Question

I’m trying to save my canvas using the postscript method, and Tkinter crashes…

w.postscript(file="my_drawing.ps", colormode='color')

gets the exception:

w.postscript(file="my_drawing.ps", colormode='color')
File "C:\python27\lib\lib-tk\Tkinter.py", line 2307, in postscript
self._options(cnf, kw))
_tkinter.TclError: invalid command name ".57816328L"

I’m not sure what this error means – has anyone encountered that before?

I tried without the color option too, with no avail.

---

Edit – widgit stripped down to basics gives same error:

from Tkinter import *
master = Tk()
w = Canvas(master, width=1000, height=1000)
w.pack()
w.create_oval(450,550,550,450)
mainloop()
w.postscript(file="my_drawing.ps")

Answer 1

It seems to work if you simply move the w.postscript() call above the mainloop() call. This means that the error is due to calling w.postscript() after the Tkinter GUI is closed (since mainloop() runs until the window is closed).

I noticed this was a difference between your code and this example, so I tried it and saw that the .ps file was created as soon as the script is ran.