# Main Command: Go [XLogo]
# LED Display by Guy Walker
# www.logoarts.co.uk

to new
  # set default screen, pen and turtle
  ResetAll SetScreenSize [400 400] HideTurtle
  SetSC Black SetPC Green SetPS 1 PenUp
end

to init
  # Global list, Display
  Make "Display [] Make "Line []
  Repeat 11 [Make "Line LPut 0 :Line]
  Repeat 12 [Make "Display LPut :Line :Display]
end

to footer :x
  # write value of :X as footer
  SetPos [-190 -186]
  SetPW 11 SetH 90 SetPC DarkBlue PenDown Forward 378
  PenUp SetPos [-190 -190] SetPC White
  SetPW 1 SetH 0 Label :X
end

to draw :display
  # draw grid of LED's in correct color
  For [N 1 12] [
    For [M 1 11] [
    Make "Col Item :M Item :N :Display
    SetPC ( List :Col 36 36 )
    SetPenWidth 24 Dot List :N*32-210 :M*33-187] ]
end

to scan :n
  # create list from vertical single pixel line in footer 
  Make "Line [] 
  For [M 1 11] [
    Make "Col FindColor List :N :M-192
    Make "Line LPut (Item 1 :Col) :Line ]
    # draw a green text underscore in footer
  SetPC Green SetPW 1 Dot List :N Minus 192
  Output :Line
end

to messagelength :x
  # calculate length of message list :X
  Make "Length 0
  For (List "N 1 Count :X) [
    Make "Length :Length + LabelLength Item :N :X]
    Output 9 + :Length + 4*Count :X
end

to go :x
  New Animation Init Footer :X
  Make "Length MessageLength :X
  # stop when whole label length drawn
  For (List "N 0 :Length) [
    # update display list by removing first and adding last item
    Make "Display ButFirst LPut Scan :N-190 :Display
    Draw :Display 
    Refresh Wait 12]    # Wait time adjusts scroll speed
end