[instaviz-users] how to set a default style for a node?

[Ryan Schmidt]

On Mar 29, 2009, at 02:35, Andy Dent wrote:

> On 29/03/2009, at 1:51 PM, Ryan Schmidt wrote:
>
>> uld be extended to support these kinds of user style
>> definitions. In existing Graphviz syntax, you can only have a single
>> global node or edge style, and then you can override that in
>> individual nodes and edges, but there's no concept of being able to
>> define multiple node or edge style templates and have those templates
>> then used for specific nodes and edges.
>
> That is not quite accurate.
>
> Any time you redefine attributes using node[...] or edge[...], they
> stay in force as defaults for nodes and edges defined afterwards.
>
> I make very heavy use of this to keep diagrams from being cluttered
> with lots of decoration. There's an example file in this style and
> output at:
> http://aussiedesignedsoftware.com/blog/?p=72#more-72

True enough. I totally forgot that when I wrote that. I've made  
extensive use of this feature as well.

The problem is it requires you to group your nodes and edges by  
style, which could make the graph source file harder to read and  
understand. Sometimes it makes more sense to order nodes and edges in  
a different way.


> I agree it would be nice to have a way to use something like CSS
> classes to associate a style with a node defined in an arbitrary
> location.

That's what I was going after. And it has been suggested on the  
Graphviz lists before. I think some kind of hypothetical syntax may  
even have been mentioned, I believe it may even have been by one of  
the Graphviz developers.

You could also probably solve this today by pre-processing a dot file  
with gvpr, replacing some custom style attribute with the inline  
style definitions, before handing it to the layouter.