Global Variable


Linear keyframe values are interpolated to produce an even pace throughout the animation.


const CAAnimationCalculationMode kCAAnimationPaced;


kCAAnimationPaced gives a linearly interpolated animation, but keyTimes and timingFunction are ignored and keyframe times are automatically generated to give the animation a constant velocity.

Listing 1 shows how to create a keyframe animation object using paced interpolation.

Listing 1

Creating paced key values

let keyframeAnimation = CAKeyframeAnimation(keyPath: "position.y")
keyframeAnimation.calculationMode = kCAAnimationPaced
keyframeAnimation.values = [310, 60, 120, 60, 310]

A layer animated with the keyframe animation created by the code above and with linearly interpolated horizontal movement would describe a path similar to Figure 1.

Figure 1

Tracing the path of an animation using paced key values

Tracing the path of an animation using paced key values

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