GRAPH Layout algorithm

[Alexander]

Hello,

I like canviz very much and I would like to use it in some firefox
extension project. Can you give me a hint on how you perform the
layout of the graph for a given set of nodes ?

Is it cpu intensive ? Do you think its hard to implement drag&drop for
canviz ?

Thank you very much !

Regards, Alexander

[Ryan Schmidt]

On May 11, 2010, at 12:35, Alexander wrote:

> I like canviz very much

Thank you!

> and I would like to use it in some firefox
> extension project. Can you give me a hint on how you perform the
> layout of the graph for a given set of nodes ?
>
> Is it cpu intensive ?

Canviz (which runs in the web browser on the client side) does not do the layout; Graphviz (which runs on the server side) does. If you'd like to know how the various Graphviz layout algorithms work, the graphviz-interest mailing list would be a good place to ask.

> Do you think its hard to implement drag&drop for
> canviz ?

Well, there are multiple problems to be tackled. For example, detecting when the mouse cursor is within a node or edge (hit detection). There's a ticket filed for that.

Then there's the matter of what do you want to happen when a node is dragged and dropped? Are you looking to be able to arbitrarily position nodes on the canvas (not something Graphviz supports very well), or something else? Likely the answers to this would be project-specific and so Canviz should probably just offer hooks so that you can write functions to implement whatever behavior it is that you want.