ios二维码生成

    //创建滤镜对象

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

    //恢复滤镜的默认属性

    [filter setDefaults];

    NSData *infoData = [data dataUsingEncoding:NSUTF8StringEncoding];

    //设置filter的InputMessages数据

    [filter setValue:infoData forKeyPath:@"inputMessage"];

    CIImage *outputImage = [filter outputImage];

    UIImage *image = [self createUIImageFromCIImage:outputImage withWidth:width];

    return image;
}

根据CIImage生成指定大小的UIImage

+ (UIImage *)createUIImageFromCIImage:(CIImage *)CIImage withWidth:(CGFloat)imageWidth{

    CGRect extent = CGRectIntegral(CIImage.extent);
    CGFloat scale = MIN(imageWidth / CGRectGetWidth(extent), imageWidth / CGRectGetHeight(extent));
    
    //创建bitMap
    size_t width = CGRectGetWidth(extent) * scale;
    size_t height = CGRectGetHeight(extent) * scale;
    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceGray();
    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, colorSpaceRef, (CGBitmapInfo)kCGImageAlphaNone);
    CIContext *context = [CIContext contextWithOptions:nil];
    
    CGImageRef bitmapImage = [context createCGImage:CIImage fromRect:extent];
    CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
    CGContextScaleCTM(bitmapRef, scale, scale);
    CGContextDrawImage(bitmapRef, extent, bitmapImage);
    
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    
    return [UIImage imageWithCGImage:scaledImage];
}

+ (UIImage *)generateLogoQRCode:(NSString *)data imageWidth:(CGFloat)imageWidth logoImageName:(NSString *)logoImageName logoScaleToSuperView:(CGFloat)logoScale{
    
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    //恢复滤镜的默认属性
    [filter setDefaults];
    
    NSData *infoData = [data dataUsingEncoding:NSUTF8StringEncoding];
    
    //设置filter的InputMessages数据
    [filter setValue:infoData forKeyPath:@"inputMessage"];
    CIImage *outputImage = [filter outputImage];
    
//    outputImage = [outputImage imageByApplyingTransform:CGAffineTransformMakeScale(20, 20)];
    //将CIImage转化为UIImage类型
    UIImage *start_image = [self createUIImageFromCIImage:outputImage withWidth:imageWidth];
    
    //添加logo
    UIGraphicsBeginImageContext(start_image.size);
    [start_image drawInRect:CGRectMake(0, 0, start_image.size.width, start_image.size.height)];
    
    //画logo
    UIImage *logoImage = [UIImage imageNamed:logoImageName];
    CGFloat logoWidth = start_image.size.width * logoScale;
    CGFloat logoHeight = start_image.size.height * logoScale;
    CGFloat logoX = (start_image.size.width - logoWidth) / 2;
    CGFloat logoY = (start_image.size.width - logoHeight) / 2;
    [logoImage drawInRect:CGRectMake(logoX, logoY, logoWidth, logoHeight)];
    
    //获取最后的图片
    UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return finalImage;
}

扫描

扫描前需要申请调用摄像头的权限

    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    //创建输入流
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    //创建输出流
    AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
    //设置代理，在主线程中刷新
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    //设置扫描范围（取值范围0-1，一屏幕右上角为坐标原点）
    output.rectOfInterest = CGRectMake(0.2, 0.2, 0.6, 0.6);
    
    _session = [[AVCaptureSession alloc] init];
    //设置采集率
    [_session setSessionPreset:AVCaptureSessionPresetHigh];
    
    //添加会话输入输出
    [_session addInput:input];
    [_session addOutput:output];
    
    //设置输出数据类型，需要将元数据输出添加到会话中，才能指定元数据类型
    //设置扫码支持的编码格式
    output.metadataObjectTypes = @[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN8Code,AVMetadataObjectTypeEAN13Code,AVMetadataObjectTypeCode128Code];
    
    //初始化previewLayer，传递给session将要显示什么
    _previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:_session];
    _previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    _previewLayer.frame = self.view.layer.bounds;
    
    //将图层插入当前视图
    [self.view.layer insertSublayer:_previewLayer atIndex:0];
    //启动会话
    [_session startRunning];

具体代码见GitHub：https://github.com/huyong668/HYQRCode