DopusWorX

A document viewer and in-place editor that lives inside Directory Opus.

Markdown, maths, diagrams, code, CSV, HTML and binary files, rendered and editable right in the Opus viewer pane.

DopusWorX in action

Get the plugin from the Releases Page

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What it is

A native Directory Opus viewer plugin: a Windows DLL that renders documents in the Opus viewer pane, the pop-out viewer window, and QuickShow popups. It is not a separate app; it loads inside Opus and uses the Microsoft Edge WebView2 runtime to draw itself.

Under the hood it is two layers, not just a web page in a window. The plugin itself is a native C++ viewer DLL built against the Directory Opus plugin SDK, which is why it works in the viewer pane, the pop-out viewer and QuickShow rather than as a standalone window. WebView2 is only the surface it draws on: inside it, CodeMirror and its Lezer grammars drive the source and editing views across around 150 languages, markdown-it parses the Markdown, KaTeX and Temml draw the maths, and Mermaid draws the diagrams. The hex inspector, the CSV grid, the spell check and the theming are all written for this.

It is file-type aware: open a file and DopusWorX picks the right view for it.

Markdown gets Reading, Live and Source, with a split preview, and renders maths (LaTeX / AsciiMath) and Mermaid diagrams inline.
Source-code files open in Source view with syntax highlighting (around 150 languages).
CSV / TSV open as an editable grid.
HTML renders as its own page, with a Source view and a split.
Binary files open in a hex inspector (offset / hex / ASCII with a data inspector), with an opt-in byte editor.

Reading, Live and Source

For a Markdown document there are three ways to look at it:

Reading is the finished, fully rendered page.
Live renders the page too, but the moment your cursor lands on a line the formatting marks for that line come back, so you can edit without dropping out of the rendered view.
Source is the raw text. Click Source a second time and it splits: raw on the left, live preview on the right, with a draggable divider you can slide to resize the panes, and a toggle to link or unlink their scrolling.

You pick which of these a Markdown file opens in under Settings (Open markdown in: Reading, Live or Source). DopusWorX also remembers the view you last used for each file, and you can keep that always, turn it off, or have it expire after anything from five minutes to a year.

Reading Live

The split view. Click Source a second time and the pane splits down the middle: the raw Markdown on the left, the live preview on the right, with a divider you can drag to resize the two panes and a button to link or unlink their scrolling.

A full formatting toolbar sits underneath: bold, italic, strikethrough, highlight, inline code, links, footnotes, clear formatting, a heading button that cycles H1 to H6, bulleted, numbered and task lists, indent and outdent, blockquotes, fenced code, image insert, and a table insert with a size grid. Find and replace handles case, whole word and regex, and Ctrl+G jumps to a line. There is undo and redo with a history dropdown, and a live word, character and line count.

Insert a Table of Contents that keeps itself up to date as you edit (list style and title style are configurable in Settings), and fold whole heading sections away with the fold glyph in the margin.

Spell check underlines misspellings as you type in Live and Source, skipping code, links and URLs; English (US) is built in and more than fifty other dictionaries download once and are cached offline.

A right-click menu is there throughout, and you do not need a mouse for it: open it from the keyboard and the arrows move, Home and End jump, Enter or Space activate, and Escape closes; on a touchscreen a press and hold opens it. Press F1 anywhere (or ? in Reading) for a pop-up guide to every keyboard shortcut; it is also in the right-click menu. Markdown documents (and CSV tables) can be printed or saved as a PDF of the whole rendered document, colours and all, from the right-click menu. The Print option is also in the Save menu for every file type. Ctrl+P works from anywhere in the viewer. See docs/06-context-menus.md for the full set.

The viewer keeps a back/forward history of the files it has shown - step through it with the mouse back and forward buttons or Ctrl+Alt+Left/Right, browser-style.

Maths

Write it in LaTeX or AsciiMath, inline with $...$ , on its own line with $$...$$, or as an ```am block.
Auto-render reads each equation on its own and works out which style you used, so you can mix the two in one note and not think about it.
The symbol panel (Σ) lets you browse symbols by category and drop them in. It inserts to match your Maths syntax setting: \alpha in LaTeX and Auto-render, alpha in AsciiMath.
Click into a rendered equation and the source comes back; click away and it redraws. A live preview shows the equation under your cursor, and a convert button rewrites it from one style to the other in place.
Slanted fractions (\sfrac, \nicefrac), eight maths fonts, and a choice of KaTeX or Temml as the engine.
Define your own macros, either typed into Settings or kept in a file, so your usual shorthands work everywhere.

Prices are safe: $5 stays as text, and \$ gives you a literal dollar sign. The maths engine only loads on notes that actually contain equations, so plain notes stay quick. See docs/04-maths.md for the full guide.

