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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
type alias KeyMarkup a =
{ offset : Int
, isHighlit : Bool
, note : Theory.Note
}
-> 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 : Int
naturalWidth =
45
{-| Pixel height of the white keys.
-}
naturalHeight : Int
naturalHeight =
250
{-| Pixel width of the black keys.
-}
accidentalWidth : Int
accidentalWidth =
round (toFloat naturalWidth * 0.4)
{-| Pixel height of the black keys.
-}
accidentalHeight : Int
accidentalHeight =
round (toFloat naturalHeight * 0.63)
{-| These are the white keys on most modern pianos.
-}
natural : KeyMarkup a
natural { offset, isHighlit, note } =
div
[ style "background-color"
(if isHighlit then
"red"
else
"white"
)
, style "border-right" "1px solid black"
, style "border-top" "1px solid black"
, style "border-bottom" "1px solid black"
, style "width" (pixelate naturalWidth)
, style "height" (pixelate naturalHeight)
, style "position" "absolute"
, style "left" (String.fromInt offset ++ "px")
]
[]
{-| These are the black keys on most modern pianos.
-}
accidental : KeyMarkup a
accidental { offset, isHighlit, note } =
div
[ style "background-color"
(if isHighlit then
"red"
else
"black"
)
, style "border-top" "1px solid black"
, style "border-left" "1px solid black"
, style "border-right" "1px solid black"
, style "border-bottom" "1px solid black"
, style "width" (pixelate accidentalWidth)
, style "height" (pixelate accidentalHeight)
, style "position" "absolute"
, style "left" (String.fromInt offset ++ "px")
, style "z-index" "1"
]
[]
makeKey : List Theory.Note -> Theory.Note -> (Int -> Html a)
makeKey highlight note =
if Theory.isNatural note then
\x ->
natural
{ offset = x
, isHighlit = List.member note highlight
, note = note
}
else
\x ->
accidental
{ offset = x
, isHighlit = List.member note highlight
, note = note
}
{-| A section of the piano consisting of all twelve notes. The name octave
implies eight notes, which most scales (not the blues scale) honor.
-}
octave : Theory.Note -> Theory.Note -> List Theory.Note -> List (Html a)
octave start end highlight =
let
isHighlit note =
List.member note highlight
spacing prevOffset prev curr =
case ( Theory.keyClass prev, Theory.keyClass curr ) of
( Theory.Natural, Theory.Accidental ) ->
-- idk this calculation yet
prevOffset + naturalWidth - round (toFloat accidentalWidth / 2)
( Theory.Accidental, Theory.Natural ) ->
-- accidentalWidth / 2
prevOffset + round (toFloat accidentalWidth / 2)
( Theory.Natural, Theory.Natural ) ->
-- naturalWidth
prevOffset + naturalWidth
-- 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, makeKey highlight curr 0 :: result )
( Just po, Just p ) ->
let
offset =
spacing po p curr
in
( Just offset
, Just curr
, makeKey highlight curr offset :: 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" ]
(octave start end highlight |> List.reverse |> List.repeat 1 |> List.concat)
|
