# L-32 MCS 260 Fri 9 Nov 2007 : exscale2.py
#
# The third example of a scale uses the command
# argument in the scale widget and does not need
# the value button.

from Tkinter import *

class ShowScale():
   """
   GUI to demonstrate use of a scale.
   """
   def __init__(self,wdw):
      "determines the layout of the GUI"
      wdw.title('example of a scale')
      self.low = 0.0
      self.high = 1.0
      self.f = DoubleVar()
      self.s = Scale(wdw,\
        orient='horizontal',\
        from_=self.low,to=self.high,\
        tickinterval=(self.high-self.low)/5.0,\
        resolution=(self.high-self.low)/1000.0,\
        length=300,variable=self.f,\
        command=self.ShowValue)
      self.s.grid(row=0,column=0)
      self.e = Entry(wdw)
      self.e.grid(row=1,column=0)

   def ShowValue(self,v):
      "shows the value of the scale variable"
      self.e.delete(0,END)
      sv = 'value = ' + str(v)
      self.e.insert(INSERT,sv)

def main():
   top = Tk()
   show = ShowScale(top)
   top.mainloop()

if __name__ == "__main__": main()