Brent,
I think what happens is the following : when mapserver gets your wms
request with FORMAT=png, it selects the the GD PNG 8 bit driver. I am
not sure right now wms/outputformat should be handled so that this king
of situation does not happen.
A quick work around from what I can see would be
- define an agg output format is your map file :
OUTPUTFORMAT
NAME "agg/png24"
MIMETYPE "image/png; mode=24bit"
DRIVER "AGG/PNG"
EXTENSION "png"
END
- set you imagetyppe in the map file to be IMAGETYPE agg/png24
- when doing a wms request use FORMAT=image/png; mode=24bit
This should ensure that your agg output format is used.
Best Regards,
Brent Fraser wrote:
Christopher,
Sorry for the terse question, here are some more
details...
I'm using the AGG/PNG output driver (see RFC-32) in
Mapserver 5.0 beta 4 to render shapefile vectors (no raster
input) to a PNG graphic file. When I use Mapserver's CGI
interface to request a graphic map, the lines appear
anti-aliased (smooth, no jaggies) Great! But when I use
Mapserver's WMS interface, I get the same old rendering
Mapserver always gave (lines with jaggies).
Note there was an email
(http://lists.umn.edu/cgi-bin/wa?A2=ind0703&L=mapserver-dev&;
T=0&O=D&X=639F0B08FDD720FAC9&P=6714) saying "WSM right now
only advertise gd and gdal based drivers. See bug 455".
After some review of the images, it looks like my "DRIVER
AGG/PNG" produces a 24 bit png file via CGI, but an 8 bit
png file via WMS. When I try to do AGG/PNG24, I get
"General error message. OUTPUTFORMAT clause references
driver AGG/PNG24, but this driver isn't configured." from
Mapserver. I'll have to do some more digging...
Brent Fraser
GeoAnalytic Inc.
Calgary, Alberta
----- Original Message -----
From: "Christopher Schmidt" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, August 23, 2007 1:03 PM
Subject: Re: [UMN_MAPSERVER-USERS] AGG and WMS
On Thu, Aug 23, 2007 at 12:32:41PM -0600, Brent Fraser
wrote:
Is AGG supposed to do anti-aliased output when Mapserver
is
used as a WMS server?
I'm not sure what 'antialiased' output means -- perhaps
you mean 'alpha
transparency', perhaps you mean antialiasing within the
images, perhaps
you mean something else. Can you clarify?
The answer to the first is, I believe, "no". WMS spec
only allows for
'transparency or no transparency', and MapServer does not
implement
alpha transparency output in the WMS images.
The answer to the second is "Sure" -- the images for
http://boston.freemap.in/ are fetched from WMS (by
TileCache).
Regards,
--
Christopher Schmidt
MetaCarta
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Email: [EMAIL PROTECTED]
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