animation(_:valueForProgress:)
Requests a custom curve value for the current progress value.
Declaration
nonisolated optional func animation(_ animation: NSAnimation, valueForProgress progress: NSAnimation.Progress) -> FloatParameters
- animation:
An
NSAnimationobject that is running. - progress:
A
floatvalue (typed asNSAnimationProgress) that indicates a progress mark ofanimation. This value is always between 0.0 and 1.0.
Return Value
A float value representing a custom curve.
Discussion
The delegate can compute and return a custom curve value for the given progress value. If the delegate does not implement this method, NSAnimation computes the current curve value.
The animation:valueForProgress: message is sent to the delegate when an NSAnimation object receives a currentValue message. The value the delegate returns is used as the value of currentValue; if there is no delegate, or it doesn’t implement animation:valueForProgress:, NSAnimation computes and returns the current value. NSAnimation does not invoke currentValueitself, but subclasses might.
See the description of currentValue for more information.