[mapserver-users] PNG Optimization

[Yves Moisan]

Hi Thomas,

Thanx for sharing this benchmark.  I've tried optipng for fun and didn't 
see much difference with a 27 KB Agg/png file (saved about 600 bytes 
even with -o7).  I'm eager to see compression post-processing strategies 
that are worth it.

Cheers,

Yves

> Cedric,
> Mapserver currently doesn't support png options, although this
> souldn't be to difficult to add as a FORMATOPTION (at least for the
> non GD renderers).
> You should note that the quality of the compression you apply to pngs
> has a non trivial effect on the overall rendering time, so we can't
> just add maximum compression by default.
>
> ps: you can see the effect of png compression schemes (on throughput
> and image size) on this small benchmark I ran for mod-geacache. the
> use case is the on the fly merging of two 256x256 png tiles:
> http://mod-geocache.googlecode.com/svn-history/r69/trunk/static/benchmark.png
>
> regards,
> thomas
>
>
> 2010/12/10 Cédric MOULLET<cedric.moullet at gmail.com>:
>> Hi,
>> We are using MapServer to generate tiles and the following ouptut format is
>> used:
>>
>> OUTPUTFORMAT
>>   NAME "pnga"
>>   MIMETYPE "image/pnga"
>>   DRIVER "AGG/PNG"
>>   EXTENSION "png"
>>   IMAGEMODE "RGBA"
>>   TRANSPARENT TRUE
>>   FORMATOPTION "INTERLACE=OFF"
>> END
>>
>> We observe that the size of the tiles can be reduced by a at least factor 2
>> if we use a tool like optipng.
>> Is it possible to configure MapServer in order to optimize the file output
>> (and for example use optipng)  ? Or do you see another way to optimize the
>> image (I'd like to do that on the MapServer side in order to avoid a
>> postprocessing) ?
>> Thanks in advance for any hints.
>> Cédric
>>
>> --
>> Welcome to my world: http://www.cedricmoullet.com/
>> My Linked In profile: http://www.linkedin.com/in/cedricmoullet
>> Twitter: http://twitter.com/cedricmoullet
>> Home sweet home:
>> http://map.geo.admin.ch/?crosshair=bowl&zoom=11&X=185241.24219&Y=561288.90625&bgOpacity=0&selectedNode=node_ch.swisstopo.fixpunkte-lage1
>>
>> _______________________________________________
>> mapserver-users mailing list
>> mapserver-users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
>>
> _______________________________________________
> mapserver-users mailing list
> mapserver-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>