How to do dynamic custom background highlighting

[oscarmorrison]

@lukas-reineke would love to be able to add this to the wiki? or maybe add an examples section to the repo.
Spent a long time working this out:

Dynamic Background Stripes with indent-blankline.nvim

This guide explains how to set up alternating background stripes for indentation levels in Neovim using indent-blankline.nvim. The configuration dynamically adapts the background colors based on the active colorscheme, ensuring seamless integration with both dark and light themes.

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Features

• Dynamic Highlight Groups: Automatically adjusts colors for both dark and light themes.
• Alternating Background Stripes: Provides subtle visual cues for nested indentation levels using background colors.
• No Characters: Relies on background highlights instead of displaying visible characters, maintaining a clean and minimal aesthetic.
• Dynamic Colorscheme Support: Automatically updates the colors when switching between themes.

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Configuration

Lua Code

(lazyvim in a /plugins/indent-blank.lua

return {
  {
    "lukas-reineke/indent-blankline.nvim",
    main = "ibl",
    event = { "BufReadPre", "BufNewFile" },
    config = function()
      -- Function to dynamically calculate colors based on the background
      local function setup_highlight_groups()
        local background = vim.o.background -- 'dark' or 'light'
        if background == "dark" then
          -- Dark theme colors
          vim.api.nvim_set_hl(0, "IndentStripe1", { bg = "#1B2B34" }) -- Original dark background
          vim.api.nvim_set_hl(0, "IndentStripe2", { bg = "#232E38" }) -- Slightly lighter
        else
          -- Light theme colors
          vim.api.nvim_set_hl(0, "IndentStripe1", { bg = "#FDF6E3" }) -- Light theme background
          vim.api.nvim_set_hl(0, "IndentStripe2", { bg = "#F6EFD9" }) -- Slightly darker
        end
      end

      -- Set up highlight groups for the current colorscheme
      setup_highlight_groups()

      -- Autocmd to update highlight groups when the colorscheme changes
      vim.api.nvim_create_autocmd("ColorScheme", {
        callback = setup_highlight_groups,
      })

      -- Configure indent-blankline.nvim
      require("ibl").setup({
        indent = {
          highlight = { "IndentStripe1", "IndentStripe2" }, -- Alternating subtle backgrounds
          char = "", -- No character, only background
        },
        whitespace = {
          highlight = { "IndentStripe1", "IndentStripe2" },
          remove_blankline_trail = false,
        },
        scope = { enabled = false },
      })
    end,
  },
}

Dynamic Background Colors

The configuration dynamically detects the current theme using vim.o.background:

• Dark Themes:
  • IndentStripe1: #1B2B34 (dark base color)
  • IndentStripe2: #232E38 (slightly lighter)
• Light Themes:
  • IndentStripe1: #FDF6E3 (light base color)
  • IndentStripe2: #F6EFD9 (slightly darker)