Show HN: GUI for editing Mermaid class diagrams

[MarkMarine]

My front end to mermaid is usually claude. I can’t count how many times trying to convey a complicated idea (last week, a one time use token in a 3 party where my backend can’t talk to the client) has been made simple to explain with a quick diagram claude made.

I am a paid mermaid account holder but claude is still my first front end, because it’s the tool I’m in most of the time anyway. What I’m excited for in the GUI is I can take that quick diagram and add the styling, colors, and hopefully move some of the boxes around such that the arrows are better than the auto layout drops them.

From reading the blog post, the first thing I’d like which is changing the visual colors and styling of individual boxes in the diagram might be missed. I find that the most time consuming thing to do manually with the code, I would love to see rich tools there.

[specialist]

Very interesting. Any hiccups?

I just tried this last week for the first time. I asked claude to create a syntax diagram for a toy grammar. The resulting mermaid source had a syntax error (unescaped special character). Despite having its own mermaid widget thingie, I couldn't compel claude to fix its own code.

[dominicdewalt]

Hi all, I'm Dominic and I'm on the product team at Mermaid. I enjoyed reading a lot of your feedback!

It seems there's several good ideas and thoughts on the direction of the platform that we'd love to learn more about. If you have problems with the current product, improvement requests, or would like to chat then let's connect! Please email me at [e-mail] or book time on my calendar: (https://calendly.com/dominic-01w/mermaid-shapers-product-int...)

Thanks for taking a look at our latest release!

[thangalin]

Any idea when Mermaid diagrams will render outside of web browsers?

https://github.com/mermaid-js/mermaid/issues/2485

<rant> Aside, I'm the author of KeenWrite (https://keenwrite.com/), a Markdown text editor that allows embedding diagrams using the triple-backtick syntax. Here's a GraphViz example:

    ``` diagram-graphviz
    digraph {
        rankdir="LR";
        a -> b -> c;
    }
    ```

KeenWrite parses the `diagram-` prefix then passes the word `graphviz` to Kroki (https://kroki.io/), which has an API for rendering a variety of ASCII diagrams, including Mermaid. Meaning, if Kroki adds a new diagram type, KeenWrite gets it for free (without modification).

In Markdown, formatting a source code snippet entails using the standard syntax for code blocks:

    ``` graphviz
    digraph {
        rankdir="LR"
        a -> b -> c;
    }
    ```

GitHub created a de facto standard for Mermaid diagrams that breaks the convention of having triple-backticks followed by a language identifier to show the source code for that language in a monospace font. This was an unfortunate decision. </rant>

[baobun]

Hello Dominic.

Seconding the question on browserless rendering in the other comment. Having to (unseccessfully for us so far; the text renders incorrectly) tweak selenium setups to do headless builds is madness and I would have thought this to be top prio as a base feature beyond PoC for anything aiming for wide adoption.

[jb3689]

I’d like to see better controls for keeping diagram components from colliding. I’m sure that’s a nontrivial ask, but I run into poorly placed components quite frequently, and I feel like that’d be a major selling point for Mermaid for me if you could solve it

[philfreo]

I spent some time playing around with this recently and loved it at first. I also realized ChatGPT is pretty good at generating Mermaid diagrams (didn't try your own AI features).

However after getting into it some I ran into some significant frustrations. After creating a medium-complexity diagram, I was excited to see the Whiteboard feature to drag things around / improve the layout manually. But it really started breaking, it just wouldn't let me organize/drag things where I wanted, and I couldn't get things to not overlap. I also wished more diagram types supported Whiteboard (I noticed some didn't).

Also I some confusion between the capabilities of mermaidchart.com and mermaid.live. Are these competitors? Variations of similar apps. I was confused. Also "Playground" vs "Live Editor" is confusing.

Overall glad this exists and hope it continues to improve.

[AFirestone]

Hi there, Mermaid CEO here:)

I hear you on the whiteboard. It's still in its early days. Should be substantially improved in the coming months.

