AVLayerVideoGravityResize 在新设备上不匹配，iOS 10？
AVLayerVideoGravityResize does not match on new devices, iOS 10?
带全屏实时预览功能的相机，
previewLayer!.videoGravity = AVLayerVideoGravityResize
制作图像...
stillImageOutput?.captureStillImageAsynchronously(
from: videoConnection, completionHandler:
全屏实时预览将或应该与静止图像精确匹配。
（为清楚起见：假设您不小心使用了 AVLayerVideoGravityResizeAspectFill。在这种情况下，实时预览将与静止图像不匹配 - 您会在拉伸时看到“跳跃”。）
然而...
如果您尝试以下操作（因此使用 AVLayerVideoGravityResize - 正确的选择）和 iOS10...
它并不完全有效：你在实时预览和静止图像之间得到一个小跳跃。一个或另一个稍微拉伸不正确。
这实际上可能只是某些设备的错误吗？或 iOS?
（它在旧设备上运行完美 - 没有跳转，如果你用 iOS9 试试。）
还有其他人看过吗？
// CameraPlane ... the actual live camera plane per se
import UIKit
import AVFoundation
class CameraPlane:UIViewController
{
var captureSession: AVCaptureSession?
var stillImageOutput: AVCaptureStillImageOutput?
var previewLayer: AVCaptureVideoPreviewLayer?
fileprivate func fixConnectionOrientation()
{
if let connection = self.previewLayer?.connection
{
let previewLayerConnection : AVCaptureConnection = connection
guard previewLayerConnection.isVideoOrientationSupported else
{
print("strangely no orientation support")
return
}
previewLayerConnection.videoOrientation = neededVideoOrientation()
previewLayer!.frame = view.bounds
}
}
func neededVideoOrientation()->(AVCaptureVideoOrientation)
{
let currentDevice:UIDevice = UIDevice.current
let orientation: UIDeviceOrientation = currentDevice.orientation
var r:AVCaptureVideoOrientation
switch (orientation)
{
case .portrait: r = .portrait
break
case .landscapeRight: r = .landscapeLeft
break
case .landscapeLeft: r = .landscapeRight
break
case .portraitUpsideDown: r = .portraitUpsideDown
break
default: r = .portrait
break
}
return r
}
override func viewDidLayoutSubviews()
{
super.viewDidLayoutSubviews()
fixConnectionOrientation()
}
func cameraBegin()
{
captureSession = AVCaptureSession()
captureSession!.sessionPreset = AVCaptureSessionPresetPhoto
// remember that of course, none of this will work on a simulator, only on a device
let backCamera = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
var error: NSError?
var input: AVCaptureDeviceInput!
do {
input = try AVCaptureDeviceInput(device: backCamera)
} catch let error1 as NSError
{
error = error1
input = nil
}
if ( error != nil )
{
print("probably on simulator? no camera?")
return;
}
if ( captureSession!.canAddInput(input) == false )
{
print("capture session problem?")
return;
}
captureSession!.addInput(input)
stillImageOutput = AVCaptureStillImageOutput()
stillImageOutput!.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
if ( captureSession!.canAddOutput(stillImageOutput) == false )
{
print("capture session with stillImageOutput problem?")
return;
}
captureSession!.addOutput(stillImageOutput)
previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
// previewLayer!.videoGravity = AVLayerVideoGravityResizeAspect
// means, won't reach the top and bottom on devices, gray bars
// previewLayer!.videoGravity = AVLayerVideoGravityResizeAspectFill
// means, you get the "large squeeze" once you make photo
previewLayer!.videoGravity = AVLayerVideoGravityResize
// works perfectly on ios9, older devices etc.
// on 6s+, you get a small jump between the video live preview and the make photo
fixConnectionOrientation()
view.layer.addSublayer(previewLayer!)
captureSession!.startRunning()
previewLayer!.frame = view.bounds
}
/*Video Gravity.
These string constants define how the video is displayed within a layer’s bounds rectangle.
You use these constants when setting the videoGravity property of an AVPlayerLayer or AVCaptureVideoPreviewLayer instance.
AVLayerVideoGravityResize
Specifies that the video should be stretched to fill the layer’s bounds.
AVLayerVideoGravityResizeAspect
Specifies that the player should preserve the video’s aspect ratio and fit the video within the layer’s bounds.
AVLayerVideoGravityResizeAspectFill
Specifies that the player should preserve the video’s aspect ratio and fill the layer’s bounds.
