Hatari low res (which is a speed boost and high res is useless unless you use high res mode for some applications) in options not working in all devices i tested, 3 Windows laptops and 2 Android phones. Just a black screen with a deformed portion of the screen visible. Plus almost all shaders need low res.
Yeah, seems to be the case. It looks like in low-res mode, it’s not scaling to fit the screen.
Would you mind opening a ticket on the core’s github issue tracker?
It should work if you have crop overscan on, Core has some border issues. High Res is misleadingy labeled, because it’s not ST high (640x400 mono) but rather allows to use the medium resolution mode (640x200). Other than apps, this is also used for a few games (e.g. Magnetic scrolls adventures I believe). However, that mode is line-doubled by RA core scaling, so it’s not correct either, and the core doesn’t really use a correct aspect ratio regardless of resolution ( should be close to C64 I think), so it’s really recommended to use custom scaling.
True aspect ratio is close to C64 (but not exactly the same). I would say the ST visible image is approximately 352x232, the C64 is 352x256 (larger border up and down).