iOS音視頻學習9——AVFoundation拍照

UIImagePickerController確實強大，但是與MPMoviePlayerController類似，由于它的高度封裝性，要進行某些自定義工作就比較復雜了。例如要做出一款類似于美顏相機的拍照界面就比較難以實現了，此時就可以考慮使用AVFoundation來實現。
AVFoundation中提供了很多現成的播放器和錄音機，但是事實上它還有更加底層的內容可以供開發者使用。因為AVFoundation中抽了很多和底層輸入、輸出設備打交道的類，依靠這些類開發人員面對的不再是封裝好的音頻播放器AVAudioPlayer、錄音機（AVAudioRecorder）、視頻（包括音頻）播放器AVPlayer，而是輸入設備（例如麥克風、攝像頭）、輸出設備（圖片、視頻）等。

首先了解一下使用AVFoundation做拍照和視頻錄制開發用到的相關類：

AVCaptureSession：媒體（音、視頻）捕獲會話，負責把捕獲的音視頻數據輸出到輸出設備中。一個AVCaptureSession可以有多個輸入輸出：
AVCaptureDevice：輸入設備，包括麥克風、攝像頭，通過該對象可以設置物理設備的一些屬性（例如相機聚焦、白平衡等）。
AVCaptureDeviceInput：設備輸入數據管理對象，可以根據AVCaptureDevice創建對應的AVCaptureDeviceInput對象，該對象將會被添加到AVCaptureSession中管理。
AVCaptureOutput：輸出數據管理對象，用于接收各類輸出數據，通常使用對應的子類AVCaptureAudioDataOutput、AVCaptureStillImageOutput、AVCaptureVideoDataOutput、AVCaptureFileOutput，該對象將會被添加到AVCaptureSession中管理。

注意：前面幾個對象的輸出數據都是NSData類型，而AVCaptureFileOutput代表數據以文件形式輸出，類似的，AVCcaptureFileOutput也不會直接創建使用，通常會使用其子類：AVCaptureAudioFileOutput、AVCaptureMovieFileOutput。
當把一個輸入或者輸出添加到AVCaptureSession之后AVCaptureSession就會在所有相符的輸入、輸出設備之間建立連接（AVCaptionConnection）：

AVCaptureVideoPreviewLayer：相機拍攝預覽圖層，是CALayer的子類，使用該對象可以實時查看拍照或視頻錄制效果，創建該對象需要指定對應的AVCaptureSession對象。

使用AVFoundation拍照和錄制視頻的一般步驟如下：

創建AVCaptureSession對象。
使用AVCaptureDevice的靜態方法獲得需要使用的設備，例如拍照和錄像就需要獲得攝像頭設備，錄音就要獲得麥克風設備。
利用輸入設備AVCaptureDevice初始化AVCaptureDeviceInput對象。
初始化輸出數據管理對象，如果要拍照就初始化AVCaptureStillImageOutput對象；如果拍攝視頻就初始化AVCaptureMovieFileOutput對象。
將數據輸入對象AVCaptureDeviceInput、數據輸出對象AVCaptureOutput添加到媒體會話管理對象AVCaptureSession中。
創建視頻預覽圖層AVCaptureVideoPreviewLayer并指定媒體會話，添加圖層到顯示容器中，調用AVCaptureSession的startRuning方法開始捕獲。
將捕獲的音頻或視頻數據輸出到指定文件。

