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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