feat(image): added support for math expressions in latex and markdown doc + images in latex. Closes #1223

lua/snacks/image/doc.lua

@@ -6,16 +6,35 @@ local M = {}
 ---@field win snacks.win
 ---@field buf number
 
----@alias snacks.image.transform fun(buf:number, src:string, anchor: TSNode, image: TSNode): string
+---@alias TSMatch {node:TSNode, meta:vim.treesitter.query.TSMetadata}
+---@alias snacks.image.ctx {buf:number, pos?: TSMatch, src?: TSMatch, content?: TSMatch}
+---@alias snacks.image.match {id: string, pos: snacks.image.Pos, src?: string, content?: string, ext?: string}
+---@alias snacks.image.transform fun(match: snacks.image.match, ctx: snacks.image.ctx)
 
 ---@type table<string, snacks.image.transform>
 M.transforms = {
-  ---@param anchor TSNode
-  ---@param img TSNode
-  norg = function(buf, _, anchor, img)
-    local row, col = img:start()
-    local line = vim.api.nvim_buf_get_lines(buf, row, row + 1, false)[1]
-    return line:sub(col + 1)
+  norg = function(img, ctx)
+    local row, col = ctx.src.node:start()
+    local line = vim.api.nvim_buf_get_lines(ctx.buf, row, row + 1, false)[1]
+    img.src = line:sub(col + 1)
+  end,
+  latex = function(img, ctx)
+    local fg = Snacks.util.color({ "@markup.math.latex", "Special", "Normal" }) or "#000000"
+    img.ext = "tex"
+    local content = vim.trim(img.content or "")
+    content = content:gsub("^%$+`?", ""):gsub("`?%$+$", "")
+    content = content:gsub("^\\%[", ""):gsub("\\%]$", "")
+    if not content:find("^\\begin") then
+      content = ("\\[%s\\]"):format(content)
+    end
+    img.content = ([[
+\documentclass[preview,border=2pt,varwidth]{standalone}
+\usepackage{xcolor, amsmath, amssymb}
+\begin{document}
+{ \large \color[HTML]{%s}
+%s}
+\end{document}
+    ]]):format(fg:upper():sub(2), content)
   end,
 }
 
@@ -62,7 +81,7 @@ function M.find(buf, from, to)
     return {}
   end
   parser:parse(from and to and { from, to } or true)
-  local ret = {} ---@type {id:string, pos:snacks.image.Pos, src:string}[]
+  local ret = {} ---@type snacks.image.match[]
   parser:for_each_tree(function(tstree, tree)
     if not tstree then
       return
@@ -72,31 +91,56 @@ function M.find(buf, from, to)
       return
     end
     for _, match, meta in query:iter_matches(tstree:root(), buf, from and from - 1 or nil, to and to - 1 or nil) do
-      local src, pos, nid ---@type string, snacks.image.Pos, string
-      local anchor, image ---@type TSNode, TSNode
+      local ctx = {} ---@type snacks.image.ctx
+      local lang = meta["injection.language"] or tree:lang()
       for id, nodes in pairs(match) do
         nodes = type(nodes) == "userdata" and { nodes } or nodes
         local name = query.captures[id]
-        for _, node in ipairs(nodes) do
-          if name == "image" then
-            image = node
-            src = vim.treesitter.get_node_text(node, buf, { metadata = meta[id] })
-          elseif name == "anchor" then
-            anchor = node
-            local range = { node:range() }
-            pos = { range[1] + 1, range[2] }
-            nid = node:id()
-          end
+        local field = name == "image" and "pos" or name:match("^image%.(.*)$")
+        if field then
+          ctx[field] = { node = nodes[1], meta = meta[id] or {} }
         end
       end
-      if src and pos and nid then
-        local transform = M.transforms[tree:lang()]
-        if transform then
-          src = transform(buf, src, anchor, image)
-        end
-        src = M.resolve(buf, src)
-        ret[#ret + 1] = { id = nid, pos = pos, src = src }
+      assert(ctx.src or ctx.content, "no image src or content")
+      ctx.pos = ctx.pos or ctx.src or ctx.content
+      assert(ctx.pos, "no image node")
+
+      local range = vim.treesitter.get_range(ctx.pos.node, buf, ctx.pos.meta)
+      ---@type snacks.image.match
+      local img = {
+        ext = meta.ext,
+        id = ctx.pos.node:id(),
+        pos = {
+          range[1] == range[4] and (range[1] + 1) or (range[4] + 1),
+          math.min(range[2], range[5]),
+        },
+      }
+      img.pos[1] = math.min(img.pos[1], vim.api.nvim_buf_line_count(buf))
+      if ctx.src then
+        img.src = vim.treesitter.get_node_text(ctx.src.node, buf, { metadata = ctx.src.meta })
       end
+      if ctx.content then
+        img.content = vim.treesitter.get_node_text(ctx.content.node, buf, { metadata = ctx.content.meta })
+      end
+
+      local transform = M.transforms[lang]
+      if transform then
+        transform(img, ctx)
+      end
+      if img.src then
+        img.src = M.resolve(buf, img.src)
+      end
+      if img.content and not img.src then
+        local root = Snacks.image.config.cache
+        vim.fn.mkdir(root, "p")
+        img.src = root .. "/" .. vim.fn.sha256(img.content):sub(1, 8) .. "-content." .. (img.ext or "png")
+        if vim.fn.filereadable(img.src) == 0 then
+          local fd = assert(io.open(img.src, "w"), "failed to open " .. img.src)
+          fd:write(img.content)
+          fd:close()
+        end
+      end
+      ret[#ret + 1] = img
     end
   end)
   return ret