[cairo] Redoing SOURCE and CLEAR

Behdad Esfahbod behdad at cs.toronto.edu
Wed Aug 17 10:21:41 PDT 2005

On Wed, 17 Aug 2005, Carl Worth wrote:

> On Wed, 17 Aug 2005 12:38:02 -0400 (EDT), Behdad Esfahbod wrote:
> > Ok, then what's wrong with simply using OVER?  In other words,
> > why should people use SOURCE at all?
> What I want SOURCE for is to set the destination (within a shape) to a
> known alpha value (other than 0.0 or 1.0) without respect to the
> existing content of the destination.
> OVER does not allow this.
> And the current implementation doesn't make this easy since SOURCE has
> the additional effect of clearing the destination in the area between
> my shape and the clip.

Ok, I'm convinced.  So we want mask to be a local clip by
definition. (except for those third category in Owen's proposal)

> -Carl


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