[mapserver-users] transparent symbol clobbering

[Zak James]

Ben,

I think there probably is a bug in the case of GD output with 24 bit
icons on a transparent background. If you have the agg driver
configured, setting TRANSPARENT TRUE in the map and using the built-in
aggpng24 outputformat works.

If you want the result to be 8-bits deep, you could try enabling
--with-experimental-png. See
http://trac.osgeo.org/mapserver/ticket/2436 for some background.

zak

-- 
Zak James
Applications and Software Development
DM Solutions Group Inc.
http://www.dmsolutions.ca

On Thu, Jun 26, 2008 at 2:58 PM, Ben Brehmer <bbrehmer at refractions.net> wrote:
> Thanks Paul,
>
> Unfortunately no luck. Setting "transparency alpha" makes the transparent
> part around the symbols completely white :)
>
> It seems to be the exact same problem as Jim Clack encountered [1], who
> never found a solution either. Makes me think its actually a bug and not
> intended behavior. Perhaps I'll start digging through the code.
>
> Cheers,
>
> Ben
>
> [1]
> http://www.mail-archive.com/mapserver-users@lists.osgeo.org/msg00569.html
>
>
> Paul Spencer wrote:
>>
>> just a guess, try transparency alpha
>>
>> Cheers
>>
>> Paul
>>
>> On 25-Jun-08, at 7:33 PM, Ben Brehmer wrote:
>>
>>> I have a very simple mapfile to display a bunch of points as PNG symbols.
>>>
>>> Problem is that the transparent part of the symbols are clobbering each
>>> other with the background color (see attached image). What I would like to
>>> see is a whole wack of merged together symbols when they are overlapping
>>> without the background color coming through.
>>>
>>> Any thoughts as to what could be causing this?
>>>
>>> Cheers,
>>>
>>> Ben Brehmer
>>>
>>>
>>>
>>> --------------------------------------------------------
>>>
>>> The relevant parts of my very simple map file:
>>>
>>> MAP
>>>
>>> TRANSPARENT ON
>>>
>>> OUTPUTFORMAT
>>>  NAME PNG24
>>>  DRIVER "GD/PNG"
>>>  MIMETYPE "image/png"
>>>  EXTENSION "png"
>>>  IMAGEMODE RGBA
>>>  TRANSPARENT ON
>>> END
>>>
>>> LAYER
>>>  TRANSPARENCY 100
>>>  CLASS
>>>    STYLE
>>>       SYMBOL "../../htdocs/images/markers/multi_arrow.png"
>>>       SIZE 32
>>>    END #STYLE
>>>  END #CLASS
>>> ....
>>> ..
>>> .
>>>
>>>
>>> <transparent_symbol_issue.jpg>_______________________________________________
>>> 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/
>>
>
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