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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
{-| On mobile phones, the keyboard displays vertically.
-}
type Direction
= Horizontal
| Vertical
type alias KeyMarkup a =
{ offset : Int
, isHighlit : Bool
, note : Theory.Note
, direction : Direction
}
-> Html a
type alias Props =
{ highlight : List Theory.Note
, start : Theory.Note
, end : Theory.Note
}
{-| Convert an integer into its pixel representation for CSS.
-}
pixelate : Int -> String
pixelate x =
String.fromInt x ++ "px"
{-| Pixel width of the white keys.
-}
naturalWidth : Direction -> Int
naturalWidth direction =
case direction of
Vertical ->
-- Right now, I'm designing this specifically for my Google Pixel 4
-- phone, which has a screen width of 1080px.
1080
Horizontal ->
45
{-| Pixel height of the white keys.
-}
naturalHeight : Direction -> Int
naturalHeight direction =
case direction of
Vertical ->
-- Right now, I'm designing this specifically for my Google Pixel 4
-- phone, which has a screen height of 2280px. 2280 / 21
-- (i.e. no. natural keys) ~= 108
108
Horizontal ->
250
{-| Pixel width of the black keys.
-}
accidentalWidth : Direction -> Int
accidentalWidth direction =
case direction of
Vertical ->
round (toFloat (naturalWidth direction) * 0.6)
Horizontal ->
round (toFloat (naturalWidth direction) * 0.4)
{-| Pixel height of the black keys.
-}
accidentalHeight : Direction -> Int
accidentalHeight direction =
case direction of
Vertical ->
round (toFloat (naturalHeight direction) * 0.63)
Horizontal ->
round (toFloat (naturalHeight direction) * 0.63)
{-| Return the markup for either a white or a black key.
-}
pianoKey : KeyMarkup a
pianoKey { offset, isHighlit, note, direction } =
let
sharedClasses =
[ "box-border" ]
{ keyWidth, keyHeight, keyColor, offsetEdge, extraClasses } =
case ( Theory.keyClass note, direction ) of
( Theory.Natural, Vertical ) ->
{ keyWidth = naturalWidth Vertical
, keyHeight = naturalHeight Vertical
, keyColor = "white"
, offsetEdge = "top"
, extraClasses = []
}
( Theory.Natural, Horizontal ) ->
{ keyWidth = naturalWidth Horizontal
, keyHeight = naturalHeight Horizontal
, keyColor = "white"
, offsetEdge = "left"
, extraClasses = []
}
( Theory.Accidental, Vertical ) ->
{ keyWidth = accidentalWidth Vertical
, keyHeight = accidentalHeight Vertical
, keyColor = "black"
, offsetEdge = "top"
, extraClasses = [ "z-10" ]
}
( Theory.Accidental, Horizontal ) ->
{ keyWidth = accidentalWidth Horizontal
, keyHeight = accidentalHeight Horizontal
, keyColor = "black"
, offsetEdge = "left"
, extraClasses = [ "z-10" ]
}
in
div
[ style "background-color"
(if isHighlit then
"red"
else
keyColor
)
, style "border-top" "1px solid black"
, style "border-bottom" "1px solid black"
, style "border-left" "1px solid black"
, style "border-right" "1px solid black"
, style "width" (pixelate keyWidth)
, style "height" (pixelate keyHeight)
, style "position" "absolute"
, style offsetEdge (String.fromInt offset ++ "px")
, class <| String.join " " (List.concat [ sharedClasses, extraClasses ])
]
[]
{-| A section of the piano consisting of all twelve notes.
-}
keys : Direction -> Theory.Note -> Theory.Note -> List Theory.Note -> List (Html a)
keys direction start end highlight =
let
isHighlit note =
List.member note highlight
spacing prevOffset prev curr =
case ( Theory.keyClass prev, Theory.keyClass curr, direction ) of
-- Horizontal
( Theory.Natural, Theory.Accidental, Horizontal ) ->
prevOffset + naturalWidth direction - round (toFloat (accidentalWidth direction) / 2)
( Theory.Accidental, Theory.Natural, Horizontal ) ->
prevOffset + round (toFloat (accidentalWidth direction) / 2)
( Theory.Natural, Theory.Natural, Horizontal ) ->
prevOffset + naturalWidth direction
-- Vertical
( Theory.Natural, Theory.Accidental, Vertical ) ->
prevOffset + naturalHeight direction - round (toFloat (accidentalHeight direction) / 2)
( Theory.Accidental, Theory.Natural, Vertical ) ->
prevOffset + round (toFloat (accidentalHeight direction) / 2)
( Theory.Natural, Theory.Natural, Vertical ) ->
prevOffset + naturalHeight direction
-- This pattern should never hit.
_ ->
prevOffset
( _, _, notes ) =
Theory.notesFromRange start end
|> List.foldl
(\curr ( prevOffset, prev, result ) ->
case ( prevOffset, prev ) of
( Nothing, Nothing ) ->
( Just 0
, Just curr
, pianoKey
{ offset = 0
, isHighlit = List.member curr highlight
, note = curr
, direction = direction
}
:: result
)
( Just po, Just p ) ->
let
offset =
spacing po p curr
in
( Just offset
, Just curr
, pianoKey
{ offset = offset
, isHighlit = List.member curr highlight
, note = curr
, direction = direction
}
:: result
)
-- This pattern should never hit.
_ ->
( Nothing, Nothing, [] )
)
( Nothing, Nothing, [] )
in
List.reverse notes
{-| Return the HTML that renders a piano representation.
-}
render : Props -> Html a
render { highlight, start, end } =
div [ style "display" "flex" ]
(keys Vertical start end highlight |> List.reverse |> List.repeat 1 |> List.concat)
|