拍照

下面看一下如何使用AVFoundation實現一個拍照程序，在這個程序中將實現攝像頭預覽、切換前后攝像頭、閃光燈設置、對焦、拍照保存等功能。應用大致效果如下：

應用效果

在程序中定義會話、輸入、輸出等相關對象。

@interface ViewController ()
@property (strong,nonatomic) AVCaptureSession *captureSession;//負責輸入和輸出設備之間的數據傳遞
@property (strong,nonatomic) AVCaptureDeviceInput *captureDeviceInput;//負責從AVCaptureDevice獲得輸入數據
@property (strong,nonatomic) AVCaptureStillImageOutput *captureStillImageOutput;//照片輸出流
@property (strong,nonatomic) AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;//相機拍攝預覽圖層
@property (weak, nonatomic) IBOutlet UIView *viewContainer;
@property (weak, nonatomic) IBOutlet UIButton *takeButton;//拍照按鈕
@property (weak, nonatomic) IBOutlet UIButton *flashAutoButton;//自動閃光燈按鈕
@property (weak, nonatomic) IBOutlet UIButton *flashOnButton;//打開閃光燈按鈕
@property (weak, nonatomic) IBOutlet UIButton *flashOffButton;//關閉閃光燈按鈕
@property (weak, nonatomic) IBOutlet UIImageView *focusCursor; //聚焦光標
@end

在控制器視圖將要展示時創建并初始化會話、攝像頭設備、輸入、輸出、預覽圖層，并且添加預覽圖層到視圖中，除此之外還做了一些初始化工作，例如添加手勢（點擊屏幕進行聚焦）、初始化界面等。

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    //初始化會話
    _captureSession=[[AVCaptureSession alloc]init];
    if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset1280x720]) {//設置分辨率
        _captureSession.sessionPreset=AVCaptureSessionPreset1280x720;
    }
    //獲得輸入設備
    AVCaptureDevice *captureDevice=[self getCameraDeviceWithPosition:AVCaptureDevicePositionBack];//取得后置攝像頭
    if (!captureDevice) {
        NSLog(@"取得后置攝像頭時出現問題.");
        return;
    }
    
    NSError *error=nil;
    //根據輸入設備初始化設備輸入對象，用于獲得輸入數據
    _captureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:captureDevice error:&error];
    if (error) {
        NSLog(@"取得設備輸入對象時出錯，錯誤原因：%@",error.localizedDescription);
        return;
    }
    //初始化設備輸出對象，用于獲得輸出數據
    _captureStillImageOutput=[[AVCaptureStillImageOutput alloc]init];
    NSDictionary *outputSettings = @{AVVideoCodecKey:AVVideoCodecJPEG};
    [_captureStillImageOutput setOutputSettings:outputSettings];//輸出設置
    
    //將設備輸入添加到會話中
    if ([_captureSession canAddInput:_captureDeviceInput]) {
        [_captureSession addInput:_captureDeviceInput];
    }
    
    //將設備輸出添加到會話中
    if ([_captureSession canAddOutput:_captureStillImageOutput]) {
        [_captureSession addOutput:_captureStillImageOutput];
    }
    
    //創建視頻預覽層，用于實時展示攝像頭狀態
    _captureVideoPreviewLayer=[[AVCaptureVideoPreviewLayer alloc]initWithSession:self.captureSession];
    
    CALayer *layer=self.viewContainer.layer;
    layer.masksToBounds=YES;
    
    _captureVideoPreviewLayer.frame=layer.bounds;
    _captureVideoPreviewLayer.videoGravity=AVLayerVideoGravityResizeAspectFill;//填充模式
    //將視頻預覽層添加到界面中
    //[layer addSublayer:_captureVideoPreviewLayer];
    [layer insertSublayer:_captureVideoPreviewLayer below:self.focusCursor.layer];
    
    [self addNotificationToCaptureDevice:captureDevice];
    [self addGenstureRecognizer];
    [self setFlashModeButtonStatus];
}

在控制器視圖展示和視圖離開界面時啟動、停止會話。

-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    [self.captureSession startRunning];
}

-(void)viewDidDisappear:(BOOL)animated{
    [super viewDidDisappear:animated];
    [self.captureSession stopRunning];
}

