iPhone iOS: Can you add crosshairs or other visual indicator to ZBar barcode scanning?

Question

I want to know if it is possible when using Zbar barcode scanning within an iPhone/iOS app to add some sort or crosshairs or other visual indicator to the screen to assist users in aiming their camera onto a QR code?

Answer 1

That is best accomplished with a transparent PNG. Just import it to your project and then create a new UIImageView that you give to the reader.

I did this to add a logo:

// Create the reader
self.reader = [ZBarReaderViewController new];
self.reader.readerDelegate = self;

// Create image for adding a logo :)
UIImage *image = [UIImage imageNamed:@"scan_logo.png"];
UIImageView *imageLogo = [[UIImageView alloc] initWithImage:image];
imageLogo.frame = CGRectMake(0, 0, image.size.width, image.size.height);

// Configure reader
self.reader.cameraOverlayView = imageLogo;

To get the image in the center just change the frame positioning from:

imageLogo.frame = CGRectMake(0, 0, image.size.width, image.size.height);

To something like:

imageLogo.center = CGRectMake(320/2, 460/2, image.size.width, image.size.height);

Answer 2

FWIW what I did in my app is to extend the ZBarReaderViewController class, set my new class as the ZBarReaderDelegate also, and then put JeroenEijkhof's code into my init override:

- (id) init
{
    self = [super init];
    if( self ) {
        self.readerDelegate = self;
        UIImage *image = [UIImage imageNamed:...
        ...
    }
    return self;
}

This gave me the ability to control other aspects of the view, such as customizing the navigation controller on viewDidLoad and viewWillAppear since I was implementing the camera view in a NavigationController view stack and wanted the ability to add the titlebar, toolbar, etc. instead of presenting it modally, as the zbar docs demonstrate.