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Comment by lovasoa | Hacker News Reader

Excalidraw is pretty cool, but its main drawback is that is has no backend. The drawings cannot be persisted to the server, and you cannot collaborate with someone on a drawing unless you are both connected at the same time.

I maintain another opensource whiteboard web application that has a slightly different set of features, but allows persisting drawings to the server. It's called WBO :

- https://wbo.ophir.dev/

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Some people think of that as a feature.

I saw that you can save it (as a JSON file) or export to PNG,SVG or the Clipboard (was that what the icon was?).

So I prefer people let me use a tool without creating another online account.

Also, glad you have an option for people with a different view of this. And also for simultaneous collaboration, too.

The public whiteboard is very interesting. It is a nice way to showcase collaborating capabilities. It would have been a great messy canvas except for that one user or bot determined to erase everything someone else draws :-)

A few of us managed to collaborate a bit... Not really going to change the world but it was fun while it lasted https://i.stack.imgur.com/rV8gQ.png

Excalidraw can store the files, although it's a little hidden: the link option in export gives a link that downloads an encrypted JSON from their server.

Does this support touch/stylus drawing?

Yes it does.

When using the stylus, it doesn't support pressure sensitivity (I just tried with my Wacom). I created doodledocs.com as a side project, which does support it (and almost doesn't support anything else :P).

The code is open source and also purely front-end based. So the Excalidraw authors can see how it could be implemented. It's basically Bresenham's algorithm combined with the DOM API.

The code is at https://github.com/melvinroest/doodledocs/tree/master/app/co...

The relevant part: https://github.com/melvinroest/doodledocs/blob/master/app/co...

Yup, that's the Bresenham part. Somewhere else, I expose this to actually drawing it with a pencil.

Thanks for pointing it out, I was overcomplicating it a bit in my mind (I wanted to point out more things) and therefore I didn't point it out.

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