定義閃光燈開閉及自動模式功能，注意無論是設置閃光燈、白平衡還是其他輸入設備屬性，在設置之前必須先鎖定配置，修改完后解鎖。

/**
 *  改變設備屬性的統一操作方法
 *
 *  @param propertyChange 屬性改變操作
 */
-(void)changeDeviceProperty:(PropertyChangeBlock)propertyChange{
    AVCaptureDevice *captureDevice= [self.captureDeviceInput device];
    NSError *error;
    //注意改變設備屬性前一定要首先調用lockForConfiguration:調用完之后使用unlockForConfiguration方法解鎖
    if ([captureDevice lockForConfiguration:&error]) {
        propertyChange(captureDevice);
        [captureDevice unlockForConfiguration];
    }else{
        NSLog(@"設置設備屬性過程發生錯誤，錯誤信息：%@",error.localizedDescription);
    }
}

/**
 *  設置閃光燈模式
 *
 *  @param flashMode 閃光燈模式
 */
-(void)setFlashMode:(AVCaptureFlashMode )flashMode{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isFlashModeSupported:flashMode]) {
            [captureDevice setFlashMode:flashMode];
        }
    }];
}

定義切換攝像頭功能，切換攝像頭的過程就是將原有輸入移除，在會話中添加新的輸入，但是注意動態修改會話需要首先開啟配置，配置成功后提交配置。

#pragma mark 切換前后攝像頭
- (IBAction)toggleButtonClick:(UIButton *)sender {
    AVCaptureDevice *currentDevice=[self.captureDeviceInput device];
    AVCaptureDevicePosition currentPosition=[currentDevice position];
    [self removeNotificationFromCaptureDevice:currentDevice];
    AVCaptureDevice *toChangeDevice;
    AVCaptureDevicePosition toChangePosition=AVCaptureDevicePositionFront;
    if (currentPosition==AVCaptureDevicePositionUnspecified||currentPosition==AVCaptureDevicePositionFront) {
        toChangePosition=AVCaptureDevicePositionBack;
    }
    toChangeDevice=[self getCameraDeviceWithPosition:toChangePosition];
    [self addNotificationToCaptureDevice:toChangeDevice];
    //獲得要調整的設備輸入對象
    AVCaptureDeviceInput *toChangeDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:toChangeDevice error:nil];
    
    //改變會話的配置前一定要先開啟配置，配置完成后提交配置改變
    [self.captureSession beginConfiguration];
    //移除原有輸入對象
    [self.captureSession removeInput:self.captureDeviceInput];
    //添加新的輸入對象
    if ([self.captureSession canAddInput:toChangeDeviceInput]) {
        [self.captureSession addInput:toChangeDeviceInput];
        self.captureDeviceInput=toChangeDeviceInput;
    }
    //提交會話配置
    [self.captureSession commitConfiguration];
    
    [self setFlashModeButtonStatus];
}

添加點擊手勢操作，點按預覽視圖時進行聚焦、白平衡設置。

/**
 *  設置聚焦點
 *
 *  @param point 聚焦點
 */
-(void)focusWithMode:(AVCaptureFocusMode)focusMode exposureMode:(AVCaptureExposureMode)exposureMode atPoint:(CGPoint)point{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isFocusModeSupported:focusMode]) {
            [captureDevice setFocusMode:AVCaptureFocusModeAutoFocus];
        }
        if ([captureDevice isFocusPointOfInterestSupported]) {
            [captureDevice setFocusPointOfInterest:point];
        }
        if ([captureDevice isExposureModeSupported:exposureMode]) {
            [captureDevice setExposureMode:AVCaptureExposureModeAutoExpose];
        }
        if ([captureDevice isExposurePointOfInterestSupported]) {
            [captureDevice setExposurePointOfInterest:point];
        }
    }];
}

/**
 *  添加點按手勢，點按時聚焦
 */
-(void)addGenstureRecognizer{
    UITapGestureRecognizer *tapGesture=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapScreen:)];
    [self.viewContainer addGestureRecognizer:tapGesture];
}
-(void)tapScreen:(UITapGestureRecognizer *)tapGesture{
    CGPoint point= [tapGesture locationInView:self.viewContainer];
    //將UI坐標轉化為攝像頭坐標
    CGPoint cameraPoint= [self.captureVideoPreviewLayer captureDevicePointOfInterestForPoint:point];
    [self setFocusCursorWithPoint:point];
    [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint];
}

