Version 1.0.0

lua/virt-column/init.lua

@@ -0,0 +1,81 @@
+local ffi = require "ffi"
+
+ffi.cdef "int curwin_col_off(void);"
+
+local M = {
+    config = {
+        char = "┃",
+    },
+}
+
+M.clear_buf = function(bufnr)
+    if M.namespace then
+        vim.api.nvim_buf_clear_namespace(bufnr, M.namespace, 0, -1)
+    end
+end
+
+M.setup = function(config)
+    M.config = vim.tbl_deep_extend("force", M.config, config or {})
+    M.namespace = vim.api.nvim_create_namespace "virt-column"
+
+    vim.cmd [[command! VirtColumnRefresh lua require("virt-column").refresh()]]
+    vim.cmd [[highlight link VirtColumn Whitespace]]
+
+    vim.cmd [[
+        augroup VirtColumnAutogroup
+            autocmd!
+            autocmd FileChangedShellPost,TextChanged,TextChangedI,CompleteChanged,BufWinEnter,WinScrolled * VirtColumnRefresh
+            autocmd OptionSet colorcolumn VirtColumnRefresh
+        augroup END
+    ]]
+end
+
+M.refresh = function()
+    local bufnr = 0
+    local win_start = vim.fn.line "w0"
+    local win_end = vim.fn.line "w$"
+    local offset = math.max(win_start - 11, 0)
+    local range = math.min(win_end + 11, vim.api.nvim_buf_line_count(bufnr))
+    local lines = vim.api.nvim_buf_get_lines(bufnr, offset, range, false)
+    local width = vim.api.nvim_win_get_width(0) - ffi.C.curwin_col_off()
+    local textwidth = vim.opt.textwidth:get()
+    local colorcolumn = vim.opt.colorcolumn:get()
+
+    for i, c in ipairs(colorcolumn) do
+        if vim.startswith(c, "+") then
+            colorcolumn[i] = textwidth + tonumber(c:sub(2))
+        elseif vim.startswith(c, "-") then
+            colorcolumn[i] = textwidth - tonumber(c:sub(2))
+        else
+            colorcolumn[i] = tonumber(c)
+        end
+    end
+
+    table.sort(colorcolumn, function(a, b)
+        return a > b
+    end)
+
+    M.clear_buf()
+
+    for i = 1, #lines, 1 do
+        local current_offset = 0
+        local virt_text = {}
+        for _, column in ipairs(colorcolumn) do
+            local line = lines[i]:gsub("\t", string.rep(" ", vim.opt.tabstop:get()))
+            if width > column and vim.api.nvim_strwidth(line) < column then
+                table.insert(virt_text, 1, { string.rep(" ", width - column - current_offset) })
+                table.insert(virt_text, 1, { M.config.char, "VirtColumn" })
+                current_offset = width - column + 1
+            end
+        end
+        if #virt_text > 0 then
+            vim.api.nvim_buf_set_extmark(bufnr, M.namespace, i - 1 + offset, 0, {
+                virt_text = virt_text,
+                virt_text_pos = "right_align",
+                hl_mode = "combine",
+            })
+        end
+    end
+end
+
+return M