Odd question, but what is the original size of the image?
-580/320, png format.
GL_NEAREST is the fastest scaling filter but
GL_LINEAR is the one that gives you best appearance.
- It's same, nothing changes.
The image is going to look blurry no matter what, since we are re-sampling it and there are always artifacts.
To reduce artifacts, use a power-of-two texture size and snap to a scaling factor like 0.5 instead of 0.473.
For really small sizes, you can use mip-mapping in OpenGL to get smoother down-sampling, but that isn't well supported in Slick.
- Looks better if I set 0.5 value to scaling factor, but that's not size I need.
It seems, that everything below 0.5 is goint to make picture look blurry.. :/
You can see that these smaller circles (in above picture) are also blurry, which are images, scaled with factor less than 0.5..