定義拍照功能，拍照的過程就是獲取連接，從連接中獲得捕獲的輸出數據并做保存操作。

#pragma mark 拍照
- (IBAction)takeButtonClick:(UIButton *)sender {
    //根據設備輸出獲得連接
    AVCaptureConnection *captureConnection=[self.captureStillImageOutput connectionWithMediaType:AVMediaTypeVideo];
    //根據連接取得設備輸出的數據
    [self.captureStillImageOutput captureStillImageAsynchronouslyFromConnection:captureConnection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
        if (imageDataSampleBuffer) {
            NSData *imageData=[AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
            UIImage *image=[UIImage imageWithData:imageData];
            UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
//            ALAssetsLibrary *assetsLibrary=[[ALAssetsLibrary alloc]init];
//            [assetsLibrary writeImageToSavedPhotosAlbum:[image CGImage] orientation:(ALAssetOrientation)[image imageOrientation] completionBlock:nil];
        }
        
    }];
}

最后附上完整代碼：

//
//  ViewController.m
//  AVFoundationCamera
//
//  Created by Kenshin Cui on 14/04/05.
//  Copyright (c) 2014年 cmjstudio. All rights reserved.
//

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
#import <AssetsLibrary/AssetsLibrary.h>
typedef void(^PropertyChangeBlock)(AVCaptureDevice *captureDevice);

@interface ViewController ()

@property (strong,nonatomic) AVCaptureSession *captureSession;//負責輸入和輸出設備之間的數據傳遞
@property (strong,nonatomic) AVCaptureDeviceInput *captureDeviceInput;//負責從AVCaptureDevice獲得輸入數據
@property (strong,nonatomic) AVCaptureStillImageOutput *captureStillImageOutput;//照片輸出流
@property (strong,nonatomic) AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;//相機拍攝預覽圖層
@property (weak, nonatomic) IBOutlet UIView *viewContainer;
@property (weak, nonatomic) IBOutlet UIButton *takeButton;//拍照按鈕
@property (weak, nonatomic) IBOutlet UIButton *flashAutoButton;//自動閃光燈按鈕
@property (weak, nonatomic) IBOutlet UIButton *flashOnButton;//打開閃光燈按鈕
@property (weak, nonatomic) IBOutlet UIButton *flashOffButton;//關閉閃光燈按鈕
@property (weak, nonatomic) IBOutlet UIImageView *focusCursor; //聚焦光標



@end

@implementation ViewController

#pragma mark - 控制器視圖方法
- (void)viewDidLoad {
    [super viewDidLoad];
    
}

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    //初始化會話
    _captureSession=[[AVCaptureSession alloc]init];
    if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset1280x720]) {//設置分辨率
        _captureSession.sessionPreset=AVCaptureSessionPreset1280x720;
    }
    //獲得輸入設備
    AVCaptureDevice *captureDevice=[self getCameraDeviceWithPosition:AVCaptureDevicePositionBack];//取得后置攝像頭
    if (!captureDevice) {
        NSLog(@"取得后置攝像頭時出現問題.");
        return;
    }
    
    NSError *error=nil;
    //根據輸入設備初始化設備輸入對象，用于獲得輸入數據
    _captureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:captureDevice error:&error];
    if (error) {
        NSLog(@"取得設備輸入對象時出錯，錯誤原因：%@",error.localizedDescription);
        return;
    }
    //初始化設備輸出對象，用于獲得輸出數據
    _captureStillImageOutput=[[AVCaptureStillImageOutput alloc]init];
    NSDictionary *outputSettings = @{AVVideoCodecKey:AVVideoCodecJPEG};
    [_captureStillImageOutput setOutputSettings:outputSettings];//輸出設置
    
