[cairo] Alpha masks
Nathan Hurst
njh at hawthorn.csse.monash.edu.au
Thu Jan 6 22:29:30 PST 2005
On Fri, 7 Jan 2005, Carl Worth wrote:
> And I guess the other thing that I don't like about this is that we
> end up with infinitely large geometry. For some reason, it's easy for
> me to accept operators with infinite effects, (eg. draw a small object
> with SRC and the output is cleared to infinity outside the
> object). But it feels much more awkward to have to deal with
> infinitely large operands.
If you only require 'regions' to have a finite boundary and allow the
winding number/alpha outside the region to be non-zero then 'regions' are
still closed under all the operations. So they aren't really infinite
operands, merely operands that can be inside out. (You can even introduce
half-planes without complicating things much :)
njh
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