Using ZXing in OSX to get QRCode data - objective-c

Question

I'm looking to implement a class that will be able to read a QR Code from a file (jpeg, bmp, whatever) and output that information as an NSString.
The problem I'm having is that every project seems to revolve around getting the iPhone to do this with the camera.
I am looking to do this on an OSX Desktop with an Image File. I've attempted to use the Objective-C OSX project included with ZXing, but I have been unable to get it to play nice with my own projects.
Has anybody had any success in doing this? Thanks!

Answer 1

So here was what I came up with and it seems to work for me.
- (NSString*) movieFrameAsString:(CGImageRef)targetMovieFrame
{
#try
{
ZXCGImageLuminanceSource* luminancesource = [[ZXCGImageLuminanceSource alloc] initWithCGImage:targetMovieFrame];
ZXHybridBinarizer* binarizerInput = [[ZXHybridBinarizer alloc] init];
[binarizerInput initWithSource:luminancesource];
ZXBinaryBitmap* binarybitmapInput = [[ZXBinaryBitmap alloc] initWithBinarizer:binarizerInput];
ZXDecodeHints* decodehints = [[ZXDecodeHints alloc] init];
ZXQRCodeReader* qrcodereader = [[ZXQRCodeReader alloc] init];
ZXResult* results = [qrcodereader decode:binarybitmapInput hints:decodehints];
[luminancesource release];
[binarizerInput release];
[binarybitmapInput release];
[decodehints release];
[qrcodereader release];
return [results text];
}
#catch (ZXReaderException* rex)
{
if (![rex.reason isEqualToString:#"Could not find three finder patterns"])
{
//NSLog(#"failed to decode, caught ReaderException '%#'", rex.reason);
}
}
#catch (ZXIllegalArgumentException* iex)
{
//NSLog(#"failed to decode, caught IllegalArgumentException '%#'", iex.reason);
}
#catch (id ue)
{
//NSLog(#"Caught unknown exception: %#", ue);
}
return 0;
}
The targetMovieFrame is brought in, it runs it through the cocktail of filters to produce a binary image. It produces results by decoding the image using hints, and using a method included in the QRCodeReader object. Then I return the results, which is an NSString. Everything else is just exceptions being caught and returned.