    //將設備輸入添加到會話中
    if ([_captureSession canAddInput:_captureDeviceInput]) {
        [_captureSession addInput:_captureDeviceInput];
    }
    
    //將設備輸出添加到會話中
    if ([_captureSession canAddOutput:_captureStillImageOutput]) {
        [_captureSession addOutput:_captureStillImageOutput];
    }
    
    //創建視頻預覽層，用于實時展示攝像頭狀態
    _captureVideoPreviewLayer=[[AVCaptureVideoPreviewLayer alloc]initWithSession:self.captureSession];
    
    CALayer *layer=self.viewContainer.layer;
    layer.masksToBounds=YES;
    
    _captureVideoPreviewLayer.frame=layer.bounds;
    _captureVideoPreviewLayer.videoGravity=AVLayerVideoGravityResizeAspectFill;//填充模式
    //將視頻預覽層添加到界面中
    //[layer addSublayer:_captureVideoPreviewLayer];
    [layer insertSublayer:_captureVideoPreviewLayer below:self.focusCursor.layer];
    
    [self addNotificationToCaptureDevice:captureDevice];
    [self addGenstureRecognizer];
    [self setFlashModeButtonStatus];
}

-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    [self.captureSession startRunning];
}

-(void)viewDidDisappear:(BOOL)animated{
    [super viewDidDisappear:animated];
    [self.captureSession stopRunning];
}

-(void)dealloc{
    [self removeNotification];
}
#pragma mark - UI方法
#pragma mark 拍照
- (IBAction)takeButtonClick:(UIButton *)sender {
    //根據設備輸出獲得連接
    AVCaptureConnection *captureConnection=[self.captureStillImageOutput connectionWithMediaType:AVMediaTypeVideo];
    //根據連接取得設備輸出的數據
    [self.captureStillImageOutput captureStillImageAsynchronouslyFromConnection:captureConnection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
        if (imageDataSampleBuffer) {
            NSData *imageData=[AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
            UIImage *image=[UIImage imageWithData:imageData];
            UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
            //            ALAssetsLibrary *assetsLibrary=[[ALAssetsLibrary alloc]init];
            //            [assetsLibrary writeImageToSavedPhotosAlbum:[image CGImage] orientation:(ALAssetOrientation)[image imageOrientation] completionBlock:nil];
        }
        
    }];
}
#pragma mark 切換前后攝像頭
- (IBAction)toggleButtonClick:(UIButton *)sender {
    AVCaptureDevice *currentDevice=[self.captureDeviceInput device];
    AVCaptureDevicePosition currentPosition=[currentDevice position];
    [self removeNotificationFromCaptureDevice:currentDevice];
    AVCaptureDevice *toChangeDevice;
    AVCaptureDevicePosition toChangePosition=AVCaptureDevicePositionFront;
    if (currentPosition==AVCaptureDevicePositionUnspecified||currentPosition==AVCaptureDevicePositionFront) {
        toChangePosition=AVCaptureDevicePositionBack;
    }
    toChangeDevice=[self getCameraDeviceWithPosition:toChangePosition];
    [self addNotificationToCaptureDevice:toChangeDevice];
    //獲得要調整的設備輸入對象
    AVCaptureDeviceInput *toChangeDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:toChangeDevice error:nil];
    
    //改變會話的配置前一定要先開啟配置，配置完成后提交配置改變
    [self.captureSession beginConfiguration];
    //移除原有輸入對象
    [self.captureSession removeInput:self.captureDeviceInput];
    //添加新的輸入對象
    if ([self.captureSession canAddInput:toChangeDeviceInput]) {
        [self.captureSession addInput:toChangeDeviceInput];
        self.captureDeviceInput=toChangeDeviceInput;
    }
    //提交會話配置
    [self.captureSession commitConfiguration];
    
