Writing a test app to emulate PIO lines, I have a very simple Python/Tk GUI app. Using the numeric Keys 1 to 8 to simulate PIO pins 1 to 8. Press the key down = PIO High, release the Key = PIO goes low. What I need it for is not the problem. I kind of went down a rabbit hole trying to use a factory to create the key press call back functions.
Here is some stripped down code:
#!usr/bin/env python
"""
Python + Tk GUI interface to simulate a 8 Pio lines.
"""
from Tkinter import *
def cb_factory(numberic_key):
"""
Return a call back function for a specific keyboard numeric key (0-9)
"""
def cb( self, event, key=numberic_key ):
bit_val = 1<<numberic_key-1
if int(event.type) == 2 and not (bit_val & self.bitfield):
self.bitfield |= bit_val
self.message("Key %d Down" % key)
elif int(event.type) == 3 and (bit_val & self.bitfield):
self.bitfield &= (~bit_val & 0xFF)
self.message("Key %d Up" % key)
else:
# Key repeat
return
print hex(self.bitfield)
self.display_bitfield()
return cb
class App( Frame ):
"""
Main TK App class
"""
cb1 = cb_factory(1)
cb2 = cb_factory(2)
cb3 = cb_factory(3)
cb4 = cb_factory(4)
cb5 = cb_factory(5)
cb6 = cb_factory(6)
cb7 = cb_factory(7)
cb8 = cb_factory(8)
def __init__(self, parent):
"Init"
self.parent = parent
self.bitfield = 0x00
Frame.__init__(self, parent)
self.messages = StringVar()
self.messages.set("Initialised")
Label( parent, bd=1,
relief=SUNKEN,
anchor=W,
textvariable=self.messages,
text="Testing" ).pack(fill=X)
self.bf_label = StringVar()
self.bf_label.set("0 0 0 0 0 0 0 0")
Label( parent, bd=1,
relief=SUNKEN,
anchor=W,
textvariable=self.bf_label,
text="Testing" ).pack(fill=X)
# This Doesn't work! Get a traceback saying 'cb' expected 2 arguements
# but only got 1?
#
# for x in xrange(1,9):
# cb = self.cb_factory(x)
# self.parent.bind("<KeyPress-%d>" % x, cb)
# self.parent.bind("<KeyRelease-%d>" % x, cb)
self.parent.bind("<KeyPress-1>", self.cb1)
self.parent.bind("<KeyRelease-1>", self.cb1)
self.parent.bind("<KeyPress-2>", self.cb2)
self.parent.bind("<KeyRelease-2>", self.cb2)
self.parent.bind("<KeyPress-3>", self.cb3)
self.parent.bind("<KeyRelease-3>", self.cb3)
self.parent.bind("<KeyPress-4>", self.cb4)
self.parent.bind("<KeyRelease-4>", self.cb4)
self.parent.bind("<KeyPress-5>", self.cb5)
self.parent.bind("<KeyRelease-5>", self.cb5)
self.parent.bind("<KeyPress-6>", self.cb6)
self.parent.bind("<KeyRelease-6>", self.cb6)
self.parent.bind("<KeyPress-7>", self.cb7)
self.parent.bind("<KeyRelease-7>", self.cb7)
self.parent.bind("<KeyPress-8>", self.cb8)
self.parent.bind("<KeyRelease-8>", self.cb8)
def display_bitfield(self):
"""
Display the PIO lines (1 for on, 0 for off)
"""
bin_lst = []
for x in xrange(8):
bit = 1 << x
if bit & self.bitfield:
bin_lst.append("1")
else:
bin_lst.append("0")
bin_lst.reverse()
bin_str = " ".join( bin_lst )
self.bf_label.set( bin_str )
def message( self, msg_txt ):
"set"
self.messages.set( msg_txt )
def cb_factory(self, numberic_key ):
"""
Return a call back function for a specific keyboard numeric key (0-9)
"""
def cb( self, event, key=numberic_key ):
bit_val = 1<<numberic_key-1
if int(event.type) == 2:
self.bitfield |= bit_val
self.message("Key %d Down" % key)
else:
self.bitfield &= (~bit_val & 0xFF)
self.message("Key %d Up" % key)
print hex(self.bitfield)
self.display_bitfield()
return cb
##########################################################################
if __name__ == "__main__":
root = Tk()
root.title("PIO Test")
theApp = App( root )
root.mainloop()
I finally got some sort of method factory working for the callback but I don’t find it very satisfactory.
So my question is, can you have a class method factory, that will produce class methods the way I tried (see commented out code and App class method cb_factory())?
NOTES: Yes, I know that this app only lets you hold down 4 keys at a time, but that is good enough for my purposes.
cb expects ‘self’ and ‘event’. Maybe it only gets event from the bind?