Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!apple!oliveb!tymix!tardis!jms
From: jms@tardis.Tymnet.COM (Joe Smith)
Newsgroups: comp.sys.amiga
Subject: Re: Needed, IFF-HAM to RGB Bitmap
Summary: Each HAM line starts out as color 0
Message-ID: <625@tardis.Tymnet.COM>
Date: 25 Sep 89 06:18:54 GMT
References: <00313@sarek.UUCP>
Reply-To: jms@tardis.Tymnet.COM (Joe Smith)
Organization: McDonnell Douglas Field Service Co, San Jose CA
Lines: 17

In article <00313@sarek.UUCP> gsarff@sarek.UUCP (Gary Sarff) writes:
>but then when I go to look at the 6 planes worth of bits, on many lines in
>the file the first pixel will have bits set in the top two positions, which
>I thought was not to be done. I thought the first pixel on a line was a real
>color, index to one of the color registers so was of the form 00xxxx but
>many lines have first pixels with either or both of the top two bits set.

The video hardware outputs color 0 between the rightmost pixel and the start
of horizontal blanking, and also between the end of horizontal blanking and
the leftmost pixel.  Therefore the "previous color" for the first pixel is
color 0, and the first pixel can be a modification of that color.

-- 
Joe Smith (408)922-6220 | SMTP: JMS@F74.TYMNET.COM or jms@tymix.tymnet.com
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