    [self setFlashModeButtonStatus];
}

#pragma mark 自動閃光燈開啟
- (IBAction)flashAutoClick:(UIButton *)sender {
    [self setFlashMode:AVCaptureFlashModeAuto];
    [self setFlashModeButtonStatus];
}
#pragma mark 打開閃光燈
- (IBAction)flashOnClick:(UIButton *)sender {
    [self setFlashMode:AVCaptureFlashModeOn];
    [self setFlashModeButtonStatus];
}
#pragma mark 關閉閃光燈
- (IBAction)flashOffClick:(UIButton *)sender {
    [self setFlashMode:AVCaptureFlashModeOff];
    [self setFlashModeButtonStatus];
}

#pragma mark - 通知
/**
 *  給輸入設備添加通知
 */
-(void)addNotificationToCaptureDevice:(AVCaptureDevice *)captureDevice{
    //注意添加區域改變捕獲通知必須首先設置設備允許捕獲
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        captureDevice.subjectAreaChangeMonitoringEnabled=YES;
    }];
    NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];
    //捕獲區域發生改變
    [notificationCenter addObserver:self selector:@selector(areaChange:) name:AVCaptureDeviceSubjectAreaDidChangeNotification object:captureDevice];
}
-(void)removeNotificationFromCaptureDevice:(AVCaptureDevice *)captureDevice{
    NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];
    [notificationCenter removeObserver:self name:AVCaptureDeviceSubjectAreaDidChangeNotification object:captureDevice];
}
/**
 *  移除所有通知
 */
-(void)removeNotification{
    NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];
    [notificationCenter removeObserver:self];
}

-(void)addNotificationToCaptureSession:(AVCaptureSession *)captureSession{
    NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];
    //會話出錯
    [notificationCenter addObserver:self selector:@selector(sessionRuntimeError:) name:AVCaptureSessionRuntimeErrorNotification object:captureSession];
}

/**
 *  設備連接成功
 *
 *  @param notification 通知對象
 */
-(void)deviceConnected:(NSNotification *)notification{
    NSLog(@"設備已連接...");
}
/**
 *  設備連接斷開
 *
 *  @param notification 通知對象
 */
-(void)deviceDisconnected:(NSNotification *)notification{
    NSLog(@"設備已斷開.");
}
/**
 *  捕獲區域改變
 *
 *  @param notification 通知對象
 */
-(void)areaChange:(NSNotification *)notification{
    NSLog(@"捕獲區域改變...");
}

/**
 *  會話出錯
 *
 *  @param notification 通知對象
 */
-(void)sessionRuntimeError:(NSNotification *)notification{
    NSLog(@"會話發生錯誤.");
}

#pragma mark - 私有方法

/**
 *  取得指定位置的攝像頭
 *
 *  @param position 攝像頭位置
 *
 *  @return 攝像頭設備
 */
-(AVCaptureDevice *)getCameraDeviceWithPosition:(AVCaptureDevicePosition )position{
    NSArray *cameras= [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *camera in cameras) {
        if ([camera position]==position) {
            return camera;
        }
    }
    return nil;
}

/**
 *  改變設備屬性的統一操作方法
 *
 *  @param propertyChange 屬性改變操作
 */
-(void)changeDeviceProperty:(PropertyChangeBlock)propertyChange{
    AVCaptureDevice *captureDevice= [self.captureDeviceInput device];
    NSError *error;
    //注意改變設備屬性前一定要首先調用lockForConfiguration:調用完之后使用unlockForConfiguration方法解鎖
    if ([captureDevice lockForConfiguration:&error]) {
        propertyChange(captureDevice);
        [captureDevice unlockForConfiguration];
    }else{
        NSLog(@"設置設備屬性過程發生錯誤，錯誤信息：%@",error.localizedDescription);
    }
}

