CODEWITHSUNDEEP
iosuigesturerecognizeruipangesturerecognizer
santibernaldo
santibernaldo

Reputation: 835

Prevent UIPanGesture from offscreen and go out the bounds of its parent view - iOS

I guess its duplicated question, but I have checked all the info about that on stackoverflow and I'm not able to figure it out.

After zooming in the Image of a UICollectionViewCell, I want to pan the Image, but only until the borders of the UIScreen/parent view.

This is what's happening:

enter image description here

This is the code I use for Scaling & Pan:

- (void)moveImage:(UIPanGestureRecognizer *)recognizer
{
    if (self.pinchGesture.scale<1.0){
        return;
    }

    if (recognizer.state == UIGestureRecognizerStateBegan || recognizer.state == UIGestureRecognizerStateChanged) {

        CGPoint translation = [recognizer translationInView:self.superview];

        CGPoint newcenter = CGPointMake(self.center.x + translation.x, self.center.y + translation.y);

         [self setCenter:newcenter];
         [recognizer setTranslation:CGPointZero inView:self];      
    }

}


- (void)doPinch:(UIPinchGestureRecognizer *)gesture
{ 
    if([gesture state] == UIGestureRecognizerStateBegan) {

        previousScale = 1.0;

    }

    CGFloat currentScale = [[self.layer valueForKeyPath:@"transform.scale"] floatValue];

    // Constants to adjust the max/min values of zoom
    const CGFloat kMaxScale = 4.0;
    const CGFloat kMinScale = 1.0;

    CGFloat newScale = 1 -  (previousScale - [gesture scale]); // new scale is in the range (0-1)
    newScale = MIN(newScale, kMaxScale / currentScale);
    newScale = MAX(newScale, kMinScale / currentScale);

    self.transform = CGAffineTransformScale(self.transform, newScale, newScale);

}

Thanks in advance ;)

Upvotes: 1

Views: 261

Answers (1)

santibernaldo
santibernaldo

Reputation: 835

Finally I use the zoom that implements UIScrollView. I added a UIScrollView to my UICollectionViewCell.

And I've set it up the minimumZoomScale, maximumZoomScale, zoomScale of the UIScrollView, and implemented the viewForZoomingInScrollView UIScrollViewDelegate method on my Custom UICollectionViewCell, to get running the zoom functionality in the UIScrollView.

That's how looks the cellForItemAtIndexPath: method of my UICollectionView:

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{


    SBQPhotosDetailCollectionViewCell *cell = [self.collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];

    cell.imageDetail=[[UIImageView alloc] initWithFrame:cell.bounds];
    cell.imageDetail.contentMode=UIViewContentModeScaleAspectFit;
    cell.scrollView.contentSize = CGSizeMake(cell.imageDetail.frame.size.width, cell.imageDetail.frame.size.height);

;
    cell.imageDetail.transform = CGAffineTransformIdentity;

    cell.scrollView.delegate=cell;
    cell.scrollView.maximumZoomScale=4.0;
    cell.scrollView.minimumZoomScale=1.0;
    cell.scrollView.zoomScale=1.0;
    [cell.scrollView addSubview:cell.imageDetail];
    [cell.imageDetail setImageWithURL:[NSURL URLWithString:[self.arrayURLS objectAtIndex:indexPath.row]]
                     placeholderImage:[UIImage imageNamed:@"thunder"]];

    cell.delegate = self;

    return cell;
}

Upvotes: 1

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