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From: bammi@cwruecmp.UUCP (Jwahar R. Bammi)
Newsgroups: net.micro.atari16
Subject: Re: BLITTER AND 520
Message-ID: <1525@cwruecmp.UUCP>
Date: Fri, 18-Jul-86 15:12:56 EDT
Article-I.D.: cwruecmp.1525
Posted: Fri Jul 18 15:12:56 1986
Date-Received: Sun, 20-Jul-86 03:44:23 EDT
References: <8607171835.AA05912@ucbvax.Berkeley.EDU>
Organization: CWRU Dept. Epid. & Biostat., Cleveland, OH
Lines: 28

> The blitter will supposedly come with new ROMs.  I suspect that there
> will be more than just the blitter chip and the socket for the 68000 on
> the blitter board.  By the way, this thing is also expected to provide
> half-toning which I had always thought was bordering white lines with grey.
> The idea behind this is that your eye sees less contrast between any element
> of the line and the surrounding background and bloops over the jaggles on
> diiagonal lines.  The result is the illusion of a perfect line.  My point is
> that if this is to work on monochrome systems then some modification of the
> viideo circuitry is necessary to get grey as well as black and
> white.  Perhaps the half-toning will only be supported on the color
> systems.  Or it will require a little bit more than sticking it in
> the 68000 socket to make it go.

What you describe above is known as Antialiasing. In half toning a
group of pixels - normally a square group like 4x4 - behaves like one
pixel, and depending upon how many of the pixels are on you get
illusions of different shades of gray or even patterns. Of course you
loose out on resolution, but it is useful for filling type operations.

Can someone at Atari tell us if the blitter will support gray levels
too? Landon or Neil perhaps.

-- 
					Jwahar R. Bammi
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