Feature request: print only selected nodes

[Matyas-Pilz]

Hello, my idea is: generate picture quicklier when some nodes would be undetected by Minetest Mapper (not only remove them from colors.txt).
This could have two simplier features:

1. not detect specific mod under them are nodes registered, some as:
   --notmods advtrains bakedclay
   --notmodsfile nomods.txt
2. detect only nodes registered under the specified mods, some as:
   --onlymods default stairs
   --onlymodsfile onlymods.txt

and two, more difficult - I think that their priority is lower
3. not detect specific nodes to print
--notnodes advtrains:dtrack_st
--notnodesfile nonodes.txt
4. detect only specific nodes to print
--onlynodes advtrains:dtrack_st
--onlynodesfile onlynodes.txt

Could be somethink from it implementable in some variant?