/**
 *  設置閃光燈模式
 *
 *  @param flashMode 閃光燈模式
 */
-(void)setFlashMode:(AVCaptureFlashMode )flashMode{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isFlashModeSupported:flashMode]) {
            [captureDevice setFlashMode:flashMode];
        }
    }];
}
/**
 *  設置聚焦模式
 *
 *  @param focusMode 聚焦模式
 */
-(void)setFocusMode:(AVCaptureFocusMode )focusMode{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isFocusModeSupported:focusMode]) {
            [captureDevice setFocusMode:focusMode];
        }
    }];
}
/**
 *  設置曝光模式
 *
 *  @param exposureMode 曝光模式
 */
-(void)setExposureMode:(AVCaptureExposureMode)exposureMode{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isExposureModeSupported:exposureMode]) {
            [captureDevice setExposureMode:exposureMode];
        }
    }];
}
/**
 *  設置聚焦點
 *
 *  @param point 聚焦點
 */
-(void)focusWithMode:(AVCaptureFocusMode)focusMode exposureMode:(AVCaptureExposureMode)exposureMode atPoint:(CGPoint)point{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isFocusModeSupported:focusMode]) {
            [captureDevice setFocusMode:AVCaptureFocusModeAutoFocus];
        }
        if ([captureDevice isFocusPointOfInterestSupported]) {
            [captureDevice setFocusPointOfInterest:point];
        }
        if ([captureDevice isExposureModeSupported:exposureMode]) {
            [captureDevice setExposureMode:AVCaptureExposureModeAutoExpose];
        }
        if ([captureDevice isExposurePointOfInterestSupported]) {
            [captureDevice setExposurePointOfInterest:point];
        }
    }];
}

/**
 *  添加點按手勢，點按時聚焦
 */
-(void)addGenstureRecognizer{
    UITapGestureRecognizer *tapGesture=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapScreen:)];
    [self.viewContainer addGestureRecognizer:tapGesture];
}
-(void)tapScreen:(UITapGestureRecognizer *)tapGesture{
    CGPoint point= [tapGesture locationInView:self.viewContainer];
    //將UI坐標轉化為攝像頭坐標
    CGPoint cameraPoint= [self.captureVideoPreviewLayer captureDevicePointOfInterestForPoint:point];
    [self setFocusCursorWithPoint:point];
    [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint];
}

/**
 *  設置閃光燈按鈕狀態
 */
-(void)setFlashModeButtonStatus{
    AVCaptureDevice *captureDevice=[self.captureDeviceInput device];
    AVCaptureFlashMode flashMode=captureDevice.flashMode;
    if([captureDevice isFlashAvailable]){
        self.flashAutoButton.hidden=NO;
        self.flashOnButton.hidden=NO;
        self.flashOffButton.hidden=NO;
        self.flashAutoButton.enabled=YES;
        self.flashOnButton.enabled=YES;
        self.flashOffButton.enabled=YES;
        switch (flashMode) {
            case AVCaptureFlashModeAuto:
                self.flashAutoButton.enabled=NO;
                break;
            case AVCaptureFlashModeOn:
                self.flashOnButton.enabled=NO;
                break;
            case AVCaptureFlashModeOff:
                self.flashOffButton.enabled=NO;
                break;
            default:
                break;
        }
    }else{
        self.flashAutoButton.hidden=YES;
        self.flashOnButton.hidden=YES;
        self.flashOffButton.hidden=YES;
    }
}

/**
 *  設置聚焦光標位置
 *
 *  @param point 光標位置
 */
-(void)setFocusCursorWithPoint:(CGPoint)point{
    self.focusCursor.center=point;
    self.focusCursor.transform=CGAffineTransformMakeScale(1.5, 1.5);
    self.focusCursor.alpha=1.0;
    [UIView animateWithDuration:1.0 animations:^{
        self.focusCursor.transform=CGAffineTransformIdentity;
    } completion:^(BOOL finished) {
        self.focusCursor.alpha=0;
        
    }];
}
@end

最后編輯于：2017.12.03 03:49:48

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