AGG renderer in conjunction with WMS TRANSPARENT=true parameter

[thomas bonfort]

hi
bug http://trac.osgeo.org/mapserver/ticket/2436 addresses this issue
and should be included in 5.2

regards,
thomas

On Dec 19, 2007 8:27 AM, Pål Kristensen <pal.kristensen at statkart.no> wrote:
> Hi!
>
> The AGG renderer it self can not produce 8bit output, but as stated in the
> RFC GD is actually used to handle the images. The quantize method for
> reducing color depth from 24bits to 8bits works quite well with the AGG
> renderer, but not if the WMS parameter TRANSPARENT is set to true. I guess
> this has something to do with the fact that GD interprets the alpha channel
>
> backwards, hence the resulting image is in some way "broken". But for some
> reason, I don't know why, this is not the case when 24bit images is
> delivered the transparency works perfectly well.
>
> Regards
> Pål Kristensen
>
>
>
> Travis Kirstine wrote:
> >
> > Sorry Pal I  have no advice just a comment.  We were considering
> > upgrading to ms 5.0 with agg but never did do to the statment on the
> > mapserver site "The AGG driver only supports RGB output at this time."
> > on the Support for Anti-Grain Geometry (AGG) Rendering Engine
> > documents.
> >
> > http://mapserver.gis.umn.edu/development/rfc/ms-rfc-32
> >
> > I guess this in not correct?
> >
> > Travis
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > On 17/12/2007, Pål Kristensen <pal.kristensen at statkart.no> wrote:
> >> Hi!
> >>
> >> I'm trying to use the AGG renderer and reduce the resulting 24bits image
> >> to
> >> 8bits by using the quantize method. This works quite well when the WMS
> >> parameter TRANSPARENT=false, but when set to true the BGCOLOR parameter
> >> seems to be ignored and the quality of the rendered vectors clearly
> >> degrades.
> >>
> >> When requesting 24bit images the TRANSPARENT parameter works correctly.
> >> See
> >> the examples below:
> >>
> >> 24bit png, transparent true -> OK:
> >> http://159.162.103.7/cgi-bin/NorgeTopo?VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&SRS=EPSG:32633&BBOX=62423.20,6794915.15,66383.94,6797147.88&LAYERS=Hoydekurver&STYLES=&WIDTH=926&HEIGHT=522&FORMAT=image/png;%20mode=24bit&BGCOLOR=0xffffff&TRANSPARENT=true
> >>
> >> 24bit png, transparent false -> OK:
> >> http://159.162.103.7/cgi-bin/NorgeTopo?VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&SRS=EPSG:32633&BBOX=62423.20,6794915.15,66383.94,6797147.88&LAYERS=Hoydekurver&STYLES=&WIDTH=926&HEIGHT=522&FORMAT=image/png;%20mode=24bit&BGCOLOR=0xffffff&TRANSPARENT=false
> >>
> >> 8bit png, transparent false -> OK:
> >> http://159.162.103.7/cgi-bin/NorgeTopo?VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&SRS=EPSG:32633&BBOX=62423.20,6794915.15,66383.94,6797147.88&LAYERS=Hoydekurver&STYLES=&WIDTH=926&HEIGHT=522&FORMAT=image/png&BGCOLOR=0xffffff&TRANSPARENT=false
> >>
> >> 8bit png, transparent true -> NOT OK:
> >> http://159.162.103.7/cgi-bin/NorgeTopo?VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&SRS=EPSG:32633&BBOX=62423.20,6794915.15,66383.94,6797147.88&LAYERS=Hoydekurver&STYLES=&WIDTH=926&HEIGHT=522&FORMAT=image/png&BGCOLOR=0xffffff&TRANSPARENT=true
> >>
> >> This is the output formats from the mapfile:
> >> ...
> >>   OUTPUTFORMAT
> >>      NAME "png8bit"
> >>      DRIVER "AGG/PNG"
> >>      MIMETYPE "image/png"
> >>      EXTENSION "png"
> >>      FORMATOPTION "QUANTIZE_FORCE=ON"
> >>      FORMATOPTION "QUANTIZE_COLORS=256"
> >>      FORMATOPTION INTERLACE=OFF
> >>   END
> >>
> >>   OUTPUTFORMAT
> >>      NAME "png24bit"
> >>      DRIVER "AGG/PNG"
> >>      MIMETYPE "image/png; mode=24bit"
> >>      EXTENSION "png"
> >>      IMAGEMODE "RGB"
> >>      FORMATOPTION INTERLACE=OFF
> >>   END
> >>
> >>   OUTPUTFORMAT
> >>      NAME "jpeg24"
> >>      DRIVER "AGG/JPEG"
> >>      MIMETYPE "image/jpeg"
> >>      EXTENSION "jpg"
> >>      FORMATOPTION "QUALITY=60"
> >>   END
> >> ...
> >>
> >> Regards,
> >> Pål Kristensen
> >> --
> >> View this message in context:
> >> http://www.nabble.com/AGG-renderer-in-conjunction-with-WMS-TRANSPARENT%3Dtrue-parameter-tp14370293p14370293.html
> >> Sent from the Mapserver - User mailing list archive at Nabble.com.
> >>
> >
> >
> > --
> > Travis K.
> >
> > Toronto, Canada
> > ------------------------------------------------------------
> > "She knows there's no success like failure
> > And that failure's no success at all."
> > -Bob Dylan-
> > ------------------------------------------------------------
> >
> >
>
> --
> View this message in context: http://www.nabble.com/AGG-renderer-in-conjunction-with-WMS-TRANSPARENT%3Dtrue-parameter-tp14370293p14412307.html
> Sent from the Mapserver - User mailing list archive at Nabble.com.
>