Re: [Monotone-devel] Ancestry Graph

[Brian Campbell]

On Aug 19, 2004, at 9:14 PM, Phil de Joux wrote:

> What about storing xml then xslt can be used to transform the format?

Well, if we're going to do this, then maybe we should just use GXL 
<http://www.gupro.de/GXL/> There are already tools included with 
Graphviz to convert GXL to DOT format. I don't really like XML, because 
it's needlessly verbose and a pain to actually parse correctly, but if 
we're going to go with a tool neutral XML format, we should probably go 
with GXL.

OK, so at this point, it looks like we have a few options:

1) Output to GXL format, use XSLT and converters to convert to the 
format of our favorite (or least disliked) graph layout software.

2) Output in an ad-hoc format, and have a program that converts it to 
other formats

3) Output in the format of (a) questionable, unmaintained, obfuscated 
software distributed under the GPL or (b) working, maintained software 
distributed under a non-free (but almost free) licence

4) Allow people to chose between several different output formats with 
a command line switch, and support a few of the most popular (probably 
GDL (vcg) and DOT)

5) Just give up and write our own graph layout software

Then, if we chose either 3 or 4, we also have the choice of

1) Output a fixed set of information about nodes
2) Add command line switches to select information include 
in/formatting of nodes

One important thing to note is that outputting in DOT format does not 
necessarily tie you to Graphviz. I know of at least one other 
(commercial) tool that can use DOT files. I guess the options I would 
prefer, all things considered, would be either GXL, or letting people 
chose between formats and choose what information and formatting to 
include using command line switches. GXL would mean that we can use 
tools that are already available for manipulating graphs, while having 
it all built in would reduce our dependencies on external programs as 
much as possible.

Just so you know where I'm coming from, the reason I'm not happy with 
the current situation is that I want to be able to write a monotone web 
interface, and allow you to select revisions based on an image map of 
the ancestry tree. Graphviz supports rendering to PNGs and outputting 
image maps, while xvcg doesn't (as far as I can tell). Also, we use 
Windows where I work, and I'd like for people to be able to get 
ancestry visualizations on their own without having to install a full 
Cygwin with X11 just to run a graph visualizer. And, I still have not 
managed to download a copy of xvcg, uglified or not. It sounds like, 
from some mail to mailings lists I've found, that the author is willing 
to release the source code in non-uglified form, but is unclear of the 
legal implications, since a company called aiSee now owns the rights to 
it.