[mapserver-users] GD rendering: polygons vs lines
Gregor at HostGIS
gregor at hostgis.com
Mon Jan 24 23:16:31 EST 2011
Hey guys. I have an interesting rendering issue here.
We are using the GD renderer for this project, since it's faster than
AGG to the degree that we want to offer it as a speedy option. But the
polygon outlines look bad in some cases, especially circles.
The center one in black, we render the polygon as a line layer instead.
We were surprised to see that the curvature is MUCH smoother and those
wedge-cut artifacts are gone.
Any ideas as to why this is and how we can improve the edges to look
like the line version? Is this something in GD or in how MapServer uses
GD? Is there perhaps some defines we can change in the source?
An obvious approach is to make 2 layers: a polygon with no outlinecolor
for the fill, and a line for the border. But this would be two layers
instead of one, with the resulting slower rendering anyway.
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