[mapserver-users] AGG - FORMATOPTION PALETTE

[Léveillé, James]

Hi,
 
I'm trying to use my own palette for AGG as described here by Thomas :
http://www.nabble.com/forced-palette-and-quantization-for-RGBA-images-td1464
5869.html
 
As explained in the article, I'm using a typical PNG 24 bits image (produced
in RGBA mode - 4 bands).
But from this image, I'm not able to produce a 8 bits PNG image with the
ALPHA, only in RGB with 3 channels - see the GDALINFO below.
I need this 8 bits image to generate my palette.
 
gdalinfo rgb.png
Driver: PNG/Portable Network Graphics
Size is 1203, 813
Coordinate System is `'
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0,  813.0)
Upper Right ( 1203.0,    0.0)
Lower Right ( 1203.0,  813.0)
Center      (  601.5,  406.5)
Band 1 Block=1203x1 Type=Byte, ColorInterp=Palette
  Color Table (RGB with 256 entries)
    0: 17,12,12,255
    1: 27,101,44,255
    2: 0,132,0,255
    3: 19,130,16,255
...
 
How can I generate a 8 bits RGBA image from the original 24 bits image ?
 
Regards.
 

______________________________________________________

JAMES LÉVEILLÉ
Service des systèmes de Mission
Direction des technologies de l'information
Ministère des Transports du Québec

5833, boul. Pierre-Bertrand, 2ième étage
Québec (Québec) G2K 1K7
Téléphone:   (418) 380-2005 poste 227
Télécopieur: (418) 644-6653
james.leveille at mtq.gouv.qc.ca <mailto:james.leveille at mtq.gouv.qc.ca> 


 

 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/mapserver-users/attachments/20080423/66d51977/attachment.htm>