*/
func makePhotoOn(_ here:UIImageView)
{
// recall that this indeed makes a still image, which is used as
// a new background image (indeed on the "stillImage" view)
// and you can then continue to move the door around on that scene.
if ( stillImageOutput == nil )
{
print("simulator, using test image.")
here.image = UIImage(named:"ProductMouldings.jpg")
return
}
guard let videoConnection = stillImageOutput!.connection(withMediaType: AVMediaTypeVideo)
else
{
print("AVMediaTypeVideo didn't work?")
return
}
videoConnection.videoOrientation = (previewLayer!.connection?.videoOrientation)!
stillImageOutput?.captureStillImageAsynchronously(
from: videoConnection, completionHandler:
{
(sampleBuffer, error) in
guard sampleBuffer != nil else
{
print("sample buffer woe?")
return
}
let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer)
let dataProvider = CGDataProvider(data: imageData as! CFData)
let cgImageRef = CGImage(jpegDataProviderSource: dataProvider!, decode: nil, shouldInterpolate: true, intent: CGColorRenderingIntent.defaultIntent)
let ort = self.neededImageOrientation()
let image = UIImage(cgImage:cgImageRef!, scale:1.0, orientation:ort)
here.image = image
})
}
func neededImageOrientation()->(UIImageOrientation)
{
var n : UIImageOrientation
let currentDevice: UIDevice = UIDevice.current
let orientation: UIDeviceOrientation = currentDevice.orientation
switch orientation
{
case UIDeviceOrientation.portraitUpsideDown:
n = .left
case UIDeviceOrientation.landscapeRight:
n = .down
case UIDeviceOrientation.landscapeLeft:
n = .up
case UIDeviceOrientation.portrait:
n = .right
default:
n = .right
}
return n
}
/*
@IBAction func didPressTakeAnother(sender: AnyObject)
{ captureSession!.startRunning() }
*/
}
完整性检查 - 您确定 AVLayerVideoGravityResize 是您要使用的吗？这会将图像（不保留宽高比）拉伸到预览帧。如果您打算保持纵横比，您要么想要 AVLayerVideoGravityResizeAspect（正如您观察到的那样，会有灰色条，但纵横比将保持不变）或 AVLayerVideoGravityResizeAspectFill（可能是您想要的 - 的一部分预览将被截断，但纵横比将保持不变）。
假设您的 'here' 视图（传递给 makePhotoOn: 的视图）与预览视图相同 size/position，您需要设置 'here' 视图的 contentMode 以匹配预览的行为。
因此，如果您使用 AVLayerVideoGravityResizeAspect 进行预览，则：
here.contentMode = .scaleAspectFit
如果您使用 AVLayerVideoGravityResizeAspectFill 进行预览，则：
here.contentMode = .scaleAspectFill.
视图的默认 contentMode 是 .scaleToFill（此处注明：https://developer.apple.com/reference/uikit/uiview/1622619-contentmode）因此您的 'here' imageView 可能会拉伸图像以匹配其大小，而不是保持纵横比。
如果这没有帮助，您可以考虑提供一个在 github 上展示问题的准系统项目，以便我们中的 SO 修补匠可以快速构建和修补它。
带全屏实时预览功能的相机，
previewLayer!.videoGravity = AVLayerVideoGravityResize
制作图像...
stillImageOutput?.captureStillImageAsynchronously(
from: videoConnection, completionHandler:
全屏实时预览将或应该与静止图像精确匹配。
（为清楚起见：假设您不小心使用了 AVLayerVideoGravityResizeAspectFill。在这种情况下，实时预览将与静止图像不匹配 - 您会在拉伸时看到“跳跃”。）
然而...
如果您尝试以下操作（因此使用 AVLayerVideoGravityResize - 正确的选择）和 iOS10...
它并不完全有效：你在实时预览和静止图像之间得到一个小跳跃。一个或另一个稍微拉伸不正确。
这实际上可能只是某些设备的错误吗？或 iOS?
（它在旧设备上运行完美 - 没有跳转，如果你用 iOS9 试试。）
还有其他人看过吗？
// CameraPlane ... the actual live camera plane per se
import UIKit
import AVFoundation
class CameraPlane:UIViewController
{
var captureSession: AVCaptureSession?
var stillImageOutput: AVCaptureStillImageOutput?
var previewLayer: AVCaptureVideoPreviewLayer?
fileprivate func fixConnectionOrientation()
{
if let connection = self.previewLayer?.connection
{
let previewLayerConnection : AVCaptureConnection = connection
guard previewLayerConnection.isVideoOrientationSupported else
{
print("strangely no orientation support")
return
}
previewLayerConnection.videoOrientation = neededVideoOrientation()
previewLayer!.frame = view.bounds
}
}
func neededVideoOrientation()->(AVCaptureVideoOrientation)
{
let currentDevice:UIDevice = UIDevice.current
let orientation: UIDeviceOrientation = currentDevice.orientation
var r:AVCaptureVideoOrientation
switch (orientation)
{
case .portrait: r = .portrait
break
case .landscapeRight: r = .landscapeLeft
break
case .landscapeLeft: r = .landscapeRight
break
case .portraitUpsideDown: r = .portraitUpsideDown
break
default: r = .portrait
break
}
return r
}
override func viewDidLayoutSubviews()
{
super.viewDidLayoutSubviews()
fixConnectionOrientation()
}
func cameraBegin()
{
captureSession = AVCaptureSession()
captureSession!.sessionPreset = AVCaptureSessionPresetPhoto
// remember that of course, none of this will work on a simulator, only on a device
let backCamera = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
var error: NSError?
