问题
I have a view controller which allows a user to take a picture. I am setting the avcapture bounds to be the bounds of a view on screen.
Above this view I have a collection view. So users can capture multiple pictures, they are then added to the collection view above.
I am having trouble with the correct orientation appearing in my preview above.
Code is as follows:
@IBOutlet weak var imagePreviews: UICollectionView!
@IBOutlet weak var imgPreview: UIView!
var session: AVCaptureSession?
var stillImageOutput: AVCaptureStillImageOutput?
var videoPreviewLayer: AVCaptureVideoPreviewLayer?
var images: [UIImage] = [UIImage]()
var isLandscapeLeft : Bool = false
var isLandscapeRight : Bool = false
var isPortrait : Bool = false
var isPortraitUpsideDown: Bool = false
@IBAction func capture(_ sender: UIButton)
{
if let videoConnection = stillImageOutput?.connection(withMediaType: AVMediaTypeVideo)
{
stillImageOutput?.captureStillImageAsynchronously(from: videoConnection, completionHandler: { (sampleBuffer, error) in
if sampleBuffer != nil {
if let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer), let dataProvider = CGDataProvider(data: imageData as CFData), let cgImageRef = CGImage(jpegDataProviderSource: dataProvider, decode: nil, shouldInterpolate: true, intent: CGColorRenderingIntent.defaultIntent)
{
var image: UIImage
if (self.isLandscapeLeft || self.isLandscapeRight)
{
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: self.isLandscapeLeft ? UIImageOrientation.left : UIImageOrientation.right)
} else {
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: self.isPortrait ? UIImageOrientation.up : UIImageOrientation.down)
}
image = self.fixOrientation(img: image)
self.images.append(image)
DispatchQueue.main.async {
self.imagePreviews.reloadData()
}
}
}
})
}
}
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
if let connection = self.videoPreviewLayer?.connection {
let currentDevice: UIDevice = UIDevice.current
let orientation: UIDeviceOrientation = currentDevice.orientation
let previewLayerConnection : AVCaptureConnection = connection
if (previewLayerConnection.isVideoOrientationSupported) {
switch (orientation) {
case .portrait:
isLandscapeLeft = false
isLandscapeRight = false
isPortrait = true
isPortraitUpsideDown = false
updatePreviewLayer(layer: previewLayerConnection, orientation: .portrait)
break
case .landscapeRight:
isLandscapeLeft = false
isLandscapeRight = true
isPortrait = false
isPortraitUpsideDown = false
updatePreviewLayer(layer: previewLayerConnection, orientation: .landscapeRight)
break
case .landscapeLeft:
isLandscapeLeft = true
isLandscapeRight = false
isPortrait = false
isPortraitUpsideDown = false
updatePreviewLayer(layer: previewLayerConnection, orientation: .landscapeLeft)
break
case .portraitUpsideDown:
isLandscapeLeft = false
isLandscapeRight = false
isPortrait = false
isPortraitUpsideDown = true
updatePreviewLayer(layer: previewLayerConnection, orientation: .portraitUpsideDown)
break
default:
updatePreviewLayer(layer: previewLayerConnection, orientation: .portrait)
break
}
}
}
}
func fixOrientation(img: UIImage) -> UIImage {
if (img.imageOrientation == .up) {
return img
}
UIGraphicsBeginImageContextWithOptions(img.size, false, img.scale)
let rect = CGRect(x: 0, y: 0, width: img.size.width, height: img.size.height)
img.draw(in: rect)
let normalizedImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return normalizedImage
}
回答1:
When creating the image from a portrait orientation device, you should consider that a UIImage that has been rotated 90 degrees, e.g.:
switch UIApplication.shared.statusBarOrientation {
case .portrait:
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: .right)
case .landscapeRight:
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: .up)
case .landscapeLeft:
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: .down)
case .portraitUpsideDown:
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: .left)
default:
fatalError("Unexpected orientation")
}
For a complete example, see:
import UIKit
import AVFoundation
class ViewController: UIViewController {
@IBOutlet weak var imageView: UIImageView!
@IBOutlet weak var videoPreviewView: UIView!
var videoPreviewLayer: AVCaptureVideoPreviewLayer!
var session: AVCaptureSession = AVCaptureSession()
var stillImageOutput: AVCaptureStillImageOutput = {
let output = AVCaptureStillImageOutput()
output.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
return output
}()
var images: [UIImage] = [UIImage]()
var orientation = UIApplication.shared.statusBarOrientation
override func viewDidLoad() {
super.viewDidLoad()
guard let device = AVCaptureDevice.default(for: .video) else {
print("Unable to create capture device")
return
}
let input: AVCaptureDeviceInput
do {
input = try AVCaptureDeviceInput(device: device)
} catch {
print("Unable to create input", error)
return
}
guard session.canAddInput(input) else {
print("Cannot add input")
return
}
session.addInput(input)
guard session.canAddOutput(stillImageOutput) else {
print("Cannot add output")
return
}
session.addOutput(stillImageOutput)
session.startRunning()
videoPreviewLayer = AVCaptureVideoPreviewLayer(session: session)
videoPreviewView.layer.addSublayer(videoPreviewLayer)
}
@IBAction func didTapCaptureButton(_ sender: Any) {
if let connection = stillImageOutput.connection(with: .video) {
stillImageOutput.captureStillImageAsynchronously(from: connection) { sampleBuffer, error in
guard let sampleBuffer = sampleBuffer, error == nil else {
print(error ?? "Unknown error")
return
}
guard
let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer),
let dataProvider = CGDataProvider(data: imageData as CFData),
let cgImageRef = CGImage(jpegDataProviderSource: dataProvider, decode: nil, shouldInterpolate: true, intent: .defaultIntent) else {
print("unable to capture image")
return
}
var image: UIImage?
switch self.orientation {
case .portrait:
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: .right)
case .landscapeRight:
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: .up)
case .landscapeLeft:
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: .down)
case .portraitUpsideDown:
image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: .left)
default:
fatalError("Unexpected orientation")
}
guard image != nil else {
print("unable to create UIImage")
return
}
DispatchQueue.main.async {
self.images.append(image!)
self.imageView.image = image
}
}
}
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
if let connection = self.videoPreviewLayer?.connection {
orientation = UIApplication.shared.statusBarOrientation
switch orientation {
case .portrait: updatePreviewOrientation(for: connection, to: .portrait)
case .landscapeRight: updatePreviewOrientation(for: connection, to: .landscapeRight)
case .landscapeLeft: updatePreviewOrientation(for: connection, to: .landscapeLeft)
case .portraitUpsideDown: updatePreviewOrientation(for: connection, to: .portraitUpsideDown)
default: updatePreviewOrientation(for: connection, to: .portrait)
}
}
}
private func updatePreviewOrientation(for connection: AVCaptureConnection, to orientation: AVCaptureVideoOrientation) {
if connection.isVideoOrientationSupported {
connection.videoOrientation = orientation
}
videoPreviewLayer.frame = videoPreviewView.bounds
}
}
You are manually converting the image orientation in fixOrientation. Once you create UIImage from CGImage using the appropriate orientation, you don't have to mess around with recreating the image if you don't want.
来源：https://stackoverflow.com/questions/46913953/avcapture-image-orientation