Path: utzoo!attcan!uunet!cs.utexas.edu!romp!auschs!d75!sabre!robin
From: robin@sabre.uucp (Robin D. Wilson/1000000)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: (Non) Square Pixels?
Message-ID: <3053@d75.UUCP>
Date: 12 Feb 90 15:44:42 GMT
References: <4687@lmrc.uucp> <3119@cello.UUCP> <4736@lmrc.uucp>
Sender: news@d75.UUCP
Reply-To: robin@reed.UUCP (Robin D. Wilson/1000000)
Organization: IBM AWD, Austin, TX
Lines: 48

In article <4736@lmrc.uucp> hassinger@lmrc.uucp writes:
>In article <3119@cello.UUCP>, robin@sabre.uucp (Robin D. Wilson/1000000) writes:
>> Most monitors (and TV's do not have "square" pixels.  Most have round or oval
>> shaped pixels.  In fact, the only monitors that I know to have square pixels 
>> are the high-end Sony's similar to the one Apple uses for the MacII.  (The
>> Apple color monitor for the MacII is a modified Sony.)  
>
>Looks like I am going to have to explain further.  I don't care about the shape
>of the spots displayed on the screen.  I care about about how many there are.
>

The spots displayed on the screen are pixels.  Their shape is determined by the
monitor.


>On some computers the number of pixels per inch on the "standard display" for
>that system is the same in both horizontal and vertical directions.  If that is
>the case, in a program like DPaint you can take a brush of a circle or a
>square, rotate it ninety degrees, and it will still be a circle or a square
>because it is made up of the same number of dots or pixels in each direction

This is aspect ratio.  Specifically you are looking for a 1 to 1 aspect ratio.
I am not sure, but I believe a 640 by 400 hi-res interlaced screen is a 1 to 1
aspect ratio.  If the 640 by 400 screen does turn out to be 1 to 1, then any 
equal sub-division will be also.  For example, 320 by 200 should also be 1 to 
1, and any multiple of 8 to 5 will end up being 1 to 1.  If 640 by 400 is not
1 to 1, then forget what I said.

(BTW, try to remember that the monitor is wider than it is tall.  So a 1 to 1
ratio will naturally provide more "spots" (pixels) from right to left than from
top to bottom.)

Also, on my NEC 3D there is an adjustment to increase the distance between the
pixels from right to left (thus making the screen wider, and changing the 
aspect ratio from that perspective) and another adjustment that changes the 
ratio from top to bottom.  It sure helps me to get a 1 to 1 aspect ratio on my 
stuff.  (I'm not sure how NEC does this, but I think it may have something to 
do with changing the shape of the tension masks.)


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