First off, sorry if this belongs in
House Rules, and please move it there if so.
Coming off the various discussions about making dungeon maps for TFT, over the past week I've bashed together a proof-of-concept for just such a tool. It's a web-based application that should work in most browsers (though I've not tested it in mobile browsers, and they would be a pain to do this kind of design work in anyway). You can check it out here:
https://shadekeep.com/shamat.html
Most of the functions should work, though there are still quirks. And it doesn't yet support loading saved map files, so don't do any mission-critical work in this.
Basically I want to see if there is any utility value in a tool like this, before I sink any more effort into it. Please share your feedback!
PS - Be sure to check the Help tab for more information on the various features.