I think I've spotted something that may provide a clue as to the problem. I was playing around with capturing my fish in Jaguar (dark-blue background) and OS9 (black background) and noticed that in addition to the quality being markedly different, the fish are very noticable smaller in OSX than in OS9. These captures look exactly like what I see on my screen and I was running the program full screen in both OS's.
My theory is that for some reason the fish are now being scaled down in Jaguar and that is causing the jagged lines. I see almost the exact same effect when I set a picture that is too big or too small as my desktop picture wallpaper. Smooth lines and textures get very similar jaggedness to them which I believe is caused by the pixels in the image not lining up with the pixels of the screen. This is further confirmed when I look at MA in a window and observe that the jaggedness changes depending on how large I make the window... as I drag it bigger and smaller the jaggies can be made very intense or almost vanish with just a subtle jaggy line or two passing across the fish as it swims.
Maybe there is a simple line of code or preference that can be corrected to fix the entire problem by resetting the scale to 1:1. I would attribute it to my 1152/768 semiwide screen on my TiBook, but my roommate's old iMac600 has the exact same problem.
It's good to know that you are looking into the problem still and I am hopeful that the solution will be found very soon. Maybe my observations will help!
