Re: [Fresco-devel] new Path API

Tobias Hunger wrote:
> Hi!
> 
> What's the status of the new Path API stefan and nicholas have been discussing?
> Anyone implementing it? I will do so if nobody is working on that yet...
> 
> Where is the documantaion on the API? I know stefan and nicholas had lengthy
> discussions about it, but I can't find any of that on the website/mailing list nor
> the Wiki (search page there still gives a traceback, so I might have missed it).

hmm, I should try to write a summary of the discussions on the wiki, then.
I agree it would be useful for people to understand why we decided on that design.

> The questions I was trying to get answered looking for the docs are:
> Why NURBS and Bezier? Bezier curves are just a special case of NURBS after all. Do
> we really need to provide such convinience functionality at the drawingkit level? What
> about Quadrics? Aren't those special cases of NURBS as well?

while nurbs are general enough, often there is hardware (or software) support for
subsets such as quadrics or bezier. It would be exceedingly hard to detect automatically
when a given nurbs parameter set maps to a bezier, because the mapping is non-trivial.

So instead, a user of the API (or a drawing editor) may offer bezier curves directly
(or quadrics such as circle segments or spheres etc.).
This is the same logic as providing a 'convex' flag to polygons, which is basically just
a hint to the renderer that it doesn't need lengthy unwinding procedures to preprocess
the path.

Hope this helps,
		Stefan