feat: configurable starting indent level

## Details

Another feature related to org-mode indents. Rather than hard coding
that indents skip level 1 and increment from there allow users to set
whatever value they like using indent -> skip.

This tells us how many levels should be skipped before starting to
indent, default value remains 1.

Using a value of 0 will indent level 1 headings as well. Using a value
greater than 1 will indent relative to that level instead. Only kinda
tricky thing is to remember that the level change should be computed
relative to the parent level or this skip value, whichever is greater.
So setting a value of 2, then having an H1 & H3. The H3 should be
indented only once, so the parent level is calculated as 2 instead of 1.
Using negative values breaks things of course.

Author: MeanderingProgrammer

Diff for: README.md

@@ -512,6 +512,9 @@ require('render-markdown').setup({
         enabled = false,
         -- Amount of additional padding added for each heading level
         per_level = 2,
+        -- Heading levels <= this value will not be indented
+        -- Use 0 to begin indenting from the very first level
+        skip = 1,
     },
     -- Window options to use that change between rendered and raw view
     win_options = {
@@ -936,6 +939,9 @@ require('render-markdown').setup({
         enabled = false,
         -- Amount of additional padding added for each heading level
         per_level = 2,
+        -- Heading levels <= this value will not be indented
+        -- Use 0 to begin indenting from the very first level
+        skip = 1,
     },
 })
 ```

Diff for: doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*         For 0.10.0        Last change: 2024 September 12
+*render-markdown.txt*         For 0.10.0        Last change: 2024 September 13
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*
@@ -545,6 +545,9 @@ Full Default Configuration ~
             enabled = false,
             -- Amount of additional padding added for each heading level
             per_level = 2,
+            -- Heading levels <= this value will not be indented
+            -- Use 0 to begin indenting from the very first level
+            skip = 1,
         },
         -- Window options to use that change between rendered and raw view
         win_options = {
@@ -989,6 +992,9 @@ Wiki Page
             enabled = false,
             -- Amount of additional padding added for each heading level
             per_level = 2,
+            -- Heading levels <= this value will not be indented
+            -- Use 0 to begin indenting from the very first level
+            skip = 1,
         },
     })
 <

Diff for: lua/render-markdown/core/node_info.lua

@@ -52,19 +52,18 @@ function NodeInfo:has_error()
     return self.node:has_error()
 end
 
+---@param parent boolean
 ---@return integer
-function NodeInfo:parent_heading_level()
-    local parent = self:parent('section')
-    return parent ~= nil and parent:heading_level() or 1
-end
-
----@return integer
-function NodeInfo:heading_level()
-    assert(self.type == 'section', 'Node must be a section')
-    local heading = self:child('atx_heading')
+function NodeInfo:heading_level(parent)
+    local info = not parent and self or self:parent('section')
+    if info == nil then
+        return 0
+    end
+    assert(info.type == 'section', 'Node must be a section')
+    local heading = info:child('atx_heading')
     local node = heading ~= nil and heading.node:child(0) or nil
     -- Counts the number of hashtags in the heading marker
-    return node ~= nil and #vim.treesitter.get_node_text(node, self.buf) or 1
+    return node ~= nil and #vim.treesitter.get_node_text(node, self.buf) or 0
 end
 
 ---Walk through parent nodes, count the number of target nodes

Diff for: lua/render-markdown/health.lua

@@ -5,7 +5,7 @@ local M = {}
 
 ---@private
 ---@type string
-M.version = '6.3.8'
+M.version = '6.3.9'
 
 function M.check()
     vim.health.start('render-markdown.nvim [version]')

Diff for: lua/render-markdown/init.lua

@@ -29,6 +29,7 @@ local M = {}
 ---@class (exact) render.md.UserIndent
 ---@field public enabled? boolean
 ---@field public per_level? integer
+---@field public skip? integer
 
 ---@class (exact) render.md.UserSign
 ---@field public enabled? boolean
@@ -576,6 +577,9 @@ M.default_config = {
         enabled = false,
         -- Amount of additional padding added for each heading level
         per_level = 2,
+        -- Heading levels <= this value will not be indented
+        -- Use 0 to begin indenting from the very first level
+        skip = 1,
     },
     -- Window options to use that change between rendered and raw view
     win_options = {

Diff for: lua/render-markdown/render/base.lua

@@ -47,7 +47,7 @@ function Base:indent_virt_line(line)
     if not indent.enabled then
         return line
     end
-    local level = self.info:parent_heading_level() - 1
+    local level = self.info:heading_level(true) - indent.skip
     if level <= 0 then