var input: AVCaptureDeviceInput!
do {
input = try AVCaptureDeviceInput(device: backCamera)
} catch let error1 as NSError
{
error = error1
input = nil
}
if ( error != nil )
{
print("probably on simulator? no camera?")
return;
}
if ( captureSession!.canAddInput(input) == false )
{
print("capture session problem?")
return;
}
captureSession!.addInput(input)
stillImageOutput = AVCaptureStillImageOutput()
stillImageOutput!.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
if ( captureSession!.canAddOutput(stillImageOutput) == false )
{
print("capture session with stillImageOutput problem?")
return;
}
captureSession!.addOutput(stillImageOutput)
previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
// previewLayer!.videoGravity = AVLayerVideoGravityResizeAspect
// means, won't reach the top and bottom on devices, gray bars
// previewLayer!.videoGravity = AVLayerVideoGravityResizeAspectFill
// means, you get the "large squeeze" once you make photo
previewLayer!.videoGravity = AVLayerVideoGravityResize
// works perfectly on ios9, older devices etc.
// on 6s+, you get a small jump between the video live preview and the make photo
fixConnectionOrientation()
view.layer.addSublayer(previewLayer!)
captureSession!.startRunning()
previewLayer!.frame = view.bounds
}
/*Video Gravity.
These string constants define how the video is displayed within a layer’s bounds rectangle.
You use these constants when setting the videoGravity property of an AVPlayerLayer or AVCaptureVideoPreviewLayer instance.
AVLayerVideoGravityResize
Specifies that the video should be stretched to fill the layer’s bounds.
AVLayerVideoGravityResizeAspect
Specifies that the player should preserve the video’s aspect ratio and fit the video within the layer’s bounds.
AVLayerVideoGravityResizeAspectFill
Specifies that the player should preserve the video’s aspect ratio and fill the layer’s bounds.
*/
func makePhotoOn(_ here:UIImageView)
{
// recall that this indeed makes a still image, which is used as
// a new background image (indeed on the "stillImage" view)
// and you can then continue to move the door around on that scene.
if ( stillImageOutput == nil )
{
print("simulator, using test image.")
here.image = UIImage(named:"ProductMouldings.jpg")
return
}
guard let videoConnection = stillImageOutput!.connection(withMediaType: AVMediaTypeVideo)
else
{
print("AVMediaTypeVideo didn't work?")
return
}
videoConnection.videoOrientation = (previewLayer!.connection?.videoOrientation)!
stillImageOutput?.captureStillImageAsynchronously(
from: videoConnection, completionHandler:
{
(sampleBuffer, error) in
guard sampleBuffer != nil else
{
print("sample buffer woe?")
return
}
let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer)
let dataProvider = CGDataProvider(data: imageData as! CFData)
let cgImageRef = CGImage(jpegDataProviderSource: dataProvider!, decode: nil, shouldInterpolate: true, intent: CGColorRenderingIntent.defaultIntent)
let ort = self.neededImageOrientation()
let image = UIImage(cgImage:cgImageRef!, scale:1.0, orientation:ort)
here.image = image
})
}
func neededImageOrientation()->(UIImageOrientation)
{
var n : UIImageOrientation
let currentDevice: UIDevice = UIDevice.current
let orientation: UIDeviceOrientation = currentDevice.orientation
switch orientation
{
case UIDeviceOrientation.portraitUpsideDown:
n = .left
case UIDeviceOrientation.landscapeRight:
n = .down
case UIDeviceOrientation.landscapeLeft:
n = .up
case UIDeviceOrientation.portrait:
n = .right
default:
n = .right
}
return n
}
/*
@IBAction func didPressTakeAnother(sender: AnyObject)
{ captureSession!.startRunning() }
*/
}
完整性检查 - 您确定 AVLayerVideoGravityResize 是您要使用的吗？这会将图像（不保留宽高比）拉伸到预览帧。如果您打算保持纵横比，您要么想要 AVLayerVideoGravityResizeAspect（正如您观察到的那样，会有灰色条，但纵横比将保持不变）或 AVLayerVideoGravityResizeAspectFill（可能是您想要的 - 的一部分预览将被截断，但纵横比将保持不变）。
假设您的 'here' 视图（传递给 makePhotoOn: 的视图）与预览视图相同 size/position，您需要设置 'here' 视图的 contentMode 以匹配预览的行为。
因此，如果您使用 AVLayerVideoGravityResizeAspect 进行预览，则：
here.contentMode = .scaleAspectFit
如果您使用 AVLayerVideoGravityResizeAspectFill 进行预览，则：
here.contentMode = .scaleAspectFill.
视图的默认 contentMode 是 .scaleToFill（此处注明：https://developer.apple.com/reference/uikit/uiview/1622619-contentmode）因此您的 'here' imageView 可能会拉伸图像以匹配其大小，而不是保持纵横比。
如果这没有帮助，您可以考虑提供一个在 github 上展示问题的准系统项目，以便我们中的 SO 修补匠可以快速构建和修补它。