iOS animate/morph shape from circle to square

Question

I try to change a circle into a square and vice versa and I am almost there. However it doesn\'t animates as expected. I would like all corners of a square to be animated/mo

Answer 1

Based on @Danchoys answer, here it is for Objective-C.

info is a button of 60px and infoVC is the next ViewController being pushed:

    UIBezierPath * maskPath = [UIBezierPath new];
    [maskPath addArcWithCenter:info.center radius:15.0f startAngle:DEGREES_TO_RADIANS(180) endAngle:DEGREES_TO_RADIANS(270) clockwise:true];
    [maskPath addArcWithCenter:info.center radius:15.0f startAngle:DEGREES_TO_RADIANS(270) endAngle:DEGREES_TO_RADIANS(0) clockwise:true];
    [maskPath addArcWithCenter:info.center radius:15.0f startAngle:DEGREES_TO_RADIANS(0) endAngle:DEGREES_TO_RADIANS(90) clockwise:true];
    [maskPath addArcWithCenter:info.center radius:15.0f startAngle:DEGREES_TO_RADIANS(90) endAngle:DEGREES_TO_RADIANS(180) clockwise:true];
    [maskPath closePath];

    UIBezierPath * endPath = [UIBezierPath new];
    [endPath moveToPoint:CGPointMake(0,0)];
    [endPath addLineToPoint:endPath.currentPoint];
    [endPath addLineToPoint:CGPointMake(w, 0)];
    [endPath addLineToPoint:endPath.currentPoint];
    [endPath addLineToPoint:CGPointMake(w, h)];
    [endPath addLineToPoint:endPath.currentPoint];
    [endPath addLineToPoint:CGPointMake(0, h)];
    [endPath addLineToPoint:endPath.currentPoint];
    [endPath closePath];

    CAShapeLayer *maskLayer = [CAShapeLayer layer];
    maskLayer.frame = info.bounds;
    maskLayer.path = maskPath.CGPath;
    _infoVC.view.layer.mask = maskLayer;

    CABasicAnimation * animation = [CABasicAnimation animationWithKeyPath:@"path"];
    animation.fromValue = (id)maskPath.CGPath;
    animation.toValue = (id)endPath.CGPath;
    animation.duration = 0.3f;
    [maskLayer addAnimation:animation forKey:nil];
    [maskLayer setPath:endPath.CGPath];