You can try icy draw - I moved it to here (0.3.0 is the current version):
https://github.com/mkrueger/icy_tools/releases/tag/0.0.1
Runs on linux/osx and windows.
It can draw 80x25 fixed size screens, supports all common (and many uncommon :)) formats - it should be able to generate nearly optimal .ans files.
Has tons of options - it's a modern heavy weight (multi document) program.
Regards
Mike
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