How To Get A Perfect Position Of Rotating View?

Question

I am have one view and I am rotating that view using CABasicAnimation. Now my problem is that how I get a perfect position of that view while rotating. I have tried many type of codes but i can't got a perfect position during rotation of that view.

CABasicAnimation *rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
NSNumber *currentAngle = [CircleView.layer.presentationLayer valueForKeyPath:@"transform.rotation"];
rotationAnimation.fromValue = currentAngle;
rotationAnimation.toValue = @(50*M_PI);
rotationAnimation.duration = 50.0f;             // this might be too fast
rotationAnimation.repeatCount = HUGE_VALF;     // HUGE_VALF is defined in math.h so import it
[CircleView.layer addAnimation:rotationAnimation forKey:@"rotationAnimationleft"];

I am using this code for rotating my view.

I have also attached a one photo of my view.

Thank you In Advance Please Help If You Know.

enter image description here

Dennis Pashkov · Accepted Answer · 2016-01-16T09:37:50.260

To get view's parameters during the animation you should use view.layer.presentationLayer

ADDED:

In order to get the coordinate of top left corner of the view, use the following code:

- (CGPoint)currentTopLeftPointOfTheView:(UIView *)view
{
    CGRect rect = view.bounds;
    rect.origin.x = view.center.x - 0.5 * CGRectGetWidth(rect);
    rect.origin.y = view.center.y - 0.5 * CGRectGetHeight(rect);

    CGPoint originalTopLeftCorner = CGPointMake(CGRectGetMinX(rect), CGRectGetMinY(rect));
    CGPoint rectCenter = CGPointMake(CGRectGetMidX(rect), CGRectGetMidY(rect));
    CGFloat radius = sqrt(pow(rectCenter.x - originalTopLeftCorner.x, 2.0) + pow(rectCenter.y - originalTopLeftCorner.y, 2.0));

    CGFloat originalAngle = M_PI - acos((rectCenter.x - originalTopLeftCorner.x) / radius);

    CATransform3D currentTransform = ((CALayer *)view.layer.presentationLayer).transform;
    CGFloat rotation = atan2(currentTransform.m12, currentTransform.m11);

    CGFloat resultAngle = originalAngle - rotation;
    CGPoint currentTopLeftCorner = CGPointMake(round(rectCenter.x + cos(resultAngle) * radius), round(rectCenter.y - sin(resultAngle) * radius));

    return currentTopLeftCorner;
}

Resulting CGPoint will be the coordinate of the top left corner of your (rotated) view relative to its superview.

So you want to determine the coordinate of top left point of the view, right? — Dennis Pashkov, Jan 16 '16 at 07:49
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/100837/discussion-between-hardik-vyas-and-dennis-pashkov). — Hardik Vyas, Jan 16 '16 at 10:40

score 1 · Answer 2 · edited May 23 '17 at 12:04

1

Set the position of the layer that you what

[layer setPosition:endpoint];

Or you may also refer this CABasicAnimation rotate returns to original position

edited May 23 '17 at 12:04

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answered Jan 16 '16 at 07:21

viratpuar

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Sorry I Don't want original position please understand the question – Hardik Vyas Jan 16 '16 at 07:29
i want a perfect pisition while view is rotaing. – Hardik Vyas Jan 16 '16 at 07:30
where you want the perfect position can you explain more – viratpuar Jan 16 '16 at 07:33
every second every time i want position of that view – Hardik Vyas Jan 16 '16 at 07:33
while view is rotating – Hardik Vyas Jan 16 '16 at 07:34

How To Get A Perfect Position Of Rotating View?

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