Improve the styling of the piano

Create a more convincing representation of the piano.

I would like to compute the left-offset based on the naturalWidth. That change
is probably forthcoming.

website/sandbox/chord-drill-sergeant/src/Main.elm

@@ -87,7 +87,7 @@ view : State -> Html Msg
 view (State {selectedChord}) =
   div [] [ p [] [ text (viewChord selectedChord) ]
          , button [ onClick NextChord ] [ text "Next Chord" ]
-         , Piano.render { highlight = [] }
+         , Piano.render { highlight = Theory.notesForChord selectedChord }
          ]
 
 {-| For now, I'm just dumping things onto the page to sketch ideas. -}

website/sandbox/chord-drill-sergeant/src/Piano.elm

@@ -7,21 +7,52 @@ import Html.Events exposing (..)
 
 import Theory
 
+{-| 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 = 40
+
+{-| Pixel height of the white keys. -}
+naturalHeight : Int
+naturalHeight = 200
+
+{-| Pixel width of the black keys. -}
+accidentalWidth : Int
+accidentalWidth = round (toFloat naturalWidth * 0.7)
+
+{-| Pixel height of the black keys. -}
+accidentalHeight : Int
+accidentalHeight = round (toFloat naturalHeight * 0.6)
+
 {-| These are the white keys on most modern pianos. -}
-natural : Bool -> Html a
+natural : Int -> Bool -> Html a
-natural isHighlit =
+natural offset isHighlit =
-  li [ style "background-color" (if isHighlit then "red" else "white")
+  div [ style "background-color" (if isHighlit then "red" else "white")
-     , style "height" "20px"
+      , 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 : Bool -> Html a
+accidental : Int -> Bool -> Html a
-accidental isHighlit =
+accidental offset isHighlit =
-  li [ style "background-color" (if isHighlit then "red" else "black")
+  div [ style "background-color" (if isHighlit then "red" else "black")
-     , style "height" "10px"
+      , style "border-top" "1px solid black"
-     , style "width" "66%"
+      , 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"
       ] []
 
 {-| A section of the piano consisting of all twelve notes. The name octave
@@ -31,18 +62,18 @@ octave highlight =
   let
     isHighlit note = List.member note highlight
   in
-    [ natural (isHighlit Theory.C)
+    [ natural    0    (isHighlit Theory.C)
-    , accidental (isHighlit Theory.C_sharp)
+    , accidental 25   (isHighlit Theory.C_sharp)
-    , natural (isHighlit Theory.D)
+    , natural    40   (isHighlit Theory.D)
-    , accidental (isHighlit Theory.D_sharp)
+    , accidental 65   (isHighlit Theory.D_sharp)
-    , natural (isHighlit Theory.E)
+    , natural    80   (isHighlit Theory.E)
-    , natural (isHighlit Theory.F)
+    , natural    120  (isHighlit Theory.F)
-    , accidental (isHighlit Theory.F_sharp)
+    , accidental 145  (isHighlit Theory.F_sharp)
-    , natural (isHighlit Theory.G)
+    , natural    160  (isHighlit Theory.G)
-    , accidental (isHighlit Theory.G_sharp)
+    , accidental 185  (isHighlit Theory.G_sharp)
-    , natural (isHighlit Theory.A)
+    , natural    200  (isHighlit Theory.A)
-    , accidental (isHighlit Theory.A_sharp)
+    , accidental 225  (isHighlit Theory.A_sharp)
-    , natural (isHighlit Theory.B)
+    , natural    240  (isHighlit Theory.B)
     ]
 
 indexForNote : Theory.Note -> Int
@@ -64,6 +95,4 @@ indexForNote note =
 {-| Return the HTML that renders a piano representation. -}
 render : { highlight : List Theory.Note } -> Html a
 render {highlight} =
-  ul [ style "width" "100px"
+  div [ style "display" "flex" ] (octave highlight |> List.reverse |> List.repeat 1 |> List.concat)
-     , style "list-style" "none"
-     ] (octave highlight |> List.reverse |> List.repeat 1 |> List.concat)