[cairo] Seams with the image backend

[Soeren Sandmann]

Soeren Sandmann <sandmann at daimi.au.dk> writes:

> Should/does cairo provide any guarantees in this area? Possibilities
> include:
> 
>   (a) No guarantees.
> 
>   (b) No seams between polygons that share an edge that is specified
>       with the same coordinates in the two polygons.
> 
>   (c) No seams between polygons with edges that coincide.
> 
> At the moment the image backend provides (b). 

Actually, looking more closely at the application, there is actually
also a seam even when the slider is at 1.0 and the shared edge is
specified with the exact same coordinates in the two polygons.

It's a line of 0xfefefe, so it's not easy to spot, but it is
there. "xgamma -gamma 0.1" is one way to make it easier to see.

So at the moment, the image backend is in the (a) category.


Soren