Support BPM for tempo

Using BPM as the unit for tempo.

TODO: Consider a higher-fidelity way to calculate BPM, although I'm not sure
this is critical functionality; an interesting problem is just seducing me, and
this app would be better off resisting the temptation.

1 files changed, 22 insertions, 0 deletions

diff --git a/website/sandbox/chord-drill-sergeant/src/Tempo.elm b/website/sandbox/chord-drill-sergeant/src/Tempo.elm
new file mode 100644
index 000000000000..de4fa32795f9
--- /dev/null
+++ b/website/sandbox/chord-drill-sergeant/src/Tempo.elm
@@ -0,0 +1,22 @@
+module Tempo exposing (render)
+
+import Html exposing (..)
+import Html.Attributes exposing (..)
+import Html.Events exposing (..)
+
+type alias Props msg =
+  { tempo : Int
+  , handleIncrease : msg
+  , handleDecrease : msg
+  , handleInput : String -> msg
+  }
+
+render : Props msg -> Html msg
+render {tempo, handleIncrease, handleDecrease, handleInput} =
+  div [] [ p [] [ text ((String.fromInt tempo) ++ " BPM") ]
+         , button [ onClick handleDecrease ] [ text "Slower" ]
+         , input [ onInput handleInput
+                 , placeholder "Set tempo..."
+                 ] []
+         , button [ onClick handleIncrease ] [ text "Faster" ]
+         ]