Diagrams

Turn a fenced ```mermaid block into a flowchart, sequence, class, state, ER, pie, Gantt or any other Mermaid diagram type, drawn from plain text with Mermaid. On by default; the ~3 MB engine loads only on a note that actually contains a diagram.

Diagrams draw in Reading and Live. In Live, click a diagram to bring its source back, edit it, and click away to redraw.
Match page colours diagrams from your active palette, so they match the document and stay readable in light and dark. Or pin a fixed Mermaid theme.
A hand-drawn style, a flowchart edge shape, a diagram font and size (the font can follow the body font or stand on its own), optional label wrapping and sequence numbering, and a max-connections guard for very large diagrams.
A broken diagram shows a ⚠ box with its source and the reason, never taking the rest of the note down with it.

DopusWorX draws the diagram inline. With Match page the same diagram takes its colours from the active palette, so it suits a dark page or a light one:

Dark palette Light palette

See docs/08-mermaid.md for the full guide, with a live example of every diagram type.

Code and source files

Source-code files open in Source view (there is no Reading or Live mode for code, since there is nothing to render).

Syntax highlighting for around 150 languages (the common ones bundled, the rest loaded on demand), with a line-number gutter, a word-wrap toggle and a configurable tab width.
A copy button, an optional active-line highlight (with a magnify option that lifts the line you are on), and a code-theme picker that is independent of the page palette.
Colour values get a swatch and a colour picker, and diff and patch files colour their added and removed lines.

Code files are fully editable, with a code-editing toolbar: toggle comments in the file's own comment style, duplicate a line, move lines up or down, and indent or outdent. Click or drag line numbers to select whole lines, and Ctrl-click to build a multi-cursor selection.

Fenced code blocks inside a Markdown document are highlighted in every Markdown mode.

Binary files

A file that is binary rather than text opens in a hex inspector: an offset / hex / ASCII view with a side panel that reads the bytes under the cursor as integers and floats. You can select byte ranges, jump to an offset, search for hex or text, and copy as hex or text. An opt-in setting turns on byte editing, and any file can be forced open with View as hex from the right-click menu. See docs/09-binary-inspector.md.

CSV and tables

CSV and TSV open as an editable grid: click a header to sort, double-click a cell to edit, add or delete rows and columns with undo and redo, select and paste blocks of cells, filter, freeze the first column, override the delimiter, and copy the whole thing out as a Markdown table. Column widths, delimiter and zoom are remembered per file, and an untouched file saves back byte-for-byte identical.

HTML

HTML files have a rendered View, a Source view of the raw markup, and a split that shows both at once.

Rendered view View / Source split

Themes and palettes

Thirty built-in palettes, dark and light, from Dracula and Nord to Catppuccin, Everforest and Rosé Pine, alongside the signature ProWorX and GloWorX. By default a palette follows the Opus pane background automatically; you can pin one instead.

Nothing is locked down. The visual editor lets you change any colour and save it as your own named theme. Bold, italic, strikethrough and inline code each get their own colour, headings can be coloured per level, and the page surface, rules, borders and shadows are all yours to tune. See docs/07-palettes.md for a card of every palette.

Markdown extras and Obsidian syntax

Full GitHub-flavoured Markdown: tables, task lists (tick the boxes in Reading or Live), footnotes editable in place, definition lists, abbreviations, mark/highlight, and sub/superscript.

Obsidian-style linking and embeds work too:

[[note]] wiki-links, including [[note#heading]] and [[note|alias]].
![[note]] transclusion and ![[image.png]] image embeds.
The Obsidian image alt syntax for size and alignment: ![alt|400](path) and ![alt|400x300|center](path). Relative paths and Windows absolute paths resolve. This works inside table cells too, with the plain pipe and no escaping, e.g. | ![logo|72|center](path) |.

Frontmatter and the banner image

Add a banner: line to the YAML frontmatter at the top of any note and DopusWorX renders that image as a full-width strip across the top of the document. In Reading mode the frontmatter block is hidden entirely; in Live mode it shows as the banner image from the moment the file opens - click it and the raw YAML comes back for editing, move away and the banner renders again.

Right-click any markdown document and choose Set banner image to search for a picture without leaving the app: type a word, press Enter, and click a result. In the picker, drag the preview strip up or down to choose the vertical crop and set a pixel height for this file alone, then click Set. DopusWorX writes the banner:, banner_y: and banner_height: frontmatter for you. The global banner height is set in Settings under Content › Images.

