How to fade in/out on a Tkinter Frame - python-2.7

Question

How can you fade in and/or out on a Tkinter.Frame or any other widget for that matter. All of the examples that I have seen have been for either root (Tkinter.Tk) or Toplevel setting the alpha e.g.
https://stackoverflow.com/a/22491808/1552953
Is it possible to apply this to an individual widget?

Answer 1

You can't do it on individual widgets. Transparency in Tkinter is only available for instances of Tk and Toplevel.

Answer 2

Based on Bryan's answer I came up with this solution, which he inadvertently provided most of the code for also.
One thing to note is if you move the main window the toplevel doesn't move with it...
import Tkinter
import Queue
class Flash(Tkinter.Toplevel):
def __init__(self, root, **options):
Tkinter.Toplevel.__init__(self, root, width=100, height=20, **options)
self.overrideredirect(True) # remove header from toplevel
self.root = root
self.attributes("-alpha", 0.0) # set transparency to 100%
self.queue = Queue.Queue()
self.update_me()
def write(self, message):
self.queue.put(message) # insert message into the queue
def update_me(self):
#This makes our tkinter widget threadsafe
# http://effbot.org/zone/tkinter-threads.htm
try:
while 1:
message = self.queue.get_nowait() # get message from the queue
# if a message is received code will execute from here otherwise exception
# http://stackoverflow.com/questions/11156766/placing-child-window-relative-to-parent-in-tkinter-pythons
x = root.winfo_rootx() # set x coordinate of root
y = root.winfo_rooty() # set y coordinate of root
width = root.winfo_width() # get the width of root
self.geometry("+%d+%d" % (x+width-self.winfo_width() ,y)) # place in the top right cornder of root
self.fade_in() # fade in when a message is received
label_flash = Tkinter.Label(self, text=message, bg='black', fg='white', padx=5, pady=5)
label_flash.pack(anchor='e')
self.lift(self.root)
def callback():
label_flash.after(2000, label_flash.destroy) # destroy the label after 5 seconds
self.fade_away() # fade away after 3 seconds
label_flash.after(3000, callback)
except Queue.Empty:
pass
self.after(100, self.update_me) # check queue every 100th of a second
# http://stackoverflow.com/questions/3399882/having-trouble-with-tkinter-transparency
def fade_in(self):
alpha = self.attributes("-alpha")
alpha = min(alpha + .01, 1.0)
self.attributes("-alpha", alpha)
if alpha < 1.0:
self.after(10, self.fade_in)
# http://stackoverflow.com/questions/22491488/how-to-create-a-fade-out-effect-in-tkinter-my-code-crashes
def fade_away(self):
alpha = self.attributes("-alpha")
if alpha > 0:
alpha -= .1
self.attributes("-alpha", alpha)
self.after(10, self.fade_away)
if __name__ == '__main__':
root = Tkinter.Tk()
root.minsize(700, 300)
root.geometry("700x500")
flash = Flash(root) # create toplevel instance
def callback():
# put a delay between each message so we can check the behaviour depending on the lenght of the delay between messages
import time
flash.write('Hello World')
time.sleep(1)
flash.write('Ready!')
time.sleep(2)
flash.write('Steady!')
time.sleep(4)
flash.write('Go!')
# create a thread to prevent the delays from blocking our GUI
import threading
t = threading.Thread(target=callback)
t.daemon = True
t.start()
root.mainloop()
exit()