Selective Gaussian blur or hq2x are examples of image filters.
Font hinting is an example of a nonlinear downscaling though most people don’t think of it that way. It preserves line sharpness, which is a non-bandlimited feature since lines are infinitely sharp = made of infinite frequencies.
Overly sharp linear filters produce artifacts like blockiness and ringing; nonlinear ones would try to avoid that but you could still get more difficult ones like moiré.
This is mostly obsolete with High-DPI screens though; we're at the point where such hacks are no longer needed and we can use close to ideal filters (e.g. lanczos, which is a windowed sinc). macOS no longer does font subpixel AA or strong hinting by default for this reason.
This is good, because it means we can finally treat computer graphics as properly scalable images without introducing "blurriness".
Note that lines were never infinitely sharp; pixels aren't infinitely sharp, they have a shape and the screen construction determines how sharp they look. They are, however, sharper than what you'd get in a nyquist-limited system.
Font hinting is an example of a nonlinear downscaling though most people don’t think of it that way. It preserves line sharpness, which is a non-bandlimited feature since lines are infinitely sharp = made of infinite frequencies.
Overly sharp linear filters produce artifacts like blockiness and ringing; nonlinear ones would try to avoid that but you could still get more difficult ones like moiré.