#! /usr/bin/env python

#------------------------------------------------------------------------------
# Orologio con scia in dissolvenza - By C.Fin 2013 - For Python2&3
#------------------------------------------------------------------------------

try: import Tkinter as tk
except ImportError: import tkinter as tk
import time
import math

#------------------------------------------------------------------------------

WID, HEI = 400, 400         # dimensioni finestra
XC, YC = WID//2,  HEI//2    # centro finestra
RADIUS = WID / 2 * 0.85     # raggio effetto grafico
POINTS = 15                 # punti sulla scia
RP = 5                      # raggio dei punti
FNT = ("Sans", 46, "")      # font per l'orologio

#------------------------------------------------------------------------------

class App:

    def __init__(self):
        self.form = tk.Tk()
        self.form.resizable(False, False)
        self.form.title("Orologio05 - By C.Fin 2012")
        x = (self.form.winfo_screenwidth() / 2)  -  (WID / 2)
        y = (self.form.winfo_screenheight() / 2)  -  (HEI / 2)
        self.form.geometry("%dx%d+%d+%d" % (WID, HEI, x, y))
        self.canvas = tk.Canvas(
            self.form, highlightthickness=0,
            width=WID, height=HEI, bg="black")
        self.canvas.pack()
        self.deg = 0                   # anglo di partenza
        self.lp, self.lp2 = [], []     # liste coordinate punti


    def draw(self):
        self.form.after(50, self.draw)
        rad = math.radians(self.deg)
        x = XC + RADIUS * math.cos(rad)
        y = YC + RADIUS * math.sin(rad)
        self.lp.append([x, y])
        if len(self.lp) > POINTS: del self.lp[0]
        x = XC + RADIUS * math.cos(rad+math.pi)
        y = YC + RADIUS * math.sin(rad+math.pi)
        self.lp2.append([x, y])
        if len(self.lp2) > POINTS: del self.lp2[0]
        self.canvas.delete("all")
        for i,p in enumerate(self.lp):
            x, y = p[0], p[1]
            c = "#0000%02X" % (float(i+1) / POINTS * 255)
            self.canvas.create_oval(x-RP, y-RP, x+RP, y+RP, fill=c)
        for i,p in enumerate(self.lp2):
            x, y = p[0], p[1]
            c = "#0000%02X" % (float(i+1) / POINTS * 255)
            self.canvas.create_oval(x-RP, y-RP, x+RP, y+RP, fill=c)
        hour = time.strftime("%H:%M:%S", time.localtime())
        self.canvas.create_text(XC, YC, text=hour, fill="green", font=FNT)
        self.deg = (self.deg + 6) % 360


    def start(self):
        self.draw()
        self.form.mainloop()

#------------------------------------------------------------------------------

app = App()
app.start()