[mapguide-internals] Tile Palette RFC changes

Jason Birch Jason.Birch at nanaimo.ca
Tue Mar 24 12:51:13 EDT 2009

Hi UV,

I noticed that some changes had been introduced into "MapGuide RFC 60 - improvement of color palette quantization for PNG8 tiles"


It looks like the code changes are now entirely transparent to the end user.  IMHO, keeping this stuff from touching the repository is a good thing.

I do have a couple questions:

- Will this work for any request for an 8-bit image, not just Tile requests?  I would be super-happy to see this done for standard GetMapImage requests; the colour shift between the legend and the rendered image is a large concern not just for tiles.

- Is the palette extracted/stored to the runtime map regardless of the format requested, or is this code path only taken for PNG8 requests?  I'm probably showing my ignorance of the rendering code here :)

If you feel that there is value in a server configuration item to control whether this optimisation is applied at all, and what algorithm is used, then I'm not opposed to that. Given tile cache generation times and resource usage, anything to keep this under control is good.  I could see one setting being used on the tile generation server, and another on the dynamic map rendering server. 


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