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|
module Piano exposing (render)
import Browser
import Html exposing (..)
import Html.Attributes exposing (..)
import Html.Events exposing (..)
import List.Extra
import Theory
import UI
type alias KeyMarkup a =
{ offset : Int
, isHighlit : Bool
, note : Theory.Note
, isRootNote : Bool
}
-> Html a
type alias Props =
{ chord : Maybe Theory.Chord
, firstNote : Theory.Note
, lastNote : Theory.Note
}
naturalThickness : Int
naturalThickness =
105
accidentalThickness : Int
accidentalThickness =
round (toFloat naturalThickness / 2.0)
{-| Convert an integer into its pixel representation for CSS.
-}
pixelate : Int -> String
pixelate x =
String.fromInt x ++ "px"
{-| Return the markup for either a white or a black key.
-}
pianoKey : KeyMarkup a
pianoKey { offset, isHighlit, note, isRootNote } =
let
{ natColor, accColor, hiColor, rootColor } =
{ natColor = "bg-white"
, accColor = "bg-black"
, hiColor = "bg-red-400"
, rootColor = "bg-red-600"
}
sharedClasses =
[ "box-border"
, "absolute"
, "border"
, "border-black"
]
{ keyLength, keyThickness, keyColor, offsetEdge, extraClasses } =
case Theory.keyClass note of
Theory.Natural ->
{ keyLength = "w-screen"
, keyThickness = naturalThickness
, keyColor = natColor
, offsetEdge = "top"
, extraClasses = []
}
Theory.Accidental ->
{ keyLength = "w-2/3"
, keyThickness = accidentalThickness
, keyColor = accColor
, offsetEdge = "top"
, extraClasses = [ "z-10" ]
}
in
div
[ class
(case ( isHighlit, isRootNote ) of
( False, _ ) ->
keyColor
( True, True ) ->
rootColor
( True, False ) ->
hiColor
)
, class keyLength
, style "height" (pixelate keyThickness)
, style offsetEdge (String.fromInt offset ++ "px")
, class <| String.join " " (List.concat [ sharedClasses, extraClasses ])
]
[]
{-| A section of the piano consisting of all twelve notes.
-}
keys :
{ start : Theory.Note
, end : Theory.Note
, highlitNotes : List Theory.Note
, rootNote : Maybe Theory.Note
}
-> List (Html a)
keys { start, end, highlitNotes, rootNote } =
let
isHighlit note =
List.member note highlitNotes
spacing prevOffset prev curr =
case ( Theory.keyClass prev, Theory.keyClass curr ) of
( Theory.Natural, Theory.Accidental ) ->
prevOffset + naturalThickness - round (toFloat accidentalThickness / 2)
( Theory.Accidental, Theory.Natural ) ->
prevOffset + round (toFloat accidentalThickness / 2)
( Theory.Natural, Theory.Natural ) ->
prevOffset + naturalThickness
-- This pattern should never hit.
_ ->
prevOffset
( _, _, notes ) =
Theory.notesFromRange start end
|> List.reverse
|> List.foldl
(\curr ( prevOffset, prev, result ) ->
case ( prevOffset, prev ) of
( Nothing, Nothing ) ->
( Just 0
, Just curr
, pianoKey
{ offset = 0
, isHighlit = List.member curr highlitNotes
, note = curr
, isRootNote =
rootNote
|> Maybe.map (\x -> x == curr)
|> Maybe.withDefault False
}
:: result
)
( Just po, Just p ) ->
let
offset =
spacing po p curr
in
( Just offset
, Just curr
, pianoKey
{ offset = offset
, isHighlit = List.member curr highlitNotes
, note = curr
, isRootNote =
rootNote
|> Maybe.map (\x -> x == curr)
|> Maybe.withDefault False
}
:: result
)
-- This pattern should never hit.
_ ->
( Nothing, Nothing, [] )
)
( Nothing, Nothing, [] )
in
notes
{-| Return the HTML that renders a piano representation.
-}
render : Props -> Html a
render { chord } =
div [ style "display" "flex" ]
(keys
{ start = Theory.G3
, end = Theory.C6
, rootNote = chord |> Maybe.map .note
, highlitNotes =
chord
|> Maybe.andThen Theory.notesForChord
|> Maybe.withDefault []
}
)
|
