iOS 10中新特性：
- 有史以来第一次，你的app 可以拍摄和编辑
live photos - 可以响应不同的图片捕获
一、相机捕获内容显示（输入）
- 创建名为PhotoMe并设置只有IPhone使用的项目，竖屏。
- 授权：在Info.plist 中添加
<key>NSCameraUsageDescription</key>
<string>PhotoMe needs the camera to take photos. Duh!</string>
<key>NSMicrophoneUsageDescription</key>
<string>PhotoMe needs the microphone to record audio with Live Photos.</string>
<key>NSPhotoLibraryUsageDescription</key>
<string>PhotoMe will save photos in the Photo Library.</string>
- 自定义View：创建名为CameraPreviewView 的UIView子类
import UIKit
import AVFoundation
import Photos
class CameraPreviewView: UIView {
//1
override class var layerClass: AnyClass {
return AVCaptureVideoPreviewLayer.self
}
//2
var cameraPreviewLayer: AVCaptureVideoPreviewLayer {
return layer as! AVCaptureVideoPreviewLayer
}
//3
var session: AVCaptureSession? {
get {
return cameraPreviewLayer.session
}
set {
cameraPreviewLayer.session = newValue
}
}
}
- 画界面：在Main.storyboard 中，拖入一个UIView，并设定约束，上，左，右和父视图对齐，宽高比为3:4，设置自定义类为CameraPreviewView，向ViewController连接名为cameraPreviewView的outlet属性。
- 在ViewController中：
import AVFoundation
添加属性：
fileprivate let session = AVCaptureSession()
fileprivate let sessionQueue = DispatchQueue(label: "com.razeware.PhotoMe.session-queue")
var videoDeviceInput: AVCaptureDeviceInput!
添加方法：
private func prepareCaptureSession() {
// 1
session.beginConfiguration()
session.sessionPreset = AVCaptureSessionPresetPhoto
do {
// 2
let videoDevice = AVCaptureDevice.defaultDevice(
withDeviceType: .builtInWideAngleCamera,
mediaType: AVMediaTypeVideo,
position: .front)
// 3
let videoDeviceInput = try
AVCaptureDeviceInput(device: videoDevice)
// 4
if session.canAddInput(videoDeviceInput) {
session.addInput(videoDeviceInput)
self.videoDeviceInput = videoDeviceInput
// 5
DispatchQueue.main.async {
self.cameraPreviewView.cameraPreviewLayer
.connection.videoOrientation = .portrait
}
} else {
print("Couldn't add device to the session")
return
}
} catch {
print("Couldn't create video device input: \(error)")
return
}
// 6
session.commitConfiguration()
}
在viewDidLoad() 中,授权，配置session：
//1
cameraPreviewView.session = session
//2
sessionQueue.suspend()
//3
AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo) {
success in
if !success {
print("Come on, it's a camera app!")
return
}
//4
self.sessionQueue.resume()
}
sessionQueue.async {
[unowned self] in
self.prepareCaptureSession()
}
在viewWillAppear() 中,启动session：
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
sessionQueue.async {
self.session.startRunning()
}
}
二、拍照（输出）
- 在ViewController 中：
添加属性：
fileprivate let photoOutput = AVCapturePhotoOutput()
prepareCaptureSession()中，prepareCaptureSession()前面：
if session.canAddOutput(photoOutput) {
session.addOutput(photoOutput)
// 必须在session启动之前配置，否则会发生闪烁
photoOutput.isHighResolutionCaptureEnabled = true
} else {
print("Unable to add photo output")
return
}
- 画界面：
- 在Main.storyboard 中设置main view 和 camera preview view 的background 为black，main view的tint color 为 orange。
- main view拖入Visual Effect View With Blur,设置约束为左，下，右与父视图对齐。 Blur Style 为 Dark。
- Visual Effect View With Blur 拖入 button，名称为Take Photo!,字体为20，并将其放入stack View 中。
- 对stack View 添加顶部距父视图为5，底部距父视图为20的约束。
- 连接button到ViewController 中：
@IBOutlet weak var shutterButton: UIButton!
