[cairo] cairo_rectangle bordering

[Kai-Uwe Behrmann]

Hello,

when two cairo_rectangle's are drawn, each bordering the other, they 
appear sometimes with a small one pixel wide line shining through the 
background colour along the border. This is not what I expect as the area 
is positioned to be covered completely by the rectangles.


drawing geometry      expected          observed
of rectangles          result           artefacts

 +----+----+         +---------+       +----.----+
 |    |    |         |         |       |    .    |
 |    |    |         |         |       |    .    |
 |    |    |         |         |       |    .    |
 |    |    |         |         |       |    .    |
 |    |    |         |         |       |    .    |
 |    |    |         |         |       |    .    |
 |    |    |         |         |       |    .    |
 |    |    |         |         |       |    .    |
 +----+----+         +---------+       +----.----+

Unfortunedly the same happens with a transparent background too.
Is there a special way to obtain the expected result in Cairo?


kind regards
Kai-Uwe Behrmann
-- 
developing for colour management 
www.behrmann.name + www.oyranos.org