Generate a QR code and a string link based on the string Link

Generate a QR code and a string link based on the string Link

# Pragma mark-InterpolatedUIImage = because the generated QR code is a CIImage, it is difficult to control the size if we convert it directly to a UIImage. Therefore, use the following method to return the UIImage with the required size.

-(UIImage *) createNonInterpolatedUIImageFormCIImage :( CIImage *) image withSize :( CGFloat) size {

CGRect extent = CGRectIntegral (image. extent );

CGFloat scale = MIN (size/CGRectGetWidth (extent), size/CGRectGetHeight (extent ));

// Create a bitmap image that we'll draw into a bitmap context at the desired size;

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 contextwitexceptions: nil];

CGImageRef bitmapImage = [context createCGImage: image fromRect: extent];

CGContextSetInterpolationQuality (bitmapRef, kCGInterpolationNone );

CGContextScaleCTM (bitmapRef, scale, scale );

CGContextDrawImage (bitmapRef, extent, bitmapImage );

// Create an image with the contents of our bitmap

CGImageRef scaledImage = CGBitmapContextCreateImage (bitmapRef );

// Cleanup

CGContextRelease (bitmapRef );

CGImageRelease (bitmapImage );

Return [UIImage imageWithCGImage: scaledImage];

}

 

# Pragma mark-QRCodeGenerator -- first, the QR code is generated. It is very easy to use CIFilter. Just pass in the string that generates the QR code.

-(CIImage *) createQRForString :( NSString *) qrString {

// Need to convert the string to a UTF-8 encoded NSData object

NSData * stringData = [qrString dataUsingEncoding: NSUTF8StringEncoding];

// Create the filter

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

// Set the message content and error-correction level

[QrFilter setValue: stringData forKey: @ "inputMessage"];

[QrFilter setValue: @ "M" forKey: @ "inputCorrectionLevel"];

// Send the image back

Return qrFilter. outputImage;

}

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Call:

UIImage * boundImg = [self createNonInterpolatedUIImageFormCIImage: [self createQRForString: @ "http://baidu.com"] withSize: 2500000f];