How to avoid tilt/flip on CATransform3D rotation in iOS?

Question

I used below function for 3dRotation on view. But i don't want tilt/flip on view, I just want to left/right/up/down movement on view.

How i avoid tilt and flip rotation on my view ?

- (void)Move3dPan:(UIPanGestureRecognizer *)gesture
{
    if (gesture.state == UIGestureRecognizerStateChanged)
    {
        CGPoint displacement = [gesture translationInView:self.view];
        CATransform3D currentTransform = self.popUpView.layer.sublayerTransform;

        if (displacement.x==0 && displacement.y==0)
        {
            // no rotation, nothing to do
            return;
        }

        CGFloat totalRotation = sqrt(displacement.x * displacement.x + displacement.y * displacement.y) * M_PI / 360.0;
        CGFloat xRotationFactor = displacement.x/totalRotation;
        CGFloat yRotationFactor = displacement.y/totalRotation;

        CATransform3D rotationalTransform = CATransform3DRotate(currentTransform, totalRotation,
                                                            (xRotationFactor * currentTransform.m12 - yRotationFactor * currentTransform.m11),
                                                            (xRotationFactor * currentTransform.m22 - yRotationFactor * currentTransform.m21),
                                                            (xRotationFactor * currentTransform.m32 - yRotationFactor * currentTransform.m31));

        [CATransaction setAnimationDuration:0];

        self.popUpView.layer.sublayerTransform = rotationalTransform;

        [gesture setTranslation:CGPointZero inView:self.view];
    }
}

Answer 1

-(void) startAnimatingCupView

{

    [self stopAnimatingCupView];

    timer = [NSTimer scheduledTimerWithTimeInterval:0.8 repeats:true block:^(NSTimer * _Nonnull timer) {

        [self animateCupView];

    }];

}


-(void) animateCupView{

    [UIView animateWithDuration:0.4 animations:^{

        self.imgCup.transform = CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(180));

    } completion:^(BOOL finished) {

        [UIView animateWithDuration:0.4 animations:^{

            self.imgCup.transform = CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(360));

        }];

    }];

}


-(void) stopAnimatingCupView{

    if (timer != nil) {

        [timer invalidate];

        timer = nil;

    }

    [self.imgCup.layer setTransform:CATransform3DIdentity];

}

i hope this will work