旋转视图

Created: November-22, 2018
 CGRect boundingRect = CGRectMake(-150, -150, 300, 300);

CAKeyframeAnimation *orbit = [CAKeyframeAnimation animation];
orbit.keyPath = @"position";
orbit.path = CFAutorelease(CGPathCreateWithEllipseInRect(boundingRect, NULL));
orbit.duration = 4;
orbit.additive = YES;
orbit.repeatCount = HUGE_VALF;
orbit.calculationMode = kCAAnimationPaced;
orbit.rotationMode = kCAAnimationRotateAuto;

[_label.layer addAnimation:orbit forKey:@"orbit"];