[This was intended to be a reply to a discussion I found in the "NeoGAF" forum starting maybe around here http://www.neogaf.com/forum/showthread.php?p=232907220
regarding the screen size setting in games in HAMSTER Corporation's "ACA NEOGEO" line, which emulates Neo Geo arcade games on PS4--and later other consoles as well. I registered as a user on NeoGAF, but then found that in order to post you have to be approved manually by an administrator, and according to the internet, that can take hours, months, or forever--so, being the impatient sort, I'm at least posting it here for now, maybe Google will serendipitously lead some of the folks asking about the topic originally back here somehow.]
[Update 11/6/17: Well I got approved to post on NeoGAF, but I see that some folks there already did magnified pixel views and settled on either size 134 (that was on Switch) or 133, so it looks like there's no need for me to post after all, yay!]
Regarding the Display -> Size option setting, the discussion I found about it in the middle of this thread (thanks, Google!) prompted me to do some investigation using ACA NEOGEO The King of Fighters '95, on PS4; I don't have a Switch, but it sounds like the set-ups are pretty similar between the systems. Anyway, on the PS4, a display size setting of 150 is *not* the closest possible to a pixel-perfect display--the setting of 133 is much closer.
150 *is* less irregular than other settings, such as the default 160, but that doesn't mean it has a lot of perfectly square enlarged simulated pixels: rather, they're more or less regularly the same size--every *other* pixel. Here's a 1080p screenshot of size 150 from KOF95 on PS4
: it's easy to see pixel size irregularities in the checkered backgrounds of the health and power bars in the corners of the screen. Compare the height and width of pixels with their immediate neighbors, and you'll see they're alternating rectangular sizes.
Here's a screenshot of size setting 133 from the same set-up
: notice the checkered background of the health and power bars is much more regular, with square rather than rectangular enlarged pixels--except for, as far as I can see, one column of pixels on the right-hand side of player one's health bar.
The differences and irregularities are easier to see in this 3x composite enlargement of P1's health meter background at size 150 and 133
. (Pink arrows point to the one non-square column at size 133.) (Also note that the image is labelled "scale" but should say "size"--I'm too lazy to re-do it. : P)
I found size 133 just by flipping down through all the sizes, starting at the max 161. No other was as nearly flawless as 133, although those within one or two of 133 are pretty close. Now I'm not sure about this calculation, but maybe the explanation lies in math:
- Neo Geo screen resolution is 320 x 224, according to the internet : p
- 4x Neo Geo vertical screen size is 224 x 4 = 896
- ACA NEOGEO runs at 1080p (even when I set my PS4 to 720p, screenshots of the game still came out at 1080p : PP)
- The ratio of 4x Neo Geo screen size to 1080p vertical resolution is 896 / 1080 = 0.8296(296...)
- The ratio of 133 to 161 is 0.8260869565... -- which is as close as you can come in that range to 896/1080
So 133 isn't a perfect setting, but it's close--one or two rows/columns, I would guess, aren't quite square. Of course, 133 is also a bit on the small side. And because the game actually runs in 1080p, even on a 720p screen (where it is scaled down from 1080p), the same goes for both--just a little fuzzier for 720p.
Re: a point that was raised about getting a "fix" for this to add pixel-perfect scaling, I very much doubt that is going to happen; ACA NEOGEO uses the same scaling screen display that HAMSTER Corporation developed for their "Arcade Archives" series of emulated arcade titles on PS4, of which ACA NEOGEO is a subset; Arcade Archives covers all sorts of different arcade hardware and software, with lots of different native screen resolutions, and rather than try to reinvent the screen option settings for each one, HAMSTER came up with a unified, abstracted display option set-up that the emulator then scales from for each particular game.
All in all, you're probably better off just running full screen (the default 160) and not worrying about it. (I'm trying to persuade myself of this. ":P)