Customise it to your liking

The Settings dialog is organised into clear tabs, Appearance, Content, Toolbars, File types and About, with live preview and a plain-language note on each option. The Content tab groups its options by concern, Opening & views, File reading & saving, Markdown rendering, Images, Code & source files, Diagrams, then Maths. Among the things you can change:

Auto-hiding toolbars. Set the top toolbar or the formatting toolbar to slide away and reappear when you reach for them, so the document gets the whole pane.
Toolbar layout. Drag the formatting buttons into the order you want, or hide the ones you never use.
File types. Decide which extensions DopusWorX handles. Pane previews a type in the viewer pane while browsing (double-click left alone); DOpus also opens it in the DopusWorX window on double-click inside Opus; Explorer also associates it with Windows so it opens from Explorer even when Opus is closed. A Highlight Grammar column sets which grammar each type uses, so you can open .tpl as C++ or map any type to any of the supported languages.
Maths macros, fonts and engine, encoding and fallback codepage, image search folders, auto-save, separate left and right page margins, gutters, formatting marks, and the full type and colour controls behind the palettes.

Zoom any view from 50% to 300% with Ctrl and the scroll wheel or a trackpad pinch (or the right-click Zoom submenu); each view keeps its own level and the toolbars stay put.

Careful with your files

A viewer that edits your files has to be careful with them, and a lot of the work here went into exactly that.

Your edits survive. Writes are atomic (a temp file, flushed, then a single atomic replace), so a file is never left half-written. An empty buffer will not overwrite a file that has content. If Opus closes or crashes with unsaved work, a recovery copy is kept under AppData and offered back when you reopen.
No silent overwrites. If a file changes on disk while you are editing, DopusWorX notices, and tells the difference between a real change and a harmless touch by comparing the content, not just the timestamp. You get a clear choice: keep your edits, save a copy, or reload.
Remote images stay private. Off by default, an image referenced by an http(s) URL renders as a placeholder and makes no network request at all, so a remote server cannot learn you opened a document that points at it.
A hardened updater. The in-app updater talks HTTPS only, checks every redirect against an anchored allowlist of the real release hosts (so a look-alike domain gets nowhere), and refuses to install anything whose SHA256 does not match the published hash.
Tidy on your system. The viewer DLL writes a single HKCU registry value (LastPaneBg under HKCU\Software\HyperWorX\DopusWorX) to remember the Directory Opus pane background colour across restarts; beyond that it writes nothing to the registry. Its settings, themes and cache all live under your profile.

Staying up to date

DopusWorX checks for new releases from inside Settings and can fetch and install an update for you, gated by the security checks above. Releases are published on the Releases page.

Documentation

For more detail than this page covers:

Getting started - the basics, end to end.
File types and views - what each kind of file does, and how DopusWorX is file-type aware.
Editing - the modes, the formatting toolbar, find and replace, and saving.
Maths - LaTeX, AsciiMath, the symbol panel, fonts and macros.
Diagrams - Mermaid flowcharts, sequence, class, state and more, plus the diagram settings.
CSV grids - sorting, in-cell editing, filtering, freezing, delimiters and more.
Context menus - the right-click menus, driven by keyboard or touch as well as mouse, and the Save menu.
Palettes - every built-in palette and the Appearance settings.
Binary inspector - the hex view, the data inspector and the opt-in byte editor.

Installation

Download DopusWorX_v_Setup.exe from the Releases page and run it. One UAC prompt and it does the rest: closes Directory Opus, installs the plugin into the Opus Viewers folder, and starts Opus again. It registers in Apps & features, so removing it later is the normal Windows uninstall. Windows may show a SmartScreen prompt the first time, as it does for any new unsigned download - More info, then Run anyway.

Prefer a zip? DopusWorX_v.zip on the same page holds the identical plugin with plain Install.cmd and Uninstall.cmd scripts you can read before you run them. Extract it anywhere, run Install.cmd, accept the UAC prompt.

For an unattended or scripted install, the setup exe takes /VERYSILENT, and the zip scripts take /silent (or /quiet).

Requirements: Windows x64, Directory Opus 13 or later, and the Microsoft Edge WebView2 runtime. WebView2 is already on most up-to-date Windows installs; if it is missing, DopusWorX shows a download link in the pane.

Opening Markdown on double-click

Out of the box Opus opens a .md file with whatever Windows has associated. To open it in the DopusWorX viewer instead, point the Markdown file type's Left double-click event at the Show command under Settings ▸ File types (covering md markdown mdown mdwn mkd mkdn). The File types panel in the DopusWorX settings can set this up for you.

Where your data lives

Settings: %APPDATA%\HyperWorX\DopusWorX\settings.json
Custom themes: %APPDATA%\HyperWorX\DopusWorX\themes\.json
WebView2 cache: %LOCALAPPDATA%\HyperWorX\DopusWorX\

Try it

The samples/ folder has sample documents. Start with dopusworx.md, a single manual and exhibition of the Markdown and maths features, then open the CSV, code, HTML and multilingual files beside it so every view has something to show straight away.

Support

If you find this useful, you can buy me a coffee.

Licence

Directory Opus is a trademark of GP Software. DopusWorX is an independent plugin, not affiliated with or endorsed by GP Software.

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README