'''
A small function to put an error message on the screen with Tkinter.

Used by Windows programs started from a desktop icon.
'''

import string
from Tkinter import *

##
# @brief Show an error message in a GUI environment.
# @param msg The message to display.
# @note The message may contain embedded \n chars.
def tkinter_error(msg):
    ######
    # Define the Application class
    ######

    class Application(Frame):
        def createWidgets(self):
            self.LABEL = Label(self)
            self.LABEL["text"] = self.text
            self.LABEL["fg"] = "black"
            self.LABEL["bg"] = "yellow"
            self.LABEL["justify"] = "left"
            self.LABEL["font"] = "Courier"
            self.LABEL.pack()

        def __init__(self, text, master=None):
            self.text = text
            Frame.__init__(self, master)
            self.pack()
            self.createWidgets()


    # get the message text
    msg = '\n' + msg.strip() + '\n'

    msg = string.replace(msg, '\r', '')
    msg = string.replace(msg, '\n', '   \n   ')

    app = Application(msg)
    app.master.title('ERROR')
    app.mainloop()


if __name__ == '__main__':
    tkinter_error('A short message:\nHello, world!')