[mapguide-internals] PNG8 color quantization problem
uvwild at googlemail.com
Sat Nov 6 09:56:45 EDT 2010
The RFC60 was intended to correct the quantization errors of the color
table between adjoining map tiles.
To understand your ticket # 1518 better it would be important to know
how the images were created.
So please augment the ticket with the relevant information:
1. How is the map generated (which api calls are used)
2. How is the map structured. (layers and such)
3. Provide a sample map.
Given this information it should be easy to assess how the concepts of
RFC60 can be applied to our use case.
From your ticket desription I only get that the color quantization is
wrong.... which is no news as we had to fix it before.
The work on RFC60 showed that the used quantization algorithm used to be
completely detached from the map definition in
the rendering service causing those quantization errors.
RFC60 used an analyzation pass of the layer definitions to create an
explicit base color table of the map which is then passed on to the
renderer service to preserve those colors during the color quantization.
This has been applied to the use case we had then.
I can imagine that rfc60 logic can be easily be applied to your use
case, but this use case needs to be provided more specific
so it can be mapped to the inner workings of the mapguide server.
I am currently not able to understand your problem sufficiently to act.
On 5/11/2010 18:23, Jason Birch wrote:
> Hmm. I thought that RFC60 was going to affect PNG8 dynamic maps as
> well. Too bad.
> On 2010-11-05, Gabriele Monfardini<gabrimonfa at gmail.com> wrote:
>> I've filed a bug
>> regarding PNG8 color quantization.
>> What do you think about it?
>> mapguide-internals mailing list
>> mapguide-internals at lists.osgeo.org
> mapguide-internals mailing list
> mapguide-internals at lists.osgeo.org
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