视频捕捉、获取静态图片（自定义相机）

其实这相当于是一个自定义相机的功能了

github下载链接：https://github.com/SSYSSK/camera2

1、自定义相机

2、视频的捕获预览

3、视频的录制

4、拍照

5、解决了拍照照片翻转90度的问题

6、解决了前置摄像头照片颠倒的问题

关键点：

1、自从iOS10之后，获取图片的输出由AVCaptureStillImageOutput变成了AVCapturePhotoOutput，所以需要做两套适配，输出配置代码：

//6、静态图片输出
    if (@available(iOS 10.0, *)) {
        self.imageOutput = [[AVCapturePhotoOutput alloc]init];
        //输出连接 判断是否可用，可用则添加到输出连接中去
        if ([self.captureSession canAddOutput:self.imageOutput])
        {
            [self.captureSession addOutput:self.imageOutput];
        }
    }else {
        //AVCaptureStillImageOutput 实例 从摄像头捕捉静态图片
        self.stillImageOutput = [[AVCaptureStillImageOutput alloc]init];
        //配置字典：希望捕捉到JPEG格式的图片
        self.stillImageOutput.outputSettings = @{AVVideoCodecKey:AVVideoCodecTypeJPEG};
        if ([self.captureSession canAddOutput:self.stillImageOutput])
        {
            [self.captureSession addOutput:self.stillImageOutput];
        }
    }

2、拍照功能，要区分iOS10和iOS10之前：

 [output capturePhotoWithSettings:settings delegate:self];

// 从流中获取照片
-(void)getPhoto {
    // 拍照
    if (@available(iOS 10.0, *)) {
        AVCapturePhotoOutput * output = (AVCapturePhotoOutput *)self.imageOutput;
        AVCapturePhotoSettings * settings = [AVCapturePhotoSettings photoSettings];
        // 这一句代码才是执行拍照
        [output capturePhotoWithSettings:settings delegate:self];
    }else{
        AVCaptureStillImageOutput * stillImageOutput = (AVCaptureStillImageOutput *)self.stillImageOutput;
        //从 AVCaptureStillImageOutput 中取得 AVCaptureConnection
        AVCaptureConnection *connection = [stillImageOutput connectionWithMediaType:AVMediaTypeVideo];
        [stillImageOutput captureStillImageAsynchronouslyFromConnection:connection completionHandler:^(CMSampleBufferRef  _Nullable imageDataSampleBuffer, NSError * _Nullable error) {
            if (imageDataSampleBuffer != nil) {
                NSData * data = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
                UIImage *image = [[UIImage alloc]initWithData:data];
                //重点：捕捉图片成功后，将图片传递出去
                UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
            }
        }];
    }
    
}

3、拍照完成的代理回调（iOS10之后才会走这里），这里要注意一个照片翻转的问题：

            //前置摄像头拍照会旋转180解决办法
            if (self.activeVideoInput.device.position == AVCaptureDevicePositionFront) {
                UIImageOrientation imgOrientation = UIImageOrientationLeftMirrored;
                image = [[UIImage alloc]initWithCGImage:cgImage scale:1.0f orientation:imgOrientation];
            }else {
                UIImageOrientation imgOrientation = UIImageOrientationRight;
                image = [[UIImage alloc]initWithCGImage:cgImage scale:1.0f orientation:imgOrientation];
            }

#pragma mark AVCapturePhotoCaptureDelegate
- (void)captureOutput:(AVCapturePhotoOutput *)output didFinishProcessingPhoto:(AVCapturePhoto *)photo error:(NSError *)error {
    if (error) {
        NSLog(@"获取图片错误 --- %@",error.localizedDescription);
    }
    if (photo) {
        if (@available(iOS 11.0, *)) {
            
            CGImageRef cgImage = [photo CGImageRepresentation];
            UIImage * image = [UIImage imageWithCGImage:cgImage];
            NSLog(@"获取图片成功 --- %@",image);
            
            //前置摄像头拍照会旋转180解决办法
            if (self.activeVideoInput.device.position == AVCaptureDevicePositionFront) {
                UIImageOrientation imgOrientation = UIImageOrientationLeftMirrored;
                image = [[UIImage alloc]initWithCGImage:cgImage scale:1.0f orientation:imgOrientation];
            }else {
                UIImageOrientation imgOrientation = UIImageOrientationRight;
                image = [[UIImage alloc]initWithCGImage:cgImage scale:1.0f orientation:imgOrientation];
            }
            //重新画一张图片(将时间/个人信息/地址信息画上去)
//            self.image = [self drawMarkImage:image];
            
            UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
        } else {
            NSLog(@"不是走这个代理方法");
        }
    }
}