[gdal-dev] Support for the premultiplied alpha channels

[Frank Warmerdam]

Tamas Szekeres wrote:
> Folks,
> 
> Do we have any support to use bitmaps with premultiplied alpha
> channels? I think there are some raster formats that can convey these
> types of images and the viewers can take care of this option.
> 
> The only thing I'd like to see is to be able to determine if the image
> actually uses premultiplied alpha regardless of whether the drivers
> actually support this or not at the moment.
> 
> But currently I don't see which is the right place to denote this
> option. I consider this is a dataset wide property rather that
> attached to a single band.

Tamas,

There is no GDAL way of expressing whether image bands are premultipled
with alpha (unfortunately).

Best regards,
-- 
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