extensions with custom rendering of documents

[milahu]

continue #10696 (comment)

I think if Zed starts trying to support things like this themselves, there will be a never-ending stream of custom rendering features requested, until one day Markdown rendering will basically require implementing an entire browser. See also #30264. Some of them might be useful, but I suggest instead allowing extensions to provide custom rendering support. Providing some way for extensions to provide custom rendering might even allow proof assistants like Lean or Rocq/Coq to be used with Zed, which would be amazing.

VSCode calls this Custom Editor API

Custom editors allow extensions to create fully customizable read/write editors that are used in place of VS Code's standard text editor for specific types of resources. They have a wide variety of use cases, such as:

• Previewing assets, such as shaders or 3D models, directly in VS Code.
• Creating WYSIWYG editors for languages such as Markdown or XAML.
• Offering alternative visual renderings for data files such as CSV or JSON or XML.
• Building fully customizable editing experiences for binary or text files.

VS Code API Usage

• window.registerCustomEditorProvider
• CustomTextEditorProvider

in the spirit of Zed editor (high performance), this custom rendering feature
should not be limited by some high-level (html/javascript) webview renderer
but extensions should be able to use high-performance native rendering
probably down to direct OpenGL API calls
(Qt has QOpenGLBuffer and QVulkanWindow)

with this custom rendering feature, it should be possible for extensions
to either fully replace the main code editor
or to create extra panels next to the main code editor (split view, sidebar)

related

• WYSIWYG Markdown Preview #21717

[kochetkov-av]

Great suggestion! I’m quite new to the Zed editor — it looks really promising, blazing fast, and its AI integration is impressive.
I’ve used JetBrains products for years, and I was surprised that Zed doesn’t yet support rendering for diagrams (Mermaid, PlantUML), images, etc. OpenAPI rendering is also missing, among other things.
Most extensions only provide syntax highlighting or a theme.
My guess is that this has to do with Zed’s decision not to include browser/JavaScript embedding? That would obviously slow things down, but it’s really useful — and it could be left up to the user to decide whether to use such extensions.

[nahuel]

Please consider (also) a middle ground. Having some kind of WYSIWYM rich text common support can make extensions much simpler than requiring every extension to implement a full custom render. By adding support to Zed core for a simple set of:

• Images standalone / embedded in text
• Text attributes like bold/italic/etc
• Different text sizes (e.g.) for headings/subscript/superscript
• Simple tables
• Ideally, proportional fonts.

In a WYSIWYM editable way, a long list of use cases would be covered and be easily implemented by extensions. E.g., something like typora.io would be easily reimplemented. Also by supporting embedded images an extension could implement LaTeX fragments edition/preview like Emacs does (see https://youtu.be/n-AfvuV-bYo?t=339 )

You usually don't need to see the final product while editing, but you need an approximate version of it instead of looking always at the entire raw markup noise. Supporting rich text / images / tables can be a massive improvement for editing over raw text, without requiring extensions to implement/embed/use a full WebView HTML render or use low level OpenGL API calls.

We need to go beyond of having an edit panel plus a preview panel, it's very primitive. Note that even a terminal based editor like neovim is starting to implement similar features: https://github.com/Thiago4532/mdmath.nvim / https://github.com/MeanderingProgrammer/render-markdown.nvim , and also that the Emacs GUI renderer already implements most of those rich text features (but not tables) although with some brokenness (e.g. scrolling is janky for big images).

[cadojo]

Would this require a new extension type? I've seen one extension which add parts of a full WYSIWYG feature set for Markdown, MermaidJS, but that extension requires writing into multiple buffers to allow the Markdown Preview to work properly. Is that an indication that, for an extension to provide a full WYSIWYG Markdown editing experience, a new extension type is needed?

For reference, I'd love to use something like the Quarto Visual Editor in VSCode in Zed.