gns3theme

gns3theme is python tool that will adds a custom theme to gns3. Support both Linux and MacOS.

• Change gns3 theme from a predefined schemes
• Change ethernet/serial link width and color
• Apply full transparency to gns3-gui (not implemented yet)
• Create a custom gns3-gui theme.

Installation

git clone https://github.com/n3oxmind/gns3theme.git
cd gns3theme
sudo ./gns3theme.py --install /path/to/gns3/installation/directory -u $USER  --scheme <colorscheme>
./gns3theme.py --scheme <colorscheme>

Add custom theme ./gns3theme.py -s <colorscheme>. Check ./gns3theme.py --ls for supported colorschemes. Start gns3 and choose Edit->Preferences->General->Interface Style->Custom

Change grid color and/or link color (only with --install as root)

sudo ./gns3theme.py --install /path/to/gns3/installation/directory -u $USER  --scheme <colorscheme> --lc ffffff --gc 000000

Note: /path/to/gns3/installation/directory is your gns3 installation directory. For example my gns3 is installed under $HOME/.local/lib/python3.10/site-package. gns3theme does not need the gns3-gui source code anymore.

List default colorschemes

$ ./gns3theme.py --ls
solarized-light
solarized-dark
n30x-dark
n30x-darker
n30x-darkblue

Add your colorscheme in 'colorschemes.py' file

Install n30x-dark

$ ./gns3theme.sh -s n30x-dark

Install solarized-light theme

$ gns3theme -s solarized-light

Install tomorrow theme

$ gns3theme -s tomorrow

Install n30x-light

$ gns3theme -s n30x-light

Tips

./gns3theme.py --install <gns3_gui_dir> is only required on first installation and if you want to make/apply changes to grid color.

Changing colorscheme is as simple as ./gns3theme.py -s n30x-darker. To further customize specific colorscheme use --bg, bg2, --fg, --fg2 ..., etc options to target specific ui element. For example, if you like n30x-dark theme and you want to change the selection background color, you can achieve this as below:

$ ./gns3theme.py -s n30x-dark --sbg ffffff

custom colorscheme file is stored in ~/.config/gns3theme/custom_style.css. You can change any color manually with your fav text editor.

To add more colorschemes follow the format in colorschmes.py and add as many colorschmes as you want.

If you like the icons that i'm using in the screenshots. Copy the symbols folder to your GNS3 directory. They will appear under the custom_symbols when you right-click on any appliance. you can change individual devices manually or make them as default icons from gns3 preferences.

gns3theme usage

usage: gns3theme --install <path/to/gns3_gui_dir> --scheme <colorscheme>
       gns3theme --scheme <colorscheme> [options]

manditory arguments:
  -i, --install PATH            path to gns3-gui source directory
  -s, --scheme NAME             choose color scheme to apply for gns3-gui
  -u, --user USER               Specify username for installation. only used with --install option

optional arguments:
  --bg COLOR                    change primary background color
  --bg2 COLOR                   change secondary background color
  --fg COLOR                    change primary foreground color
  --fg2 COLOR                   change secondary foreground color
  --tbg COLOR                   change toolbar background color
  --sbg COLOR                   change selection background color
  --sfg COLOR                   change selection foreground color
  --bbg COLOR                   change button background color
  --lc COLOR                    change ethernet link color. Reinstall gns3-gui as root is required
  --lw NUM                      change ethernet and serial links width. Reinstall gns3-gui as root is required
  --gc COLOR                    change grid color. Reinstall gns3-gui as root is required

optional flags:
  --help                        show this help
  --ls                          list predefined color schemes