         return line
     end

Diff for: lua/render-markdown/render/section.lua

@@ -23,8 +23,8 @@ function Render:setup()
         return false
     end
 
-    local current_level = self.info:heading_level()
-    local parent_level = self.info:parent_heading_level()
+    local current_level = self.info:heading_level(false)
+    local parent_level = math.max(self.info:heading_level(true), self.indent.skip)
     self.level_change = current_level - parent_level
 
     -- Nothing to do if there is not a change in level

Diff for: lua/render-markdown/state.lua

@@ -386,6 +386,7 @@ function M.validate()
             append_errors(path .. '.indent', indent, {
                 enabled = { indent.enabled, 'boolean', nilable },
                 per_level = { indent.per_level, 'number', nilable },
+                skip = { indent.skip, 'number', nilable },
             })
         end
 

Diff for: lua/render-markdown/types.lua

@@ -18,6 +18,7 @@
 ---@class (exact) render.md.Indent
 ---@field public enabled boolean
 ---@field public per_level integer
+---@field public skip integer
 
 ---@class (exact) render.md.Sign
 ---@field public enabled boolean

Diff for: tests/ad_hoc_spec.lua

@@ -7,43 +7,30 @@ local util = require('tests.util')
 ---@param level integer
 ---@return render.md.MarkInfo[]
 local function setext_heading(start_row, end_row, level)
-    local icon = level == 1 and '󰲡 ' or '󰲣 '
-    local foreground = util.hl(string.format('H%d', level))
-    local background = util.hl(string.format('H%dBg', level))
+    local result = util.heading(start_row, level)
+    local background_mark = table.remove(result, #result)
+    local icon_mark = table.remove(result, #result)
 
-    ---@type render.md.MarkInfo
-    local sign_mark = {
-        row = { start_row },
-        col = { 0 },
-        sign_text = '󰫎 ',
-        sign_hl_group = util.hl('_' .. foreground .. '_' .. util.hl('Sign')),
-    }
-    local result = { sign_mark }
     for row = start_row, end_row do
-        ---@type render.md.MarkInfo
-        local background_mark = {
-            row = { row, row + 1 },
-            col = { 0, 0 },
-            hl_group = background,
-            hl_eol = true,
-        }
-        table.insert(result, background_mark)
+        local row_background_mark = vim.deepcopy(background_mark)
+        row_background_mark.row = { row, row + 1 }
+        table.insert(result, row_background_mark)
     end
-    ---@type render.md.MarkInfo
-    local icon_mark = {
-        row = { start_row, end_row + 1 },
-        col = { 0, 0 },
-        virt_text = { { icon, { foreground, background } } },
-        virt_text_pos = 'inline',
-    }
+
+    icon_mark.row = { start_row, end_row + 1 }
+    icon_mark.col = { 0, 0 }
+    icon_mark.virt_text[1][1] = vim.trim(icon_mark.virt_text[1][1]) .. ' '
+    icon_mark.virt_text_pos = 'inline'
     table.insert(result, 3, icon_mark)
+
     ---@type render.md.MarkInfo
     local conceal_mark = {
         row = { end_row, end_row },
         col = { 0, 3 },
         conceal = '',
     }
     table.insert(result, #result, conceal_mark)
+
     return result
 end
 

Diff for: tests/indent_spec.lua

@@ -21,7 +21,7 @@ end
 ---@return render.md.MarkInfo
 local function border(row, level, position)
     local foreground = util.hl(string.format('H%d', level))
-    local background = util.hl('_Inverse_' .. util.hl(string.format('H%dBg', level)))
+    local background = util.hl_inverse(string.format('H%dBg', level))
     local icon = position == 'above' and '▄' or '▀'
     local line = {
         { '', background },

Diff for: tests/util.lua

@@ -152,7 +152,7 @@ function M.heading(row, level)
         row = { row },
         col = { 0 },
         sign_text = '󰫎 ',
-        sign_hl_group = M.hl('_' .. foreground .. '_' .. M.hl('Sign')),
+        sign_hl_group = M.hl_sign(foreground),
     }
     local result = { sign_mark }
     if row > 0 then
@@ -254,7 +254,7 @@ function M.code_language(row, col, name, win_col)
         row = { row },
         col = { col },
         sign_text = icon,
-        sign_hl_group = M.hl('_' .. highlight .. '_' .. M.hl('Sign')),
+        sign_hl_group = M.hl_sign(highlight),
     }
     ---@type render.md.MarkInfo
     local language_mark = {
@@ -280,7 +280,7 @@ function M.code_below(row, col, width)
     return {
         row = { row },
         col = { col },
-        virt_text = { { string.rep('▀', width), M.hl('_Inverse_' .. M.hl('Code')) } },
+        virt_text = { { string.rep('▀', width), M.hl_inverse('Code') } },
         virt_text_pos = 'overlay',
     }
 end
@@ -399,6 +399,19 @@ function M.table_border(row, section, lengths, indent)
     end
 end
 
+---@private
+---@param highlight string
+---@return string
+function M.hl_sign(highlight)
+    return M.hl('_' .. highlight .. '_' .. M.hl('Sign'))
+end
+
+---@param base string
+---@return string
+function M.hl_inverse(base)
+    return M.hl('_Inverse_' .. M.hl(base))
+end
+
 ---@param suffix string
 ---@return string
 function M.hl(suffix)