5.0+AGG performance

[Andreas Albarello]

Guillaume Sueur wrote:
> I've just done some tests with AGG rendering, and I'm a little bit 
> desappointed, but it may be because of my unexperience with agg.
> 1. files are big -> from 21 to 80 ko where the raw PNG was 6.9 ko

Guillaume,

unfortunately, the better the image is going to look, the bigger it will 
be, that's pretty obvious. AGG looks so great because of the superb 
antialiasing. The drawback of antialiasing is that it affects filesize 
due to the additional colors and shadings it uses. You could try to play 
with the quantization settings as explained here:

http://mapserver.gis.umn.edu/docs/howto/agg-rendering-specifics

By reducing the number of colors in the image, you should be able to get 
smaller files.

> 2. There are artefacts on the map (some pixels are drawn in some 
> irrelevant places)

I personally didn't notice anything like that in my maps, but if yours 
do indeed show noticeable artifacts I'd suggest filing a bug report with 
a testcase. This should help the devs reproducing and fixing the issue.

Best regards,
-- 
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Andreas Albarello
Analysis & SW Development

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