@IBAction func handleShutterButtonTap(_ sender: UIButton) {
capturePhoto()
}
extension ViewController {
fileprivate func capturePhoto() {
// 1
let cameraPreviewLayerOrientation = cameraPreviewView
.cameraPreviewLayer.connection.videoOrientation
// 2
sessionQueue.async {
if let connection = self.photoOutput
.connection(withMediaType: AVMediaTypeVideo) {
connection.videoOrientation =
cameraPreviewLayerOrientation
}
// 3
let photoSettings = AVCapturePhotoSettings()
photoSettings.flashMode = .off
photoSettings.isHighResolutionPhotoEnabled = true
}
}
}
- 创建代理：因为一张照片还没处理完就可以拍另一张，所以ViewController 持有一个键为AVCapturePhotoSettings，值为代理的字典。
import AVFoundation
import Photos
class PhotoCaptureDelegate: NSObject {
// 1
var photoCaptureBegins: (() -> ())? = .none
var photoCaptured: (() -> ())? = .none
fileprivate let completionHandler: (PhotoCaptureDelegate, PHAsset?)-> ()
// 2
fileprivate var photoData: Data? = .none
// 3
init(completionHandler: @escaping (PhotoCaptureDelegate, PHAsset?) -> ()) {
self.completionHandler = completionHandler
}
// 4
fileprivate func cleanup(asset: PHAsset? = .none) {
completionHandler(self, asset)
}
}
-
原理如图：
photo capture.png - 实现代理方法
extension PhotoCaptureDelegate: AVCapturePhotoCaptureDelegate {
// Process data completed
func capture(_ captureOutput: AVCapturePhotoOutput,
didFinishProcessingPhotoSampleBuffer
photoSampleBuffer: CMSampleBuffer?,
previewPhotoSampleBuffer: CMSampleBuffer?,
resolvedSettings: AVCaptureResolvedPhotoSettings,
bracketSettings: AVCaptureBracketedStillImageSettings?,
error: Error?) {
guard let photoSampleBuffer = photoSampleBuffer else {
print("Error capturing photo \(error)")
return
}
photoData = AVCapturePhotoOutput
.jpegPhotoDataRepresentation(
forJPEGSampleBuffer: photoSampleBuffer, previewPhotoSampleBuffer: previewPhotoSampleBuffer)
}
// Entire process completed
func capture(_ captureOutput: AVCapturePhotoOutput,
didFinishCaptureForResolvedSettings
resolvedSettings: AVCaptureResolvedPhotoSettings,
error: Error?) {
// 1
guard error == nil, let photoData = photoData else {
print("Error \(error) or no data")
cleanup()
return
}
// 2
PHPhotoLibrary.requestAuthorization {
[unowned self]
(status) in
// 3
guard status == .authorized else {
print("Need authorisation to write to the photo library")
self.cleanup()
return
}
// 4
var assetIdentifier: String?
PHPhotoLibrary.shared().performChanges({
let creationRequest = PHAssetCreationRequest.forAsset()
let placeholder = creationRequest
.placeholderForCreatedAsset
creationRequest.addResource(with: .photo,
data: photoData, options: .none)
assetIdentifier = placeholder?.localIdentifier
}, completionHandler: { (success, error) in
if let error = error {
print("Error saving to the photo library: \(error)")
}
var asset: PHAsset? = .none
if let assetIdentifier = assetIdentifier {
asset = PHAsset.fetchAssets(
withLocalIdentifiers: [assetIdentifier],
options: .none).firstObject
}
self.cleanup(asset: asset)
})
}
}
}
- 在ViewController中：
添加属性：
fileprivate var photoCaptureDelegates = [Int64 : PhotoCaptureDelegate]()
在capturePhoto（）的queue 闭包末尾添加：
// 1
let uniqueID = photoSettings.uniqueID
let photoCaptureDelegate = PhotoCaptureDelegate() {
[unowned self] (photoCaptureDelegate, asset) in
self.sessionQueue.async { [unowned self] in
self.photoCaptureDelegates[uniqueID] = .none
}
}
// 2
self.photoCaptureDelegates[uniqueID] = photoCaptureDelegate
// 3
self.photoOutput.capturePhoto(
with: photoSettings, delegate: photoCaptureDelegate)
三、难以置信的
- 添加闪屏动画
在capturePhoto（）创建delegate 后，添加：
photoCaptureDelegate.photoCaptureBegins = { [unowned self] in
DispatchQueue.main.async {
self.shutterButton.isEnabled = false
self.cameraPreviewView.cameraPreviewLayer.opacity = 0
UIView.animate(withDuration: 0.2) {
self.cameraPreviewView.cameraPreviewLayer.opacity = 1
}
}
}
photoCaptureDelegate.photoCaptured = { [unowned self] in
DispatchQueue.main.async {
self.shutterButton.isEnabled = true
}
}
在PhotoCaptureDelegate的extension 中：
func capture(_ captureOutput: AVCapturePhotoOutput,
willCapturePhotoForResolvedSettings
resolvedSettings: AVCaptureResolvedPhotoSettings) {
photoCaptureBegins?()
}
func capture(_ captureOutput: AVCapturePhotoOutput,
didCapturePhotoForResolvedSettings
resolvedSettings: AVCaptureResolvedPhotoSettings) {
photoCaptured?()
}
- 展示缩略图
- 获取缩略图：在PhotoCaptureDelegate添加属性：
var thumbnailCaptured: ((UIImage?) -> ())? = .none
在代理方法didFinishProcessingPhotoSampleBuffer末尾添加:
if let thumbnailCaptured = thumbnailCaptured,
let previewPhotoSampleBuffer = previewPhotoSampleBuffer,
let cvImageBuffer =
CMSampleBufferGetImageBuffer(previewPhotoSampleBuffer) {
let ciThumbnail = CIImage(cvImageBuffer: cvImageBuffer)
let context = CIContext(options: [kCIContextUseSoftwareRenderer:
false])
let thumbnail = UIImage(cgImage: context.createCGImage(ciThumbnail,
from: ciThumbnail.extent)!, scale: 2.0, orientation: .right)
thumbnailCaptured(thumbnail)
}
-
画界面：设置switch 为 off，label 的文本颜色为white，imageView 的 clip to bounds 为 true，content mode 为 Aspect Fill。
main storyboard.png
UI.png
连线：
@IBOutlet weak var previewImageView: UIImageView!
