[mapserver-users] a question about tiffimages

[Frank Warmerdam]

Stephen Lime wrote:
> On the 24-bit side, a new version of GD is out. It will be integrated after the initial
> 3.5 release. It's unclear how useful it will be though. It definitely reads (writes?)
> truecolor but it's gotta be slower so integration may be tricky especially when
> preserving GIF support.

Steve, et al, 

Does anyone know if the new gd supports png alpha output?  For WMS purposes
it would be ideal to treat output with some transparent portions via 
an alpha value for each pixel rather than just the current approach of setting
aside one palette value as transparent.

> Note: there may be functionality in the new 3.5 GDAL support that replaces
> current TIFF support if compiled in. In know there's projection and resampling
> code in place but don't know if there's any color quantization code as well. Probably
> doesn't matter since there's still only 8-bit output.

There are algorithms in GDAL for colour quantization but they aren't directly
used by MapServer.  It seems to me that this sort of thing should be
done as a preprocessing stage before putting up data for use with MapServer.
Right?  What do people use for preprocessing their raster images into 
paletted form?  Is there interest in my providing some preparation tools 
for applying image enhancements, and doing colour quantization with 
detailed control?  I have these in rough form already as part of GDAL.

Best regards,

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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent