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Re: [udig-devel] strange problems with png8 image format
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Ciao Frank,
atm there is no way to improve the appearance of those labels if you
choose to encode with either gif or png8.
The quantization algorithm that I implemented does not take into
account transparency originally, nevertheless I modified to make it
possible to work on translucent images. This means that while going
from translucent images (various transparent levels) to
opaque/transparent images (where a pixel can be only transparent or
opaque) as supported by GIF, the non completely transparent pixels are
turned into pure opaque, therefore we generate aliasing, although we
retain full transparency.
That said, this can be improved but not overnight since the algorithm
would be quite different from what we have and performances will be
different as well (much worse).
Simone.
-------------------------------------------------------
Ing. Simone Giannecchini
GeoSolutions S.A.S.
Founder - Software Engineer
Via Carignoni 51
55041 Camaiore (LU)
Italy
phone: +39 0584983027
fax: +39 0584983027
mob: +39 333 8128928
http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://www.linkedin.com/in/simonegiannecchini
http://twitter.com/simogeo
-------------------------------------------------------
On Wed, May 19, 2010 at 8:42 AM, Frank Gasdorf
<fgdrf@xxxxxxxxxxxxxxxxxxxxx> wrote:
> Well, I just created new pictures with the missing parameter
> transparency=true and the returned pictures of these requests are different.
> The "ugly" labels using the image format png8 are generated from geoserver.
> My fault :(
> Sorry for that post, I'm going to move this question to the
> geoserver/geotools list.
>
> Frank
>
> 2010/5/19 Jody Garnett <jody.garnett@xxxxxxxxx>
>>
>> Interesting.
>> I wonder if the alpha buffer is being used to soften the edges of the
>> fonts? uDig is probably trying to respect any transparency so content can
>> show through. If you are just looking at the image on its own perhaps this
>> is not noticeable? Could you try loading the images into a paint program to
>> see what is going on with transparency...
>> Other then that we should ask on the geoserver-users email list to see if
>> we can learn the specific of how encoding transparency occurs.
>> Jody
>> On 18/05/2010, at 11:55 PM, Frank Gasdorf wrote:
>>
>> Hi,
>>
>> after the fix of bug UDIG-1650 (transparency and image format png8) the
>> labels of rendered features are ugly. What I've done:
>>
>> - default image format png8
>> - checked out response from geoserver with image format png8 and
>> transparency
>> both requests return same image :
>> png :
>> http://localhost:8092/geoserver/wms?bbox=-130,24,-66,50&styles=&Format=image/png&request=GetMap&layers=utm_grp&width=550&height=250&srs=EPSG:4326
>> png8 :
>> http://localhost:8092/geoserver/wms?bbox=-130,24,-66,50&styles=&Format=image/png8&request=GetMap&layers=utm_grp&width=550&height=250&srs=EPSG:4326
>> see attachment wms.png
>>
>> - I run the app with anti-aliasing option enabled and compared it to the
>> result when anti-aliasing was disabled. -> no difference
>>
>>
>> The effect of ugly labels (see attachment wms-2.png) I only get with the
>> udig WMS client (1.2 RC2 btw.). Do you have any suggestions why this
>> happens?
>>
>> Frank
>> <wms.png><wms-2.png>_______________________________________________
>> User-friendly Desktop Internet GIS (uDig)
>> http://udig.refractions.net
>> http://lists.refractions.net/mailman/listinfo/udig-devel
>>
>>
>> _______________________________________________
>> User-friendly Desktop Internet GIS (uDig)
>> http://udig.refractions.net
>> http://lists.refractions.net/mailman/listinfo/udig-devel
>>
>
>
> _______________________________________________
> User-friendly Desktop Internet GIS (uDig)
> http://udig.refractions.net
> http://lists.refractions.net/mailman/listinfo/udig-devel
>
>
