings = [AVVideoCodecKey:AVVideoCodecJPEG]

    if let videoConnection = videoOutput.connectionWithMediaType(AVMediaTypeVideo) {
        videoOutput.captureStillImageAsynchronouslyFromConnection(videoConnection) {
            (imageDataSampleBuffer, error) -> Void in
            let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(imageDataSampleBuffer)
            UIImageWriteToSavedPhotosAlbum(UIImage(data: imageData)!, nil, nil, nil)
        }
    }
}

}

謝謝。

Answer 1

如果要從相機捕獲照片或視頻，則應使用UIImagePickerController而不是AVFoundation 。 查看Applce文檔以獲取有關它的更多信息。

更新：

請參考此鏈接 。 它有太多自定義imagePickercontroller示例。 您可以參考這個和這個 stackobverflow的答案。

希望這會有所幫助:)

Answer 2

問題可能是因為您沒有previewLayer的框架。

輸入：

previewLayer.frame = self.view.bounds

並顯式設置視頻重力：（我認為這是可選的）

previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill // Or choose some other option if you prefer