Convenience helpers for working with keyboard inputs.
Check the pressed down state of any Key.
@WARNING Due to javascript "ghost keys" this can return incorrect information.
Pass in a list of hotkeys and some action and receive an action back if one of the hotkeys was triggered.
Only 1 hotkey can be triggered at once and it will give priority to bigger hotkeys, so if shift and tab are pressed and there are hotkeys for tab and for shift-tab it will trigger the shift-tab hotkey. This will not demand that exactly those keys are pressed to try to avoid javascript bugs with "ghost keys", so if "a" and "b" are pressed and a hotkey exists for just "a" it will be triggered (unless a better hotkey match exists, in this case a hotkey for both "a" and "b").
This is meant to be the main interface to handle hotkeys with this library.
The set of keys currently pressed.
@WARNING Due to javascript "ghost keys" this may not always be exactly what keys are pressed.
The message type Keyboard.Extra uses.
You will need to add this to your program's subscriptions.
Use this to initialize the component.
You need to call this to have the component update.
These are all the keys that have names in Keyboard.Extra.
Convert a key code into a Key.
Convert a Key into a key code.
module Keyboard.Extra
exposing
( Key(..)
, Model
, Msg(..)
, fromCode
, getHotkeyAction
, init
, isPressed
, subscriptions
, toCode
, update
)
{-| Convenience helpers for working with keyboard inputs.
# Helpers
@docs isPressed, getHotkeyAction
# Wiring
@docs Model, Msg, subscriptions, init, update
# Keyboard keys
@docs Key
# Low level
@docs fromCode, toCode
-}
import Dict exposing (Dict)
import Keyboard exposing (KeyCode)
import Set exposing (Set)
{-| The message type `Keyboard.Extra` uses.
-}
type Msg
= Down KeyCode
| Up KeyCode
{-| You will need to add this to your program's subscriptions.
-}
subscriptions : Sub Msg
subscriptions =
Sub.batch
[ Keyboard.downs Down
, Keyboard.ups Up
]
{-| The set of keys currently pressed.
@WARNING Due to javascript "ghost keys" this may not always be exactly what keys are pressed.
-}
type alias Model =
Set KeyCode
{-| Use this to initialize the component.
-}
init : Model
init =
Set.empty
{-| You need to call this to have the component update.
-}
update : Msg -> Model -> Model
update msg model =
case msg of
Down code ->
Set.insert code model
Up code ->
Set.remove code model
{-| Returns the number of currently pressed keys.
@WARNING Due to javascript "ghost keys" this may not always be exactly the correct number of keys pressed.
-}
numberOfPressedKeys : Model -> Int
numberOfPressedKeys =
Set.size
{-| Check the pressed down state of any `Key`.
@WARNING Due to javascript "ghost keys" this can return incorrect information.
-}
isPressed : Key -> Model -> Bool
isPressed =
toCode >> Set.member
{-| Pass in a list of hotkeys and some action and receive an action back if one of the hotkeys was triggered.
Only 1 hotkey can be triggered at once and it will give priority to bigger hotkeys, so if shift and tab
are pressed and there are hotkeys for tab and for shift-tab it will trigger the shift-tab hotkey. This will not demand
that exactly those keys are pressed to try to avoid javascript bugs with "ghost keys", so if "a" and "b" are pressed and
a hotkey exists for just "a" it will be triggered (unless a better hotkey match exists, in this case a hotkey for
both "a" and "b").
This is meant to be the main interface to handle hotkeys with this library.
-}
getHotkeyAction : List ( List Key, action ) -> Model -> Maybe action
getHotkeyAction hotkeys model =
let
hotkeyMatches =
List.all (\key -> isPressed key model)
-- To prevent re-sorting keys on recursive calls.
go sortedHotkeys =
case sortedHotkeys of
( hotkey, action ) :: rest ->
if hotkeyMatches hotkey then
Just action
else
go rest
[] ->
Nothing
in
hotkeys
|> List.sortBy (Tuple.first >> List.length >> Basics.negate)
|> go
{-| Convert a key code into a `Key`.
-}
fromCode : KeyCode -> Key
fromCode code =
codeDict
|> Dict.get code
|> Maybe.withDefault Other
{-| Convert a `Key` into a key code.
-}
toCode : Key -> KeyCode
toCode key =
codeBook
|> List.filter ((==) key << Tuple.second)
|> List.map Tuple.first
|> List.head
|> Maybe.withDefault 0
{-| These are all the keys that have names in `Keyboard.Extra`.
