feat: Support disabling code block backgrounds with highlights

## Details

Requested: #110

Currently when we render code blocks we set a background highlight group.

This works for most languages, however some set backgrounds as well, an
example of this is git `diff`s. Since backgrounds cannot be easily combined
we instead allow disabling backgrounds for the languages configured under
`code -> disable_background`.

Other change is a refactor for context into a class with buffer level manager.

Author: MeanderingProgrammer

README.md

@@ -247,6 +247,9 @@ require('render-markdown').setup({
         --  language: adds language icon to sign column if enabled and icon + name above code blocks
         --  full: normal + language
         style = 'full',
+        -- An array of language names for which background highlighting will be disabled
+        -- Likely because that language has background highlights itself
+        disable_background = { 'diff' },
         -- Amount of padding to add to the left of code blocks
         left_pad = 0,
         -- Amount of padding to add to the right of code blocks when width is 'block'
@@ -507,6 +510,9 @@ require('render-markdown').setup({
         --  language: adds language icon to sign column if enabled and icon + name above code blocks
         --  full: normal + language
         style = 'full',
+        -- An array of language names for which background highlighting will be disabled
+        -- Likely because that language has background highlights itself
+        disable_background = { 'diff' },
         -- Amount of padding to add to the left of code blocks
         left_pad = 0,
         -- Amount of padding to add to the right of code blocks when width is 'block'

doc/render-markdown.txt

@@ -279,6 +279,9 @@ Full Default Configuration ~
             --  language: adds language icon to sign column if enabled and icon + name above code blocks
             --  full: normal + language
             style = 'full',
+            -- An array of language names for which background highlighting will be disabled
+            -- Likely because that language has background highlights itself
+            disable_background = { 'diff' },
             -- Amount of padding to add to the left of code blocks
             left_pad = 0,
             -- Amount of padding to add to the right of code blocks when width is 'block'
@@ -539,6 +542,9 @@ CODE BLOCKS                                *render-markdown-setup-code-blocks*
             --  language: adds language icon to sign column if enabled and icon + name above code blocks
             --  full: normal + language
             style = 'full',
+            -- An array of language names for which background highlighting will be disabled
+            -- Likely because that language has background highlights itself
+            disable_background = { 'diff' },
             -- Amount of padding to add to the left of code blocks
             left_pad = 0,
             -- Amount of padding to add to the right of code blocks when width is 'block'

lua/render-markdown/context.lua

@@ -1,47 +1,81 @@
-local util = require('render-markdown.util')
-
----@class render.md.ContextCache
-local cache = {
-    ---@type table<integer, table<integer, [integer, integer][]>>
-    conceal = {},
-    ---@type table<integer, table<integer, [integer, integer, string][]>>
-    inline_links = {},
-}
-
 ---@class render.md.Context
-local M = {}
+---@field private buf integer
+---@field private win integer
+---@field private conceallevel integer
+---@field private conceal? table<integer, [integer, integer][]>
+---@field private links table<integer, [integer, integer, string][]>
+local Context = {}
+Context.__index = Context
 
 ---@param buf integer
-function M.reset_buf(buf)
-    cache.conceal[buf] = {}
-    cache.inline_links[buf] = {}
+---@param win integer
+function Context.new(buf, win)
+    local self = setmetatable({}, Context)
+    self.buf = buf
+    self.win = win
+    self.conceallevel = vim.api.nvim_get_option_value('conceallevel', { scope = 'local', win = win })
+    self.conceal = nil
+    self.links = {}
+    return self
 end
 
