For open source purists, the recently open-sourced wrcad flow can be an alternative:
https://github.com/wrcad/xictools. The interface uses gtk2 toolkit and there are already binaries for linux, mac and windows available at
http://wrcad.com/xictools/index.html. What I understand is that wrcad has been marketed since 90s as a commercial tool flow for paying customers and has been recently open-sourced.