[cairo] Antialiasing not working with glitz

[claude M]

Hello,

    i've tested Cairo+Glitz. Glitz selects the Multisample extension to
perform antialiasing if it finds it. What i can say is that it worked for
me for a Geforce Ti 4200 and for a GeforceFX5600, but didn't work
for my ATI radeon 9100.

    It should have worked on the Radon9800 but  ATI Linux driver
are a bit strange.

    I started a port to Win 32 and on Win32 the Radeon 9100 also
exhibits antialiasing.

    Best regards,

                    Claude Mench.


----- Original Message ----- 
From: "Carl Worth" <cworth at east.isi.edu>
To: "Charles Tuckey" <ctuckey at verano.com>
Cc: "Cairo List" <cairo at cairographics.org>; "Soorya Kuloor"
<sooryak at otii.com>; "David Reveman" <c99drn at cs.umu.se>
Sent: Friday, April 30, 2004 5:17 PM
Subject: Re: [cairo] Antialiasing not working with glitz


> On Fri, 30 Apr 2004 10:11:43 -0600, Charles Tuckey wrote:
> > I am using the latest cairo (0.1.22), glitz (0.1.0) and libpixman
> > (0.1.1) libraries to display an ellipse on a Linux OS. I noticed that
> > pixman displays the ellipse with antialiasing but that the opengl
> > version does not have antialiasing.
>
> Cairo computes the geometry (the trapezoids) that makes up the shapes
> that you want draw, adn then hands them off to the backend. It's up to
> the backend to rasterize that geometry.
>
> For the pixman backend, we do geometrically correct rasterization to
> within the tolerance.
>
> With OpenGL that's not as easy since it is not a pixel-perfect API. If
> you want to enable anti-aliasing in OpenGL then you'll have to consult
> your OpenGL system on how to enable it (if possible). There's not
> anything directly in cairo to affect this.
>
> Others that have more experience with OpenGL may be able to offer
> suggestions on what is possible and how to enable it.
>
> -Carl
>
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