fix: use display width for latex formula alignment

## Details

Instead of using the byte offset for latex formula alignment, calculate
the actual display width of the text before the current node.

Co-authored-by: Lexey Khom <[email protected]>

Author: MeanderingProgrammer

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*       For NVIM v0.11.3       Last change: 2025 August 19
+*render-markdown.txt*       For NVIM v0.11.3       Last change: 2025 August 21
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*

lua/render-markdown/debug/marks.lua

@@ -99,7 +99,11 @@ end
 ---@param lines render.md.mark.Line[]
 ---@return string
 function Mark.lines(lines)
-    return #lines > 0 and Mark.line(lines[1]) or ''
+    local result = {} ---@type string[]
+    for _, line in ipairs(lines) do
+        result[#result + 1] = Mark.line(line)
+    end
+    return ('{%s}'):format(table.concat(result, ', '))
 end
 
 ---@private
@@ -113,7 +117,7 @@ function Mark.line(line)
             Mark.highlight(text[2])
         )
     end
-    return table.concat(result, ' + ')
+    return ('[%s]'):format(table.concat(result, ', '))
 end
 
 ---@private

lua/render-markdown/handler/latex.lua

@@ -61,20 +61,26 @@ end
 ---@param node render.md.Node
 ---@return string[]
 function Handler:expressions(node)
+    local col = node.start_col
+    local _, first = node:line('first', 0)
+    local prefix = str.pad(first and str.width(first:sub(1, col)) or col)
+
     local result = {} ---@type string[]
     for _ = 1, self.config.top_pad do
         result[#result + 1] = ''
     end
+
     local lines = str.split(self:convert(node.text), '\n', true)
     local width = vim.fn.max(iter.list.map(lines, str.width))
     for _, line in ipairs(lines) do
-        local prefix = str.pad(node.start_col)
         local suffix = str.pad(width - str.width(line))
         result[#result + 1] = prefix .. line .. suffix
     end
+
     for _ = 1, self.config.bottom_pad do
         result[#result + 1] = ''
     end
+
     return result
 end
 

lua/render-markdown/health.lua

@@ -5,7 +5,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '8.7.9'
+M.version = '8.7.10'
 
 function M.check()
     M.start('versions')

tests/util.lua

@@ -353,10 +353,12 @@ end
 function M.table.border(virtual, above, ...)
     local chars = above and { '┌', '┬', '┐' } or { '└', '┴', '┘' }
     local highlight = above and 'RmTableHead' or 'RmTableRow'
-    local parts = vim.tbl_map(function(length)
-        return ('─'):rep(length)
-    end, { ... })
-    local text = chars[1] .. table.concat(parts, chars[2]) .. chars[3]
+    local inner = vim.iter({ ... })
+        :map(function(length)
+            return ('─'):rep(length)
+        end)
+        :join(chars[2])
+    local text = chars[1] .. inner .. chars[3]
     if virtual then
         ---@type vim.api.keyset.set_extmark
         return {
@@ -376,15 +378,16 @@ end
 ---@param ... integer[]
 ---@return vim.api.keyset.set_extmark
 function M.table.delimiter(padding, ...)
-    local parts = vim.tbl_map(function(widths)
-        local section = vim.tbl_map(function(amount)
-            return amount == 1 and '━' or ('─'):rep(amount)
-        end, widths)
-        return table.concat(section, '')
-    end, { ... })
-    local line = {
-        { '├' .. table.concat(parts, '┼') .. '┤', 'RmTableHead' },
-    }
+    local inner = vim.iter({ ... })
+        :map(function(widths)
+            return vim.iter(widths)
+                :map(function(amount)
+                    return amount == 1 and '━' or ('─'):rep(amount)
+                end)
+                :join('')
+        end)
+        :join('┼')
+    local line = { { '├' .. inner .. '┤', 'RmTableHead' } }
     if padding > 0 then
         line[#line + 1] = { (' '):rep(padding), 'Normal' }
     end