[cairo] Alpha channel [pycairo]

[Kalle Vahlman]

2007/3/10, Manuel <origin.of at gmail.com>:
> hi all, I've this "program" :
[snip]
> try execute it, the alpha channel doesn't work...
> The windows isn't semi-transparent...
> cr.set_source_rgba(0.0, 0.0, 0.0, 0.5) doesn't work ??

That's because window transparency doesn't quite work that way.

On X, windows traditionally are always fully opaque. One needs the
help of the Composite extension to achieve transparency, which pretty
much is out of scope for Cairo IMO.

I can't really comment on other systems though.

-- 
Kalle Vahlman, zuh at iki.fi
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