Incorporating setVideoScaleAndCropFactor into iOS!

[Nathan Kellert]

Hey guys! I have been searching high and low on how to zoom in and maintain proper readability when it comes to using zxing. 

I have been working for about a month on getting this app to scan tiny barcodes. Setting it to higher resolution helped a lot. However, with the iPhone not wanting to focus close objects and ZXing by default resetting any preset resolution to the bounds of the frame its been very difficult. 

I found this

http://developer.apple.com/library/ios/#samplecode/SquareCam/Introduction/Intro.html

which focuses on face detection(which I dont care about haha) but amazingly it shows how to use the AVFramework with setVideoScaleAndCropFactor.

I was wondering if anyone would know how to properly incorporate this with ZXing. I tested the app out and zooming into the frame it did an amazing job of getting in close and then refocusing once zoomed in. I was very impressed. 

Since zxing is not tied to a xib or a view in a storyboard but delegates itself I couldnt figure out how to add a gesture and a IBAction. So I managed to do it in the view did load. I then added - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer

{

if ( [gestureRecognizer isKindOfClass:[UIPinchGestureRecognizer class]] ) {

beginGestureScale = effectiveScale;

}

NSLog(@"we did should begin");

    return YES;

    

}

- (IBAction)handlePinchGesture:(UIPinchGestureRecognizer *)recognizer

{

BOOL allTouchesAreOnThePreviewLayer = YES;

NSUInteger numTouches = [recognizer numberOfTouches], i;

for ( i = 0; i < numTouches; ++i ) {

         NSLog(@"%lu",(unsigned long)i);

CGPoint location = [recognizer locationOfTouch:i inView: overlayView];

CGPoint convertedLocation = [prevLayer convertPoint:location fromLayer:prevLayer.superlayer];

if ( ! [prevLayer containsPoint:convertedLocation] ) {

allTouchesAreOnThePreviewLayer = NO;

            NSLog(@"we broke");

break;

}

}

if ( allTouchesAreOnThePreviewLayer ) {

effectiveScale = beginGestureScale * recognizer.scale;

if (effectiveScale < 1.0)

effectiveScale = 1.0;

CGFloat maxScaleAndCropFactor = [[output connectionWithMediaType:AVMediaTypeVideo] videoMaxScaleAndCropFactor];

if (effectiveScale > maxScaleAndCropFactor)

effectiveScale = maxScaleAndCropFactor;

[CATransaction begin];

        NSLog(@"transition started");

[CATransaction setAnimationDuration:.025];

[prevLayer setAffineTransform:CGAffineTransformMakeScale(effectiveScale, effectiveScale)];

[CATransaction commit];

        NSLog(@"commit");

}

}

from there I got it to recognize gestures but the whole screen turns black when touched. I get NSLogs that its recognizing and executing the code. Just isnt resizing the view. 

Any help would be insanely appreciated. Ive been digging around for a while. Many people have been trying to safely do this as well and I think this will finally be the answer people are waiting for I hope. 

Love your guys work and support more than you could ever know! 

-Nathan

[Nathan Kellert]

I figured it out and it looks amazing! Where would be the best place to add my code in the event that someone else wants it?

[Nathan Kellert]

Nevermind It seems that I havent set the stillImageOutput to use the stillImageConnection....

Is anyone even watching this thread? 

[Steven Parkes]

Push it to github.

On May 23, 2013, at 12:56 AM, Nathan Kellert <na...@yoursitedesign.net> wrote:

> I figured it out and it looks amazing! Where would be a good place to add the code in the event that someone else would want it?

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[James Hough]

Hi Nathan.

Have you posted your code for this anywhere i would be interested.

Thanks

James