Le 12/11/2015 09:58, Troed Sångberg a écrit :
Recently I realized that graphics I made on my Mac and displayed in
Hatari did not look the same as when I viewed it on my ST. On the ST
everything was stretched out vertically.
I couldn't really understand why, so I started looking for discussions
on Atari ST pixel sizes, and found the following:
"and later on the 16-bit Atari ST (low-resolution 320×200 pixels) each
pixel was roughly .9×1"
https://mmolyneaux.wordpress.com/category/atari-st/
Going by the above I stretched the graphics by a factor 1.11
horizontally and all of a sudden a photo taken from the graphics as
displayed on the ST matched perfectly what was displayed in Hatari.
Is this a general thing with modern monitors having square pixels so
that an emulator with 1:1 mapping will always display things "compress"
vertically compared to what was originally designed for target?
If so, should Hatari offer the option to not do 1:1 mapping but stretch
vertically to try to display content as close to what it would look like
natively?
Sorry if this is a topic that has been debated to death before, it was
new to me when I stumbled upon it.
Hi
that's something I already read about, but I don't think it was debated here.
Problem is : how do you stretch horizontally for example (or vertically in the other direction, that's the same) to not get visible artefacts ?
If we consider a 320x200 ST image should be displayed on a 352x200 area on modern display, this means that at one point 32 pixels will need to be duplicated. Which ones do we chose ? Going from 320 to 352 will sure look ugly.
So, to get proper 1.11 ratio we need a much bigger zoom before, maybe x4 or more. A 320x200 ST image would become a 1420x800 area ; with such an increase you can apply some more effective filters for non integer zooming.
In the end, I think it comes down to another request already made here : being able to zoom the ST image to any non-integer value. Today, we only have x2 zooming, with SDL2 and some additional code, we could have for example x3.3 zooming using HW accelerated
opengl and some filters.
Nicolas