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From: bonham@calgary.UUCP
Newsgroups: net.graphics,net.text,net.cog-eng
Subject: Re: Y positive up or down?
Message-ID: <478@vaxb.calgary.UUCP>
Date: Mon, 27-Oct-86 17:20:51 EST
Article-I.D.: vaxb.478
Posted: Mon Oct 27 17:20:51 1986
Date-Received: Mon, 3-Nov-86 21:26:44 EST
Organization: U. of Calgary, Calgary, Ab.
Lines: 23
Keywords: inverted cartesian coordinates, pixel addressing
Xref: mnetor net.graphics:1393 net.text:1125 net.cog-eng:320

Thanks to all net.graphics readers responding with opinions
on the relative merits of putting the coordinate origin for an
integrated 2-D text and graphics support system at the top left
versus the bottom left of the screen.

The consensus so far is overwhelmingly in favour of the normal
Cartesian coordinate system with <0,0> at bottom left.

However, there must be *some* reason Sun, and many other window
system developers, chose the upper left with Y increasing downward.
Perhaps it is because their systems were intended primarily for ease
in programming text  displays.  Most typesetting / page description
languages use the inverted, Y-positive-down coordinate system.

To obtain perhaps a wider representation of views, I am posting
my original message to net.text and net.cog-eng and am inviting
further discussion in all three newsgroups.  Thank you.
-- 
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   __+__    /_	         Mike Bonham
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