#!/usr/bin/env python
#
# Use a slider to write values between 0 and 255 to /dev/rtf4
#

import sys

try:
    import pygtk
    # tell pyGTK, if possible that we want GTKv2
    pygtk.require("2.0")
except:
    # Some distributions come with GTK2, but not pyGTK
    pass

try:
    import gtk
    import gtk.glade
except:
    print "You need to install pyGTK or GTKv2 ",
    print "or set your PYTHONPATH correctly."
    print "try: export PYTHONPATH=",
    print "/usr/local/lib/python2.2/site-packages/"
    sys.exit(1)

# now we have both gtk and gtk.glade imported
# Also, we know we are running GTKv2

class appgui:
    def __init__(self):
        """
        Initialize and display the main command window
        """

        self.gladefile="proj3.glade"
        windowname="ServoWindow"
        self.wTree=gtk.glade.XML(self.gladefile, windowname)
        
        handlers = { "on_quit_button_clicked" : (gtk.mainquit),
                     "on_ServoWindow_destroy" : (gtk.mainquit),
                     "on_AngleScale_value_changed" : self.set_angle}
        self.wTree.signal_autoconnect(handlers)

        self.rtfifo = open('/dev/rtf4', 'w')
        return

######################################################################
### Main Window Methods
######################################################################

    def set_angle(self, range):
        """
        Set the slider angle by writing to a real-time fifo
        """
        angle = range.get_value()
        self.rtfifo.write(chr(int(round((angle + 90.0)/180.0*255))))
	self.rtfifo.flush()
        return
    
app=appgui()
gtk.mainloop()