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Diffstat (limited to 'lua/colorizer.lua')
| -rw-r--r-- | lua/colorizer.lua | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/lua/colorizer.lua b/lua/colorizer.lua new file mode 100644 index 0000000..03d2bbc --- /dev/null +++ b/lua/colorizer.lua @@ -0,0 +1,247 @@ +--- Highlights terminal CSI ANSI color codes. +-- @module terminal +local nvim = require 'nvim' +local Trie = require 'trie' + +--- Default namespace used in `highlight_buffer` and `attach_to_buffer`. +-- The name is "terminal_highlight" +-- @see highlight_buffer +-- @see attach_to_buffer +local DEFAULT_NAMESPACE = nvim.create_namespace 'colorizer' + +local COLOR_MAP +local COLOR_TRIE + +local function initialize_trie() + if not COLOR_TRIE then + COLOR_MAP = nvim.get_color_map() + COLOR_TRIE = Trie() + + for k in pairs(COLOR_MAP) do + COLOR_TRIE:insert(k) + end + end +end + +local b_a = string.byte('a') +local b_z = string.byte('z') +local b_A = string.byte('A') +local b_Z = string.byte('Z') +local b_0 = string.byte('0') +local b_9 = string.byte('9') +local b_f = string.byte('f') +local b_hash = string.byte('#') +local bnot = bit.bnot +local band, bor, bxor = bit.band, bit.bor, bit.bxor +local lshift, rshift, rol = bit.lshift, bit.rshift, bit.rol + +-- TODO use lookup table? +local function byte_is_hex(byte) + byte = bor(byte, 0x20) + return (byte >= b_0 and byte <= b_9) or (byte >= b_a and byte <= b_f) +end + +--- Determine whether to use black or white text +-- Ref: https://stackoverflow.com/a/1855903/837964 +-- https://stackoverflow.com/questions/596216/formula-to-determine-brightness-of-rgb-color +local function color_is_bright(r, g, b) + -- Counting the perceptive luminance - human eye favors green color + local luminance = (0.299*r + 0.587*g + 0.114*b)/255 + if luminance > 0.5 then + return true -- Bright colors, black font + else + return false -- Dark colors, white font + end +end + +local HIGHLIGHT_NAME_PREFIX = "colorizer_" +--- Make a deterministic name for a highlight given these attributes +local function make_highlight_name(rgb) + return table.concat {HIGHLIGHT_NAME_PREFIX, rgb} +end + +local highlight_cache = {} + +-- Ref: https://stackoverflow.com/questions/1252539/most-efficient-way-to-determine-if-a-lua-table-is-empty-contains-no-entries +local function table_is_empty(t) + return next(t) == nil +end + +local function create_highlight(rgb_hex, options) + -- TODO validate rgb format? + local highlight_name = highlight_cache[rgb_hex] + -- Look up in our cache. + if not highlight_name then + -- Create the highlight + highlight_name = make_highlight_name(rgb_hex) + if options.mode == 'foreground' then + nvim.ex.highlight(highlight_name, "guifg=#"..rgb_hex) + else + local r, g, b = rgb_hex:sub(1,2), rgb_hex:sub(3,4), rgb_hex:sub(5,6) + r, g, b = tonumber(r,16), tonumber(g,16), tonumber(b,16) + local fg_color + if color_is_bright(r,g,b) then + fg_color = "Black" + else + fg_color = "White" + end + nvim.ex.highlight(highlight_name, "guifg="..fg_color, "guibg=#"..rgb_hex) + end + highlight_cache[rgb_hex] = highlight_name + end + return highlight_name +end + +--- Highlight a region in a buffer from the attributes specified +local function highlight_region(buf, ns, highlight_name, + region_line_start, region_byte_start, + region_line_end, region_byte_end) + -- TODO should I bother with highlighting normal regions? + if region_line_start == region_line_end then + nvim.buf_add_highlight(buf, ns, highlight_name, region_line_start, region_byte_start, region_byte_end) + else + nvim.buf_add_highlight(buf, ns, highlight_name, region_line_start, region_byte_start, -1) + for linenum = region_line_start + 1, region_line_end - 1 do + nvim.buf_add_highlight(buf, ns, highlight_name, linenum, 0, -1) + end + nvim.buf_add_highlight(buf, ns, highlight_name, region_line_end, 0, region_byte_end) + end +end + +--[[-- Highlight the buffer region. +Highlight starting from `line_start` (0-indexed) for each line described by `lines` in the +buffer `buf` and attach it to the namespace `ns`. + +@tparam integer buf buffer id. +@tparam[opt=DEFAULT_NAMESPACE] integer ns the namespace id. Create it with `vim.api.create_namespace` +@tparam {string,...