[cairo] transparency with alpha channel RGBA
M Joonas Pihlaja
jpihlaja at cc.helsinki.fi
Thu Oct 29 03:28:58 PDT 2009
On Thu, 29 Oct 2009, uray meiviar wrote:
> currently I solved it by un-multiply the RGB value (divide RGB
> values by A) on fragment shader, which is no significant penalty
> since it was done on GPU,
Ah, sounds good!
> but now my concern is the wasted CPU cycle
> for RGB*A multiplication by Cairo (since CPU is far too slow
> compared to GPU), is there any switch to turn off premultiplied RGB
No, sorry. I wouldn't worry about it though.
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