CODEWITHSUNDEEP
iosuiimagetouchuitapgesturerecognizer
Anders
Anders

Reputation: 279

Getting touch coordinates from an image while maintaining pan/zoom functionality

I'm working on a little app, on which I have a UIScrollView - and inside this, an image, twice as wide, displaying a map. The UIScrollView is made in the Storyboard Editor, the image is dynamically loaded.

It works partially - I can pan, zoom and detect a click, but I need it to return the x/y coordinates, reflecting the touch position.

Here are the relevant part of my code:

    UIImage *worldMapImage = [UIImage imageNamed:@"worldmapBig.png"];
    imageView = [[UIImageView alloc] initWithImage:worldmapImage];
    imageView.userInteractionEnabled = YES;
    imageView.multipleTouchEnabled = YES;

    [_worldmap addSubview:imageView];
    _worldmap.userInteractionEnabled = YES;
    [_worldmap setContentSize:[worldMapImage size]];
    [_worldmap setMinimumZoomScale:.5];
    [_worldmap setMaximumZoomScale:1.0];
    [self performSelectorOnMainThread:@selector(didLoadImageInBackground:) withObject:imageView waitUntilDone:YES]; // After loading, initially zoom out

    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapDetected:)];
    tapGesture.numberOfTapsRequired = 1;
    tapGesture.numberOfTouchesRequired = 1;
    [imageView addGestureRecognizer:tapGesture];
}

-(void)tapDetected:(UIGestureRecognizer*)recognizer{
    UIView *myView = [recognizer view]; <--
CGPoint touch = [recognizer locationInView:myView]; <--
NSLog(@"%f", touch.x);
}

I've searched a LOT of webpages, addressing a similar problem - and also tried replacing the image with a button, using the map as background. It returns the coordinates, but then I can't pan/zoom anymore; haven't been able to get both coordinates and pan/zoom functionality in the same code.

Can you help me out here? I've been stuck for quite some days...

UPDATE: the event handler has been changed - now it works :-)

Upvotes: 0

Views: 943

Answers (1)

neoneye
neoneye

Reputation: 52221

Perhaps try this.

The -[UIGestureRecognizer locationInView:] method computes the center point of all the touche points in the gesture.

Upvotes: 1

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