53 lines
1.9 KiB
Forth
53 lines
1.9 KiB
Forth
namespace web_api_cookbook
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open WebSharper
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open WebSharper.JavaScript
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open WebSharper.UI
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open WebSharper.UI.Client
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open WebSharper.UI.Html
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[<JavaScript>]
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module UI =
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module Components =
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let button attrs label =
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button (attrs @ [attr.``type`` "button"]) [ text label ]
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[<JavaScript>]
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module Animate =
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open Units.Animation
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open Units.Time
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let value (startPoint:float) endPoint (targetFps:float<frames/s>) (animationSeconds:float<s>) =
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let frameInterval = 1. / targetFps * 1000.0<ms/s>
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let frameCount = animationSeconds * targetFps
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let diff = startPoint - endPoint
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let increment = abs (diff / frameCount)
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let lerp = Math.lerp startPoint endPoint
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let interpolatedValue = Var.Create startPoint
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let rec callback (lastRedrawAt:float<ms> option) frameNo (now:float) =
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let now = now * 1.0<ms>
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let lastRedrawAt = Option.getOrElse now lastRedrawAt
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let elapsed = now - lastRedrawAt
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let readyToRender = elapsed >= frameInterval * 1.<frames>
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match readyToRender with
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| false ->
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JS.Window.RequestAnimationFrame (callback (Some lastRedrawAt) frameNo) |> ignore
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| true ->
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let t = float frameNo * increment * 1.<frames>
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let nextVal = lerp t
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Var.Set interpolatedValue nextVal
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if nextVal <> endPoint
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then
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JS.Window.RequestAnimationFrame (callback (Some now) (frameNo + 1))
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|> ignore
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JS.Window.RequestAnimationFrame (callback None 0) |> ignore
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interpolatedValue.View
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let valueWhen beginAnimation startPoint endPoint targetFps animationSeconds =
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function
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| true -> value startPoint endPoint targetFps animationSeconds
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| false -> View.Const startPoint
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|> View.MapCached <| beginAnimation
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|> View.Join
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