tkinter dependency about gdspy

[heitzmann]

@trezitorul When Tkinter is not found, importing gdspy should issue a warning ("[GDSPY] LayoutViewer not available"). I don't see that in your code... have you disabled warnings?

Anyway, Tkinter is part of the python standard library, so I'm not sure it should be listed as a dependency.

[mpinihin]

Hello,
I have this same problem, I've been using gdspy on my windows computer with python 3 with no problems, but I just installed the gdspy module on my laptop running ubuntu using pip and I get the same error message as OP.

[heitzmann]

It seems i'm wrong about tkinter being parto of the standard library: https://docs.python.org/3/library/tkinter.html

Still there should be a warning message if tkinter is not foud: "[GDSPY] LayoutViewer not available"
Do you see this warning @mpinihin?

[mpinihin]

I was not getting that warning message. On my windows computer I installed python though the Anaconda distribution and it seems like tkinter was included there, but on my laptop python 3.6.3 came standard with ubuntu 17.10 and tkinter was not included. I fixed the problem by using sudo apt-get install python3-tk

[heitzmann]

I've added Tkinter as an optional dependency. I believe this fixes the issue, but feel free to reopen it if you think there's anything else.