二维码生成和识别二维码生成和识别

生成二维码常见应用是我的二维码，然后就是一张二维码图片，展示出来，让人家扫描
先生成CIImage

/** *根据字符串生成二维码 CIImage 对象 * *@param urlString 需要生成二维码的字符串 * *@return 生成的二维码 */ + (CIImage *)createQRcodeWithUrlString:(NSString *)urlString { // 1.实例化二维码滤镜 CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"]; // 2.恢复滤镜的默认属性 (因为滤镜有可能保存上一次的属性) [filter setDefaults]; // 3.将字符串转换成NSdata NSData *data= https://www.it610.com/article/[urlString dataUsingEncoding:NSUTF8StringEncoding]; // 4.通过KVO设置滤镜, 传入data, 将来滤镜就知道要通过传入的数据生成二维码 [filter setValue:data forKey:@"inputMessage"]; // 5.生成二维码 CIImage *outputImage = [filter outputImage]; return outputImage; }

然后合成UIImage

/** * 根据CIImage生成指定大小的UIImage * * @param image CIImage * @param size 图片宽度 */ + (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat)size { CGRect extent = CGRectIntegral(image.extent); CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent)); // 1.创建bitmap; size_t width = CGRectGetWidth(extent) * scale; size_t height = CGRectGetHeight(extent) * scale; CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray(); CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone); CIContext *context = [CIContext contextWithOptions:nil]; CGImageRef bitmapImage = [context createCGImage:image fromRect:extent]; CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone); CGContextScaleCTM(bitmapRef, scale, scale); CGContextDrawImage(bitmapRef, extent, bitmapImage); // 2.保存bitmap到图片 CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef); CGContextRelease(bitmapRef); CGImageRelease(bitmapImage); return [UIImage imageWithCGImage:scaledImage]; }

合成一个对外接口

+ (UIImage *)createWithUrlString:(NSString *)urlString size:(CGFloat)size { if ((urlString == nil) || [urlString isEqualToString:@""]) { return nil; } if (size <= 0 ) { return nil; } CIImage *ci = [KJTQrGenerate createQRcodeWithUrlString:urlString]; return [KJTQrGenerate createNonInterpolatedUIImageFormCIImage:ci withSize:size]; }

这里的size是指width和height相等的正方形

识别二维码常见的场景是长按二维码图片，识别二维码内容

+ (NSString *)stringFromImage:(UIImage *)image { if (image == nil) { return nil; } // 创建 CIDetector，并设定识别类型：CIDetectorTypeQRCode CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{CIDetectorAccuracy: CIDetectorAccuracyHigh}]; // 获取识别结果 NSArray *features = [detector featuresInImage:[CIImage imageWithCGImage:image.CGImage]]; if (features.count == 0) { return nil; } else { NSString *resultString = nil; for (int index = 0; index < [features count]; index ++) { CIQRCodeFeature *feature = [features objectAtIndex:index]; resultString = feature.messageString; } return resultString; } }

参考文章 iOS 使用CIDetector扫描相册二维码、原生扫描
ios开发根据URL或字符串生成二维码
【二维码生成和识别】IOS中生成二维码、扫描二维码