how to generate a preview for a map string?

[Dixi]

I can't find a way to generate a map preview picture for a string.

I dunno how to pass a map string in command line, so I launched Factorio normally, generated a new map with a map string, saved it, then tried to launch command line:

factorio --generate-map-preview map20.bmp --map-preview-size 3000 --load-game test20.zip

It does not work for me, even if I write full path to save game (C:\Games\Factorio\saves\test20.zip).
It always generate a new map and creates a preview of it.

There are a lot of strings around, and should be an easy way to see a map for a string, but I can't find it.

The only way to see a map I've found, is to open map editor, and generate a map with particular string. But map editor is quite slow in displaying big areas, so generating a bitmap is much better, and I think it should work some way.

Update:
It seems that map geography (sizes, forms and locations of lakes, forests, soil types) depends only on a map seed.
So preview can be generated from a command line. Another question that to get a seed from a map string I still need to launch Factorio GUI, and paste a string. As I got from wiki, it should not be so problematic to get the seed from a string, but one need a script for it, I suppose.

[Dixi]

A little .lua program + a .cmd file can do that (had to write both myself), while I still think there should be a standard Factorio way to create an image from a map string, that I just did not found.

[Koub]

Iirc, next version should come with something like this.
[Edit] There it is