QRCode Demo

NSData *stringData = [text dataUsingEncoding: NSUTF8StringEncoding];
//生成
CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
[qrFilter setValue:stringData forKey:@"inputMessage"];
[qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];

UIColor *onColor = [UIColor whiteColor];
UIColor *offColor = [UIColor darkGrayColor];

//上色
CIFilter *colorFilter = [CIFilter filterWithName:@"CIFalseColor"
                                   keysAndValues:
                         @"inputImage",qrFilter.outputImage,
                         @"inputColor0",[CIColor colorWithCGColor:onColor.CGColor],
                         @"inputColor1",[CIColor colorWithCGColor:offColor.CGColor],
                         nil];

CIImage *qrImage = colorFilter.outputImage;

//绘制
CGSize size = CGSizeMake(width, width);
CGImageRef cgImage = [[CIContext contextWithOptions:nil] createCGImage:qrImage fromRect:qrImage.extent];
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(context, kCGInterpolationNone);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextDrawImage(context, CGContextGetClipBoundingBox(context), cgImage);
_codeImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

CGImageRelease(cgImage);