Animation

func Animate(duration time.Duration) Animation
 
func (a Animation) WithCurve(c EaseCurve) Animation
func (a Animation) Reversed() Animation
func (a Animation) Repeat(n int) Animation
 
func UseAnimation(s *Scope, anim Animation) *AnimationHandle
 
func (h *AnimationHandle) Start(tick func(float32))
func (h *AnimationHandle) Stop()
func (h *AnimationHandle) Running() bool

Animations are descriptors

Animate(duration) returns a value type. Chain WithCurve, Reversed, and Repeat to configure it. The default curve is EaseInOut.

anim := gova.Animate(400 * time.Millisecond).
    WithCurve(gova.EaseOut).
    Repeat(gova.AnimateForever)

Easing curves

const (
    EaseLinear EaseCurve = iota
    EaseInOut
    EaseIn
    EaseOut
)

UseAnimation returns a persistent handle for the component. Call Start(tick) to run the animation; tick is invoked repeatedly at roughly 60 frames per second with the current progress value from 0 to 1.

func (v Spinner) Body(s *gova.Scope) gova.View {
    progress := gova.State(s, float32(0))
    handle := gova.UseAnimation(s, gova.Animate(time.Second).
        WithCurve(gova.EaseLinear).
        Repeat(gova.AnimateForever))
 
    gova.UseEffect(s, func(ctx context.Context) func() {
        handle.Start(func(p float32) { progress.Set(p) })
        return handle.Stop
    })
 
    return gova.Text(fmt.Sprintf("%.0f%%", progress.Get()*100))
}

AnimateForever equals -1; pass it to Repeat for a loop that only stops when Stop() is called (or the component unmounts, at which point the effect cleanup runs).

AutoReverse (produced by .Reversed()) plays the animation forward then backward before counting as one cycle for Repeat.

Animations are descriptors

Easing curves

Running an animation

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