Use:
OUTPUTFORMAT
OUTPUTFORMAT
NAME "AGG_Q"
DRIVER "AGG/PNG"
MIMETYPE "image/png; mode=8bit"
IMAGEMODE RGB
EXTENSION "png"
FORMATOPTION "PALETTE_FORCE=TRUE"
FORMATOPTION "PALETTE=/path/to/palette.txt"
END
where palette.txt is a text file with RGB tuples in the form:
RRR,GGG,BBB
For example:
0,0,0
255,255,255
127,127,127
MapServer will use AGG 24 bit rendering but reduce the output file to
8 bit and reserve the colours in your palette.txt file. This will
give you consistent colours for the ones you care about.
Specifically, you should reserve all the colours that you actually
reference in your map file plus any colours of pixmap symbols. Don't
put in more colours than you actually need to because MapServer needs
to use whatever space is left (255 less your colours) for antialiasing.
Cheers
Paul
On 6-Jun-08, at 7:53 AM, BrainDrain wrote:
I use this output format in my map file:
OUTPUTFORMAT
NAME "AGG_Q"
DRIVER "AGG/PNG"
MIMETYPE "image/png; mode=8bit"
IMAGEMODE RGB
EXTENSION "png"
FORMATOPTION "QUANTIZE_FORCE=ON"
FORMATOPTION "QUANTIZE_DITHER=OFF"
FORMATOPTION "QUANTIZE_COLORS=256"
END
but every time map draw called (or map image requested fom cgi
mapserv.exe)
polygons has a little difference in fill color (I think this is
because
color palette recalculated slightly different each time). This is
unacceptable for me. How can i correct this? (maybe some
FORMATOPTION?)
--
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__________________________________________
Paul Spencer
Chief Technology Officer
DM Solutions Group Inc
http://www.dmsolutions.ca/
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