@IBOutlet weak var thumbnailSwitch: UISwitch!
- 设置缩略图格式： 在capturePhoto（）中，创建delegate之前添加：
if self.thumbnailSwitch.isOn
&& photoSettings.availablePreviewPhotoPixelFormatTypes
.count > 0 {
photoSettings.previewPhotoFormat = [
kCVPixelBufferPixelFormatTypeKey as String :
photoSettings
.availablePreviewPhotoPixelFormatTypes.first!,
kCVPixelBufferWidthKey as String : 160,
kCVPixelBufferHeightKey as String : 160
]
}
- 展示缩略图：在创建delegate之后添加：
photoCaptureDelegate.thumbnailCaptured = { [unowned self] image in
DispatchQueue.main.async {
self.previewImageView.image = image
}
}
- Live Photos
- 画界面：在Option Stack 中拖入一Horizontal Stack View，嵌入一个switch 和 一个 label，设置switch 为 off，label 的text 为 Live Photo Mode, text color 为 white。向Control Stack 加入一个label ，text 为 capturing...，字体大小为35，hidden 为 true，text color 为 orange。
连线：
@IBOutlet weak var capturingLabel: UILabel!
@IBOutlet weak var livePhotoSwitch: UISwitch!
- 添加音频输入：在prepareCaptureSession()中，创建video device input 之后添加：
do {
let audioDevice = AVCaptureDevice.defaultDevice(withMediaType:
AVMediaTypeAudio)
let audioDeviceInput = try AVCaptureDeviceInput(device: audioDevice)
if session.canAddInput(audioDeviceInput) {
session.addInput(audioDeviceInput)
} else {
print("Couldn't add audio device to the session")
return
}
} catch {
print("Unable to create audio device input: \(error)")
return
}
- 设置Photo 输出：在photoOutput.isHighResolutionCaptureEnabled = true 之后添加：
photoOutput.isLivePhotoCaptureEnabled =
photoOutput.isLivePhotoCaptureSupported
DispatchQueue.main.async {
self.livePhotoSwitch.isEnabled =
self.photoOutput.isLivePhotoCaptureSupported
- 设置输出路径：在capturePhoto（）中，创建delegate之前添加：
if self.livePhotoSwitch.isOn {
let movieFileName = UUID().uuidString
let moviePath = (NSTemporaryDirectory() as NSString)
.appendingPathComponent("(movieFileName).mov")
photoSettings.livePhotoMovieFileURL = URL(
fileURLWithPath: moviePath)
} - 捕获live photo：在PhotoCaptureDelegate添加属性：
var capturingLivePhoto: ((Bool) -> ())? = .none
fileprivate var livePhotoMovieURL: URL? = .none
在代理方法willCapturePhotoForResolvedSettings末尾添加:
if resolvedSettings.livePhotoMovieDimensions.width > 0
&& resolvedSettings.livePhotoMovieDimensions.height > 0 {
capturingLivePhoto?(true)
}
添加代理方法：
func capture(_ captureOutput: AVCapturePhotoOutput,
didFinishRecordingLivePhotoMovieForEventualFileAt
outputFileURL: URL,
resolvedSettings: AVCaptureResolvedPhotoSettings) {
capturingLivePhoto?(false)
}
func capture(_ captureOutput: AVCapturePhotoOutput,
didFinishProcessingLivePhotoToMovieFileAt outputFileURL:
URL,
duration: CMTime,
photoDisplay photoDisplayTime: CMTime,
resolvedSettings: AVCaptureResolvedPhotoSettings,
error: Error?) {
if let error = error {
print("Error creating live photo video: \(error)")
return
}
livePhotoMovieURL = outputFileURL
}
- 添加视频到相册：在代理方法didFinishCaptureForResolvedSettings:error:)中，addResource 后添加:
if let livePhotoMovieURL = self.livePhotoMovieURL {
let movieResourceOptions = PHAssetResourceCreationOptions()
movieResourceOptions.shouldMoveFile = true
creationRequest.addResource(with: .pairedVideo,
fileURL: livePhotoMovieURL, options:
movieResourceOptions)
}
- 更新UI：在ViewController添加属性：
fileprivate var currentLivePhotoCaptures: Int = 0
在capturePhoto()中，创建delegate之后添加：
// Live photo UI updates
photoCaptureDelegate.capturingLivePhoto = { (currentlyCapturing) in
DispatchQueue.main.async { [unowned self] in
self.currentLivePhotoCaptures += currentlyCapturing ? 1 : -1
UIView.animate(withDuration: 0.2) {
self.capturingLabel.isHidden =
self.currentLivePhotoCaptures == 0
}
}
}
