[hatari-devel] Hatari fullscreen resolution handling

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

This is related to issue here:
https://www.atari-forum.com/viewtopic.php?f=51&t=40340


SDL2 doesn't seem to have any option to state
that one wants fullscreen letterboxed in both
dimensions, SDL2 does that only for one
dimension.

Because of that, one needs to make sure that
dimension closest to screen size is evenly
divisible by screen size, otherwise SDL2 scaling
results look like crap, if Hatari would allow use
of nearest neighbor filtering (= non-blurred
pixels) for it, like most users seem to want.

=> I just relaxed Hatari check for this, so that
both dimensions are required only for windowed
mode, one dimension for fullscreen.


However, max resolution setting is pretty awkward
way to control whether Hatari screen size will match evenly to monitor 
size i.e. whether
fullscreen scaling should be allowed to use
nearest neighbor filtering or not.


For example, with my 1680x1050 monitor, only these
settings would give crisp pixels for fullscreen:
--borders on --statusbar off --max-width 336 --max-height 210

Which results in 5 pixel top & bottom borders, and
no horizontal borders.

Whereas with FullHD monitor, following would need
to be (for fullscreen):
--borders on --statusbar off --max-width 384 --max-height 216

Which is only marginally better, giving 8 pixels
of top & bottom borders, and 32 pixels of left &
right borders.

(Before those options one could give "--zoom 2" so
that windowed mode looks OK too, and "--drive-led
on", so that one sees disk accesses.)


Statusbar isn't possible in either of these
fullscreen resolutions because monitor height
would not be evenly divisible by Hatari window
height with statusbar.


=> If we want good looking crisp pixels with
larger borders in fullscreen when using SDL2,
I think Hatari itself would need to letterbox its
SDL2 texture suitably, before asking SDL2 to scale
it to screen. :-/


After that, it's probable better to offer user
directly options to select the fullscreen filter
mode and whether Hatari shows less Atari borders,
or adds its own letterboxing (to achieve suitable
screen scalability), rather than require users to
specify suitable max resolution that will
indirectly result in given fullscreen filtering
mode...


Btw. Is max resolution still useful for video recording?


	- Eero