-}
type Key
= Cancel
| Help
| BackSpace
| Tab
| Clear
| Enter
| Shift
| Control
| Alt
| Pause
| CapsLock
| Escape
| Convert
| NonConvert
| Accept
| ModeChange
| Space
| PageUp
| PageDown
| End
| Home
| ArrowLeft
| ArrowUp
| ArrowRight
| ArrowDown
| Select
| Print
| Execute
| PrintScreen
| Insert
| Delete
| Number0
| Number1
| Number2
| Number3
| Number4
| Number5
| Number6
| Number7
| Number8
| Number9
| Colon
| Semicolon
| LessThan
| Equals
| GreaterThan
| QuestionMark
| At
| CharA
| CharB
| CharC
| CharD
| CharE
| CharF
| CharG
| CharH
| CharI
| CharJ
| CharK
| CharL
| CharM
| CharN
| CharO
| CharP
| CharQ
| CharR
| CharS
| CharT
| CharU
| CharV
| CharW
| CharX
| CharY
| CharZ
| Super
| ContextMenu
| Sleep
| Numpad0
| Numpad1
| Numpad2
| Numpad3
| Numpad4
| Numpad5
| Numpad6
| Numpad7
| Numpad8
| Numpad9
| Multiply
| Add
| Separator
| Subtract
| Decimal
| Divide
| F1
| F2
| F3
| F4
| F5
| F6
| F7
| F8
| F9
| F10
| F11
| F12
| F13
| F14
| F15
| F16
| F17
| F18
| F19
| F20
| F21
| F22
| F23
| F24
| NumLock
| ScrollLock
| Circumflex
| Exclamation
| DoubleQuote
| Hash
| Dollar
| Percent
| Ampersand
| Underscore
| OpenParen
| CloseParen
| Asterisk
| Plus
| Pipe
| HyphenMinus
| OpenCurlyBracket
| CloseCurlyBracket
| Tilde
| VolumeMute
| VolumeDown
| VolumeUp
| Comma
| Minus
| Period
| Slash
| BackQuote
| OpenBracket
| BackSlash
| CloseBracket
| Quote
| Meta
| Altgr
| Other
codeDict : Dict KeyCode Key
codeDict =
Dict.fromList codeBook
codeBook : List ( KeyCode, Key )
codeBook =
[ ( 3, Cancel )
, ( 6, Help )
, ( 8, BackSpace )
, ( 9, Tab )
, ( 12, Clear )
, ( 13, Enter )
, ( 16, Shift )
, ( 17, Control )
, ( 18, Alt )
, ( 19, Pause )
, ( 20, CapsLock )
, ( 27, Escape )
, ( 28, Convert )
, ( 29, NonConvert )
, ( 30, Accept )
, ( 31, ModeChange )
, ( 32, Space )
, ( 33, PageUp )
, ( 34, PageDown )
, ( 35, End )
, ( 36, Home )
, ( 37, ArrowLeft )
, ( 38, ArrowUp )
, ( 39, ArrowRight )
, ( 40, ArrowDown )
, ( 41, Select )
, ( 42, Print )
, ( 43, Execute )
, ( 44, PrintScreen )
, ( 45, Insert )
, ( 46, Delete )
, ( 48, Number0 )
, ( 49, Number1 )
, ( 50, Number2 )
, ( 51, Number3 )
, ( 52, Number4 )
, ( 53, Number5 )
, ( 54, Number6 )
, ( 55, Number7 )
, ( 56, Number8 )
, ( 57, Number9 )
, ( 58, Colon )
, ( 59, Semicolon )
, ( 60, LessThan )
, ( 61, Equals )
, ( 62, GreaterThan )
, ( 63, QuestionMark )
, ( 64, At )
, ( 65, CharA )
, ( 66, CharB )
, ( 67, CharC )
, ( 68, CharD )
, ( 69, CharE )
, ( 70, CharF )
, ( 71, CharG )
, ( 72, CharH )
, ( 73, CharI )
, ( 74, CharJ )
, ( 75, CharK )
, ( 76, CharL )
, ( 77, CharM )
, ( 78, CharN )
, ( 79, CharO )
, ( 80, CharP )
, ( 81, CharQ )
, ( 82, CharR )
, ( 83, CharS )
, ( 84, CharT )
, ( 85, CharU )
, ( 86, CharV )
, ( 87, CharW )
, ( 88, CharX )
, ( 89, CharY )
, ( 90, CharZ )
, ( 91, Super )
, ( 93, ContextMenu )
, ( 95, Sleep )
, ( 96, Numpad0 )
, ( 97, Numpad1 )
, ( 98, Numpad2 )
, ( 99, Numpad3 )
, ( 100, Numpad4 )
, ( 101, Numpad5 )
, ( 102, Numpad6 )
, ( 103, Numpad7 )
, ( 104, Numpad8 )
, ( 105, Numpad9 )
, ( 106, Multiply )
, ( 107, Add )
, ( 108, Separator )
, ( 109, Subtract )
, ( 110, Decimal )
, ( 111, Divide )
, ( 112, F1 )
, ( 113, F2 )
, ( 114, F3 )
, ( 115, F4 )
, ( 116, F5 )
, ( 117, F6 )
, ( 118, F7 )
, ( 119, F8 )
, ( 120, F9 )
, ( 121, F10 )
, ( 122, F11 )
, ( 123, F12 )
, ( 124, F13 )
, ( 125, F14 )
, ( 126, F15 )
, ( 127, F16 )
, ( 128, F17 )
, ( 129, F18 )
, ( 130, F19 )
, ( 131, F20 )
, ( 132, F21 )
, ( 133, F22 )
, ( 134, F23 )
, ( 135, F24 )
, ( 144, NumLock )
, ( 145, ScrollLock )
, ( 160, Circumflex )
, ( 161, Exclamation )
, ( 162, DoubleQuote )
, ( 163, Hash )
, ( 164, Dollar )
, ( 165, Percent )
, ( 166, Ampersand )
, ( 167, Underscore )
, ( 168, OpenParen )
, ( 169, CloseParen )
, ( 170, Asterisk )
, ( 171, Plus )
, ( 172, Pipe )
, ( 173, HyphenMinus )
, ( 174, OpenCurlyBracket )
, ( 175, CloseCurlyBracket )
, ( 176, Tilde )
, ( 181, VolumeMute )
, ( 182, VolumeDown )
, ( 183, VolumeUp )
, ( 186, Semicolon )
, ( 187, Equals )
, ( 188, Comma )
, ( 189, Minus )
, ( 190, Period )
, ( 191, Slash )
, ( 192, BackQuote )
, ( 219, OpenBracket )
, ( 220, BackSlash )
, ( 221, CloseBracket )
, ( 222, Quote )
, ( 224, Meta )
, ( 225, Altgr )
]