----@param buf integer
----@param parser vim.treesitter.LanguageTree
-function M.compute_conceal(buf, parser)
+---@param info render.md.NodeInfo
+---@param icon string
+function Context:add_link(info, icon)
+    local row = info.start_row
+    if self.links[row] == nil then
+        self.links[row] = {}
+    end
+    table.insert(self.links[row], { info.start_col, info.end_col, icon })
+end
+
+---@param row integer
+---@return [integer, integer, string][]
+function Context:get_links(row)
+    return self.links[row] or {}
+end
+
+---@return integer
+function Context:get_width()
+    return vim.api.nvim_win_get_width(self.win)
+end
+
+---@param row integer
+---@return [integer, integer][]
+function Context:get_conceal(row)
+    if self.conceal == nil then
+        self.conceal = self:compute_conceal()
+    end
+    return self.conceal[row] or {}
+end
+
+---Cached row level implementation of vim.treesitter.get_captures_at_pos
+---@private
+---@return table<integer, [integer, integer][]>
+function Context:compute_conceal()
+    if self.conceallevel == 0 then
+        return {}
+    end
     local ranges = {}
-    if util.get_win(util.buf_to_win(buf), 'conceallevel') > 0 then
-        parser:for_each_tree(function(tree, language_tree)
-            local nodes = M.get_conceal_nodes(buf, language_tree:lang(), tree:root())
-            for _, node in ipairs(nodes) do
-                local row, start_col, _, end_col = node:range()
-                if ranges[row] == nil then
-                    ranges[row] = {}
-                end
-                table.insert(ranges[row], { start_col, end_col })
+    local parser = vim.treesitter.get_parser(self.buf)
+    parser:for_each_tree(function(tree, language_tree)
+        local nodes = self:compute_conceal_nodes(language_tree:lang(), tree:root())
+        for _, node in ipairs(nodes) do
+            local row, start_col, _, end_col = node:range()
+            if ranges[row] == nil then
+                ranges[row] = {}
             end
-        end)
-    end
-    cache.conceal[buf] = ranges
+            table.insert(ranges[row], { start_col, end_col })
+        end
+    end)
+    return ranges
 end
 
 ---@private
----@param buf integer
 ---@param language string
 ---@param root TSNode
 ---@return TSNode[]
-function M.get_conceal_nodes(buf, language, root)
+function Context:compute_conceal_nodes(language, root)
     if not vim.tbl_contains({ 'markdown', 'markdown_inline' }, language) then
         return {}
     end
@@ -50,38 +84,30 @@ function M.get_conceal_nodes(buf, language, root)
         return {}
     end
     local nodes = {}
-    for _, node, metadata in query:iter_captures(root, buf) do
+    for _, node, metadata in query:iter_captures(root, self.buf) do
         if metadata.conceal ~= nil then
             table.insert(nodes, node)
         end
     end
     return nodes
 end
 
----@param buf integer
----@param row integer
----@return [integer, integer][]
-function M.concealed(buf, row)
-    return cache.conceal[buf][row] or {}
-end
+---@type table<integer, render.md.Context>
+local cache = {}
+
+---@class render.md.ContextManager
+local M = {}
 
 ---@param buf integer
----@param info render.md.NodeInfo
----@param icon string
-function M.add_inline_link(buf, info, icon)
-    local inline_links = cache.inline_links[buf]
-    local row = info.start_row
-    if inline_links[row] == nil then
-        inline_links[row] = {}
-    end
-    table.insert(inline_links[row], { info.start_col, info.end_col, icon })
+---@param win integer
+function M.reset(buf, win)
+    cache[buf] = Context.new(buf, win)
 end
 
 ---@param buf integer
----@param row integer
----@return [integer, integer, string][]
-function M.inline_links(buf, row)
-    return cache.inline_links[buf][row] or {}
+---@return render.md.Context
+function M.get(buf)
+    return cache[buf]
 end
 
 return M

lua/render-markdown/extmark.lua

@@ -11,6 +11,7 @@ Extmark.__index = Extmark
 ---@param namespace integer
 ---@param buf integer
 ---@param mark render.md.Mark
+---@return render.md.Extmark
 function Extmark.new(namespace, buf, mark)
     local self = setmetatable({}, Extmark)
     self.namespace = namespace