mcp-pandoc-md2pptx

--[[ diagram – create images and figures from code blocks. See copyright notice in file LICENSE. ]] -- The filter uses the Figure AST element, which was added in pandoc 3. PANDOC_VERSION:must_be_at_least '3.0' local version = pandoc.types.Version '1.2.0' -- Report Lua warnings to stderr if the `warn` function is not plugged into -- pandoc's logging system. if not warn then -- fallback warn = function(...) io.stderr:write(table.concat({ ... })) end elseif PANDOC_VERSION < '3.1.4' then -- starting with pandoc 3.1.4, warnings are reported to pandoc's logging -- system, so no need to print warnings to stderr. warn '@on' end local io = require 'io' local pandoc = require 'pandoc' local system = require 'pandoc.system' local utils = require 'pandoc.utils' local List = require 'pandoc.List' local stringify = utils.stringify local with_temporary_directory = system.with_temporary_directory local with_working_directory = system.with_working_directory --- Returns a filter-specific directory in which cache files can be --- stored, or nil if no such directory is available. local function cachedir () local cache_home = os.getenv 'XDG_CACHE_HOME' if not cache_home or cache_home == '' then local user_home = system.os == 'windows' and os.getenv 'USERPROFILE' or os.getenv 'HOME' if not user_home or user_home == '' then return nil end cache_home = pandoc.path.join{user_home, '.cache'} or nil end -- Create filter cache directory return pandoc.path.join{cache_home, 'pandoc-diagram-filter'} end --- Path holding the image cache, or `nil` if the cache is not used. local image_cache = nil local mimetype_for_extension = { jpeg = 'image/jpeg', jpg = 'image/jpeg', pdf = 'application/pdf', png = 'image/png', svg = 'image/svg+xml', } local extension_for_mimetype = { ['application/pdf'] = 'pdf', ['image/jpeg'] = 'jpg', ['image/png'] = 'png', ['image/svg+xml'] = 'svg', } --- Converts a list of format specifiers to a set of MIME types. local function mime_types_set (tbl) local set = {} local mime_type for _, image_format_spec in ipairs(tbl) do mime_type = mimetype_for_extension[image_format_spec] or image_format_spec set[mime_type] = true end return set end --- Reads the contents of a file. local function read_file (filepath) local fh = io.open(filepath, 'rb') local contents = fh:read('a') fh:close() return contents end --- Writes the contents into a file at the given path. local function write_file (filepath, content) local fh = io.open(filepath, 'wb') fh:write(content) fh:close() end --- Like `pandoc.pipe`, but allows "multi word" paths: -- Supplying a list as the first argument will use the first element as -- the executable path and prepend the remaining elements to the list of -- arguments. local function pipe (command, args, input) local cmd if pandoc.utils.type(command) == 'List' then command = command:map(stringify) cmd = command:remove(1) args = command .. args else cmd = stringify(command) end return pandoc.pipe(cmd, args, input) end -- -- Diagram Engines -- -- PlantUML engine; assumes that there's a `plantuml` binary. local plantuml = { line_comment_start = [[']], mime_types = mime_types_set{'pdf', 'png', 'svg'}, compile = function (self, puml) local mime_type = self.mime_type or 'image/svg+xml' -- PlantUML format identifiers correspond to common file extensions. local format = extension_for_mimetype[mime_type] if not format then format, mime_type = 'svg', 'image/svg+xml' end local args = {'-t' .. format, "-pipe", "-charset", "UTF8"} return pipe(self.execpath or 'plantuml', args, puml), mime_type end, } --- GraphViz engine for the dot language local graphviz = { line_comment_start = '//', mime_types = mime_types_set{'jpg', 'pdf', 'png', 'svg'}, mime_type = 'image/svg+xml', compile = function (self, code) local mime_type = self.mime_type -- GraphViz format identifiers correspond to common file extensions. local format = extension_for_mimetype[mime_type] if