[Cairo] mouse pointer and cairo

[Carl Worth]

On Oct 12, Thomas Hunger wrote:
 > Since cairo_stroke starts a new path, cairo_in_stroke would either need to be 
 > called before cairo_stroke and perform a virtual "what would be if" stroke,  
 > or a programm would have to do all operations twice, one run for drawing, the 

PostScript follows the "what would be if" approach. The
instroke/infill operators do not modify the current path.

 > other for intersection testing. In both cases the tesselation into traps 
 > would be done twice, is that bad for speed?

It wouldn't be hard for Cairo to cache the traps from one operation
and use them for the next. As for speed, I haven't looked at things
closely yet, (still trying to get the API finished first), so I don't
know how critical the tessellation is for performance.

-Carl