[MAPSERVER-USERS] help! agg palette quantize algorithm imperfection

[BrainDrain]

$? You're kidding)) Anyway, thanks for advise. Will try. 
And what about agg rgba mode (bug, invalid color interpretation (inverting?)
or something like that)? When
this problem will be fixed? I need it, because I want to use map
transparency (only rgba mode) to combine with google map layer in openlayers
rich client app.

Stephen Woodbridge wrote:
> 
> Hey, that's what they pay you the BIG BUCKS for! :)
> 
> Write a perl/bash/{your favorite} script to grab all the COLOR lines 
> from you mapfile and reformat the r g b to r,g,b in you palette file.
> 
> I have a few hundred symbols in my symbol library, but I only use about 
> 10 of them regularly so I made sure the primary colors were also in the 
> palette file. I make the script add them so I don't have to think about
> it.
> 
> It sounds like a big deal, but it not that bad.
> 
> YMMV,
>    -Steve W
> 
> BrainDrain wrote:
>> Thanks, i already read about preparing palette index file & I see 2
>> obstacles:
>> 1) I need to monitor my map file (big size) to keep relevant my palette
>> file. It is inflexible to extract rgb colors used in pixmap symbols
>> (hundreds, updatable). Can I use html palette for ex. (or any other
>> 'universal' palette) - to make this process not so time-consuming?
>> 2) If I have strict palette, can I be sure that agg renderer will always
>> use
>> the nearest(?) color from my palette?
>> 
>> pagameba wrote:
>>> 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?)
>>>> -- 
>>>> View this message in context:
>>>> http://www.nabble.com/help%21-agg-palette-quantize-algorithm-imperfection-tp17667733p17667733.html
>>>> Sent from the Mapserver - User mailing list archive at Nabble.com.
>>>>
>>>> _______________________________________________
>>>> mapserver-users mailing list
>>>> mapserver-users at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>>
>>> __________________________________________
>>>
>>>     Paul Spencer
>>>     Chief Technology Officer
>>>     DM Solutions Group Inc
>>>     http://www.dmsolutions.ca/
>>> _______________________________________________
>>> mapserver-users mailing list
>>> mapserver-users at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>>
>>>
>> 
> 
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> 

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