not format then format, mime_type = 'svg', 'image/svg+xml' end return pipe(self.execpath or 'dot', {"-T"..format}, code), mime_type end, } --- Mermaid engine local mermaid = { line_comment_start = '%%', mime_types = mime_types_set{'pdf', 'png', 'svg'}, compile = function (self, code) local mime_type = self.mime_type or 'image/svg+xml' local file_extension = extension_for_mimetype[mime_type] return with_temporary_directory("diagram", function (tmpdir) return with_working_directory(tmpdir, function () local infile = 'diagram.mmd' local outfile = 'diagram.' .. file_extension write_file(infile, code) pipe( self.execpath or 'mmdc', {"--pdfFit", "--input", infile, "--output", outfile}, '' ) return read_file(outfile), mime_type end) end) end, } --- TikZ -- --- LaTeX template used to compile TikZ images. local tikz_template = pandoc.template.compile [[ \documentclass{standalone} \usepackage{tikz} $for(header-includes)$ $it$ $endfor$ $additional-packages$ \begin{document} $body$ \end{document} ]] --- The TikZ engine uses pdflatex to compile TikZ code to an image local tikz = { line_comment_start = '%%', mime_types = { ['application/pdf'] = true, }, --- Compile LaTeX with TikZ code to an image compile = function (self, src, user_opts) return with_temporary_directory("tikz", function (tmpdir) return with_working_directory(tmpdir, function () -- Define file names: local file_template = "%s/tikz-image.%s" local tikz_file = file_template:format(tmpdir, "tex") local pdf_file = file_template:format(tmpdir, "pdf") -- Treat string values as raw LaTeX local meta = { ['header-includes'] = user_opts['header-includes'], ['additional-packages'] = {pandoc.RawInline( 'latex', stringify(user_opts['additional-packages'] or '') )}, } local tex_code = pandoc.write( pandoc.Pandoc({pandoc.RawBlock('latex', src)}, meta), 'latex', {template = tikz_template} ) write_file(tikz_file, tex_code) -- Execute the LaTeX compiler: local success, result = pcall( pipe, self.execpath or 'pdflatex', { '-interaction=nonstopmode', '-output-directory', tmpdir, tikz_file }, '' ) if not success then warn(string.format( "The call\n%s\nfailed with error code %s. Output:\n%s", result.command, result.error_code, result.output )) end return read_file(pdf_file), 'application/pdf' end) end) end } --- Asymptote diagram engine local asymptote = { line_comment_start = '%%', mime_types = { ['application/pdf'] = true, }, compile = function (self, code) return with_temporary_directory("asymptote", function(tmpdir) return with_working_directory(tmpdir, function () local pdf_file = "pandoc_diagram.pdf" local args = {'-tex', 'pdflatex', "-o", "pandoc_diagram", '-'} pipe(self.execpath or 'asy', args, code) return read_file(pdf_file), 'application/pdf' end) end) end, } --- Cetz diagram engine local cetz = { line_comment_start = '%%', mime_types = mime_types_set{'jpg', 'pdf', 'png', 'svg'}, mime_type = 'image/svg+xml', compile = function (self, code) local mime_type = self.mime_type local format = extension_for_mimetype[mime_type] if not format then format, mime_type = 'svg', 'image/svg+xml' end local preamble = [[ #import "@preview/cetz:0.3.4" #set page(width: auto, height: auto, margin: .5cm) ]] local typst_code = preamble .. code return with_temporary_directory("diagram", function (tmpdir) return with_working_directory(tmpdir, function () local outfile = 'diagram.' .. format local execpath = self.execpath if not execpath and quarto and quarto.version >= '1.4' then -- fall back to the Typst exec shipped with Quarto. execpath = List{'quarto', 'typst'} end pipe( execpath or 'typst', {"compile", "-f", format, "-", outfile}, typst_code ) return read_file(outfile), mime_type end) end) end, } local default_engines = { asymptote = asymptote, dot = graphviz, mermaid = mermaid, plantuml = plantuml, tikz = tikz, cetz = cetz, } -- -- Configuration -- --- Options for the output format of the given name. local function format_options (name) local pdf2svg = name ~= 'latex' and name ~= 'context' local is_office_format = name == 'docx' or name == 'odt' -- Office formats seem to work better with PNG than with SVG. local preferred_mime_types = is_office_format and pandoc.List{'image/png', 'application/pdf'} or pandoc.List{'application/pdf', 'image/png'} -- Prefer SVG for non-PDF output formats, except for Office formats if is_office_format then preferred_mime_types:insert('image/svg+xml') elseif pdf2svg then preferred_mime_types:insert(1, 'image/svg+xml') end return { name = name, pdf2svg = pdf2svg, preferred_mime_types = preferred_mime_types, best_mime_type = function (self, supported_mime_types, requested) return self.preferred_mime_types:find_if(function (preferred) return supported_mime_types[preferred] and (not requested or (pandoc.utils.type(requested) == 'List' and requested:includes(preferred)) or (pandoc.utils.type(requested) == 'table' and requested[preferred]) or -- Assume string, Inlines, and Blocks values specify the only -- acceptable MIME type. stringify(requested) == preferred) end) end } end --- Returns a configured diagram engine. local function get_engine (name, engopts, format) local engine = default_engines[name] or select(2, pcall(require, stringify(engopts.package))) -- Sanity check if not engine then warn(PANDOC_SCRIPT_FILE, ": No such engine '", name, "'.") return nil elseif engopts == false then -- engine is disabled return nil elseif engopts == true then -- use default options return engine end local execpath = engopts.execpath or os.getenv(name:upper() .. '_BIN') local mime_type = format:best_mime_type( engine.mime_types, engopts['mime-type'] or engopts['mime-types'] ) if not mime_type then warn(PANDOC_SCRIPT_FILE, ": Cannot use ", name, " with ", format.name) return nil end return { execpath = execpath, compile = engine.compile, line_comment_start = engine.line_comment_start, mime_type = mime_type, opt = engopts or {}, } end --- Returns the diagram engine configs. local function configure (meta, format_name) local conf = meta.diagram or {} local format = format_options(format_name) meta.diagram = nil -- cache for image files if conf.cache then image_cache = conf['cache-dir'] and stringify(conf['cache-dir']) or cachedir() pandoc.system.make_directory(image_cache, true) end -- engine configs local engine = {} for name, engopts in pairs(conf.engine or default_engines) do engine[name] = get_engine(name, engopts, format) end return { engine = engine, format = format, cache = image_cache and true, image_cache = image_cache, } end -- -- Format conversion -- --- Converts a PDF to SVG. local pdf2svg = function (imgdata) -- Using `os.tmpname()` instead of a hash would be slightly cleaner, but the -- function causes problems on Windows (and wasm). See, e.g., -- https://github.com/pandoc-ext/diagram/issues/49 local pdf_file = 'diagram-' .. pandoc.utils.sha1(imgdata) .. '.pdf' write_file(pdf_file, imgdata) local args = { '--export-type=svg', '--export-plain-svg', '--export-filename=-', pdf_file } return pandoc.pipe('inkscape', args, ''), os.remove(pdf_file) end local function properties_from_code (code, comment_start) local props = {} local pattern = comment_start:gsub('%p', '%%%1') .. '| ' .. '([-_%w]+): ([^\n]*)\n' for key, value in code:gmatch(pattern) do if key == 'fig-cap' then props['caption'] = value else props[key] = value end end return props end local function diagram_options (cb, comment_start) local attribs = comment_start and properties_from_code(cb.text, comment_start) or {} for key, value in pairs(cb.attributes) do attribs[key] = value end local alt local caption local fig_attr = {id = cb.identifier} local filename local image_attr = {} local user_opt = {} for attr_name, value in pairs(attribs) do if attr_name == 'alt' then alt = value elseif attr_name == 'caption' then -- Read caption attribute as Markdown caption = attribs.caption and pandoc.read(attribs.caption).blocks