Getting an RGB color from highlight group

Question

In putting together and addon for blender to integrate neovim.

Where I'm at with it, github colo imported to blender text editor from nvim_gtk

One component is grabbing the current colorscheme of a running vim and importing it into blender's text editor theme.

So far I have some re code that looks at the return of hi and follows links if need be till I get a guifg or guibg

# vim is a pynvim.api.nvim.Nvim object
vim_color = vim.command_output(f"highlight {g}")

which for g = "pythonBuiltin" returns

pythonBuiltin xxx links to GruvboxOrange

and so on

GruvboxOrange xxx ctermfg=208 guifg=#fe8019

in which case I can get the RGB colour for blender from the hex. Other colour codes not so easy. And the code is getting unwieldly.

Could you point me to a more direct way, possibly a plugin, to get the RGB value of a highlight?

Answer 1

Consider using the synIDattr() function, which can take special attributes such as fg# and bg# to return RGB for attributes, when a GUI is running.

"fg#"   like "fg", but for the GUI and the GUI
        is running the name in "#RRGGBB" form
"bg#"   like "fg#" for "bg"
"sp#"   like "fg#" for "sp"

The first argument to this function is a numeric {synID}, if you have a file styled with syntax elements you can look up the id from a specific position in the file.

If you want to find all syntax groups, then perhaps you could iterate them starting from 1 and looking up the name with synIDattr(..., 'name') to build a full map from name to RGB attributes.

For instance, to get the RGB for the foreground color of pythonComment, you can use the following command:

echo synIDattr(synIDtrans(hlID("pythonComment")), "fg#")

Answer 2

I don't know about any plugins for this but it should be easy to code up lookup tables for the other codes.

The decimal numbers, like 208 in your example, are 256-color palette codes. It's easy to find translations to/from hex code. Like the top of the google search for 256 color to hex.

The spelled-out colors (e.g. DarkSeaGreen4) are system dependent. You didn't mention what system you're using, I don't think. But for *nix that same translation page includes spelled colors, too.. For windows start with :h win32-colors and go from there.