Type Property

linear

Simple linear calculation between keyframe values.

Declaration

static let linear: CAAnimationCalculationMode

Discussion

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

Listing 1

Creating linearly interpolated keyframes

let keyframeAnimation = CAKeyframeAnimation(keyPath: "position.y")
keyframeAnimation.calculationMode = kCAAnimationLinear
keyframeAnimation.keyTimes = [0, 0.25, 0.5, 0.75, 1]
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 linearly interpolated keyframes

Tracing the path of an animation using linearly interpolated keyframes