[mapserver-users] Re: GD rendering: polygons vs lines

[Stephen Woodbridge]

On 1/26/2011 10:57 PM, Gregor at HostGIS wrote:
> *bump* Any developers out there care to comment on the visual artifacts?
> https://www.cartograph.com/~gregor/1.gif
>
> Normal polygons with corners aren't a real problem, but circles and
> curves like this render better as lines than polygons.
>
> Any ideas as to how we can smooth these out, still using GD? Or is it a
> lost cause for GD?
>
> Like I said, Plan B would be to render a line layer and then a
> no-outline fill layer; but the performance hit would obviate the
> advantage of GD.
>

Hi Gregor,

A while back someone, maybe Thomas Bonfort, did some performance tests 
comparing GD to AGG, and if I recall AGG was only slightly slower and in 
at least a couple of cases it was faster the GD. That said, I can't find 
the posts I was think of.

And this very limited test of one single image:
    http://www.perrygeo.net/wordpress/?p=77
Implies the GD is about 2x the speed of AGG.

More here if you care to look:
http://www.google.com/#q=mapserver+performance+gd+agg

Also I should point out that the GD renderer is getting removed in 6.0 
as part of the rendering pipeline refactoring, unless that plan has 
changed. So I'm not sure there is much interest in chasing issue in the 
gd renderer.

Best regards,
   -Steve W