Elm resizeable SVG canvas filling the screen

I am toying with writing an SVG-based game in (exciting-looking JavaScript-replacement) Elm, and I wanted an SVG that filled the whole screen and resized when the screen resized. I found it harder than I expected, so here is what I came up with for your information and comment.

Try the demo.

Because I was using Html.App.programWithFlags I was not able to shortcut the process and use just elm-reactor – I needed to create an HTML file and compile my code with elm-make.

index.html sets up a full-screen app and passes in the window size:

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="UTF-8"/>
    <title>Sootl</title>
    <script src="sootl.js"></script>
    <style>
        html, body, svg
        {
            margin: 0px;
            padding: 0px;
            border: 0px;
            overflow: hidden;
        }
    </style>
</head>
<body>
</body>
<script>
var app = Elm.Main.fullscreen(
    {
        width:  window.innerWidth,
        height: window.innerHeight
    }
);
</script>
</html>

elm-package.json requires the Html, Svg and Window packages:

{
    "version": "1.0.0",
    "summary": "Stay out of the light!",
    "repository": "https://github.com/andybalaam/sootl.git",
    "license": "GPL2",
    "source-directories": [
        "."
    ],
    "exposed-modules": [],
    "dependencies": {
        "elm-lang/core": "4.0.5 <= v < 5.0.0",
        "elm-lang/html": "1.1.0 <= v < 2.0.0",
        "elm-lang/svg": "1.1.1 <= v < 2.0.0",
        "elm-lang/window": "1.0.0 <= v < 2.0.0"
    },
    "elm-version": "0.17.1 <= v < 0.18.0"
}

Main.elm contains the Elm code, which starts off with the window size from JavaScript, and then listens to resize events using the Window module.

import Html exposing (Html)
import Html.App exposing (programWithFlags)
import Svg exposing (..)
import Svg.Attributes exposing (..)
import Window


type alias Flags =
    { width : Int
    , height : Int
    }


type Msg = Resize Int Int


type alias Model =
    { screen :
        { width : Int
        , height : Int
        }
    }


init : Flags -> (Model, Cmd Msg)
init flags =
    (
        { screen =
            { width = flags.width
            , height = flags.height
            }
        }
    , Cmd.none
    )



view : Model -> Html Msg
view model =
    let
        sw = model.screen.width  - 0
        sh = model.screen.height - 0
    in
        svg
        [ width  <| toString sw
        , height <| toString sh
        ]
        [ rect
            [ x "0"
            , y "0"
            , width (toString model.screen.width)
            , height (toString model.screen.height)
            , fill "#eeffee"
            ]
            []
        , text'
            [ x <| toString <| sw / 2
            , y <| toString <| sh / 2
            , fontSize <| toString <| sh / 10
            , textAnchor "middle"
            ]
            [ text
                ((toString model.screen.width)
                ++ ", "
                ++ (toString model.screen.height))
            ]
        ]


update : Msg -> Model -> (Model, Cmd Msg)
update msg model =
    let m =
        case msg of
            Resize w h -> {model | screen = {width = w, height = h}}
    in
        (m, Cmd.none)


subscriptions : Model -> Sub Msg
subscriptions model =
    Window.resizes (\size -> Resize size.width size.height)


main =
   programWithFlags
     { init = init
     , view = view
     , update = update
     , subscriptions = subscriptions
     }

I installed all the packages with:

elm-package install

Then I compiled the code with:

elm-make --output=sootl.js Main.elm

Now I launched elm-reactor:

elm-reactor

And navigated my browser to http://localhost:8000/index.html to see it working.

Snake in Python 3 + Qt 5

Series: Groovy, Ruby, BASIC, Dart, Elm, Python3+Qt5

I’m writing the game Snake in lots of programming languages, for fun, and to try out new languages.

Python 3 broke compatibility to fix some mistakes – was it worth it? Qt 5 continues to offer more and more features – can it win me over?

Slides: Snake in Python 3 + Qt 5

If you want to, you can Support me on Patreon.

Snake in Elm

Snake Series: Groovy, Ruby, BASIC, Dart, Elm, Python3+Qt5

Elm Series: Snake in Elm, Elm makes me happy, Elm Basics, Elm Unit Test

I’m writing the game Snake in lots of programming languages, for fun, and to try out new languages.

Elm brings the comfortable feeling and scary syntax of a pure functional language to writing dynamic web sites.

Slides: Snake in Elm

If you want to, you can Support me on Patreon.

Rabbit Escape 0.3.1 – now with zoom!

I’ve just release the latest version of Rabbit Escape, which makes things look a lot nicer because you can zoom in, getting you much closer to your rabbits:

rabbitescape-android-zoomed

There are still 60 levels of Lemmings and Pingus -like gameplay, all downloadable for free artificialworlds.net/rabbit-escape/.

I’ve also improved performance significantly, so you should notice things get smoother on older devices.

All those zoomed images increase the download size to 9MB, which is a pity, but that’s still pretty small.