} lines the lines to highlight from the buffer. +@tparam integer line_start should be 0-indexed +]] +local function highlight_buffer(buf, ns, lines, line_start, options) + options = options or {} + -- TODO do I have to put this here? + initialize_trie() + ns = ns or DEFAULT_NAMESPACE + for current_linenum, line in ipairs(lines) do + -- @todo it's possible to skip processing the new code if the attributes hasn't changed. + current_linenum = current_linenum - 1 + line_start + local i = 1 + while i < #line do + local byte = line:byte(i) + if byte == b_hash then + i = i + 1 + if #line >= i + 5 then + local invalid = false + for n = i, i+5 do + byte = line:byte(n) + if not byte_is_hex(byte) then + invalid = true + break + end + end + if not invalid then + local rgb_hex = line:sub(i, i+5) + -- TODO figure out proper background/foreground + local highlight_name = create_highlight(rgb_hex, options) + -- Subtract one because 0-indexed, subtract another 1 for the '#' + nvim.buf_add_highlight(buf, ns, highlight_name, current_linenum, i-1-1, i+6-1) + i = i + 5 + end + end + else + -- TODO skip if the remaining length is less than the shortest length + -- of an entry in our trie. + local prefix = COLOR_TRIE:longest_prefix(line:sub(i)) + if prefix then + local rgb = COLOR_MAP[prefix] + local rgb_hex = bit.tohex(rgb):sub(-6) + -- TODO figure out proper background/foreground + local highlight_name = create_highlight(rgb_hex, options) + nvim.buf_add_highlight(buf, ns, highlight_name, current_linenum, i-1, i+#prefix-1) + i = i + #prefix + else + i = i + 1 + end + end + end + end +end + +--- Attach to a buffer and continuously highlight changes. +-- @tparam[opt=0] integer buf A value of 0 implies the current buffer. +-- @see highlight_buffer +local function attach_to_buffer(buf, options) + local ns = DEFAULT_NAMESPACE + if buf == 0 or buf == nil then + buf = nvim.get_current_buf() + end + -- Already attached. + if pcall(vim.api.nvim_buf_get_var, buf, "colorizer_attached") then + return + end + nvim.buf_set_var(buf, "colorizer_attached", true) + do + nvim.buf_clear_namespace(buf, ns, 0, -1) + local lines = nvim.buf_get_lines(buf, 0, -1, true) + highlight_buffer(buf, ns, lines, 0, options) + end + -- send_buffer: true doesn't actually do anything in Lua (yet) + nvim.buf_attach(buf, false, { + on_lines = function(event_type, buf, changed_tick, firstline, lastline, new_lastline) + nvim.buf_clear_namespace(buf, ns, firstline, new_lastline) + local lines = nvim.buf_get_lines(buf, firstline, new_lastline, true) + highlight_buffer(buf, ns, lines, firstline, options) + end; + }) +end + +--- Easy to use function if you want the full setup without fine grained control. +-- Establishes an autocmd for `FileType terminal` +-- @usage require'colorizer'.setup() +local function auto_setup(filetypes, default_options) + if not nvim.o.termguicolors then + nvim.err_writeln("&termguicolors must be set") + return + end + initialize_trie() + local filetype_options = {} + function COLORIZER_SETUP_HOOK() + local filetype = nvim.bo.filetype + local options = filetype_options[filetype] or default_options + attach_to_buffer(nvim.get_current_buf(), options) + end + nvim.ex.augroup("ColorizerSetup") + nvim.ex.autocmd_() + if not filetypes then + nvim.ex.autocmd("FileType * lua COLORIZER_SETUP_HOOK()") + else + for k, v in pairs(filetypes) do + local filetype + local options = default_options or {} + if type(k) == 'string' then + filetype = k + if type(v) ~= 'table' then + nvim.err_writeln("colorizer: Invalid option type for filetype "..filetype) + else + options = vim.tbl_extend("keep", v, default_options) + end + else + filetype = v + end + filetype_options[filetype] = options + -- TODO What's the right mode for this? BufEnter? + nvim.ex.autocmd("FileType", filetype, "lua COLORIZER_SETUP_HOOK(%s)") + end + end + nvim.ex.augroup("END") +end + +--- @export +return { + DEFAULT_NAMESPACE = DEFAULT_NAMESPACE; + setup = auto_setup; + attach_to_buffer = attach_to_buffer; + highlight_buffer = highlight_buffer; + initialize = initialize_trie; +} + |