init =
(Model { width = 0, height = 0 } [] { x=0 , y=0 }, Task.perform
never WindowResize Window.size)
with never from
http://package.elm-lang.org/packages/elm-community/basics-extra.
2016-05-19 16:24 GMT+02:00 Matic Zavadlal <[email protected]>:
> The problem is that init sets width and height of screen to 0 and doesn't
> update them until the screen resizes. How can I get the values of window
> width and height in init with Tasks?
>
>
> Here's my code:
>
>
> import Color exposing (..)
> import Collage exposing (..)
> import Element exposing (..)
> import Random
> import Window exposing (..)
> import Mouse
> import Task
> import Platform.Sub as Sub
>
> import Html.App as App
> import Html exposing (..)
>
>
>
> main =
> App.program
> { init = init
> , view = view
> , update = update
> , subscriptions = subscriptions
> }
>
>
> -- MODEL
>
> type alias Model =
> { screen : Size
> , balls : List (Ball)
> , previousMouse : Mouse
> }
>
>
> type alias Ball =
> { position : (Int, Int)
> , color : Color
> }
>
> type alias Mouse =
> { x : Int
> , y : Int
> }
>
>
>
> -- UPDATE
>
> type Msg
> = Move Mouse
> | Click Mouse
> | NewBall Color
> | WindowResize Size
>
> update : Msg -> Model -> (Model, Cmd Msg)
> update msg ({previousMouse} as model) =
> case msg of
> Move position ->
> let
> (px,py) = (previousMouse.x, previousMouse.y)
> (x, y) = (position.x, position.y)
> newBalls = List.map (updateCoordinates (x-px, py-y))
> model.balls
> in
> (Model model.screen newBalls position, Cmd.none)
>
> Click _ ->
> (model, Random.generate NewBall rgb)
>
> NewBall color ->
> let
> newBalls = model.balls ++ [ Ball (0,0) color ]
> in
> (Model model.screen newBalls model.previousMouse, Cmd.none)
>
> WindowResize size ->
> (Model size model.balls model.previousMouse, Cmd.none)
>
>
> updateCoordinates : (Int,Int) -> Ball -> Ball
> updateCoordinates upd ball =
> let
> (x,y) = ball.position
> (dx,dy) = upd
> newPosition = (x+dx, y+dy)
> in
> { ball |
> position = newPosition
> }
>
>
> rgb : Random.Generator Color.Color
> rgb =
> Random.map3 Color.rgb (Random.int 0 255) (Random.int 0 255) (Random.int
> 0 255)
>
>
>
>
> -- VIEW
>
> view : Model -> Html Msg
> view model =
> -- div [] [ Html.text (toString (Window.height \a -> a)) ]
> (collage model.screen.width model.screen.height
> (List.map drawBall model.balls))
> |> Element.toHtml
>
>
>
> drawBall : Ball -> Form
> drawBall ball =
> let
> (x,y) = ball.position
> color = ball.color
> in
> circle 10
> |> filled color
> |> move ((toFloat x), (toFloat y))
>
>
>
> -- SUBSCRIPTIONS
>
> subscriptions : Model -> Sub Msg
> subscriptions model =
> Sub.batch
> [ (Mouse.moves Move)
> , (Mouse.clicks Click)
> , (Window.resizes WindowResize)
> ]
>
>
> -- INIT
>
> init : (Model, Cmd Msg)
> init =
> (Model { width = 0, height = 0 } [] { x=0 , y=0 }, Cmd.none)
>
>
>
>
>
>
>
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