CODEWITHSUNDEEP
objective-ccocoa-touchiosqr-code
sumderungHAY
sumderungHAY

Reputation: 1337

QRCode generate OFFLINE

Is there an objective-c library which will allow me to generate QRCodes offline? Thanks

Upvotes: 2

Views: 1968

Answers (3)

Adeel
Adeel

Reputation: 878

Just a simple and native way of generating the QR code:

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

    NSData *stringData = [qrString dataUsingEncoding: NSISOLatin1StringEncoding];

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

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

    return qrFilter.outputImage; }

Upvotes: 0

Erik Engheim
Erik Engheim

Reputation: 8482

In Mavericks and iOS7 QR code generation is part of Core Image. You just use the CIQRCodeGenerator filter. On Github you can find a class which implements this for iOS. I've adapted this code to get the OS X compatible code below: 

NSString *website = @"http://stackoverflow.com/";
NSData *urlAsData = [website dataUsingEncoding:NSUTF8StringEncoding];

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

[filter setValue: urlAsData forKey:@"inputMessage"];
[filter setValue:@"M" forKey:@"inputCorrectionLevel"];

CIImage *outputImage = [filter valueForKey:kCIOutputImageKey];

If you want to draw the CIImage there are several possibilities. You can create an NSImage like this:

CIContext *context = [[NSGraphicsContext currentContext] CIContext];
CGImageRef cgImage = [context createCGImage:outputImage
                                   fromRect:[outputImage extent]];

NSImage *image = [[NSImage alloc] initWithCGImage:cgImage size:NSZeroSize];

But this image will typicall be much smaller than you want. I believe each black dot in the QR code just becomes one pixel. Not quite what you want. To scale up the image without making it blurry, do this:

NSSize largeSize = NSMakeSize(image.size.width * 10, image.size.height * 10);

[image setScalesWhenResized:YES];
NSImage *largeImage = [[NSImage alloc] initWithSize:largeSize];
[largeImage lockFocus];
[image setSize:largeSize];
[[NSGraphicsContext currentContext] setImageInterpolation:NSImageInterpolationNone];
[image drawAtPoint:NSZeroPoint fromRect:CGRectMake(0, 0, largeSize.width, largeSize.height) operation:NSCompositeCopy fraction:1.0];
[largeImage unlockFocus];

largeImage is then your result image which you can display.

If you want to decode a QR you use AVFoundation as explained in this blog. Unfortunately this seems to only be supported on iOS7 at the moment.

Upvotes: 3

patrick
patrick

Reputation: 111

See: https://github.com/jverkoey/ObjQREncoder#readme

To use

#import <QREncoder/QREncoder.h>

UIImage* image = [QREncoder encode:@"http://www.google.com/"];

Upvotes: 6

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