OK, I give in, I installed the nik collection in Wine (only 466 MB) 
Using kubuntu 20.04 here so I can get Gimp 2.10.32 from a PPA and python support from some old packages. For Mint 21 use the appimage I indicated in the previous post. The Gimp flatpak comes with python2 but being sandboxed I do not know if it picks up anything from wine.
This video of the procedure I followed: https://youtu.be/Riarm7rFJIQ
1. Check that Dfine2.exe works in the Wine folders
2. For simplicity make a new 'nik' folder in home
3. Make sym link from Dfine2.exe to the nik folder
4. Edit the NIKDfine2.py plugin (attached). This came originally from the Partha Windows Gimp. Line 85-87 change user-name to whatever is your home.
5. Try out in Gimp
You can try and bypass stage 3 if you want. I had problems with the 64 bit version. Stupid MS and their spaces in file names.
Using kubuntu 20.04 here so I can get Gimp 2.10.32 from a PPA and python support from some old packages. For Mint 21 use the appimage I indicated in the previous post. The Gimp flatpak comes with python2 but being sandboxed I do not know if it picks up anything from wine.
This video of the procedure I followed: https://youtu.be/Riarm7rFJIQ
1. Check that Dfine2.exe works in the Wine folders
2. For simplicity make a new 'nik' folder in home
3. Make sym link from Dfine2.exe to the nik folder
Code:
ln -s "/home/user-name/.wine/drive_c/Program Files/Google/Nik Collection/Dfine 2/Dfine 2 (64-Bit)/Dfine2.exe" /home/user-name/nikCode:
# Build command line call
# command = "\"C:\\Program Files\\Google\\Nik Collection\\Dfine 2\\Dfine 2 (64-Bit)\\Dfine2.exe\"" + " \"" + tempfilename + "\""
command = "wine /home/user-name/nik/Dfine2.exe" + " \"" + tempfilename + "\""You can try and bypass stage 3 if you want. I had problems with the 64 bit version. Stupid MS and their spaces in file names.