AGG and WMS

[Brent Fraser]

Assefa,

Stranglely, adding
   MIMETYPE "image/png"
or
   MIMETYPE "image/png; mode=24bit"
gives a 24 bit file, anti-aliased, but with grey instead of
a white background.

Brent Fraser
GeoAnalytic Inc.
Calgary, Alberta
----- Original Message ----- 
From: "Yewondwossen Assefa" <assefa at dmsolutions.ca>
To: "Brent Fraser" <bfraser at GEOANALYTIC.COM>
Cc: <MAPSERVER-USERS at LISTS.UMN.EDU>
Sent: Thursday, August 23, 2007 2:18 PM
Subject: Re: [UMN_MAPSERVER-USERS] AGG and WMS


> 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" <crschmidt at METACARTA.COM>
> > To: <MAPSERVER-USERS at LISTS.UMN.EDU>
> > 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
> >
>
>
> -- 
> ----------------------------------------------------------
------
> Assefa Yewondwossen
> Software Analyst
>
> Email: assefa at dmsolutions.ca
> http://www.dmsolutions.ca/
>
> Phone: (613) 565-5056 (ext 14)
> Fax:   (613) 565-0925
> ----------------------------------------------------------
------
>