[cairo] cairo_paint_with_alpha()

Carl Worth cworth at redhat.com
Fri May 6 11:43:32 PDT 2005


On Thu, 05 May 2005 17:39:52 -0400, Owen Taylor wrote:
> Here's a patch to implement cairo_paint_with_alpha(). It turned
> up one bug in cairo-pattern.c which this patch also fixes.

Thanks, Owen!

The new functionality was as easy as I had hoped. We might change the
documentation for cairo_paint_with_alpha to something like:

> + * A drawing operator that paints the current source everywhere within
> + * the current clip region, (as cairo_paint()), but through a mask
> + * of a constant alpha value @alpha.

The idea here is that there will be an introductory chapter
(eventually) that introduces the fundamental drawing operator, along
with terms such as "source" and "mask", so that we can refer to them
consistently here.

> It's not really clear to me what the distinction between the
> coverage.c and mask.c is.

Yes, it did seem we were getting fairly arbitrary sets of overlapping
test matrices here.

> I wonder if we should just remove coverage... with text disabled
> it doesn't test anything that isn't already tested by 
> mask, and trap-clip.c.

Sounds fine to me. If we're getting just as much test coverage, I'd
prefer to have it in fewer tests. (Speaking about the matrix-based
tests here. For focused tests, it is still quite useful to test
individual pieces of functionality in separate tests; they are much
easier to tweak, expand, or share for real use, for example).

The patch looks good to me, (not having look closely at the test
portions which I'll trust "make check" to do for me).

-Carl
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