iOS原生CIFilter创建二维码
关于二维码生成,网上也是有很多,很早以前的第三方库大多数都是通过C++写,也是有的如zxing,也是挺好用,这里介绍的是通过CIFilter创建二维码。
创建二维码非常简单,只要传入简单的字符串就好了
- (CIImage *)createQRForString:(NSString *)qrString { NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding]; // 创建filter CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"]; // 设置内容和纠错级别 [qrFilter setValue:stringData forKey:@"inputMessage"]; [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"]; // 返回CIImage return qrFilter.outputImage; }
为生成的二维码是一个CIImage,我们直接转换成UIImage的话大小不好控制,所以使用下面方法返回需要大小的UIImage:
- (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); //原图 UIImage *outputImage = [UIImage imageWithCGImage:scaledImage]; UIGraphicsBeginImageContextWithOptions(outputImage.size, NO, [[UIScreen mainScreen] scale]); [outputImage drawInRect:CGRectMake(0,0 , size, size)]; //水印图 UIImage *waterimage = [UIImage imageNamed:@"icon"]; [waterimage drawInRect:CGRectMake((size-waterImagesize)/2.0, (size-waterImagesize)/2.0, waterImagesize, waterImagesize)]; UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return newPic; }
未来CTO
微信号:wlaicto