NSView not rotating around center - nsview

Question

I'm trying to rotate a NSView around its center. But even if I change the anchorPoint, the NSView continue to rotate around its top left corner. Just a precision : I'm working on OSX 10.8.5.
Thanks in advance for your help.
Here is my code :
// myView.m
- (id)initWithFrame:(NSRect)rect
{
if(self = [super initWithFrame:(NSRect)rect])
{
self.frame = rect;
[self setWantsLayer:YES];
self.layer.backgroundColor = [NSColor whiteColor].CGColor;
self.layer.borderColor = [NSColor grayColor].CGColor;
self.layer.borderWidth = 1.0;
NSView *aView = [[NSView alloc] initWithFrame:NSMakeRect(0, 0, 50, 50)];
[aView setWantsLayer:YES];
aView.layer.backgroundColor = [NSColor redColor].CGColor;
aView.layer.anchorPoint = CGPointMake(0.5, 0.5);
[self addSubview:aView];
CABasicAnimation *rotateAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation"];
rotateAnimation.byValue = [NSNumber numberWithFloat:2*M_PI];
rotateAnimation.duration = 4;
rotateAnimation.repeatCount = INFINITY;
[aView.layer addAnimation:rotateAnimation forKey:#"rotationAnimation"];
}
}
EDITED 30-11-2018 : I managed to get the centered rotation using the layers :
// myView.m
- (id)initWithFrame:(NSRect)rect
{
if(self = [super initWithFrame:(NSRect)rect])
{
self.frame = rect;
[self setWantsLayer:YES];
self.layer.backgroundColor = [NSColor whiteColor].CGColor;
self.layer.borderColor = [NSColor grayColor].CGColor;
self.layer.borderWidth = 1.0;
NSView *aView = [[NSView alloc] init];
[aView setWantsLayer:YES];
aView.layer.backgroundColor = [NSColor redColor].CGColor;
aView.layer.bounds = CGRectMake(0, 0, 50, 50);
aView.layer.frame = CGRectMake(0, 0, 50, 50);
aView.layer.anchorPoint = CGPointMake(0.5, 0.5);
aView.layer.position = CGPointMake(0, 0);
[self.layer addSublayer:aView.layer];
CABasicAnimation *rotateAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation"];
rotateAnimation.byValue = [NSNumber numberWithFloat:2*M_PI];
rotateAnimation.duration = 4;
rotateAnimation.repeatCount = INFINITY;
[aView.layer addAnimation:rotateAnimation forKey:#"rotationAnimation"];
}
}

Answer 1

If you want to rotate a view you can do:
-(void)rotateByCenter:(NSView*)aView {
[aView setWantsLayer:YES];
aView.layer.anchorPoint = CGPointMake(0.5, 0.5);
aView.layer.position = CGPointMake(aView.frame.origin.x + aView.frame.size.width/2.,aView.frame.origin.y + aView.frame.size.height/2.) ;
CABasicAnimation *rotateAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation"];
rotateAnimation.byValue = [NSNumber numberWithFloat:2*M_PI];
rotateAnimation.duration = 20;
rotateAnimation.repeatCount = INFINITY;
[aView.layer addAnimation:rotateAnimation forKey:#"rotationAnimation"]; }