A Time represents an instant in sprite time.

The application using the sprite engine is responsible for determining sprite time.

Typically time 0 is when the app is initialized and time is quantized at the intended frame rate. For example, an app may record wall time when it is initialized

var start = time.Now()

and then compute the current instant in time for 60 FPS:

now := clock.Time(time.Since(start) * 60 / time.Second)

An application can pause or reset sprite time, but it must be aware of any stateful sprite.Arranger instances that expect time to continue.