iOS扫描二维码与生成二维码

objective-c二维码的扫码与生成

扫描二维码

生成二维码

1.扫描二维码

获取输入设备（当前是摄像头）

AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

根据输入设备获取输入对象

AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];

创建输出对象

AVCaptureMetadataOutput *output = [AVCaptureMetadataOutput new];

设置代理监听对象输出的数据，在主线程回调

[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];

创建会话

AVCaptureSession *session = [AVCaptureSession new];

//实现高质量的输出和摄像，默认值为AVCaptureSessionPresetHigh，可以不写
[session setSessionPreset:AVCaptureSessionPresetHigh];

添加输入输出到会话中（判断session是否已满）

if ([session canAddInput:input]) {
[session addInput:input];
}
if ([session canAddOutput:output]) {
[session addOutput:output];
}

设置输出对象的输出什么样的数据（二维码、条码）

output.metadataObjectTypes = @[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeCode128Code,AVMetadataObjectTypeCode93Code,AVMetadataObjectTypeCode39Code,AVMetadataObjectTypeCode39Mod43Code,AVMetadataObjectTypeEAN8Code,AVMetadataObjectTypeEAN13Code,AVMetadataObjectTypeUPCECode,AVMetadataObjectTypePDF417Code,AVMetadataObjectTypeAztecCode];

创建预览图层

AVCaptureVideoPreviewLayer *previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:session];
[previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
previewLayer.frame = self.view.bounds;
[self.view.layer insertSublayer:previewLayer atIndex:0];

设置有效扫描区域

CGRect rect = CGRectMake(0.1,0.1,0.8,0.8);
output.rectOfInterest = rect;

设置周边空白区域（中间扫描区域透明度比其他地方低）

UIView *maskView = [[UIView alloc] initWithFrame:self.view.bounds];
maskView.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.4f];
[self.view addSubview:maskView];
UIBezierPath *rectPath = [UIBezierPath bezierPathWithRect:self.view.bounds];
[rectPath appendPath:[[UIBezierPath bezierPathWithRoundedRect:CGRectMake(20.0f, 20.0f, 200.0f, 200.0f) cornerRadius:1] bezierPathByReversingPath]];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = rectPath.CGPath;
maskView.layer.mask = shapeLayer;

扫描成功后的回调

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{
if (metadataObjects.count > 0) {
//停止扫描（不停止有可能这个方法会执行好几次）
[self.session stopRunning];
//取出扫描到得数据
AVMetadataMachineReadableCodeObject *obj = [metadataObjects lastObject];
if (obj) {
NSLog(@"result = %@",[obj stringValue]);
}
}
}

2.生成二维码

二维码滤镜

CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

设置滤镜的默认属性

[filter setDefaults];

将字符串转成二进制数据

NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];

通过KVO设置滤镜inputmessage数据

[filter setValue:data forKey:@"inputMessage"];

获取滤镜输出的图片

CIImage *outputImage = [filter outputImage];

//转成UIImage返回
UIImage *image = [UIImage imageWithCIImage:outputImage];