ref!(math-renderer): modularize image generation to make way for typst

Author: benlubas

lua/neorg/modules/core/highlights/module.lua

@@ -368,10 +368,10 @@ module.config.public = {
             escape = "+@type",
         },
 
-        -- Rendered Latex, this will dictate the foreground color of latex images rendered via
-        -- core.latex.renderer
+        -- Rendered Latex, this will dictate the foreground color of math images rendered via
+        -- core.math.renderer
         rendered = {
-            latex = "+Normal",
+            math = "+Normal",
         },
     },
 

lua/neorg/modules/core/math/renderer/latex/module.lua

@@ -0,0 +1,135 @@
+--[[
+    file: Core-Math-Renderer-LaTeX
+    title: Convert LaTeX snippets into image files
+    summary: A module that provides images of LaTeX for `core.math.renderer`
+    ---
+
+The module is used by `core.math.renderer` to render math blocks as LaTeX.
+
+Requires:
+- `latex` executable in path with the following packages:
+    - standalone
+    - amsmath
+    - amssymb
+    - graphicx
+- `dvipng` executable in path (normally comes with LaTeX)
+
+A highlight group that controls the foreground color of the rendered math: `@norg.rendered.latex`,
+configurable in `core.highlights`. It links to `Normal` by default
+
+Note, when `'concealcursor'` contains `"n"` This plugin will fail for the time being.
+--]]
+local nio
+local neorg = require("neorg.core")
+local module = neorg.modules.create("core.math.renderer.latex")
+
+assert(vim.re ~= nil, "Neovim 0.10.0+ is required for the `core.math.renderer.latex` module!")
+
+module.load = function()
+    nio = require("nio")
+end
+
+module.config.public = {
+    -- "Dots Per Inch" increasing this value will result in crisper images at the expense of
+    -- performance
+    dpi = 350,
+}
+
+module.private = {}
+
+---@type MathImageGenerator
+module.public = {
+    ---Returns a filepath where the rendered image sits
+    ---@async
+    ---@param snippet string the full latex snippet to convert to an image
+    ---@param foreground_color { r: number, g: number, b: number }
+    ---@return string | nil
+    async_generate_image = function(snippet, foreground_color)
+        local document_name = module.private.async_create_latex_document(snippet)
+
+        if not document_name then
+            return
+        end
+
+        local cwd = nio.fn.fnamemodify(document_name, ":h")
+        local create_dvi = nio.process.run({
+            cmd = "latex",
+            args = {
+                "--interaction=nonstopmode",
+                "--output-format=dvi",
+                document_name,
+            },
+            cwd = cwd,
+        })
+        if not create_dvi or type(create_dvi) == "string" then
+            return
+        end
+        local res = create_dvi.result()
+        if res ~= 0 then
+            return
+        end
+
+        local png_result = nio.fn.tempname()
+        png_result = ("%s.png"):format(png_result)
+
+        local fg = module.private.format_color(foreground_color)
+        local dvipng = nio.process.run({
+            cmd = "dvipng",
+            args = {
+                "-D",
+                module.config.public.dpi,
+                "-T",
+                "tight",
+                "-bg",
+                "Transparent",
+                "-fg",
+                fg,
+                "-o",
+                png_result,
+                document_name .. ".dvi",
+            },
+        })
+
+        if not dvipng or type(dvipng) == "string" then
+            return
+        end
+        res = dvipng.result()
+        if res ~= 0 then
+            return
+        end
+
+        return png_result
+    end,
+}
+
+---Writes a latex snippet to a file and wraps it with latex headers so it will render nicely
+---@async
+---@param snippet string latex snippet (if it's math it should include the surrounding $$)
+---@return string temp file path
+module.private.async_create_latex_document = function(snippet)
+    local tempname = nio.fn.tempname()
+    local tempfile = nio.file.open(tempname, "w")
+
+    local content = table.concat({
+        "\\documentclass[6pt]{standalone}",
+        "\\usepackage{amsmath}",
+        "\\usepackage{amssymb}",
+        "\\usepackage{graphicx}",
+        "\\begin{document}",
+        snippet,
+        "\\end{document}",
+    }, "\n")
+
+    tempfile.write(content)
+    tempfile.close()
+
+    return tempname
+end
+
+---Format the foreground color information into something that can be passed to the dvipng command
+---@param foreground_color {r: number, g: number, b: number}
+module.private.format_color = function(foreground_color)
+    return ("rgb %s %s %s"):format(foreground_color.r, foreground_color.g, foreground_color.b)
+end
+
+return module