分分钟钟搞定iOS自定义相机

相机属于系统硬件，这就需要我们来手动调用iPhone的相机硬件，分为以下步骤：

2016-03-30 上午9.51.09.png

1、首先声明以下对象

#import

//捕获设备，通常是前置摄像头，后置摄像头，麦克风（音频输入）

@property (nonatomic,strong)AVCaptureDevice *device;

//AVCaptureDeviceInput 代表输入设备，他使用AVCaptureDevice 来初始化

@property (nonatomic,strong)AVCaptureDeviceInput *input;

//输出图片

@property (nonatomic,strong)AVCaptureStillImageOutput *imageOutput;

//session：由他把输入输出结合在一起，并开始启动捕获设备（摄像头）

@property (nonatomic,strong)AVCaptureSession *session;

//图像预览层，实时显示捕获的图像

@property (nonatomic,strong)AVCaptureVideoPreviewLayer *previewLayer;

2、初始化各个对象

- (void)cameraDistrict

{

// AVCaptureDevicePositionBack 后置摄像头

// AVCaptureDevicePositionFront 前置摄像头

self.device= [selfcameraWithPosition:AVCaptureDevicePositionFront];

self.input= [[AVCaptureDeviceInputalloc] initWithDevice:self.deviceerror:nil];

self.imageOutput= [[AVCaptureStillImageOutputalloc] init];

self.session= [[AVCaptureSessionalloc] init];

// 拿到的图像的大小可以自行设定

// AVCaptureSessionPreset320x240

// AVCaptureSessionPreset352x288

// AVCaptureSessionPreset640x480

// AVCaptureSessionPreset960x540

// AVCaptureSessionPreset1280x720

// AVCaptureSessionPreset1920x1080

// AVCaptureSessionPreset3840x2160

self.session.sessionPreset= AVCaptureSessionPreset640x480;

//输入输出设备结合

if ([self.sessioncanAddInput:self.input]){

[self.sessionaddInput:self.input];

}

if ([self.sessioncanAddOutput:self.imageOutput]){

[self.sessionaddOutput:self.imageOutput];

}

//预览层的生成

self.previewLayer= [[AVCaptureVideoPreviewLayeralloc] initWithSession:self.session];

self.previewLayer.frame= CGRectMake(0,64,SCREEN_WIDTH, SCREEN_HEIGHT-64);

self.previewLayer.videoGravity= AVLayerVideoGravityResizeAspectFill;

[self.view.layeraddSublayer:self.previewLayer];

//设备取景开始

[self.sessionstartRunning];

if ([_device lockForConfiguration:nil]){

//自动闪光灯，

if ([_device isFlashModeSupported:AVCaptureFlashModeAuto]){

[_device setFlashMode:AVCaptureFlashModeAuto];

}

//自动白平衡,但是好像一直都进不去

if ([_device isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeAutoWhiteBalance]){

[_device setWhiteBalanceMode:AVCaptureWhiteBalanceModeAutoWhiteBalance];

}

[_device unlockForConfiguration];

}

}

根据前后置位置拿到相应的摄像头：

- (AVCaptureDevice*)cameraWithPosition:(AVCaptureDevicePosition)position{

NSArray *devices = [AVCaptureDevicedevicesWithMediaType:AVMediaTypeVideo];

for ( AVCaptureDevice *device in devices )

if ( device.position== position ){

return device;

}

return nil;

}

3、拍照拿到相应图片：

- (void)photoBtnDidClick

{

AVCaptureConnection *conntion = [self.imageOutputconnectionWithMediaType:AVMediaTypeVideo];

if (!conntion) {

NSLog(@"拍照失败!");

return;

}

[self.imageOutputcaptureStillImageAsynchronouslyFromConnection:conntioncompletionHandler:^(CMSampleBufferRef imageDataSampleBuffer,NSError *error) {

if (imageDataSampleBuffer == nil){

return ;

}

NSData *imageData = [AVCaptureStillImageOutputjpegStillImageNSDataRepresentation:imageDataSampleBuffer];

self.image= [UIImageimageWithData:imageData];

[self.sessionstopRunning];

[self.viewaddSubview:self.cameraImageView];

}

4、保存照片到相册：

#pragma - 保存至相册

- (void)saveImageToPhotoAlbum:(UIImage*)savedImage

{

UIImageWriteToSavedPhotosAlbum(savedImage,self,@selector(image:didFinishSavingWithError:contextInfo:),NULL);

}

// 指定回调方法

- (void)image:(UIImage*) image didFinishSavingWithError: (NSError*) error contextInfo: (void*) contextInfo

{

NSString *msg = nil ;

if(error!= NULL){

msg = @"保存图片失败" ;

}else{

msg = @"保存图片成功" ;

}

UIAlertView *alert = [[UIAlertViewalloc] initWithTitle:@"保存图片结果提示"

message:msg

delegate:self

cancelButtonTitle:@"确定"

otherButtonTitles:nil];

[alert show];

}

5、前后置摄像头的切换

- (void)changeCamera{

NSUInteger cameraCount = [[AVCaptureDevicedevicesWithMediaType:AVMediaTypeVideo]count];

if (cameraCount > 1){

NSError *error;

//给摄像头的切换添加翻转动画

CATransition *animation = [CATransitionanimation]；

animation.duration= .5f；

animation.timingFunction= [CAMediaTimingFunctionfunctionWithName:kCAMediaTimingFunctionEaseInEaseOut];

animation.type= @"oglFlip";

AVCaptureDevice *newCamera = nil;

AVCaptureDeviceInput *newInput = nil;

