feat(nvim): create custom color themes for lualine

nvim/after/plugin/lualine.lua

@@ -1,18 +1,8 @@
 -- https://github.com/nvim-lualine/lualine.nvim
-local theme = require("lualine.themes.auto")
-
-theme.normal.c.bg = "#1F2335"
-theme.normal.b.bg = "#24283B"
-theme.insert.b.bg = "#24283B"
-theme.visual.b.bg = "#24283B"
-theme.replace.b.bg = "#24283B"
-theme.command.b.bg = "#24283B"
-theme.inactive.b.bg = "#24283B"
-
 require("lualine").setup({
 	options = {
 		icons_enabled = true,
-		theme = theme,
+		theme = "transparent",
 		component_separators = { left = "", right = "" },
 		section_separators = { left = "", right = "" },
 		disabled_filetypes = { "alpha", "dashboard", "NvimTree", "Outline " },

nvim/lua/lualine/themes/custom.lua

@@ -0,0 +1,177 @@
+-- Copyright (c) 2020-2021 shadmansaleh
+-- MIT license, see LICENSE for more details.
+local utils = require("lualine.utils.utils")
+local loader = require("lualine.utils.loader")
+
+local custom = {
+	A = "#1F2335",
+	B = "#24283B",
+}
+
+local color_name = vim.g.colors_name
+if color_name then
+	-- All base16 colorschemes share the same theme
+	if "base16" == color_name:sub(1, 6) then
+		color_name = "base16"
+	end
+
+	-- Check if there's a theme for current colorscheme
+	-- If there is load that instead of generating a new one
+	local ok, theme = pcall(loader.load_theme, color_name)
+	if ok and theme then
+		return theme
+	end
+end
+
+---------------
+-- Constants --
+---------------
+-- fg and bg must have this much contrast range 0 < contrast_threshold < 0.5
+local contrast_threshold = 0.3
+-- how much brightness is changed in percentage for light and dark themes
+local brightness_modifier_parameter = 10
+
+-- Turns #rrggbb -> { red, green, blue }
+local function rgb_str2num(rgb_color_str)
+	if rgb_color_str:find("#") == 1 then
+		rgb_color_str = rgb_color_str:sub(2, #rgb_color_str)
+	end
+	local red = tonumber(rgb_color_str:sub(1, 2), 16)
+	local green = tonumber(rgb_color_str:sub(3, 4), 16)
+	local blue = tonumber(rgb_color_str:sub(5, 6), 16)
+	return { red = red, green = green, blue = blue }
+end
+
+-- Turns { red, green, blue } -> #rrggbb
+local function rgb_num2str(rgb_color_num)
+	local rgb_color_str = string.format("#%02x%02x%02x", rgb_color_num.red, rgb_color_num.green, rgb_color_num.blue)
+	return rgb_color_str
+end
+
+-- Returns brightness level of color in range 0 to 1
+-- arbitrary value it's basically an weighted average
+local function get_color_brightness(rgb_color)
+	local color = rgb_str2num(rgb_color)
+	local brightness = (color.red * 2 + color.green * 3 + color.blue) / 6
+	return brightness / 256
+end
+
+-- returns average of colors in range 0 to 1
+-- used to determine contrast level
+local function get_color_avg(rgb_color)
+	local color = rgb_str2num(rgb_color)
+	return (color.red + color.green + color.blue) / 3 / 256
+end
+
+-- Clamps the val between left and right
+local function clamp(val, left, right)
+	if val > right then
+		return right
+	end
+	if val < left then
+		return left
+	end
+	return val
+end
+
+-- Changes brightness of rgb_color by percentage
+local function brightness_modifier(rgb_color, parcentage)
+	local color = rgb_str2num(rgb_color)
+	color.red = clamp(color.red + (color.red * parcentage / 100), 0, 255)
+	color.green = clamp(color.green + (color.green * parcentage / 100), 0, 255)
+	color.blue = clamp(color.blue + (color.blue * parcentage / 100), 0, 255)
+	return rgb_num2str(color)
+end
+
+-- Changes contrast of rgb_color by amount
+local function contrast_modifier(rgb_color, amount)
+	local color = rgb_str2num(rgb_color)
+	color.red = clamp(color.red + amount, 0, 255)
+	color.green = clamp(color.green + amount, 0, 255)
+	color.blue = clamp(color.blue + amount, 0, 255)
+	return rgb_num2str(color)
+end
+
+-- Changes brightness of foreground color to achieve contrast
+-- without changing the color
+local function apply_contrast(highlight)
+	local hightlight_bg_avg = get_color_avg(highlight.bg)
+	local contrast_threshold_config = clamp(contrast_threshold, 0, 0.5)
+	local contranst_change_step = 5
+	if hightlight_bg_avg > 0.5 then
+		contranst_change_step = -contranst_change_step
+	end
+
+	-- Don't waste too much time here max 25 iteration should be more than enough
+	local iteration_count = 1
+	while math.abs(get_color_avg(highlight.fg) - hightlight_bg_avg) < contrast_threshold_config and iteration_count < 25 do
+		highlight.fg = contrast_modifier(highlight.fg, contranst_change_step)
+		iteration_count = iteration_count + 1
+	end
+end
+
+-- Get the colors to create theme
+-- stylua: ignore
+local colors = {
+  normal  = utils.extract_color_from_hllist('bg', { 'PmenuSel', 'PmenuThumb', 'TabLineSel' }, '#000000'),
+  insert  = utils.extract_color_from_hllist('fg', { 'String', 'MoreMsg' }, '#000000'),
+  replace = utils.extract_color_from_hllist('fg', { 'Number', 'Type' }, '#000000'),
+  visual  = utils.extract_color_from_hllist('fg', { 'Special', 'Boolean', 'Constant' }, '#000000'),
+  command = utils.extract_color_from_hllist('fg', { 'Identifier' }, '#000000'),
+  back1   = utils.extract_color_from_hllist('bg', { 'Normal', 'StatusLineNC' }, '#000000'),
+  fore    = utils.extract_color_from_hllist('fg', { 'Normal', 'StatusLine' }, '#000000'),
+  back2   = utils.extract_color_from_hllist('bg', { 'StatusLine' }, '#000000'),
+}
+
+-- Change brightness of colors
+-- Darken if light theme (or) Lighten if dark theme
+local normal_color = utils.extract_highlight_colors("Normal", "bg")
+if normal_color ~= nil then
+	if get_color_brightness(normal_color) > 0.5 then
+		brightness_modifier_parameter = -brightness_modifier_parameter
+	end
+	for name, color in pairs(colors) do
+		colors[name] = brightness_modifier(color, brightness_modifier_parameter)
+	end
+end
+
+-- Basic theme definition
+local M = {
+	normal = {
+		a = { bg = colors.normal, fg = colors.back1, gui = "bold" },
+		b = { bg = custom.B, fg = colors.normal },
+		c = { bg = custom.A, fg = colors.fore },
+	},
+	insert = {
+		a = { bg = colors.insert, fg = colors.back1, gui = "bold" },
+		b = { bg = custom.B, fg = colors.insert },
+		c = { bg = colors.back2, fg = colors.fore },
+	},
+	replace = {
+		a = { bg = colors.replace, fg = colors.back1, gui = "bold" },
+		b = { bg = custom.B, fg = colors.replace },
+		c = { bg = colors.back2, fg = colors.fore },
+	},
+	visual = {
+		a = { bg = colors.visual, fg = colors.back1, gui = "bold" },
+		b = { bg = custom.B, fg = colors.visual },
+		c = { bg = colors.back2, fg = colors.fore },
+	},
+	command = {
+		a = { bg = colors.command, fg = colors.back1, gui = "bold" },
+		b = { bg = custom.B, fg = colors.command },
+		c = { bg = colors.back2, fg = colors.fore },
+	},
+}
+
+M.terminal = M.command
+M.inactive = M.normal
+
+-- Apply proper contrast so text is readable
+for _, section in pairs(M) do
+	for _, highlight in pairs(section) do
+		apply_contrast(highlight)
+	end
+end
+
+return M

