fix: empty lines in indented code blocks

## Details

Follow up to: #133

Empty lines in indented code blocks ignore start_col when adding
background highlight, since any value > 0 is out of the valid range.

To fix this we need to add an inline mark to shift the starting point
based on the overall block start_col.

To do this update code block parsing to track empty rows. Update the
left padding logic to add more additional padding to these empty lines.

Author: MeanderingProgrammer

CHANGELOG.md

@@ -16,6 +16,8 @@
   [4c823b1](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/4c823b1df151dbf1ed3ddaacac517be606b1e145)
 - do not set noref in vim.deepcopy [#139](https://github.com/MeanderingProgrammer/render-markdown.nvim/pull/139)
 - gate virt_text_repeat_linebreak to neovim >= 0.10.0 [98f9965](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/98f996563591b753470942165d2d5134df868529)
+- account for folds when computing visible range [#138](https://github.com/MeanderingProgrammer/render-markdown.nvim/issues/138)
+  [cd0a5ad](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/cd0a5ad8c77c3754d02437048bc0bb604a2fe268)
 
 ### Collaborator Shoutouts
 

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*          For 0.10.0          Last change: 2024 August 18
+*render-markdown.txt*          For 0.10.0          Last change: 2024 August 19
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*

lua/render-markdown/handler/markdown.lua

@@ -369,18 +369,30 @@ end
 ---@param add_background boolean
 function Handler:code_left_pad(code_block, add_background)
     local code = self.config.code
-    if code.left_pad <= 0 then
+    if (code_block.col == 0 or #code_block.empty_rows == 0) and code.left_pad <= 0 then
         return
     end
-    local padding = str.pad(code.left_pad)
-    local highlight = add_background and code.highlight or 'Normal'
+
+    -- Use low priority to include other marks in padding when code block is at edge
+    local priority = code_block.col == 0 and 0 or nil
+    local outer_text = { str.pad(code_block.col), 'Normal' }
+    local left_text = { str.pad(code.left_pad), add_background and code.highlight or 'Normal' }
+
     for row = code_block.start_row, code_block.end_row - 1 do
-        -- Uses a low priority so other marks are loaded first and included in padding
-        self:add(false, row, code_block.col, {
-            priority = 0,
-            virt_text = { { padding, highlight } },
-            virt_text_pos = 'inline',
-        })
+        local virt_text = {}
+        if code_block.col > 0 and vim.tbl_contains(code_block.empty_rows, row) then
+            table.insert(virt_text, outer_text)
+        end
+        if code.left_pad > 0 then
+            table.insert(virt_text, left_text)
+        end
+        if #virt_text > 0 then
+            self:add(false, row, code_block.col, {
+                priority = priority,
+                virt_text = virt_text,
+                virt_text_pos = 'inline',
+            })
+        end
     end
 end
 

lua/render-markdown/health.lua

@@ -5,7 +5,7 @@ local M = {}
 
 ---@private
 ---@type string
-M.version = '6.1.7'
+M.version = '6.1.8'
 
 function M.check()
     vim.health.start('render-markdown.nvim [version]')

lua/render-markdown/parser/code_block.lua

@@ -8,6 +8,7 @@ local M = {}
 ---@field start_row integer
 ---@field end_row integer
 ---@field leading_spaces integer
+---@field empty_rows integer[]
 ---@field longest_line integer
 ---@field width integer
 ---@field code_info_hidden boolean
@@ -25,15 +26,17 @@ function M.parse(config, context, info)
     if info.end_row - info.start_row <= 1 then
         return nil
     end
+    local widths = vim.tbl_map(str.width, info:lines())
     local code_info = info:child('info_string', info.start_row)
     local language_info = code_info ~= nil and code_info:child('language', info.start_row) or nil
-    local longest_line, width = M.get_width(config, context, info)
+    local longest_line, width = M.get_width(config, context, widths)
     ---@type render.md.parsed.CodeBlock
     return {
         col = info.start_col,
         start_row = info.start_row,
         end_row = info.end_row,
         leading_spaces = str.leading_spaces(info.text),
+        empty_rows = M.get_empty_rows(info.start_row, widths),
         longest_line = longest_line,
         width = width,
         code_info_hidden = context:hidden(code_info),
@@ -44,14 +47,27 @@ function M.parse(config, context, info)
     }
 end
 
+---@private
+---@param start_row integer
+---@param widths integer[]
+---@return integer[]
+function M.get_empty_rows(start_row, widths)
+    local empty_rows = {}
+    for row, width in ipairs(widths) do
+        if width == 0 then
+            table.insert(empty_rows, start_row + row - 1)
+        end
+    end
+    return empty_rows
+end
+
 ---@private
 ---@param config render.md.Code
 ---@param context render.md.Context
----@param info render.md.NodeInfo
+---@param widths integer[]
 ---@return integer, integer
-function M.get_width(config, context, info)
-    local lines = info:lines()
-    local code_width = vim.fn.max(vim.tbl_map(str.width, lines))
+function M.get_width(config, context, widths)
+    local code_width = vim.fn.max(widths)
     local longest_line = config.left_pad + code_width + config.right_pad
     local width = math.max(longest_line, config.min_width)
     if config.width == 'block' then

tests/code_spec.lua

@@ -24,9 +24,8 @@ describe('code.md', function()
             util.code_row(11, 2),
             util.code_language(11, 5, 8, 'lua'),
             util.code_row(12, 2),
-            -- TODO: look into fixing indented code with blank lines
-            --       probably need to fill with inline extmark
             util.code_row(13, 0),
+            util.padding(13, 2),
             util.code_row(14, 2),
             util.code_below(15, 2),
         })

tests/util.lua

@@ -185,6 +185,19 @@ function M.quote(row, format, highlight)
     }
 end
 
+---@param row integer
+---@param spaces integer
+---@return render.md.MarkInfo
+function M.padding(row, spaces)
+    ---@type render.md.MarkInfo
+    return {
+        row = { row },
+        col = { 0 },
+        virt_text = { { string.rep(' ', spaces), 'Normal' } },
+        virt_text_pos = 'inline',
+    }
+end
+
 ---@param row integer
 ---@param col integer
 ---@param head boolean