[gdal-dev] Giventiff with colortable, how do i assign one of the colors to be an alpha channel

[Isaac Gerg]

Hi All,

I have a tiff in which each pixel is a single byte (0-255) which references
a colortable.  Each element of the colortable has 4 values (RGBA).

I would like to convert my "black" color (entry 1 in the color table
(0,0,0,255)) to be transparent (new colortable entry is (0,0,0,0))

Another way to say it is, how do I create a tiff with an indexed colormap
but also have it contain an alpha channel?

Thanks in advance,
Isaac
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