[mapguide-trac] #465: Rendering enhancement: user-defined palettes for PNG8

[MapGuide Open Source]

#465: Rendering enhancement:  user-defined palettes for PNG8
---------------------------------+------------------------------------------
   Reporter:  jbirch             |       Owner:     
       Type:  enhancement        |      Status:  new
   Priority:  medium             |   Milestone:     
  Component:  Rendering Service  |     Version:     
   Severity:  major              |    Keywords:     
External_id:                     |  
---------------------------------+------------------------------------------
 Now that MapGuide supports 8bit PNG, there is a use case for also
 supporting custom palettes.  Both MapServer and GeoServer have implemented
 this functionality.

 I haven't tested the experimental tiled PNG 8 support, but I have seen
 other implementations where small differences between the individually re-
 mapped tiles make the boundaries between the images visually distracting.
 Ensuring consistent tiles would be the primary incentive to add support
 for paletted images.  However, there are potential benefits for non-tiled
 applications as well:

  - It may allow legend images to be transformed using a known palette so
 the legend actually matches the map.

  - If performance numbers are similar to the geoserver ones, some
 situations will see considerable performance gains:
 [http://geoserver.org/display/GEOSDOC/Paletted+images+tutorial GeoServer
 Paletted Images]

  - In some cases, this will allow carto-geeks more control over map
 presentation

 I believe that an ideal implementation of this would allow for the use of
 separate palettes for each zoom level within a map or tiled map group.

-- 
Ticket URL: <https://trac.osgeo.org/mapguide/ticket/465>
MapGuide Open Source <http://mapguide.osgeo.org/>
MapGuide Open Source Internals