[cairo] cairo_rectangle bordering

[Behdad Esfahbod]

On Tue, 2008-08-05 at 23:50 +0200, Kai-Uwe Behrmann wrote:
> 
> 
> 
> 
> 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?

Use CAIRO_OPERATOR_ADD or CAIRO_OPERATOR_SATURATE?

-- 
behdad
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