[cairo] Re: Using ADD operator to prevent seams

[Robert O'Callahan]

On Tue, 22 Mar 2005 19:30:24 -0500, Owen Taylor <otaylor at redhat.com> wrote:
> When doing antialiased rendering, it's indispensable to position
> horizontal/vertical edges to integer pixel boundaries. Full-screen
> supersampling doesn't help: you'll still have fuzz at the edges of the
> boxes, it will just be "correct" fuzz.

That is another issue. We can tweak layout logic in a few places, but
we can't fiddle with  layout coordinates much without breaking
standards or other expectations. And I don't know how to pixel-align
rectilinear graphics at paint time in a way that's really consistent
and preserves sub-pixel-size features. Any suggestions? :-)

> Do adjoining diagonal (or curved) edges really come up enough in web
> pages to be worth worrying about? (Obviously, you can get whatever
> problems you have with SVG by embedding an SVG, but that doesn't seem
> to be the normal case...)

They're not important outside of SVG, no. But we need a graphics
substrate that will be robust when people start doing HTML inside of
SVG; infrastructure for tomorrow's Web, not just today's. If someone
starts rotating their Web page, we don't want crazy join lines
suddenly appearing.

Rob
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