diff options
Diffstat (limited to 'runtime/lua/vim/_defaults.lua')
| -rw-r--r-- | runtime/lua/vim/_defaults.lua | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/runtime/lua/vim/_defaults.lua b/runtime/lua/vim/_defaults.lua index c1b50e6950..0d7b4f1884 100644 --- a/runtime/lua/vim/_defaults.lua +++ b/runtime/lua/vim/_defaults.lua @@ -164,3 +164,133 @@ do end, }) end + +--- Guess value of 'background' based on terminal color. +--- +--- We write Operating System Command (OSC) 11 to the terminal to request the +--- terminal's background color. We then wait for a response. If the response +--- matches `rgba:RRRR/GGGG/BBBB/AAAA` where R, G, B, and A are hex digits, then +--- compute the luminance[1] of the RGB color and classify it as light/dark +--- accordingly. Note that the color components may have anywhere from one to +--- four hex digits, and require scaling accordingly as values out of 4, 8, 12, +--- or 16 bits. Also note the A(lpha) component is optional, and is parsed but +--- ignored in the calculations. +--- +--- [1] https://en.wikipedia.org/wiki/Luma_%28video%29 +do + --- Parse a string of hex characters as a color. + --- + --- The string can contain 1 to 4 hex characters. The returned value is + --- between 0.0 and 1.0 (inclusive) representing the intensity of the color. + --- + --- For instance, if only a single hex char "a" is used, then this function + --- returns 0.625 (10 / 16), while a value of "aa" would return 0.664 (170 / + --- 256). + --- + --- @param c string Color as a string of hex chars + --- @return number? Intensity of the color + local function parsecolor(c) + local len = #c + assert(len > 0 and len <= 4, 'Invalid hex color string') + if not c:match('^0x') then + c = string.format('0x%s', c) + end + + local max = tonumber(string.format('0x%s', string.rep('f', len))) + return tonumber(c) / max + end + + --- Parse an OSC 11 response + --- + --- Either of the two formats below are accepted: + --- + --- OSC 11 ; rgb:<red>/<green>/<blue> + --- + --- or + --- + --- OSC 11 ; rgba:<red>/<green>/<blue>/<alpha> + --- + --- where + --- + --- <red>, <green>, <blue>, <alpha> := h | hh | hhh | hhhh + --- + --- The alpha component is ignored, if present. + --- + --- @param resp string OSC 11 response + --- @return string? Red component + --- @return string? Green component + --- @return string? Blue component + local function parseosc11(resp) + local r, g, b + r, g, b = resp:match('^\027%]11;rgb:(%x+)/(%x+)/(%x+)$') + if not r and not g and not b then + local a + r, g, b, a = resp:match('^\027%]11;rgba:(%x+)/(%x+)/(%x+)/(%x+)$') + if not a or #a > 4 then + return nil, nil, nil + end + end + + if r and g and b and #r <= 4 and #g <= 4 and #b <= 4 then + return r, g, b + end + + return nil, nil, nil + end + + local tty = false + for _, ui in ipairs(vim.api.nvim_list_uis()) do + if ui.chan == 1 and ui.stdout_tty then + tty = true + break + end + end + + if tty then + local timer = assert(vim.uv.new_timer()) + + local id = vim.api.nvim_create_autocmd('TermResponse', { + nested = true, + callback = function(args) + if vim.api.nvim_get_option_info2('background', {}).was_set then + -- Don't do anything if 'background' is already set + timer:stop() + timer:close() + return true + end + + local resp = args.data ---@type string + local r, g, b = parseosc11(resp) + if r and g and b then + local rr = parsecolor(r) + local gg = parsecolor(g) + local bb = parsecolor(b) + + if rr and gg and bb then + local luminance = (0.299 * rr) + (0.587 * gg) + (0.114 * bb) + local bg = luminance < 0.5 and 'dark' or 'light' + if bg ~= vim.o.background then + vim.o.background = bg + end + end + + timer:stop() + timer:close() + + return true + end + end, + }) + + io.stdout:write('\027]11;?\027\\') + + timer:start(1000, 0, function() + -- No response received. Delete the autocommand + vim.schedule(function() + -- Suppress error if autocommand has already been deleted + pcall(vim.api.nvim_del_autocmd, id) + end) + timer:close() + end) + end +end |