[cairo] unexpected behaviour image pattern fill

[Theo Veenker]

Hi,

I had reported some problems with surface pattern fills. The message was
unfortunately unnoticed.

> I have noticed strangeness with some backends when filling a path
> using an image pattern. I don't know if these problems are yet known.
> Applies to cairo-1.6.4.
> 
> The svg backend does CAIRO_EXTEND_REPEAT when CAIRO_EXTEND_NONE or
> CAIRO_EXTEND_PAD selected.
> 
> For PDF and PS for CAIRO_EXTEND_PAD behaves like CAIRO_EXTEND_NONE.
> I suppose the feature hasn't been implemented yet?
> 
> With the xlib backend drawing a rectangle filled with an CAIRO_EXTEND_NONE
> image pattern and then rotating that path, for some angles the bounding
> box of the fill is opaque black instead of tranparent. See attached
> image. Run the xpatfill test program to test this (use cursor up/down
> to rotate). The image, svg, pdf, and ps backends don't show this
> behaviour.
> 
> I didn't check if similar problems exist with gradient patterns.

The programs attached in
http://lists.cairographics.org/archives/cairo/2008-August/014922.html
demonstrate the problems. Could someone please take a look at it?

Thanks,
Theo