[cairo] Questions and optimizations in cairo-arc

[Jason Dorje Short]

Behdad Esfahbod wrote:

> A viable signature would be:
> 
> void
> cairo_arc_to (cairo_t *cr,
>               double x, double y,
>               double radius);
> 
> and draws the unique arc with the specified radius that connects
> the current point to x,y.  This still has the problem that it is
> not the '_to' version of cairo_arc.

But that's not sufficient because you need to know in which direction
the arc arcs.

-jason