or nil elseif attr_name == 'filename' then filename = value elseif attr_name == 'label' then fig_attr.id = value elseif attr_name == 'name' then fig_attr.name = value else -- Check for prefixed attributes local prefix, key = attr_name:match '^(%a+)%-(%a[-%w]*)$' if prefix == 'fig' then fig_attr[key] = value elseif prefix == 'image' or prefix == 'img' then image_attr[key] = value elseif prefix == 'opt' then user_opt[key] = value else -- Use as image attribute image_attr[attr_name] = value end end end return { ['alt'] = alt or (caption and pandoc.utils.blocks_to_inlines(caption)) or {}, ['caption'] = caption, ['fig-attr'] = fig_attr, ['filename'] = filename, ['image-attr'] = image_attr, ['opt'] = user_opt, } end local function get_cached_image (hash, mime_type) if not image_cache then return nil end local filename = hash .. '.' .. extension_for_mimetype[mime_type] local imgpath = pandoc.path.join{image_cache, filename} local success, imgdata = pcall(read_file, imgpath) if success then return imgdata, mime_type end return nil end local function cache_image (codeblock, imgdata, mimetype) -- do nothing if caching is disabled or not possible. if not image_cache then return end local ext = extension_for_mimetype[mimetype] local filename = pandoc.sha1(codeblock.text) .. '.' .. ext local imgpath = pandoc.path.join{image_cache, filename} write_file(imgpath, imgdata) end -- Executes each document's code block to find matching code blocks: local function code_to_figure (conf) return function (block) -- Check if a converter exists for this block. If not, return the block -- unchanged. local diagram_type = block.classes[1] if not diagram_type then return nil end local engine = conf.engine[diagram_type] if not engine then return nil end -- Unified properties. local dgr_opt = diagram_options(block, engine.line_comment_start) for optname, value in pairs(engine.opt or {}) do dgr_opt.opt[optname] = dgr_opt.opt[optname] or value end local run_pdf2svg = engine.mime_type == 'application/pdf' and conf.format.pdf2svg -- Try to retrieve the image data from the cache. local imgdata, imgtype if conf.cache then imgdata, imgtype = get_cached_image( pandoc.sha1(block.text), run_pdf2svg and 'image/svg+xml' or engine.mime_type ) end if not imgdata or not imgtype then -- No cached image; call the converter local success success, imgdata, imgtype = pcall(engine.compile, engine, block.text, dgr_opt.opt) -- Bail if an error occurred; imgdata contains the error message -- when that happens. if not success then warn(PANDOC_SCRIPT_FILE, ': ', tostring(imgdata)) return nil elseif not imgdata then warn(PANDOC_SCRIPT_FILE, ': Diagram engine returned no image data.') return nil elseif not imgtype then warn(PANDOC_SCRIPT_FILE, ': Diagram engine did not return a MIME type.') return nil end -- Convert SVG if necessary. if imgtype == 'application/pdf' and conf.format.pdf2svg then imgdata, imgtype = pdf2svg(imgdata), 'image/svg+xml' end -- If we got here, then the transformation went ok and `img` contains -- the image data. cache_image(block, imgdata, imgtype) end -- Use the block's filename attribute or create a new name by hashing the -- image content. local basename, _extension = pandoc.path.split_extension( dgr_opt.filename or pandoc.sha1(imgdata) ) local fname = basename .. '.' .. extension_for_mimetype[imgtype] -- Store the data in the media bag: pandoc.mediabag.insert(fname, imgtype, imgdata) -- Create the image object. local image = pandoc.Image(dgr_opt.alt, fname, "", dgr_opt['image-attr']) -- Create a figure if the diagram has a caption; otherwise return -- just the image. return dgr_opt.caption and pandoc.Figure( pandoc.Plain{image}, dgr_opt.caption, dgr_opt['fig-attr'] ) or pandoc.Plain{image} end end return setmetatable( {{ Pandoc = function (doc) local conf = configure(doc.meta, FORMAT) return doc:walk { CodeBlock = code_to_figure(conf), } end }}, { version = version, } )