[mapserver-users] AGG FORMATOPTION "PALETTE_FORCE=TRUE" - transparent background

[thomas bonfort]

for this to work, you'll *have* to compile mapserver with
"--with-experimental-png".
(i.e. mapserv -v should ouput SUPPORTS=RGBA_PNG)

once this is done, you should supply a palette file with rgba
quadruplets. In your example, your palette entries are incorrect:
0,0,0   is a triplet instead of a quadruplet (should be  0,0,0,0)

On a side note,  your 230,230,230,0 isn't usefull, as it corresponds
to 0,0,0,0 , thus eating up a entry in your generated palette (and
palette entries in rgba mode are very expensive :) )

--
Thomas Bonfort
CampToCamp

On Thu, Mar 5, 2009 at 10:29, Ivan Mincik <ivan.mincik at gmail.com> wrote:
> I am not sure if is it possible to reduce AGG PNG image to 8bit by "PALETTE_FORCE=TRUE" option and keep transparent background.
> I went through all posts about this issue and it is not clear for me if I still need to compile mapserver with "--with-experimental-png" switch or it is currently not possible.
>
> I have tested all possible parameters and combinations of RGB or RGBA in  OUTPUTFORMAT and palette file with BLACK BACKGROUND as result.
>
> /usr/lib/cgi-bin/mapserv -v
> MapServer version 5.2.1 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=SVG SUPPORTS=PROJ SUPPORTS=AGG SUPPORTS=FREETYPE SUPPORTS=ICONV SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER SUPPORTS=FASTCGI SUPPORTS=THREADS SUPPORTS=GEOS INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE
>
> I use mapserver as WMS server.
>
> Currently I have this in mapfile:
>
>        NTERLACE OFF
>        TRANSPARENT TRUE
>        IMAGETYPE AGG8
>         OUTPUTFORMAT
>                NAME "AGG8"
>                DRIVER "AGG/PNG"
>                MIMETYPE "image/png"
>                EXTENSION "png"
>                IMAGEMODE "RGBA" - #(IMAGEMODE "RGB" is working, nice result without transparent background)
>                FORMATOPTION  INTERLACE=OFF
>                FORMATOPTION "PALETTE_FORCE=TRUE"
>                FORMATOPTION "PALETTE=/s/agg_8bit_pal.txt"
>        END
>
> And palette file:
>
>        0,0,0
>        255,255,255,255
>        230,230,230,0
>        174,17,52,255
>        174,17,52,255
>        242,221,190,255
>
> Please, can anybody clarify this?
> Thanks
> Ivan
>
>
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