摄像头拍照

转载：
http://www.cnblogs.com/kenshincui/p/4186022.html#avFoundationCamera

#import "ViewController.h"#import <AVFoundation/AVFoundation.h>#import <AssetsLibrary/AssetsLibrary.h>typedef void(^PropertyChangeBlock)(AVCaptureDevice *captureDevice);@interface ViewController ()@property (strong,nonatomic) AVCaptureSession *captureSession;//负责输入和输出设备之间的数据传递@property (strong,nonatomic) AVCaptureDeviceInput *captureDeviceInput;//负责从AVCaptureDevice获得输入数据@property (strong,nonatomic) AVCaptureStillImageOutput *captureStillImageOutput;//照片输出流@property (strong,nonatomic) AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;//相机拍摄预览图层@property (weak, nonatomic) IBOutlet UIView *viewContainer;@property (weak, nonatomic) IBOutlet UIButton *takeButton;//拍照按钮@property (weak, nonatomic) IBOutlet UIButton *flashAutoButton;//自动闪光灯按钮@property (weak, nonatomic) IBOutlet UIButton *flashOnButton;//打开闪光灯按钮@property (weak, nonatomic) IBOutlet UIButton *flashOffButton;//关闭闪光灯按钮@property (weak, nonatomic) IBOutlet UIImageView *focusCursor; //聚焦光标@end@implementation ViewController#pragma mark - 控制器视图方法- (void)viewDidLoad {    [super viewDidLoad];}-(void)viewWillAppear:(BOOL)animated{    [super viewWillAppear:animated];    //初始化会话    _captureSession=[[AVCaptureSession alloc]init];    if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset1280x720]) {//设置分辨率        _captureSession.sessionPreset=AVCaptureSessionPreset1280x720;    }    //获得输入设备    AVCaptureDevice *captureDevice=[self getCameraDeviceWithPosition:AVCaptureDevicePositionBack];//取得后置摄像头    if (!captureDevice) {        NSLog(@"取得后置摄像头时出现问题.");        return;    }    NSError *error=nil;    //根据输入设备初始化设备输入对象，用于获得输入数据    _captureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:captureDevice error:&error];    if (error) {        NSLog(@"取得设备输入对象时出错，错误原因：%@",error.localizedDescription);        return;    }    //初始化设备输出对象，用于获得输出数据    _captureStillImageOutput=[[AVCaptureStillImageOutput alloc]init];    NSDictionary *outputSettings = @{AVVideoCodecKey:AVVideoCodecJPEG};    [_captureStillImageOutput setOutputSettings:outputSettings];//输出设置    //将设备输入添加到会话中    if ([_captureSession canAddInput:_captureDeviceInput]) {        [_captureSession addInput:_captureDeviceInput];    }    //将设备输出添加到会话中    if ([_captureSession canAddOutput:_captureStillImageOutput]) {        [_captureSession addOutput:_captureStillImageOutput];    }    //创建视频预览层，用于实时展示摄像头状态    _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    //将视频预览层添加到界面中    //[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 {    //根据设备输出获得连接    AVCaptureConnection *captureConnection=[self.captureStillImageOutput connectionWithMediaType:AVMediaTypeVideo];    //根据连接取得设备输出的数据    [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 切换前后摄像头- (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];    //获得要调整的设备输入对象    AVCaptureDeviceInput *toChangeDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:toChangeDevice error:nil];    //改变会话的配置前一定要先开启配置，配置完成后提交配置改变    [self.captureSession beginConfiguration];    //移除原有输入对象    [self.captureSession removeInput:self.captureDeviceInput];    //添加新的输入对象    if ([self.captureSession canAddInput:toChangeDeviceInput]) {        [self.captureSession addInput:toChangeDeviceInput];        self.captureDeviceInput=toChangeDeviceInput;    }    //提交会话配置    [self.captureSession commitConfiguration];    [self setFlashModeButtonStatus];}#pragma mark 自动闪光灯开启- (IBAction)flashAutoClick:(UIButton *)sender {    [self setFlashMode:AVCaptureFlashModeAuto];    [self setFlashModeButtonStatus];}#pragma mark 打开闪光灯- (IBAction)flashOnClick:(UIButton *)sender {    [self setFlashMode:AVCaptureFlashModeOn];    [self setFlashModeButtonStatus];}#pragma mark 关闭闪光灯- (IBAction)flashOffClick:(UIButton *)sender {    [self setFlashMode:AVCaptureFlashModeOff];    [self setFlashModeButtonStatus];}#pragma mark - 通知/** *  给输入设备添加通知 */-(void)addNotificationToCaptureDevice:(AVCaptureDevice *)captureDevice{    //注意添加区域改变捕获通知必须首先设置设备允许捕获    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {        captureDevice.subjectAreaChangeMonitoringEnabled=YES;    }];    NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];    //捕获区域发生改变    [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];    //会话出错    [notificationCenter addObserver:self selector:@selector(sessionRuntimeError:) name:AVCaptureSessionRuntimeErrorNotification object:captureSession];}/** *  设备连接成功 * *  @param notification 通知对象 */-(void)deviceConnected:(NSNotification *)notification{    NSLog(@"设备已连接...");}/** *  设备连接断开 * *  @param notification 通知对象 */-(void)deviceDisconnected:(NSNotification *)notification{    NSLog(@"设备已断开.");}/** *  捕获区域改变 * *  @param notification 通知对象 */-(void)areaChange:(NSNotification *)notification{    NSLog(@"捕获区域改变...");}/** *  会话出错 * *  @param notification 通知对象 */-(void)sessionRuntimeError:(NSNotification *)notification{    NSLog(@"会话发生错误.");}#pragma mark - 私有方法/** *  取得指定位置的摄像头 * *  @param position 摄像头位置 * *  @return 摄像头设备 */-(AVCaptureDevice *)getCameraDeviceWithPosition:(AVCaptureDevicePosition )position{    NSArray *cameras= [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];    for (AVCaptureDevice *camera in cameras) {        if ([camera position]==position) {            return camera;        }    }    return nil;}/** *  改变设备属性的统一操作方法 * *  @param propertyChange 属性改变操作 */-(void)changeDeviceProperty:(PropertyChangeBlock)propertyChange{    AVCaptureDevice *captureDevice= [self.captureDeviceInput device];    NSError *error;    //注意改变设备属性前一定要首先调用lockForConfiguration:调用完之后使用unlockForConfiguration方法解锁    if ([captureDevice lockForConfiguration:&error]) {        propertyChange(captureDevice);        [captureDevice unlockForConfiguration];    }else{        NSLog(@"设置设备属性过程发生错误，错误信息：%@",error.localizedDescription);    }}/** *  设置闪光灯模式 * *  @param flashMode 闪光灯模式 */-(void)setFlashMode:(AVCaptureFlashMode )flashMode{    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {        if ([captureDevice isFlashModeSupported:flashMode]) {            [captureDevice setFlashMode:flashMode];        }    }];}/** *  设置聚焦模式 * *  @param focusMode 聚焦模式 */-(void)setFocusMode:(AVCaptureFocusMode )focusMode{    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {        if ([captureDevice isFocusModeSupported:focusMode]) {            [captureDevice setFocusMode:focusMode];        }    }];}/** *  设置曝光模式 * *  @param exposureMode 曝光模式 */-(void)setExposureMode:(AVCaptureExposureMode)exposureMode{    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {        if ([captureDevice isExposureModeSupported:exposureMode]) {            [captureDevice setExposureMode:exposureMode];        }    }];}/** *  设置聚焦点 * *  @param point 聚焦点 */-(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];        }    }];}/** *  添加点按手势，点按时聚焦 */-(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];    //将UI坐标转化为摄像头坐标    CGPoint cameraPoint= [self.captureVideoPreviewLayer captureDevicePointOfInterestForPoint:point];    [self setFocusCursorWithPoint:point];    [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint];}/** *  设置闪光灯按钮状态 */-(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;    }}/** *  设置聚焦光标位置 * *  @param point 光标位置 */-(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