#!/usr/bin/env python3
from tkinter import *
import serial,sys

window = 600 # window size
xf = yf = zf = 0 # filtered values
eps = 0.1 # filter fraction

# idle routine
def idle(parent,canvas):
   global xf,yf,zf
   byte2 = 0
   byte3 = 0
   byte4 = 0
   ser.flush()
   while 1:

      # find framing 
      byte1 = byte2
      byte2 = byte3
      byte3 = byte4
      byte4 = ord(ser.read())
      if ((byte1 == 1) & (byte2 == 2) & (byte3 == 3) & (byte4 == 4)):
         break

   # read data
   v0 = ord(ser.read())
   v1 = ord(ser.read())
   v2 = ord(ser.read())
   v3 = ord(ser.read())
   v4 = ord(ser.read())
   v5 = ord(ser.read())
   x = (v0 << 4)+((v4 & 0xF0) >> 4)
   y = (v1 << 4)+(v4 & 0x0F)
   z = (v2 << 4)+(v5 & 0x0F)
   if (x > 2047):
      x = x-4096
   if (y > 2047):
      y = y-4096
   if (z > 2047):
      z = z-4096
   xf = (1-eps)*xf+eps*x
   yf = (1-eps)*yf+eps*y
   zf = (1-eps)*zf+eps*z

   # update canvas (set dimensions of rectangle)
   #canvas.coords...
   canvas.update()

   # call idle
   parent.after_idle(idle,parent,canvas)

#  check command line arguments
if (len(sys.argv) != 2):
   print("command line: hello.TLE493D.t412.py serial_port")
   sys.exit()
port = sys.argv[1]

# open serial port
ser = serial.Serial(port,115200)
ser.setDTR()

# set up GUI
root = Tk()
root.title('hello.TLE493D.t412.py (q to exit)')
root.bind('q','exit')
canvas = Canvas(root,width=window,height=window,background='white')

# ..initialize shapes
#canvas.create_...
canvas.pack()

# start idle loop
root.after(100,idle,root,canvas)
root.mainloop()