I've started using draw.io [1] for diagrams I want to embed in markdown files. The cool feature about draw.io is that it can embed the data structure describing the diagram in a png file. So you get a PNG file that is both source code for your diagram (so you can edit it later), as well as the presentation (you can embed png files and they will render fine in Github hosted md files).

Then I use the markdown-images package [2] for Sublime Text, and I can see those png images in my markdown files in the editor as well.

Benefits of this approach:

* Powerful diagram editor, free to use.

* Editable diagram and embedable image in one file.

* Diagrams rendered in text editor.

[1] https://github.com/jgraph/drawio-desktop

[2] https://packagecontrol.io/packages/Markdown%20Images

The method I've considered: add a separate .mermaid file, render it as a png or svg file, and put that in the markdown file.

Looks like there is an open feature request on GitHub for supporting Mermaid charts: https://github.community/t/feature-request-support-mermaid-m...

You could publish "html" that is actually http://casual-effects.com/markdeep/

I tend to prefer diagrams as code, so yoi can just embed an image that be updated, version controlled, etc, instead of ascii diagrams. Any reason in particular you want ascii instead of images?

I always just use ASCII art in code blocks.