Show progress of song as its played.

showsong.elm

import Time exposing (Time)
import Graphics.Element exposing (show, image)
import Graphics.Collage exposing (collage, path, solid, traced, defaultLine, toForm, move)
import Signal
import Window
import Color exposing (..)
import String

duration = 60 * 5
multiplier = 0.95
offset = 0.03
--main = Signal.map2 view Window.dimensions (Time.every 200)
main = Signal.map2 view fractionSoFar Window.dimensions


timeSoFar : Signal Time
timeSoFar =
    Signal.foldp (\x y -> y + 0.01) 0 (Time.every 10)

fractionSoFar: Signal Time
fractionSoFar = Signal.map (\a -> a / duration) timeSoFar


view fraction (w, h) = 
  let w' = toFloat(w)
      h' = toFloat(h)
      x = -w'/2 + w' * fraction * multiplier + (offset * w')
      line = path [(x,-h'/2),(x,h'/2)] |> traced s
      sec = (round (duration * fraction))
  in collage w h 
      [ image w (floor (w' / 4.76)) "http://i.imgur.com/v5LzpgD.png" |> toForm
      , line
      , show (printsec sec) |> toForm |> move (x + 30,200)]
  
s = { defaultLine 
      | width = 4
      , color = red}
      
printsec s = 
  let min = floor ((toFloat s) / 60)
      sec = toString (s - (min * 60))
      padding = if (String.length sec) < 2 then "0" else ""
  in (toString min) ++ ":" ++ padding ++ sec