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Re: Converting 8-bit image + pallete to 24 bit image with alpha channel [message #19308 is a reply to message #19304]

Thu, 09 March 2000 00:00

davidf
Messages: 2866
Registered: September 1996

Senior Member

Ricardo Fonseca (zamb@physics.ucla.edu) writes:

> I'm trying to convert an 8-bit grayscale image to a 24 bit image with an
> alpha channel, mapping the colors of the 8-bit image through a palette.
> Right now I'm doing it like this:
>
> CT = 23
> LoadCT,CT
> TVLCT, rr, gg, bb, /get
>
> Data = BytScl(Abs(Data), MAX = max, MIN = min)
> s = Size(Data)
> AlphaImage = BytArr(4, s[1], s[2])
> AlphaImage[0,*,*] = rr(Data[*,*])
> AlphaImage[1,*,*] = gg(Data[*,*])
> AlphaImage[2,*,*] = bb(Data[*,*])
> AlphaImage[3,*,*] = 128
>
> Which works, but I was wondering if there was a more efficient way of doing
> this. Can anyone help?

That's about the size of it, I'm afraid. :-(

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting
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		Re: Converting 8-bit image + pallete to 24 bit image with alpha channel By: Struan Gray on Fri, 10 March 2000 00:00
		Re: Converting 8-bit image + pallete to 24 bit image with alpha channel By: davidf on Thu, 09 March 2000 00:00

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