Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!cbmvax!mitchell
From: mitchell@cbmvax.UUCP (Fred Mitchell - QA)
Newsgroups: comp.sys.amiga
Subject: Re: RGB to HAM IFF
Message-ID: <8242@cbmvax.UUCP>
Date: 23 Oct 89 17:36:04 GMT
References: <495@nigel.udel.EDU> <333@amgraf.UUCP>
Reply-To: mitchell@cbmvax.UUCP (Fred Mitchell - QA)
Organization: Commodore Technology, West Chester, PA
Lines: 23

In article <333@amgraf.UUCP> huver@amgraf.UUCP (Huver) writes:
>
>In article <495@nigel.udel.EDU>, webb@udel.edu (David Webb) forwarded comment
>from Fred Mitchell (mitchell@cbmvax.uucp) on converting RGB bitmap to HAM:
>
>  [...bitplane reduction, 16-color palette picking stuff deleted]
>
>But the original question was:
>>>
>>>   Has anyone worked out a method of converting RGBs to HAM. I have
>>>   three B/W images (8 bits/pixel), and I would like to covert them
>>>   to a HAM image. If somebody could show me the way I would not writing
>>>   the C-code and making it public...
>
>So, is Fred Mitchell at Commodore able to display B/W in HAM mode?  Which
>Amiga model was used so that, for example, the previous pixel is 0xFFF and by
>HAM we can get 0x999 for the current pixel?  Maybe Dave Haynie knows?  It IS
>the rumored Amiga 3000, isn't it?  :^)

I was speaking of the more general *color* case. Obviously, in the n-bit
b&w case, to convert it to m bits, where m < n, you drop the lower n - m
bits. You can also employ some type of dithering scheme if m is very
small ( <= 3 bits ), but that's another story.