我如何 accelerate/Slow 向下旋转 CABasicAnimation 中的按钮

Question

我想让我的星球在靠近太阳时加速运动，在远离太阳时减速.. 请帮助我！谢谢

CABasicAnimation* rotationAnimation;

rotationAnimation=[CABasicAnimationanimationWithKeyPath:@"transform.rotation.z"];
rotationAnimation.toValue = [NSNumber numberWithFloat: -M_PI * 2.0 /* full rotation*/ * 1/period ];//multiply more to add speed
rotationAnimation.duration = 15;
rotationAnimation.cumulative = YES;
rotationAnimation.repeatCount =  HUGE_VALF;
[planet.layer addAnimation:rotationAnimation forKey:@"orbit"];

Answer 1

您想使用 CAMediaTimingFunction。查看 pre-defined timing functions。您可以将其中之一分配给 rotationAnimation.timingFunction。听起来你想要 kCAMediaTimingFunctionEaseInEaseOut。我假设行星的起点远离太阳。在代码中，它看起来像这样：

Swift:

rotationAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)

Objective-C:

rotationAnimation.timingFunction = [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseInEaseOut];

我如何 accelerate/Slow 向下旋转 CABasicAnimation 中的按钮

How Can I accelerate/Slow down the rotation of a button in CABasicAnimation

objective-c

cabasicanimation

ios