On Tue, Nov 17, 2009 at 09:35:18AM -0600, Jason Grout wrote: > > Rob Beezer wrote: > > A few quick comments: > > > >> * I think talk=True was a bad choice of option name. It's limiting, > >> potentially conflicts with other options, etc. > > > > +1 This seems to happen often; an option gets implemented as a > > boolean, and later a similar option is added, ... when an option with > > several keyword possibilities makes more sense long-term. > > > > Rendering graphs with LaTeX via tikz refers to collections of > > rendering options as a "style" - maybe that would be more descriptive > > than "mode." What color is your bike shed? ;-) > > > > A real strength of graphs in Sage is the possibility of any hashable > > object being used to label a vertex. My previous experience was to > > only be able to number vertices and then I'd somehow manage the > > mapping from the integers to the desired labels. So I agree that the > > graphs are more appealing visually without labels, but this hides an > > advantage from view for the novice. If they are there in the default > > view, then perhaps you figure out quickly that they could be turned > > off? I think some care has gone into the graph generators to provide > > labels in many cases that make more sense than just integers (eg > > bipartite graphs). > > > > I think the bigger problem is that moderately complicated labels (like > > in the notebook example given) are written centered on a vertex, and > > often they are bigger (wider) than the vertex itself. But drawing > > them off to one side would be a little harder to figure out, and might > > be just as messy looking in the end. > > > > Finally, I find that if I really want to study or learn something > > about a graph, the labels are necessary. In other words, the label- > > less plots are pretty, but often not useful for any serious analysis. > > > > So I guess I'm giving some reasons for labels being a good idea as the > > default, but I don't feel strongly about it. Better might be a > > strategy for placing labels in a graph, perhaps something like a > > keyword "label_location" that takes on values like center, above, > > below, left, right, northwest, northeast, southeast, southwest. > > Graphviz just draws ovals that are big enough to contain the label text.
+1 for improving the default graph style; that would have been much better for a talk of mine yesterday :-) +1 for labels +1 for a shape sized to contain the label text +1 for taking inspiration from graphviz (they are the experts in that kind of stuff after all). Though I prefer rectangles which tend to take the minimal amount of space, and handle better long labels. See e.g. (shameless plug :-)): http://sagetrac.org/sage_trac/attachment/wiki/CategoriesRoadMap/sage-category-graph.pdf And by the way: +1 for scaling down the font when there are a lot of nodes, so that the labels do not overlap on each other. Since William mentioned graphviz, let me also readvertize (#7004), and the discussion about it about one month ago. Note: the patch up there needs a rebase. But that's about layout, not style. Best, Nicolas -- Nicolas M. Thiéry "Isil" <[email protected]> http://Nicolas.Thiery.name/ -- To post to this group, send an email to [email protected] To unsubscribe from this group, send an email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
