Pixel aspect ratio of each screen resolution?

Started by ces, March 31, 2014, 01:22:58 AM

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Is there any accurate info on the aspect ratio of one pixel in each of the X68000 display modes? Was there any mode with square pixels and support for 65K colors?

Note that this is crucial information if you've a photo and you wish it to be properly displayed on the X68000 without a distorted aspect.


This isn't a possible question to answer unless you're prepared to limit your question to specific monitors and come up with an arbitrary specification for width and height settings on them.  Users on a Sharp monitor might see a slightly disproportionate image compared to someone using a PC98 or FMTowns or PC monitor, or even a TV.  For the most part they're all 4:3 but not always exactly (though the variance is admittedly small).

It's never crucial information.  Not in the analogue era.  It couldn't be.

If you want to work it out, just do the math: a 4:3 rectangle with the horizontal and vertical resolutions.  Presto, there's your aspect ratio.


Well, when working with computers that had non-square pixels, I remember that the technical docs usually told you the pixel aspect ratio if the monitor was an analog one with the same scale for X and Y. This was important not only for photos, but also for CAD, so that a circle was indeed drawn as a circle. And I used such documented aspect ratio for scaling the output of my applications accordingly.

From your suggestion of supposing a 4:3 output... do you mean the X68000 had no borders? I remember that most computers had borders when using an analog output, and the horizontal borders weren't usually the same size of the vertical borders, so while the monitor was always 4:3, your output area had another ratio most of the times.


Well that's sort of my point.  First, we're not doing CAD here, so the perfect circle-ness of our output isn't important.  I'm of the opinion that the tiny percentage of difference you'll encounter isn't going to affect your photos much either.  As for 4:3, I'm sure that's a reasonable approximation, even if the reality is 4:3.08 or something.  Go measure, let's find out.  ;)


A little additional information, though I lack the details. You can program the video hardware to output pretty much any resolution you want. Seems like you set some registers in the MFP like the front porch and dot clock and that sort of thing. So in theory, limitations of CRT's aside, you can set any resolution you've got VRAM for if you do the math.


Quote from: Lawrence on March 31, 2014, 07:49:15 AM[...] First, we're not doing CAD here, so the perfect circle-ness of our output isn't important [...]
Maybe most of the X68000 revival is focused in games, because X68K games are excellent. But, from my web research, my impression is that the X68K was used for work and for creative tasks in Japan (as well as for gaming, of course). There's a Japanese TV show on YouTube, monographic about the X68K, and it discusses everything except gaming (video, printing, drawing, and even BASIC programming). That's an important symptom telling the X68K wasn't a "gaming box" even if its games were excellent.

So, I suppose there must be some Japanese document explaining how to get reasonably calibrated X/Y scales. Regarding what neko68k said, such freedom of programming display modes may complicate things, although I'm not sure.


How long is a piece of string?  Japanese string, I mean.  From 1994.  I saw it on TV once, it was about yay long.  Anyone?