[cairo] [PATCH] [API] Support component-alpha.

Soeren Sandmann sandmann at daimi.au.dk
Tue Oct 20 06:46:51 PDT 2009


Chris Wilson <chris at chris-wilson.co.uk> writes:

> So we need component-alpha support on patterns internally, so present
> the same power to the users as well. For indeed, they may well be
> dreaming of demonstrating sub-pixel geometry masks...

Would this be expected to be useful for gradients, or would it be
considered some crazy thing you could set if you knew what you were
doing?

I could sort of see a gradient from say 

        (ffff, ffee, ffdd) 

to 

        (0022, 0011, 0000) 

being interesting as a component alpha mask, but the documentation for
the proposed API implies that no filtering or gamma correction would
takes place, which would result in color errors. And expecting users
to compute pixel values from a gradient is not really in the spirit of
cairo.


Soren


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