iOS球形旋转动画

CGPathRef aPath;
aPath = CGPathCreateWithEllipseInRect(CGRectMake(0, 0, 200, 200), NULL);

[CATransaction begin];

CAKeyframeAnimation * arcAnimation = [CAKeyframeAnimation animationWithKeyPath: @"position"];
[arcAnimation setBeginTime:CACurrentMediaTime()];
[arcAnimation setDuration: 3.0];
[arcAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]];
[arcAnimation setAutoreverses: NO];
[arcAnimation setRepeatCount:HUGE_VALF];
arcAnimation.removedOnCompletion = NO;
arcAnimation.fillMode = kCAFillModeRemoved;
[arcAnimation setCalculationMode:kCAAnimationPaced];
[arcAnimation setPath: aPath];
[cyanLayer addAnimation: arcAnimation forKey: @"position"];

[CATransaction commit];
CFRelease(aPath);