port-theme

name	port-theme
description	Port a Vim or other editor colorscheme to a Textbringer theme file. Use when the user provides a URL or name of a theme to port.
argument-hint	<github-url-or-theme-name>

Port the colorscheme at $ARGUMENTS to lib/textbringer/themes/<name>.rb.

Steps

1. Identify the theme type and fetch the source

Vim themes (.vim files) live in colors/<name>.vim. Fetch the raw file:

https://raw.githubusercontent.com/<owner>/<repo>/master/colors/<name>.vim

Neovim themes (Lua-based) are structured differently. Typical layout:

lua/<name>/
  colors/        ← palette definitions (storm.lua, night.lua, …)
  groups/        ← highlight group tables (base.lua, syntax.lua, treesitter.lua, …)
  colors/init.lua ← computed/derived colors (blended backgrounds, semantic aliases)

Fetch colors/init.lua (or the main palette file) first to get raw hex values, then groups/base.lua and groups/treesitter.lua (or equivalent) to see how highlight groups map to palette entries. Also fetch colors/init.lua for derived colors computed from blend formulas.

2. Choose colors — always use GUI hex values

Always use GUI hex values (guifg/guibg for Vim, hex strings for Neovim) as the hex: value in the palette. Textbringer supports true color via TERM=xterm-direct and uses these hex values directly in that mode. For 256-color terminals, the Color module automatically finds the closest 256-color palette match.

Vim themes: Use the guifg/guibg hex values (e.g. #f92672), NOT ctermfg/ctermbg numbers. If a Vim theme only provides cterm values without GUI values, convert them to hex using the xterm-256 color table:

• 0–15: standard ANSI (#000000, #800000, #008000, #808000, #000080, #800080, #008080, #c0c0c0, #808080, #ff0000, #00ff00, #ffff00, #0000ff, #ff00ff, #00ffff, #ffffff)
• 16–231 (color cube): index = n - 16, then r = index/36, g = (index%36)/6, b = index%6; ramp = [0, 95, 135, 175, 215, 255]; hex = #RRGGBB
• 232–255 (grayscale): value = 8 + 10*(n - 232); hex = #VVVVVV

Neovim themes: Use the GUI hex strings from the palette as-is.

For colors computed via blend formulas (e.g. blend(color, alpha, bg)), compute them manually:

result = alpha * color_component + (1 - alpha) * bg_component   (per R, G, B channel)

3. Map highlight groups to Textbringer faces

When a Neovim theme defines both traditional groups (e.g. Keyword) and treesitter groups (e.g. @keyword), prefer the treesitter group — it is what Neovim actually applies by default.

Source group(s)	Textbringer face
Normal	defines :bg / :fg palette entries
Comment, @comment	:comment
String, Character, @string	:string
Number, Boolean, Float, @number, @boolean	:number
Keyword, Conditional, Repeat, Statement, @keyword, @keyword.conditional	:keyword (preserve bold:)
Constant, @constant	:constant (preserve bold:)
Function, @function, @function.method	:function_name
Identifier, StorageClass, @variable	:variable
Type, Typedef, Structure, @type	:type
PreProc, Define, Include, PreCondit, Macro, @keyword.import, @keyword.directive	:preprocessing_directive
Special, @constant.builtin, @function.builtin	:builtin
Operator, @operator

Omit faces with no meaningful color definition in the source.

4. Choose ANSI fallbacks

Each palette color needs an ansi: value for 8-color terminals. Pick the closest named color:

Hue / role	ansi: value
Black, very dark gray	"black"
Dark gray	"brightblack"
Medium–light gray, near-white	"white"
Red, hot pink, crimson	"red"
Green, lime	"green"
Yellow, tan, orange, gold	"yellow"
Blue	"blue"
Magenta, violet, purple	"magenta"
Cyan, teal	"cyan"

5. Write the theme file

Follow this structure exactly:

# <ThemeName> theme for Textbringer
# Based on <source URL>
# <one-line description if useful>
#
# GUI hex values from the source's guifg/guibg definitions.

Textbringer::Theme.define "<theme-name>" do |t|
  t.palette :dark do |p|
    # Background / foreground
    p.color :bg,  hex: "#......", ansi: "black"
    p.color :fg,  hex: "#......", ansi: "white"
    # ... other neutral tones ...

    # Accent colors
    p.color :red,  hex: "#......", ansi: "red"
    # ...
  end

  # Include a :light palette only if the source theme has a light variant.

  t.default_colors foreground: :fg, background: :bg

  # Programming faces
  t.face :comment,                 foreground: :comment
  t.face :keyword,                 foreground: :pink, bold: true
  # ...

  # Basic faces
  t.face ,                ,  
  t.face ,                   
  t.face ,                  ,  
  t.face ,                     ,  
  t.face ,          ,  

  
  t.face ,         ,  
  t.face ,  ,  

  
  t.face ,          ,  
  t.face ,            
  t.face ,         
  t.face ,            

• Theme name in define must match the filename (without .rb).
• Hex values must be lowercase (#d7005f, not #D7005F).
• Always put a space after the comma in p.color arguments: p.color :name, hex: … (not p.color :name,hex: …).
• Include a comment after each palette color noting the source variable name (e.g. # Normal guifg, # c.blue, # bright_red).
• Use bold: true where the source specifies cterm=bold / gui=bold / bold = true.
• Neovim themes often apply italic to keywords/functions via opts.styles; skip italic since Textbringer does not support it.

6. Verify

Run this to confirm the theme loads without error:

ruby -Ilib -e "require 'textbringer'; Textbringer::Theme.load('<name>'); puts 'OK'"

If it prints OK, the theme is ready. Save the file to lib/textbringer/themes/<name>.rb.