Path: utzoo!attcan!uunet!wuarchive!brutus.cs.uiuc.edu!apple!rutgers!bellcore!wind!sdh
From: sdh@wind.bellcore.com (Stephen D Hawley)
Newsgroups: comp.sys.mac.programmer
Subject: Re: turning on a pixel
Message-ID: <17470@bellcore.bellcore.com>
Date: 24 Aug 89 19:04:07 GMT
References: <6294@hubcap.clemson.edu> <863@eutrc3.urc.tue.nl> <843@cf-cm.UUCP>
Sender: news@bellcore.bellcore.com
Reply-To: sdh@wind.UUCP (Stephen D Hawley)
Organization: Bellcore, Morristown, NJ
Lines: 26

In article <843@cf-cm.UUCP> ralph@computing-maths.cardiff.ac.uk (Ralph Martin) writes:
>If you look at Inside Mac, it clearly says that coordinates refer to
>points at the corner of pixels, not the pixels themselves. Thus, it
>seems to me that any code like moveto(x,y) lineto(x,y) should draw a
>line of zero length, ie nothing at all. It seems to me that all of you
>have it wrong when you do this (including you guys at Apple, who
>actually apparently make such code not draw a line of zero length, but
>a single pixel).  I've always used (the equivalent of) moveto(x,y),
>lineto(x+1,y+1) to set a given pixel.
>So, hit me with the flamethrower! Who's right, and who's wrong?!
>As I said, its the rest of the world thats crazy......



One flame thrower coming up.  Inside Mac also claims that the pen hangs
below and to the right of the pixel's coordinates.  If you use a pen size
of 0,0 then nothing should happen.  A pen size of 1,1 will plot a single
point.


Nice try, though.

Steve Hawley
sdh@flash.bellcore.com
"Up is where you hang your hat."
	--Jim Blandy, computer scientist