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From: hutch@sdcsvax.UCSD.EDU (Jim Hutchison)
Newsgroups: comp.sys.amiga
Subject: Re: Getting fonts printed out right
Message-ID: <2384@sdcsvax.UCSD.EDU>
Date: Tue, 23-Dec-86 07:26:29 EST
Article-I.D.: sdcsvax.2384
Posted: Tue Dec 23 07:26:29 1986
Date-Received: Tue, 23-Dec-86 21:44:25 EST
References: <1157@cbmvax.cbmvax.cbm.UUCP>
Reply-To: hutch@sdcsvax.UUCP (Jim Hutchison)
Organization: UCSD EMU Project (Educational Microcomputer Unix)
Lines: 28

In article <1157@cbmvax.cbm.UUCP> daveb@cbmvax.UUCP (Dave Berezowski) writes:
>	The dithering works on a 4x4 dither matrix which produces 16
>possible shades per base color (yellow, magenta, cyan, and black (maybe)).
>	(Your printer doesn't have black, so black isn't used).
>	These base colors are then mixed to produce 16 possible shades of
>	red (y+m), green(y+c), blue(m+c).  Since the Amiga's colors have
>	16 intensity levels (0-15), the translation works very smothly.

This raises a question in my mind, which way to you push it?  4x4 is 0-16.
On a screen I have always favored the lighter image (which means making
15 and 16 full white).  Here in the subtractive world of CYM (Oh no, no
black!), I presume you lean this way since you can't get real black anyway.
Note: CYM mixed is dark grey, not black.  4 bits is 17 distinct values.

Not to besmearch your driver, I presume your were just glossing over this
common technical problem with the unexpected perversity of powers of 2.

How is the dot pitch?  You use an ordered dither, I presume.  This will
result in dotted lines for off-tone text/fonts with narrow charastics.

Have you considered applying a clamping algorythm to your dither for cases
where people refuse to loose the fine detail, and would rather loose some
of the color replication?  It's just a thought.

-- 
    Jim Hutchison   		UUCP:	{dcdwest,ucbvax}!sdcsvax!hutch
		    		ARPA:	Hutch@sdcsvax.ucsd.edu
"The more you drive, the less intelligent you are." - "Repo Man"