Rotating a CALayer 90 degrees?

Question

How do I rotate a CALayer 90 degrees? I need to rotate everything include sublayers and the coordinate system.

Answer 1

Obj-C:

theLayer.transform = CATransform3DMakeRotation(90.0 / 180.0 * M_PI, 0.0, 0.0, 1.0);

Swift:

theLayer.transform = CATransform3DMakeRotation(90.0 / 180.0 * .pi, 0.0, 0.0, 1.0)

That is, transform the layer such that it is rotated by 90 degrees (π / 2 radians), with 100% of that rotation taking place around the z-axis.

Answer 2

If I'm animating it I use something like this in my apps:

- (NSObject *) defineZRotation {
    // Define rotation on z axis
    float degreesVariance = 90;
    // object will always take shortest path, so that
    // a rotation of less than 180 deg will move clockwise, and more than will move counterclockwise
    float radiansToRotate = DegreesToRadians( degreesVariance );
    CATransform3D zRotation;
    zRotation = CATransform3DMakeRotation(radiansToRotate, 0, 0, 1.0);  
    // create an animation to hold "zRotation" transform
    CABasicAnimation *animateZRotation;
    animateZRotation = [CABasicAnimation animationWithKeyPath:@"transform"];
    // Assign "zRotation" to animation
    animateZRotation.toValue = [NSValue valueWithCATransform3D:zRotation];
    // Duration, repeat count, etc
    animateZRotation.duration = 1.5;//change this depending on your animation needs
    // Here set cumulative, repeatCount, kCAFillMode, and others found in
    // the CABasicAnimation Class Reference.
    return animateZRotation;
}

Of course you can use it anywhere, don;t have to return it from a method if that doesn;t suit your needs.

Answer 3

Basically something like that:

CGAffineTransform rotateTransform = CGAffineTransformMakeRotation(M_PI / 2.0); [myCALayer setAffineTransform:rotateTransform];

EDIT: It'll rotate clockwise or counter-clockwise depending on the platform (iOS or Mac OS).

Answer 4

To rotate 90' right:

myView.transform = CGAffineTransformMakeRotation(M_PI_2);