一、引入AVFoundation框架
添加头文件
#import <AVFoundation/AVFoundation.h>
二、定义以下对象：
AVCaptureDevice * device; // 图像捕捉设备
AVCaptureDeviceInput * input; // 输入流
AVCaptureStillImageOutput * output; //输出流
AVCaptureSession * session; // 输入设备和输出设备之间的数据传递
AVCaptureVideoPreviewLayer * preview; // 预览图层，显示摄像头捕捉到的画面
UIButton * cameraButton; // 拍照按钮
三、初始化对象
//1.实例化捕捉会话
self.session = [[AVCaptureSession alloc]init];
// 将捕捉会话的预设设置为图像
self.session.sessionPreset = AVCaptureSessionPresetPhoto;
//2.初始化捕捉设备
//self.device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
self.device = [self backCamera]; // 这里使用后置摄像头
//3.用captureDevice创建输入流
self.input = [[AVCaptureDeviceInput alloc]initWithDevice:self.device error:nil];
// 将输入流添加到会话中
if ([self.session canAddInput:self.input]) {
[self.session addInput:self.input];
}
//4.创建媒体数据输出流为静态图像
self.output = [[AVCaptureStillImageOutput alloc]init];
// 将输出流设置成JPEG的图片格式输出，这里输出流的设置参数AVVideoCodecJPEG参数表示以JPEG的图片格式输出图片
NSDictionary * outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG,AVVideoCodecKey, nil];
[self.output setOutputSettings:outputSettings];
// 5.将输出流添加到会话中
if ([self.session canAddOutput:self.output]) {
[self.session addOutput:self.output];
}
// 6. 通过会话创建预览图层
self.preview = [AVCaptureVideoPreviewLayer layerWithSession:self.session];
// 设置预览图层填充方式
self.preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
CGFloat max = MAX([UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
CGFloat min = MIN([UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
// 设置预览图层的大小
self.preview.frame = CGRectMake(0, 0, min, max);
// 将预览图层放置在最上面
[self.view.layer insertSublayer:self.preview atIndex:0];
- (void)viewDidAppear:(BOOL)animated{
if (self.session) {
[self.session startRunning];
}
}
- (void)viewDidDisappear:(BOOL)animated{
if (self.session) {
[self.session stopRunning];
}
}
四、初始化设备时，可选择前置或后置摄影头；
// 根据位置获取前后摄像头设备
- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition) position {
AVCaptureDeviceDiscoverySession * deviceDiscoverSession = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera] mediaType:AVMediaTypeVideo position:position];
NSArray * devices = deviceDiscoverSession.devices;
for (AVCaptureDevice *device in devices) {
if ([device position] == position) {
return device;
}
}
return nil;
}
// 获取前置摄像头
- (AVCaptureDevice *)frontCamera {
return [self cameraWithPosition:AVCaptureDevicePositionFront];
}
// 获取后置摄像头
- (AVCaptureDevice *)backCamera {
return [self cameraWithPosition:AVCaptureDevicePositionBack];
}
// 切换摄像头
- (void)switchDevice{
NSArray *inputs = self.session.inputs;
for ( AVCaptureDeviceInput *input in inputs ) {
AVCaptureDevice *device = input.device;
if ( [device hasMediaType:AVMediaTypeVideo] ) {
AVCaptureDevicePosition position = device.position;
AVCaptureDevice *newCamera = nil;
AVCaptureDeviceInput *newInput = nil;
if (position == AVCaptureDevicePositionFront)
newCamera = [self cameraWithPosition:AVCaptureDevicePositionBack];
else
newCamera = [self cameraWithPosition:AVCaptureDevicePositionFront];
newInput = [AVCaptureDeviceInput deviceInputWithDevice:newCamera error:nil];
[self.session beginConfiguration];
[self.session removeInput:input];
[self.session addInput:newInput];
[self.session commitConfiguration];
break;
}
}
}
五、在拍照按钮的点击事件中获取捕捉到的图像，并可将其转成base64字符串
- (void)captureStillImage{
AVCaptureConnection * videoConnection = [self.output connectionWithMediaType:AVMediaTypeVideo];
if (!videoConnection) {
NSLog(@"take photo failed!");
return;
}
[self.output captureStillImageAsynchronouslyFromConnection:videoConnection
completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
if (imageDataSampleBuffer == NULL) {
return;
}
NSData * imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
UIImage * image = [UIImage imageWithData:imageData];
UIImage * smallImage = [self scaleImage:image toScale:0.5];
NSData * resultImageData = UIImageJPEGRepresentation(smallImage, 1.0);
NSString * imageBase64String = [resultImageData base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}];
}
P.S. 这里可以将获取到的图片进行缩小；
// 等比率缩放图片
- (UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize{
UIGraphicsBeginImageContext(CGSizeMake(image.size.width * scaleSize, image.size.height * scaleSize));
[image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height * scaleSize)];
UIImage * scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return scaledImage;
}
六、横屏时，调整预览图层frame
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
[super willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];
CGFloat max = MAX([UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
CGFloat min = MIN([UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft) {
self.preview.frame = CGRectMake(0, 0, max, min);
}
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {
self.preview.frame = CGRectMake(0, 0, max, min);
}
if (toInterfaceOrientation == UIInterfaceOrientationPortrait) {
self.preview.frame = CGRectMake(0, 0, min, max);
}
}
