Article View: net.graphics
Article #1560Re: Y positive up or down?
From: Henry Spencer
Date: Thu, 06 Nov 1986 19:06
Date: Thu, 06 Nov 1986 19:06
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> Henry stated that the Blit was 4th-quadrant; I believe the Blit
> was originally 1st-quadrant, changed to 4th-quadrant for the DMD
> (which is NOT a Blit!). There is evidence for this in some of
> the older DMD software.
Tsk, tsk, Doug, obviously reading all the DMD software has affected your
mind! :-) To quote from "Hardware/Software Trade-offs for Bitmap Graphics
on the Blit", Pike/Locanthi/Reiser, Software-Practice&Experience Feb 1985:
" ... (The Teletype DMD 5620 is a commercial product based on the Blit,
but this paper is about the Blit itself.) ... All bitmaps share a single
coordinate space, with (0,0) in the upper left. (The orientation of the
y-axis is one thing we might change were we to do it again.)"
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,decvax,pyramid}!utzoo!henry
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: net.graphics Subject: Re: Y positive up or down? Message-ID: <7291@utzoo.UUCP> Date: Thu, 6-Nov-86 14:06:08 EST Article-I.D.: utzoo.7291 Posted: Thu Nov 6 14:06:08 1986 Date-Received: Thu, 6-Nov-86 14:06:08 EST References: <478@vaxb.calgary.UUCP>, <5139@brl-smoke.ARPA> Organization: U of Toronto Zoology Lines: 16