//拿到另外一个摄像头位置

AVCaptureDevicePosition position = [[_input device] position];

if (position == AVCaptureDevicePositionFront){

newCamera = [selfcameraWithPosition:AVCaptureDevicePositionBack];

animation.subtype= kCATransitionFromLeft;//动画翻转方向

}

else {

newCamera = [selfcameraWithPosition:AVCaptureDevicePositionFront];

animation.subtype= kCATransitionFromRight;//动画翻转方向

}

//生成新的输入

newInput = [AVCaptureDeviceInputdeviceInputWithDevice:newCamera error:nil];

[self.previewLayeraddAnimation:animation forKey:nil];

if (newInput != nil){

[self.sessionbeginConfiguration];

[self.sessionremoveInput:self.input];

if ([self.sessioncanAddInput:newInput]) {

[self.sessionaddInput:newInput];

self.input= newInput;

} else {

[self.sessionaddInput:self.input];

}

[self.sessioncommitConfiguration];

} else if (error) {

NSLog(@"togglecarema failed, error = %@",error);

}

}

}

6、相机的其它参数设置

//AVCaptureFlashMode 闪光灯

//AVCaptureFocusMode 对焦

//AVCaptureExposureMode 曝光

//AVCaptureWhiteBalanceMode 白平衡

//闪光灯和白平衡可以在生成相机时候设置

//曝光要根据对焦点的光线状况而决定,所以和对焦一块写

//point为点击的位置

- (void)focusAtPoint:(CGPoint)point{

CGSize size = self.view.bounds.size;

CGPoint focusPoint = CGPointMake(point.y/size.height,1-point.x/size.width);

NSError *error;

if ([self.devicelockForConfiguration:&error]) {

//对焦模式和对焦点

if ([self.deviceisFocusModeSupported:AVCaptureFocusModeAutoFocus]){

[self.devicesetFocusPointOfInterest:focusPoint];

[self.devicesetFocusMode:AVCaptureFocusModeAutoFocus];

}

//曝光模式和曝光点

if ([self.deviceisExposureModeSupported:AVCaptureExposureModeAutoExpose]) {

[self.devicesetExposurePointOfInterest:focusPoint];

[self.devicesetExposureMode:AVCaptureExposureModeAutoExpose];

}

[self.deviceunlockForConfiguration];

//设置对焦动画

_focusView.center= point;

_focusView.hidden= NO;

[UIViewanimateWithDuration:0.3animations:^{

_focusView.transform= CGAffineTransformMakeScale(1.25,1.25);

}completion:^(BOOLfinished) {

[UIViewanimateWithDuration:0.5animations:^{

_focusView.transform= CGAffineTransformIdentity;

} completion:^(BOOLfinished) {

_focusView.hidden= YES;

}];

}];

}

}

7、遇到的一些坑和解决办法

1)前后置摄像头的切换

　　前后值不能切换，各种尝试找了半天没找到有原因。后来发现我在设置图片尺寸的时候设置为1080P [self.sessioncanSetSessionPreset: AVCaptureSessionPreset1920x1080]，前置摄像头并不支持这么大的尺寸，所以就不能切换前置摄像头。我验证了下前置摄像头最高支持720P,720P以内可自由切换。　　当然也可以在前后置摄像头切换的时候，根据前后摄像头来设置不同的尺寸，这里不在赘述。

2）焦点位置

　　CGPoint focusPoint = CGPointMake( point.y /size.height,1-point.x/size.width );

setExposurePointOfInterest：focusPoint函数后面Point取值范围是取景框左上角（0，0）到取景框右下角（1，1）之间。官方是这么写的：

　　The value of this property is a CGPoint that determines thereceiver's focus point of interest, if it has one. A value of (0,0)indicates that the camera should focus on the top left corner ofthe image, while a value of (1,1) indicates that it should focus onthe bottom right. The default value is (0.5,0.5).

　　我也试了按这个来但位置就是不对，只能按上面的写法才可以。前面是点击位置的y/PreviewLayer的高度，后面是1-点击位置的x/PreviewLayer的宽度

3）对焦和曝光

　　我在设置对焦是先设置了模式setFocusMode，后设置对焦位置，就会导致很奇怪的现象，对焦位置是你上次点击的位置。所以一定要先设置位置，再设置对焦模式。

　　曝光同上

补充：

AVCaptureDevice iOS摄像头属性：

AVCaptureDevice.h，主要用来获取iphone一些关于相机设备的属性。

AVCaptureDevice.h，必须要引入AVFoundation.framework包。

1. 前置和后置摄像头

enum {

   AVCaptureDevicePositionBack = 1,

   AVCaptureDevicePositionFront = 2

};

typedef NSInteger AVCaptureDevicePosition;

2. 闪光灯开关

enum {

   AVCaptureFlashModeOff = 0,

   AVCaptureFlashModeOn = 1,

   AVCaptureFlashModeAuto = 2

};

typedef NSInteger AVCaptureFlashMode;

3. 手电筒开关

enum {

   AVCaptureTorchModelOff = 0,

   AVCaptureTorchModelOn = 1,

   AVCaptureTorchModeAuto = 2

};

typedef NSInteger AVCaptureTorchMode;

4. 焦距调整

enum {

   AVCaptureFocusModelLocked = 0,

   AVCaptureFocusModeAutoFocus = 1,

   AVCaptureFocusModeContinousAutoFocus = 2

};

typedef NSInteger AVCaptureFocusMode;

5. 曝光量调节

enum {

   AVCaptureExposureModeLocked = 0,

   AVCaptureExposureModeAutoExpose = 1,

   AVCaptureExposureModeContinuousAutoExposure = 2

};

typedef NSInteger AVCaptureExposureMode;

6. 白平衡

enum {

   AVCaptureWhiteBalanceModeLocked = 0,

   AVCaptureWhiteBalanceModeAutoWhiteBalance = 1,

   AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance =2

};

typedef NSInteger AVCaptureWhiteBalanceMode;