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：
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*deviceindevices )
if( device.position== position ){
returndevice;
}
returnnil;
}
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:conntion completionHandler:^(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{
NSUIntegercameraCount = [[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
AVCaptureDevicePositionposition = [[_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];
}elseif(error) {
NSLog(@"toggle carema 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{
CGSizesize =self.view.bounds.size;
CGPointfocusPoint =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.session canSetSessionPreset: 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 the receiver'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 of the image, while a value of (1,1) indicates that it should focus on the 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;