nvim/lua/lualine/themes/transparent.lua

@@ -0,0 +1,42 @@
+local colors = {
+	white = "#ffffff",
+	blue = "#88A1BB",
+	green = "#b7d670",
+	magenta = "#a889d2",
+	orange = "#fd9f4d",
+	yellow = "#f3fa9b",
+	transparent = "None",
+}
+
+return {
+	normal = {
+		a = { bg = colors.transparent, fg = colors.blue, gui = "bold" },
+		b = { bg = colors.transparent, fg = colors.white },
+		c = { bg = colors.transparent, fg = colors.white },
+	},
+	insert = {
+		a = { bg = colors.transparent, fg = colors.green, gui = "bold" },
+		b = { bg = colors.transparent, fg = colors.white },
+		c = { bg = colors.transparent, fg = colors.white },
+	},
+	visual = {
+		a = { bg = colors.transparent, fg = colors.magenta, gui = "bold" },
+		b = { bg = colors.transparent, fg = colors.white },
+		c = { bg = colors.transparent, fg = colors.white },
+	},
+	replace = {
+		a = { bg = colors.transparent, fg = colors.orange, gui = "bold" },
+		b = { bg = colors.transparent, fg = colors.white },
+		c = { bg = colors.transparent, fg = colors.white },
+	},
+	command = {
+		a = { bg = colors.transparent, fg = colors.yellow, gui = "bold" },
+		b = { bg = colors.transparent, fg = colors.white },
+		c = { bg = colors.transparent, fg = colors.white },
+	},
+	inactive = {
+		a = { bg = colors.transparent, fg = colors.white, gui = "bold" },
+		b = { bg = colors.transparent, fg = colors.white },
+		c = { bg = colors.transparent, fg = colors.white },
+	},
+}