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Comparing screen resolution

Posted: Thu Nov 26, 2020 10:29 am
by KnuddlMac
Dear aficionados,

For years I just got stuck with Basilisk II only. After some suggestions from our valued member Cat_7, I also tried the SheepShaver setup and got blown away about availability of additional tools I was desperately missing with System 7 only.

But testing SheepShaver was not enough, so why not also trying QEMU? - Done thing, I installed QEMU and was surprised about the display quality on a reasonable 31" screen and capable Mac hardware.
But one last thing...

Might be just imagination, but is the screen resolution a little sharper with QEMU compared to SheepShaver and Basilisk?
The monitor setting supports more colors with QEMU. But this is not what I am about. The resolution seems to be more precise, a little sharper.
I've seen that there were new switches employed with SheepShaver to adjust the gamma settings. Here I am not experienced and I might have simply failed to optimize the system.

Could someone please shed some light on the facts, if this is just my imagination or technical facts work in the background?

Stay confident,


Re: Comparing screen resolution

Posted: Thu Nov 26, 2020 11:23 am
by Ronald P. Regensburg
For BasiliskII and SheepShaver builds posted here, at least on macOS (not sure about Windows) there are advanced settings for changing the scaling algorithms that will improve display on high resolution (Retina) screens. These are explained in the setup manuals:

BasiliskII: ... uilds_only
SheepShaver: ... uilds_only

Re: Comparing screen resolution

Posted: Thu Nov 26, 2020 11:35 am
by KnuddlMac
Dear Ronald,

Thank you for pointing me to the sources!
I'll try to amend setting and I am curious to see how optimization will find traction.

Stay confident,


Re: Comparing screen resolution

Posted: Thu Nov 26, 2020 6:49 pm
by KnuddlMac
Sorry Ronald,

I forgot to specifically ask, if there are technical differences in the resolution capabilites of BA II, SheepShaver and QEMU?
So in theory all should/could obtain the same resolution and sharp display or are there calculated resolutions employing some blurriness?


Re: Comparing screen resolution

Posted: Thu Nov 26, 2020 7:10 pm
by Cat_7
As far as I can tell, those versions using SDL as graphics solution should all be able to display the same screen. (barring actual screen differences)
Note that Apple at some point changed the screen rendering engine, and that is why Mac OS 8 fonts can look sharp but edgy while in Mac OS 9 and later things might look more rounded and hence a bit blurry.
And then, as you saw, we have some settings specific for macOS/OSX users with high resolution screens leading to other levels of interpolation (calculating a best solution when the pixels cannot be matched one on one to the screen). The higher the resolution, the more chance no-one sees the blurring happening... ;-) Think of what happens when you do not run your monitor at its optimal 1-1 resolution.
There also has been a difference in screen rendering between macOS and Windows hosts for a long time. And, as said, these have changed inside the hosts over time as well.


Re: Comparing screen resolution

Posted: Fri Nov 27, 2020 8:04 am
by KnuddlMac
Thank you for highlighting the historic development and technical dependencies.

Specifically, comparison was about OS9 versions on both sides and hosting was macOS centric.

Yet, I didn't start counting pixels. J
There was just a feeling that lines are more sharp and fine.

I'll start playing around with the switches Ronald mentioned, to see if there are unused optimizations in the tool box.

Still with all emulators I have bigger screens than ever before running on good ol' CRTs and more space ever on the desktop.

Thanks gain for clarification and guidance.