[mapserver-users] Mapserver rendering with 24 bit colour

[Rahkonen Jukka]

Hi,
 
Not so that everybody gets answered, sometimes nobody just knows the answer, and after all, this is voluntary.  But still, I can see from the archives that Thomas Bonfort had a try on the same day and only one and a half hours delayed :)
 
-Jukka Rahkonen-
 
 
________________________________

Lähettäjä: mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org] Puolesta David Nugent
Lähetetty: 14. toukokuuta 2009 8:01
Vastaanottaja: David Nugent
Kopio: mapserver-users at lists.osgeo.org
Aihe: Re: [mapserver-users] Mapserver rendering with 24 bit colour



	On 06/05/2009, at 1:52 PM, David Nugent wrote:


		Once I completed upgrading to mapserver 5.4, I decided I'd give the new AGG renderer a try.
		~
		However, as a by-product of changing renderer, the metatiles produced by mapserver differ slightly in colour. Some agree exactly to the RBG colours I am providing, others are rendered with slight variations, and when viewed on the web it becomes fairly obvious where the meta tile borders are.



	This is to follow up on my own question to which I received no response either on the list or otherwise in case anyone else runs into the same or a similar problem.

	I finally found the problem in that the php mapscript had a bug, and that "AGG_Q" (AGG with quantize enabled) was being selected regardless that I was trying to tell it to do it differently. Once I correctly set it to AGG without quantize, the colour variation between tiles disappeared and all is well.

	One interesting aspect of this is that the average file size did not increase significantly when dropping quantize although in general the tiles rendered using AGG are around 40-50% larger than PNG8.

	Regards,
	
	
	--
	David Nugent (davidn at datalinktech.com.au)
	Software Engineer
	datalink technologies pty ltd
	Mobile GPS/GPRS business process solutions
	http://www.datalinktech.com.au/




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