To clarify on mermaidchart.com and mermaid.live, we are the same team. Mermaid.live is our fully open source hosted editor. This was the original editor for our 10 year old open source project. The creator of Mermaid recently founded mermaidchart.com with the CEO of Gitlab's venture studio to expand the capabilities of Mermaid for more users and build an enterprise grade product. The company is open core and venture backed. The Mermaid project will remain forever open source and will continue to invest in growing it and the company for those that desire more advanced business features.

We really appreciate your feedback and support. Ping me if you'd like to chat with our product team about the features you're hoping for:) [e-mail]

[LordDragonfang]

> it just wouldn't let me organize/drag things where I wanted, and I couldn't get things to not overlap

I suspect this might be a fundamental issue with mermaid. I've always had issues getting it to lay things out in any other way than how it "wants" me to, with giant gaps between things

[directevolve]

I had the exact same set of issues and questions.

[Xmd5a]

I only use diagramming tools with automatic layout algos to generate visualizations programmatically to debug things. For documentation purpose, I largely prefer to draw them by hand using OmniGraffle, because making graphs look nice using tools like graphviz is very complex and you find yourself abusing features to hack your vision into reality

What's dearly needed in my opinion is a graph layout algo based on a machine learning model (so that it can take into account readability and aesthetics). Unfortunately what I found so far is mostly concerned with displaying large graphs, which is kind of another domain altogether.

I hope Mermaid is collecting every single edition point that happens on their UI, that would make for a nice dataset I guess.

[terrastruct]

We make (and sell) one, you can play with it here: https://play.d2lang.com/?script=qlDQtVOo5AIEAAD__w%3D%3D&lay...

Bigger example: https://play.d2lang.com/?script=rJLfavMwDMXv_RR6gYbvo3ce7FWG...

(I don't like to self promo on competitor posts, but since Mermaid doesn't compete in making its own layout engine I felt sharing this under this thread is relevant to HN. If anyone from Mermaid finds it in poor taste just let me know and I'll delete)

[Xmd5a]

Also, some interesting links I stumbled upon while exploring this space:

Graphviz-like generic graph-drawing library. More options, more control.

https://eclipse.dev/elk/

Experiments by the same team responsible for the development of ELK, at Kiel University

https://github.com/kieler/KLighD

Kieler project wiki

https://rtsys.informatik.uni-kiel.de/confluence/display/KIEL...

Constraint-based graph drawing libraries

https://www.adaptagrams.org/

JS implementation

https://ialab.it.monash.edu/webcola/

Some cool stuff:

HOLA: Human-like Orthogonal Network Layout

https://ialab.it.monash.edu/~dwyer/papers/hola2015.pdf

Confluent Graphs demos: makes edges more readable.

https://www.aviz.fr/~bbach/confluentgraphs/

Stress-Minimizing Orthogonal Layout of Data Flow Diagrams with Ports

https://arxiv.org/pdf/1408.4626.pdf

Improved Optimal and Approximate Power Graph Compression for Clearer Visualisation of Dense Graphs

https://arxiv.org/pdf/1311.6996v1.pdf

[dominicdewalt]

Hi! I'm Dominic from the Mermaid product team. You raise some good points here. We released the whiteboard to help users get an exact layout they'd like, but it's in its early stages and is undergoing a lot of improvements.

I understand that automatic layout algos is one of the big draws of Mermaid since it creates a lot of speed, but our current layouts can get a little convoluted. I like your idea on creating a machine learning model, but I'm curious what your biggest pain points are or if you have any basic requirements for a readable and aesthetic diagram. Is it made with hard corners on edges? Rounded?

Would love to hear any thoughts you might have on this! You can email me at [e-mail] if you'd be willing to share. Thanks for your comment!

[Koffiepoeder]

I am working on a diagramming tool that has the combination of a syntax for diagramming as code, extended with a syntax to define rendering constraints (e. g. this part of the diagram shoukd be left of this part, or this arrow must not cross this arrow). I hope this will greatly ease consistent diagram rendering and also getting the final mile pixel perfect.

Currently already have a very alpha version working of the renderer using Cassowary, and working on making a good GUI.

[webprofusion]

You lost me at Create your account. I would just want to play with the editor and store in the local browser storage until I decide I like it.

[maho]

Nice! I love how mermaid keeps getting better!

For sequence-diagrams, nothing beats https://sequencediagram.org/ (I am not connected with them in any way, just a happy user)

[brandall10]

I've used this in the past for collaborative diagramming sessions and love its ease and simplicity, but the point of Mermaid is its portability - ie. can be embedded in Markdown docs and viewed in various editors/platforms.

[dominicdewalt]

Thanks @maho! We're hoping to keep the improvements flowing. I'm non-technical but from my perspective I thought Mermaid sequence diagram functionality really shines! Would love to fill the gap in my knowledge. What is better about https://sequencediagram.org/ than Mermaid sequence diagrams?

[mlhpdx]

Agreed. I’ve tried other editors but so far I’ve always come back to sequencediagram.org — it just works, low fuss.

[sebmellen]

FWIW, I find MermaidChart's sequence diagram editor better than the sequencediagram.org one!

[tcoff91]

sequencediagram.org is using PlantUML I believe, so you can do these locally without their website.

[elashri]

I understand that it is different philosophy but I really would like to see the day when I can use Mermaid inside latex. Or at least get some robust mermaid to tikz converter. That would make my life much easy when preparing slides. I understand that exporting to PNG/JPG can work but usually you lose a lot of customization and you only know can make be bigger or smaller to fit the page.

I was exploring this yesterday and actually came acorss the new GUI that is being introduced in this submission. I ended up exporting to PNG and suffer with fitting it inside beamer page layout.

[sergius]

With Draw.io embedding Mermaid diagrams and plug-ins available for VSCode and other IDEs, why is this so special?

[akshatha1017]

Hi! I'm Akshatha from the Product team at Mermaid Chart :)

While Draw.io's integration with Mermaid and the availability of plug-ins for VSCode and other IDEs are great, they primarily support programmatic editing of diagrams. What sets Mermaid Chart apart is its bi-directional editing capability. You can edit the code to update the diagram and make changes directly to the diagram, which will automatically reflect in the code.

Currently, this two-way editing functionality is available for class diagrams and flowcharts, but we're excited to expand it to other popular diagram types in the future. Stay tuned!

[lgas]

Competition is good for innovation and choice is good for everyone. Does it need to be special?

[Celeo]

Heads up: the "Theme Customization in Toolbar" image isn't rendered.

Thanks for sharing!

[knsv]

Thanks, I uploaded it!

[crvdgc]

The project itself is cool, but I'm doubtful on the philosophical side.

Mermaid aspires to be the Markdown of diagrams, so being editable and consumable via plaintext is paramount. If I have to use a visual editor, why not fetch for more powerful tools and be liberated from the limiting format?

This is akin to a WYSIWYG Markdown editor (which to be fair has a niche market). I would ask why not just use Google Doc or MS Word at that point?

[nejsjsjsbsb]

I used this recently as someone shared a link to a diagram at work and I edited it for my own comprehension. It's nice. I'd prefer to have this in VSCode tho!

[rbanffy]

On a related subject, is there a tool to read code and generate Mermaid class diagrams, and, maybe, vice-versa?

[ConfusedDog]

That's pretty cool. Wish PlantUML community would have something like it.

[mlhpdx]

Do Mermaid class diagrams support generics (parameterized types)?

[knsv]

Yes

[tomovo]

Is there a demo available without creating an account?

[knsv]

Yes! You can use this in the free mermaid playground: https://www.mermaidchart.com/play

[sBqQu3U0wH]

Finally. I am not fond of code-to-diagram tools and wanted to try Mermaid, as it seems like one of the better diagramming tools around. Will definitely give it a try now.

[sirjaz]

This is great and all, but this would better be served as a desktop app with lower overhead.