[cairo] Antialiasing not working with glitz

Carl Worth cworth at east.isi.edu
Fri Apr 30 08:17:39 PDT 2004

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.


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