SyntaxWarning: name 'color' is assigned to before global declaration global color Python
In the code below it says: "SyntaxWarning: name 'color' is assigned to before global declaration global color" However, I declared global color before I assign it? I am very confused. I ran it and it works but I just don't understand what the syntax warning is pointing to...
from Tkinter import *
from sys import exit
from random import *
color = "black" #Sets default color to black
w,h=640,480 #Width, height of canvas
root=Tk()
pixelcount = 0 #Sets the inital pixelcount to 1
tool = 1 #Sets deafu
ptX, ptY, ptX2, ptY2 = 0, 0, 0, 0
cnvs=Canvas(root,width=w,height=h,bg='#D2B48C') # 210 180 140
cnvs.pack(side = RIGHT)
buttons = Frame(root, width = 80, height = h) #Creates region for buttons
buttons.pack(side = LEFT) #Put button region on left
def quit(evt):
exit(0)
def menu(arg): #Accepts arguments from button clicks and binds appropriate stimulus to appropriate tool function
print arg
global tool
cnvs.unbind('<Button-1>')
if arg == 1:
cnvs.bind('<Button-1>', line)
elif arg == 2:
cnvs.bind('<Button-1>', poly)
elif arg == 3:
cnvs.bind('<Button-1>', rect)
elif arg == 4:
cnvs.bind('<B1-Motion>', pencil)
elif arg == 5:
cnvs.bind('<B1-Motion>', spray)
elif arg == 6:
cnvs.bind('<B1-Motion>', blotter)
elif arg == 7:
global color
color = "red"
elif arg == 8:
global color
color = "black"
elif arg == 9:
global color
color = "blue"
elif arg == 10:
global color
color = "purple"
def line(evt): #Line function
global pixelcount
global color
pixelcount += 1
if pixelcount % 2 == 1:
ptX, ptY, = (evt.x, evt.y)
global ptX, ptY
print ptX, ptY
else:
ptX2, ptY2, = (evt.x, evt.y)
cnvs.create_line(ptX, ptY, ptX2, ptY2, fill = color)
def lineButtonClick(): #Activated when line button clicked
menu(1)
lineButton = Button(root, text = "line", command = lineButtonClick)
lineButton.pack()
lineButton.config(width = 10)
def poly(evt): #Poly function
global pixelcount
pixelcount += 1
global color
print str(pixelcount) + "pixel"
if pixelcount == 1:
global ptX, ptY
ptX, ptY, = (evt.x, evt.y)
print ptX, ptY
else:
global ptX2, ptY2
ptX2, ptY2, = (evt.x, evt.y)
print str(ptX2) + " " + " " +str(ptY2) + "pt2"
cnvs.create_line(ptX, ptY, ptX2, ptY2, fill = color)
ptX, ptY = ptX2, ptY2
def polyButtonClick(): #Activated when poly button clicked
menu(2)
polyButton = Button(root, text = "poly", command = polyButtonClick)
polyButton.pack()
polyButton.config(width = 10)
def rect(evt): #Rectangle function
global pixelcount
if pixelcount % 2 == 0:
global ptX, ptY
ptX, ptY, = (evt.x, evt.y)
print ptX, ptY
pixelcount += 1
else:
global ptX2, ptY2
ptX2, ptY2, = (evt.x, evt.y)
pixelcount += 1
cnvs.create_rectangle(ptX, ptY, ptX2, ptY2, fill = color, outline = color)
def rectButtonClick(): #Activated when rectangle button clicked
menu(3)
rectButton = Button(root, text = "rect", command = rectButtonClick)
rectButton.pack()
rectButton.config(width = 10)
def pencil(evt):#Pencil function
global pixelcount
if cnvs.bind('<ButtonRelease-1>'):
pixelcount = 0
pixelcount += 1
print str(pixelcount) + "pixel"
if pixelcount == 1:
global ptX, ptY
ptX, ptY, = (evt.x, evt.y)
print ptX, ptY
else:
global ptX2, ptY2
ptX2, ptY2, = (evt.x, evt.y)
print str(ptX2) + " " + " " +str(ptY2) + "pt2"
cnvs.create_line(ptX, ptY, ptX2, ptY2, fill = color)
ptX, ptY = ptX2, ptY2
def pencilButtonClick():
menu(4)
pencilButton = Button(root, text = "pencil", command = pencilButtonClick)
pencilButton.pack()
pencilButton.config(width = 10)
def spray(evt): #Spray function
global pixelcount
if cnvs.bind('<ButtonRelease-1>'):
pixelcount = 0
pixelcount += 1
print str(pixelcount) + "pixel"
ptX, ptY, = (evt.x, evt.y)
randomX = evt.x + randint(-10, 10)
randomY = evt.y + randint(-10, 10)
cnvs.create_oval(randomX -1, randomY-1, randomX + 1, randomY + 1, fill = color)
def sprayButtonClick():#Activated when spray button clicked
menu(5)
sprayButton = Button(root, text = "spray", command = sprayButtonClick)
sprayButton.pack()
sprayButton.config(width = 10)
def blotter(evt): #Blotter function
global pixelcount
if cnvs.bind('<ButtonRelease-1>'):
pixelcount = 0
pixelcount += 1
print str(pixelcount) + "pixel"
ptX, ptY, = (evt.x, evt.y)
cnvs.create_oval(ptX-5, ptY-5,ptX + 5, ptY + 5, fill = color)
def blotterButtonClick():#Activated when blotter button clicked
menu(6)
blotterButton = Button(root, text = "blotter", command = blotterButtonClick)
blotterButton.pack()
blotterButton.config(width = 10)
def red(): #Red color function
menu(7)
redButton = Button(root, text = "red", command = red)
redButton.pack()
redButton.config(width = 10)
def black(): #Black color function
menu(8)
blackButton = Button(root, text = "black", command = black)
blackButton.pack()
blackButton.config(width = 10)
def blue(): #Blue color function
menu(9)
blueButton = Button(root, text = "blue", command = blue)
blueButton.pack()
blueButton.config(width = 10)
def purple(): #Purple color function
menu(10)
purpleButton = Button(root, text = "purple", command = purple)
purpleButton.pack()
purpleButton.config(width = 10)
mainloop()
Thank you so much!!!
Answer
You don't put a global declaration immediately before every use of the variable; you use it once, at the beginning of the function in which the variable is declared global:
def menu(arg):
global tool
global color
cnvs.unbind('<Button-1>')
if arg == 1:
cnvs.bind('<Button-1>', line)
elif arg == 2:
cnvs.bind('<Button-1>', poly)
elif arg == 3:
cnvs.bind('<Button-1>', rect)
elif arg == 4:
cnvs.bind('<B1-Motion>', pencil)
elif arg == 5:
cnvs.bind('<B1-Motion>', spray)
elif arg == 6:
cnvs.bind('<B1-Motion>', blotter)
elif arg == 7:
color = "red"
elif arg == 8:
color = "black"
elif arg == 9:
color = "blue"
elif arg == 10:
color = "purple"